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Introduction: Gastrointestinal (GI) distress in endurance athletes is prevalent and detrimental to performance. Adverse GI symptomatology can be analogous with irritable bowel syndrome, where fermentable oligosaccharide, disaccharide, monosaccharide and polyols (FODMAP) reduction has demonstrated efficacy. This study investigated the effects of low FODMAP (LFOD) diet on GI distress parameters in runners with a history of non-clinical exercise-associated GI symptoms. Methods: Eleven recreationally competitive runners (5 males, 6 females; 5km personal best 23:00±4:02 min:sec) participated in the study. Runners were allocated to a randomized 6-day LFOD or high FODMAP (HFOD) diet separated by a 1-day wash-out in a controlled, single-blinded cross-over study. In each period participants completed two strenuous running sessions consisting of 5x1000m and a 7km threshold run. GI symptoms (during-exercise and daily) and the Daily Analysis of Life Demand for Athletes (DALDA) questionnaires were completed. Area under the curve (AUC) was calculated for daily GI symptoms across each dietary period and analysis was conducted using multilevel mixed-effects linear regression for comparison between the two diets. Results: A significantly smaller AUC for daily GI symptoms.6-days during the LFOD compared to HFOD (mean difference -13.4, 95% CI [-22, -4.60], P=0.003) was observed. The daily GI symptoms that were significantly lower during LFOD were flatulence (P<0.001), urge to defecate (P=0.04), loose stool (P=0.03) and diarrhea (P=0.004). No significant differences in during exercise symptoms or DALDA responses were observed between diets (p>0.05). Conclusion: Preliminary findings suggest that short-term FODMAP reduction may be a beneficial intervention to minimize daily GI symptoms in runners with exercise-related GI distress.
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Copyright © 2017 American College of Sports Medicine
Low FODMAP:
A Preliminary Strategy to Reduce Gastrointestinal Distress in Athletes
Dana M. Lis1, Trent Stellingwerff1,2, Cecilia M. Kitic1, James W. Fell1, and Kiran D.K. Ahuja1
1Sport Performance Optimisation Research Team, School of Health Sciences University
of Tasmania, Launceston, Tasmania, Australia; 2Canadian Sports Institute Pacific,
Victoria, British Columbia, Canada
Accepted for Publication: 31 August 2017
ACCEPTED
d o
nal Distress in Athletnal Distress in Athlet
, James W, James W
.
F
e
ll1
, and Kirand Ki
Team, School of Health Seam, School of Health
22
Canadian SportsCanadian Sport
tish Columbia, Canadah Columbia,
Accepted for Publicad for Publica
Low FODMAP: A Preliminary Strategy to Reduce Gastrointestinal Distress
in Athletes
Dana M. Lis1, Trent Stellingwerff1,2, Cecilia M. Kitic1,
James W. Fell1, and Kiran D.K. Ahuja1
1 Sport Performance Optimisation Research Team, School of Health Sciences
University of Tasmania, Launceston, Tasmania, Australia; 2Canadian Sports Institute Pacific,
Victoria, British Columbia, Canada
Address for correspondence and reprint requests:
Dana Lis
School of Health Sciences
University of Tasmania
Locked Bag 1322
Launceston, Tasmania, Australia 7250
Email: Dana.Lis@utas.edu.au
The King and Amy O’Malley Trust provided scholarship support. The results of this study are
presented clearly, honestly, and without fabrication, falsification, or inappropriate data
manipulation. The results of the present study do not constitute endorsement by ACSM. This
study was supported in part by the Canadian Sport Institute Pacific. No conflict of interest is
present.
Medicine & Science in Sports & Exercise, Publish Ahead of Print
DOI: 10.1249/MSS.0000000000001419
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Health SciencesHealth Sciences
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rint requests:rint requests:
nia
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n, Tasmania, Australia 72mania, Australi
ail: Dana.Lis@utas.edu.au
: Dana.Lis@utas.edu.au
g and Amand A
Abstract
Introduction: Gastrointestinal (GI) distress in endurance athletes is prevalent and detrimental to
performance. Adverse GI symptomatology can be analogous with irritable bowel syndrome,
where fermentable oligosaccharide, disaccharide, monosaccharide and polyols (FODMAP)
reduction has demonstrated efficacy. This study investigated the effects of low FODMAP
(LFOD) diet on GI distress parameters in runners with a history of non-clinical exercise-
associated GI symptoms. Methods: Eleven recreationally competitive runners (5 males, 6
females; 5km personal best 23:00±4:02 min:sec) participated in the study. Runners were
allocated to a randomized 6-day LFOD or high FODMAP (HFOD) diet separated by a 1-day
wash-out in a controlled, single-blinded cross-over study. In each period participants completed
two strenuous running sessions consisting of 5x1000m and a 7km threshold run. GI symptoms
(during-exercise and daily) and the Daily Analysis of Life Demand for Athletes (DALDA)
questionnaires were completed. Area under the curve (AUC) was calculated for daily GI
symptoms across each dietary period and analysis was conducted using multilevel mixed-effects
linear regression for comparison between the two diets. Results: A significantly smaller AUC
for daily GI symptoms.6-days-1 during the LFOD compared to HFOD (mean difference -13.4,
95% CI [-22, -4.60], P=0.003) was observed. The daily GI symptoms that were significantly
lower during LFOD were flatulence (P<0.001), urge to defecate (P=0.04), loose stool (P=0.03)
and diarrhea (P=0.004). No significant differences in during exercise symptoms or DALDA
responses were observed between diets (p>0.05). Conclusion: Preliminary findings suggest that
short-term FODMAP reduction may be a beneficial intervention to minimize daily GI symptoms
in runners with exercise-related GI distress.
Key words: gastrointestinal distress, exercise, diet, short-chain carbohydrates, athlete, runner’s
trots
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clinical e
clinical e
e runners (5 males,
runners (5 male
n the study. Runners w
n the study. Runners
HFOD) diet separated bHFOD) diet separated b
y. In each period participy. In each period particip
000m and 00m a
a
7km thresho7km th
Analysis of Life DemanAnalysis of Life Deman
under the curve (AUCunder the curv
riod and analysis was cond and analysis was con
rr
isonison
be
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wobetween the two
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P=0
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P=0.003
)
was
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obseobse
ng LFOD were flatulencFOD were flatul
diarrhea (P=0.004).
iarrhea (P=0.004).
No No
sponses
es
were observedwere observe
rm FODMAFOD
Introduction
Optimal athletic performance can be directly compromised by gastrointestinal (GI) dysfunction
(1). High rates of GI distress are reported to occur in 30-50% of endurance athletes (2, 3).
Although most symptoms occurring are mild to moderate, severe symptoms may impair training
capacity and performance (2). During strenuous exercise GI symptoms are triggered in part by
significant splanchnic hypoperfusion, as blood is shunted away from the GI tract towards the
working muscles, which instigates acute enterocyte injury, increased intestinal permeability and
altered motility (4). Symptoms associated with exercise-induced GI distress are numerous, but
many are analogous with clinical indications associated with irritable bowel syndrome (IBS) (5,
4). In particular, lower abdominal symptoms such as diarrhea, bloating, abdominal pain and
flatulence share remarkable similarities in both conditions. Interestingly, fermentable
oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) restriction has been
emerging as an efficacious treatment for IBS symptoms (6, 7, 5, 8). Therefore, it is plausible that
FODMAP manipulation may also positively affect exercise-associated GI symptoms (9, 10).
Nutritionists and athletes employ various dietary strategies to reduce exercise-associated GI
distress, including limiting dietary fiber and lactose, eating low-residue foods around
competition, training the gut to tolerate larger carbohydrate loads or removing gluten (11, 12). A
gluten-free diet has become a popular regimen to supposedly alleviate exercise-associated in
non-celiac athletes (13) and IBS-related GI symptoms (14) although negligible peer-reviewed
evidence exists supporting these anecdotal claims (13). Conversely, data in non-athlete clinical
populations proposes that GI symptom improvement associated with gluten elimination may
actually be modulated by the subsequent reduction in FODMAP content that generally
accompanies a gluten-free diet, and not necessarily gluten elimination itself (3, 15). A low
FODMAP diet is predicted to be the next popular equivalent to the gluten-free diet (16).
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tract tow
tract tow
stinal permeability a
tinal permeability
GI distress are numerous,
I distress are numerous
irritable bowel syndromerritable bowel syndrome
diarrhea, bloating, abdomdiarrhea, bloating, abdo
both conditions. Intereoth conditions.
arides and polyols (FODMrides and polyols (FOD
r IBS symptoms r IBS symptoms
(6, 7, 5,
positively affectositively affe
exercisexercise
etes employ various dieemploy various die
ing limiting dietary fibng limiting dietary fib
n, training the gut to tolerining the gut to
n-free diet has become
-free diet has become
on
-ce
lia
c
athl
e
t
es
iac athletes
(13) (13)
ce exists supexists
FODMAPs are poorly absorbed short chain carbohydrates that have been shown to increase
osmotic load in the small intestine and colonic gas volume, which instigates adverse symptoms
in hypersensitive individuals (10). Examples of foods restricted with a low FODMAP diet
include: lactose-containing products such as cow’s milk, a range of fruit high in fructose, wheat-
based products, onions and garlic encompassing fructans and galactooligosaccharides, and fruits
with stones (pits) or confectionary with naturally occurring or added polyols. In Western diets up
to 40 g of undigested carbohydrates reach the colon daily (17) including an average of 1-10
g.day-1 of inulin and oligofructans (18). In sensitive individuals, FODMAPs can cause adverse
GI symptoms. FODMAPs are also important dietary constituents offering favorable prebiotic
effects such as acting as a substrate for beneficial microbial populations, increasing stool bulk,
enhancing micronutrient absorption and immune function (19), so unnecessary restriction is not
advocated. To date, studies suggest that healthy individuals without IBS would not benefit from
restricting FODMAP intake (9, 20) and a prolonged strict low FODMAP diet does not appear to
be a common practice amongst athletes (21). However, in athletes looking to reduce GI
symptoms self-reported data indicates that over half eliminate high FODMAP foods, without
necessarily realizing that these foods were considered part of the FODMAP family (21). Eighty-
six percent of these athletes report subsequent symptom improvement (21). Therefore, it is
plausible that the physiological mechanisms and symptoms associated with exercise-associated
GI injury increase sensitivity to all, or some FODMAPs, and it is relevant to consider if
symptoms could be reduced with FODMAP restriction in endurance athletes.
We have recently published a case study showing positive outcomes of a low FODMAP dietary
intervention in a multisport athlete (22). Based on these results, and encouraging clinical
research on low FODMAP diets (10), it is imperative that the manipulation of short-chain
carbohydrate be investigated as a novel tool for individualized dietary management aimed at
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Western
Western
ng an average of 1-
g an average of
ODMAPs can cause adv
ODMAPs can cause adv
uents offering favorable uents offering favorable
obial populations, increaobial populations, increa
function (19),unction (19),
so unneces so un
thy individuals without IBhy individuals without I
d a prolonged strict low Fa prolonged stri
t athletes (21)athletes (21)
.
HoweveHoweve
a indicatesa indicat
that over halhat over ha
hat these foods were conshese foods were con
hese athletes report subhese athletes report sub
hat the physiological mehe physiological
njury increase sensitivity
jury increase sensitivity
ymptoms could be redu
ms could be redu
attenuating GI distress in a group of healthy athletes. Hence, the purpose of this preliminary
study was to examine the effect of a low FODMAP vs a high FODMAP diet on symptoms of
self-reported GI distress and perceived wellbeing in clinically healthy recreationally competitive
runners with a history of GI symptoms. Our a priori hypothesis was that a short-term low
FODMAP diet would reduce the severity of GI symptoms appearing daily and during strenuous
running sessions.
Methods
Participants
Eleven recreational competitive runners (>25 km running per week) aged 18-50 years with self-
reported persistent exercise-associated GI symptoms were invited to participate in this study.
Inclusion criteria included: a minimum of three chronic exercise-associated GI symptoms (e.g.
nausea, bloating, diarrhea) with score greater than 4 (quite often) on the background GI
questionnaire (23), a habitual high FODMAP intake of 20 g FODMAP.day-1 (24) as assessed
with the Complete Nutrition Assessment Questionnaire (CNAQ; http://www.cnaq.com.au/) (25)
and the capacity to complete two consecutive days of prescribed strenuous running training
during the study. Exclusion criteria included: a history of food intolerance (e.g. diagnosed lactose
intolerance), known celiac disease or known familial history of celiac disease, clinically
diagnosed non-celiac gluten sensitivity or IBS, current adherence to any special diet, or any pre-
existing medical condition that could be affected by dietary intervention. The dietary
intervention periods were purposefully scheduled to avoid the potential influence of hormone
changes over the menstrual cycle for the female runners. Ethics approval was obtained from the
Tasmanian Health and Medical Human Research Ethics Committee (H0015151). All participants
provided signed informed consent.
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g per week) aged 18-50 g per week) aged 18-50
oms were invited to partms were invited t
hree chronic exercise-assree chronic exercise-ass
e greater than 4 (quite e greater than 4
h FODMAP intake of FODMAP intake of
n Assessment Questionnan Assessment Questionna
omplete two consecutivlete two consecutiv
Exclusion criteria includExclusion criteria includ
), known celiac diseasnown celiac di
nosed non-celiac gluten se
osed non-celiac gluten se
xisting medical cond
medical cond
ntion periodon pe
Experimental Design
Utilizing a single-blind, cross-over design participants were randomized to receive either a high
FODMAP (HFOD) or a low FODMAP (LFOD) diet for 6-days, separated by a 1-day washout,
followed by the alternative diet (Figure 1). Randomization was generated using GraphPad
QuickCals software. Participants were informed that they would be assigned Specific
Carbohydrate Diet A or B for the first dietary period then the alternate diet for the subsequent
dietary period, with no specific reference to FODMAPs or gluten. Participants self-selected their
training schedule based on study guidelines (see details below). All training was replicated
during the subsequent dietary period. Participants were asked to record their daily exercise, food
intake and complete a post-exercise GI questionnaire, daily GI questionnaire and Daily Analysis
of Life Demands (DALDA) questionnaire each day throughout the two dietary periods.
Food Preparation & Provision
Participants were provided with pre-made frozen lunch and dinner meals (prepared, weighed and
frozen in a commercial kitchen; Matson’s Catering, Launceston, Australia), breakfast (cereals,
breads, milk, yoghurt) and snack foods (muesli bars, crackers). As the study participants were
blinded, all food was packaged in the same opaque containers and labeled according to each
dietary period (e.g. week-1 muesli bars, day-2 lunch). Alongside the controlled study food
provisions, the participants were able to self-select from a suggested list (of choose and avoid)
and supplement the study food with fresh fruits, vegetables and nuts with the stipulation that a
counterpart substitution be exchanged in the second dietary period. A registered dietitian (lead
researcher) provided dietary education to participants on nutrition intake recording and
appropriate food selections. LFOD and HFOD meals were established based on previous
research (20), Monash University’s low FODMAP diet resources
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or the sub
or the sub
pants self-selected th
ants self-selected
All training was replic
All training was replic
to record their daily exerto record their daily exer
aily GI questionnaire and ily GI questionnaire and
y throughout the two dietathroughout the two
with pre-made frozen lunwith pre-made frozen lun
al kitchen; Matstchen; Mats
on’s Caton’s Ca
ghurt) and snack foods (ghurt) and snack foods (
l food was packaged in d was packaged
ry period (e.g. week-1
y period (e.g. week-1
rovisions, the participa
ons, the participa
pplement themen
(http://www.med.monash.edu/cecs/gastro/fodmap/) and typical athlete diets (26). Recipes for
LFOD and HFOD were similar, but ingredients modified to alter the FODMAP content (Table
1). Meals were matched for content of total energy, protein, carbohydrate, fat and fiber; however,
resistant starch information was not available due to the absence of comprehensive resistant
starch food composition tables. Each meal was analyzed for FODMAP content using a
FODMAP specific database (Monash University, FoodWorks Professional 7, Xyris, Brisbane,
Australia) to ensure that LFOD meals contained less <0.5 g FODMAP.meal-1 (27). An example
of the study meals for each diet are provided in Table 1. The prototype study menu presented a
macronutrient profile containing carbohydrate 5-7 g.kg-1, protein 1.2-1.7 g.kg-1 and fat 0.8-1.2
g.kg-1 (26) (FoodWorks Professional 7, Xyris, Brisbane, Australia).
Exercise and Prescribed Running
Participants self-selected their training schedule based on study guidelines which indicated: day
1 and 2 to be light to moderate intensity training, day 3 to be rest or very light non-running
exercise (e.g. yoga, swimming). Day 4 and 5 were prescribed very intense running sessions and
day 6 was entirely self-selected exercise or rest. Day 4 (interval session) consisted of a 10 min
self-prescribed warm up with increasing intensity, 5 x 1000 m interval pace (100% of predicted
vV02max) with 3-min brisk walk or light jog between intervals followed by a 10-min self-selected
cool down. Day 5 (threshold session) consisted of a 710 min self-selected warm up with
increasing intensity, 7 km at threshold pace (~90% of predicted vV02max) followed by a 10-min
self-selected cool down. Prescribed running sessions were individually monitored using
participants’ personal Garmin GPS running watches (Forerunner® 735XT, 630XT, 235 or
910XT) and all training was replicated in the second intervention period. Interval and threshold
paces were individually prescribed based on calculations from a recent race performance using
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Xyris, B
Xyris, B
mealeal
-
1
-1
(27). An examp
(27). An exam
type study menu presente
type study menu presen
otein 1.2-1.7tein 1.2-1.7
g.k
g g.k
-
1
and fand f
Australia). Austral
ining schedule based on ing schedule based on
derate intensity training, erate intensity training,
wimming). Day 4 and 5 wming). Day 4 and 5 w
ely self-selected exercise ly self-selected exercise
ibed warm up with increawarm up with in
max
max
)
)
with 3-min brisk walwith 3-min brisk wal
ool down. Day 5 (thr
wn. Day 5 (thr
ing intensityinten
VDOT (velocity at vV02max) tables (28). Running sessions were completed on flat terrain, at the
same time of day (±30 min) over the period of data collection (December 2015 to February
2016).
Gastrointestinal Symptom Monitoring
During-exercise GI questionnaires and daily GI questionnaires were used to assess the
occurrence and severity of upper and lower abdominal symptoms determined using a 10-point
scale ranging from 0 “no problem at all” to 9 ‘‘the worst it has ever been” (23). Section 1 of the
questionnaire addresses upper abdominal symptoms: reflux, heartburn, burping, bloating,
stomach pain/cramps, vomiting and nausea. Section 2 addresses lower abdominal symptoms:
flatulence, urge to defecate, left abdominal pain (side stitch), right abdominal pain (side stitch),
loose stool, diarrhea and intestinal bleeding (23). Diarrhea criteria was defined as an increase in
the number of bowel movements per day compared with the participants usual bowel habit.
Participants completed the during-exercise GI questionnaire immediately following their training
session and the daily GI questionnaire at the end of each day at the same time. GI symptom
scores were tabulated for each day and exercise session (23). Mean scores for daily GI
symptoms, during-exercise GI symptoms, and incremental area under the curve (AUC) for daily
GI symptoms across all 6-days of each dietary period were compared between the diets.
Perceptual Wellbeing Monitoring
Participants completed the DALDA questionnaire at the end of each day. This questionnaire is
used to assess general stress levels (Part A) and to determine stress-reaction symptoms (Part B)
using a rating scheme of “worse than normal,” “normal,” or “better than normal” for variables.
Scores were tabulated and the “worse than normal” and “better than normal” scores compared
between the two dietary periods.
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ed to ass
d to as
mined using a 10-po
ined using a 10-p
r beenbeen
(23). Section 1 of
). Section 1 o
ux, heartburn, burping, ux, heartburn, burping,
addresses lower abdomiaddresses lower abdom
side stitch), right abdomiide stitch), right ab
(23). Diarrhea criteria wa23). Diarrhea criteria wa
day compared with the day compared w
-exercisexercise
GI questionnairGI questionnair
uestionnaire at the end ouestionnaire at the end o
d for each day and exr each day and ex
ng-exercise GI symptomsg-exercise GI symptoms
ms across all 6-daysross all 6-days
of
o
ea
erceptual Wellbeing M
ual Wellbeing M
pants complts co
Statistical Analysis
All GI symptoms and DALDA scores and dietary variables were treated as continuous data (29)
and compared between the two diets using multilevel mixed-effects repeated measure linear
regression adjusted for order and period effects (Stata 13.0, StataCorp LP, College Station, TX).
Regression residuals were tested for assumptions of linear regression (heteroscedasticity,
skewness, kurtosis or linearity). Where regression residuals did not meet the assumptions of
linear regression the analyses were repeated with multilevel mixed-effects ordered logistic
regression. For consistency, all comparison results are presented as mean difference (95%
Confidence Interval). For each dietary intake variable, the mean±SD was calculated and
compared between the diets using mixed-effects ordered logistic regression. P values (P<0.05)
are from the relevant analyses (linear regression or ordered logistics regression in case of
violation of linear regression assumptions). Incremental AUC, above zero, for daily GI
symptoms was calculated from total daily GI symptom scores over each 6-day diet (GraphPad
Prism, version 6.0, San Diego, CA) and compared between the two diets.
Results
Participants details and compliance
Dietary intake (Table 2), GI symptom assessment (Figure 2) and DALDA results were available
for 11 of 12 participants (5 males, 6 females, 41±10 years, weight 69.0±12.0 kg, height
171.1±10.0 cm, 5 km personal best 23:00±04:02 min:sec). One participant was removed due to
incomplete data. Background GI symptoms, primarily boating, flatulence, urge to defecate and
loose stool were predominant and were reported to occur quite often to always (score of 4 to
9). Total habitual daily FODMAP intake was 43.8±16.9 g FODMAPs.day-1. The prescribed
running sessions were completed as assigned, and exercise volume matched in each period
(HFOD total exercise volume 50:12:43 hh:min:sec, 0:56:51±0:25:33 daily mean±SD; LFOD
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e assump
e assump
ffects ordered logis
fects ordered log
d as mean difference (9
d as mean difference (
he meane mean
±±
SD was calcuSD was calcu
d logistic regression. d logistic regression.
P vP
n or ordered logistics ren or ordered logis
).).
II
nc
r
e
m
e
ntal
ncrementa
AUC
,
aily GI aily GI
s
ymptom
mptom
scores
A)
and compared betweenand compared between
ails and complianceails and compliance
ake (Table 2), GI symptoTable 2), GI sym
1 of 12 participants (5
1 of 12 participants (5
71.1±10.0 cm, 5 km pe
0.0 cm, 5 km p
lete data. Be dat
50:36:42, 0:57:18±0:23:55) with no significant differences in temperature (16.2±5.2 vs
15.7±4.9°C) or humidity (64.0±14.9 vs 55.3±19.6%) for the LFOD or HFOD dietary periods,
respectively.
All participants consumed the prescribed diets and dietary intake was analyzed from food intake
records for HFOD and LFOD. The composition of the diets is shown in Table 2. The two test
diets were similarly matched for total energy, carbohydrate, and fiber. Protein and fat were
statistically different between the diets (P=0.03 and P=0.003, respectively). These differences are
of negligible clinical significance given the 5 g protein and 7 g fat daily variances. As designed,
FODMAP intake differed significantly between the two diets being 41.4±7.9 g.day-1 HFOD and
8.1±3.5 g.day-1 LFOD (P<0.0001).
Gastrointestinal Symptoms: Daily and During Exercise
Daily GI symptoms scores were collected each day of the study and tabulated. Individual AUC
responses show that 82.0% (9 of 11) of participants had a smaller AUC for daily GI symptom
scores.6-days-1 during the LFOD compared to HFOD (mean difference -13.4, 95% CI [-22, -
4.60], P=0.003; Figure 2a). The group AUC (Figure 2b) was lower in LFOD (31.4±24.6;
mean±SD) compared to HFOD (44.6±33.6). Specific daily GI symptoms that were reduced
during LFOD included: flatulence (mean difference -1.12 95% CI [-1.55, -0.75], P<0.001), urge
to defecate (mean difference -0.41, 95% CI [-0.81, -0.02], P=0.04), loose stool (mean difference
-0.38, 95% CI [-0.73, -0.04], P=0.03) and diarrhea (mean difference -0.45, 95% CI [-0.75, -0.14],
P=0.004). The mean GI symptoms scores for day 1 to 6 were higher during HFOD compared to
LFOD (mean difference -2.45, 95% CI [-4.21, -0.69], P=0.006; Figure 2c). No order or period
effects were observed for total daily GI symptoms, during-exercise GI symptoms on any of
analyzed variables except for loose stool (mean difference -0.35, 95% CI [-0.79, -0.01], P=0.03).
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diets being 41.4±7.9 g.ddiets being 41.4±7.9 g.d
During Exercise During Exercise
collected each day of thellected each day of the
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During-exercise GI symptoms scores for the HFOD and LFOD dietary periods for day 4 and day
5, when prescribed strenuous running sessions, were compared. Half of the participants rated GI
symptoms during the prescribed running sessions to be moderate to severe (3). Burping was the
one symptom that was significantly higher (mean difference 0.30, 95% CI [0.01, 0.58], P=0.04)
during LFOD compared to HFOD. No significant differences in any other GI symptoms were
found during the prescribed running sessions between HFOD and LFOD.
Perceptual Wellbeing
Overall wellbeing was measured using DALDA and the worse and better than normal scores
were compared for each dietary period, as well as the scores on the prescribed training days (day
4 and 5). Total worse than normal scores for stress (part A) and stress response (part B)
combined were not different (mean difference -0.45, 95% CI [-1.30, 0.40], P=0.30) during
HFOD (3.71±3.18) compared to LFOD (3.30±3.31). Similarly, total better than normal scores for
the HFOD (2.59±2.80) and LFOD (2.97±3.66) were not significantly different across each
dietary period (mean difference 0.43, 95% CI [-0.52, 1.37], P=0.38). Total worse than normal
scores on day 4 or day 5 were not different (mean difference -0.82, 95% CI [-2.26, 0.63], P=0.30;
mean difference -0.91, 95% CI [-2.35, 0.53], P=0.25, respectively). Total better than normal
scores on day 4 or day 5 were not different (mean difference 0.5, 95% CI [-1.11, 2.11], P=0.55;
mean difference 1.23, 95% CI [-0.39, 2.84], P=0.10, respectively). No order or period effects
were observed for DALDA scores.
Discussion
Dietary intake, and its interactions with strenuous exercise, are of particular importance to
athletes as resulting GI distress is a common problem potentially impairing training capacity and
performance (12). This is the first study to examine the effects of a short-term low FODMAP
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rse and better than normrse and better than norm
ores on the prescribed traores on the prescribed tra
stress (part A) and strestress (part A) and
nce -0.45, 95% CI [-1.nce -0.45, 95% CI [-1.
(3.30(3.30
±
3.31
)
.
±3.31).
Similarly, Sim
to
OD (2.97D (2.97
±
3
.
6
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)
were nowere n
ence 0.4ence 0.4
33
, 95% CI [-0.55% CI [-0.5
5 were not different (meere not different (me
-0.-0.
9
1
91
, 95% CI [-2.35, 95% CI [-2.35
,,
day 4 or day 5 were not dor day 5 were n
n difference 1.23, 95% C
difference 1.23, 95% C
ere
observed for DALD
served for DAL
diet on GI symptoms and perceptual wellbeing in athletes with a history of exercise-associated
GI distress. The aim of this preliminary study was to investigate if self-reported and case-study
outcomes, demonstrating beneficial effects of FODMAP reduction on exercise-associated GI
symptoms (22, 21), could be substantiated in a larger cohort. Results from this preliminary study
indicate that a low FODMAP diet had a positive effect on daily GI symptoms in 82% of
participants.
Effect of low FODMAPs on daily GI symptoms
In participants with persistent exercise-associated GI symptoms, 9 of the 11 reported a reduction
in daily GI symptoms on a short-term low FODMAP diet (Figure 2). To date, low FODMAP diet
research has predominantly focused on clinical populations, specifically individuals with IBS.
Discernible symptomatic improvements in approximately 70% of IBS patients encourage the use
of this diet as first line treatment (10). A limited number of investigations have included healthy
controls (9, 30, 20) and results suggest that although healthy individuals demonstrate functional
changes with FODMAP ingestion, GI symptoms remain very minor or non-existent (30, 20).
Low level GI symptoms likely have a negligible impact on athletic performance, but more
moderate to severe symptoms may be detrimental (1). Although healthy populations, including
healthy athletes, would be assumed to not benefit from FODMAP reduction with reduced GI
symptoms, it is interesting to consider if the unique physiological, mechanical and nutritional
stress encountered by endurance athletes could increase susceptibility to any dietary triggers,
such as FODMAPs, for some of these athletes. GI symptoms are largely variable but our
preliminary data suggests that a short-term low FODMAP diet may be efficacious in the
management of daily GI symptoms (Figure 2); particularly lower abdominal GI symptoms, in
healthy athletes. Although changes in GI symptoms during exercise were not found, the ability to
reduce daily GI symptoms would be very advantageous in extended events like the Tour de
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ms, 9 of the 11 reported a ms, 9 of the 11 reported a
(Figure (Figur
2
)
.
To date, lowo date, low
opulations, specifically iopulations, specific
pproximately 70% of IBSproximately 70% of IBS
A limited number of inveA limited numbe
uggest that although healtgest that although heal
gestion,gestion,
GI symptoms re GI symptoms re
oms likely have a negliglikely have a negli
ere symptoms may be deere symptoms may be de
hletes, would be assumed, would be assu
ptoms,
oms,
it is interesting to it is interesting to
ress encountered by e
ncountered by e
s FODMAPODM
France, rigorous training camps or multi-event athletics, which feature sequential days of
intensive and extensive exercise.
Effect of low FODMAPS on exercise specific GI symptoms
GI symptoms during prescribed running sessions were similar for the HFOD and LFOD dietary
periods. In race conditions four to 32% of athletes report GI distress and some symptoms are so
severe that withdrawal from competition results (23). Numerous factors exacerbate GI symptoms
during exercise including dietary intake/timing, mechanical impact and physiological stress.
Significantly greater GI issues are reported during prolonged events (e.g. Ironman), as compared
to relatively shorter events, such as the marathon (23). Ingestion of carbohydrates as consumed
in endurance sport, particularly solutions with a high osmolality, are associated with the
development of GI symptoms during exercise (31). Exercise duration in the current study did not
warrant carbohydrate ingestion, however it is interesting to consider if ingestion of short-chain
carbohydrates during exercise or pre-existing FODMAPs in the GI tract would have additive
osmotic actions and consequent symptoms (2). It is possible that the chosen exercise duration
(45-60 min.day-1), coupled with no CHO ingestion during exercise, curtailed any measurable
difference in during exercise GI symptoms between the diets. Timing of FODMAP intake may
also influencing symptoms. In the present study runners replicated their usual dietary patterns
(e.g. timing) before exercise, which was fundamental in this research design to avoid altering
habitual food intake timing and adding a confounding variable to the primary measure. Although
this study did not investigate mechanistic hypotheses it may also be conceivable that GI
symptoms during exercise could be exacerbated with the presence of short-chain carbohydrates
in the gut or during exercise FODMAP ingestion. In overall GI symptom reduction, our
preliminary findings support further research of the hypothesis that FODMAP reduction would
positively affect the severity or occurrence of exercise-associated GI symptoms.
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symptom
symptom
xacerbate GI symptom
acerbate GI sympt
act and physiological str
ct and physiological st
events (e.g. Ironman), as vents (e.g. Ironman), as
Ingestion of carbohydratengestion of carbohydrat
a high osmolality, are a high osmolality
e (31). Exercise duration (31). Exercise duration
er it is interesting to coner it is interestin
pre-existing FODMAPspre-existing FODMAPs
quent symptoms (2). It isuent symptoms (2). It is
upled with no CHO ingd with no CHO ing
ring exercise GI symptoming exercise GI symptom
ncing symptoms. In the symptoms. In
timing) before exercise,
iming) before exercise,
abitual food intake timi
l food intake tim
udy did nodid
Effects of altering FODMAPS on perceptual wellbeing
Extreme and persistently high chronic training loads are associated with greater psychosomatic
stress. Psychological wellbeing, personality traits and psychosocial factors, such as stress, also
have the potential to influence perceptions of GI symptom presence and severity (32). The
reverse may also occur, in that GI symptoms caused by exercise may be reflected by reductions
in overall perceptual wellbeing. In the current study DALDA evaluation was conducted
alongside each dietary intervention with the aim to capture the relationship between perceptual
wellbeing and GI symptoms influenced by diet and exercise stress. In athletes, the multifactorial
nature of GI distress is well known and the influence of psychological wellbeing or stress on
alterations of the autonomic nervous system has been recognized (33, 34). These changes in
homeostatic balance have been characterized by slowing of gastric emptying, increased distal
colonic motility and acceleration of intestinal transit, further contributing to adverse GI
symptoms (35). In the present study, it is possible that DALDA was not a sensitive enough tool
to detect any FODMAP related changes. A more chronic fatigue state over several days/weeks or
longer is likely required to capture changes in DALDA responses (36).
Reflections for future studies
Dietary control was achieved, however three reasons are suggested as to why no difference in GI
symptoms were observed during the prescribed strenuous running sessions. First, daily GI
symptoms on the LFOD diet were lower compared to HFOD. Lower pre-exercise symptomology
during the LFOD may have skewed perceptions of the during exercise GI symptoms toward
being more exaggerated (greater net difference) resulting in reporting of higher during exercise
symptom scores for LFOD. Secondly, although residual FODMAPs are suggested to transit
through the GI tract in less than 3-days (11) a longer period of LFOD may be necessary to
augment further symptom reduction. Changes in the gut microbiome occur over time as the
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n was co
was co
hip between perceptu
ip between percep
In athletes, the multifacto
In athletes, the multifact
ychological wellbeing or ychological wellbeing or
recognized (33, 34).recognized (33, 34).
Th Th
slowing of gastric emptylowing of gastric
tinal transit, further coinal transit, further co
is possible that DALDAis possible that D
hanges. A more chronic fanges. A more chronic f
apture changes in DALDapture changes in DALD
uture studies ture stud
ntrol was achieved, howewas achieved, h
ptoms were observed du
oms were observed du
ymptoms on the LFOD
ms on the LFOD
the LFOD e LFO
biomass evolves and it is possible that the full benefits of the diet are not realized until 7-days
(24) or a few weeks (10). Most importantly, exercise duration and climatic factors have been
correlated with GI distress (23). Longer running sessions may be required to distinguish
differences in GI symptoms between the diets. Although, the outdoor running climate throughout
the current study was moderate with nominal variance between intervention periods, differences
in climate and hydration status should be considered as influencers of GI symptoms. A greater
effect may be observed under more extreme exercise conditions and future research should
consider this element in the methodology.
FODMAP manipulation considerations for the practitioner
Our developing work proposes that FODMAP manipulation may be an innovative addition to the
sport nutrition practitioners’ toolbox for management of exercise-associated GI distress. Certain
considerations must be taken into account when trialing short-chain carbohydrate restriction with
athletes as dietary requirements are individual and unnecessary food restriction may compromise
optimal fueling (37). When appropriately planned, under the guidance of a dietetic professional,
a low FODMAP diet can be matched for energy, macronutrients and fiber (Table 2). Although
differences in protein and fat intake were statistically significant between LFOD and HFOD, 7
and 5 g, respectively, these findings are not clinically significant. As a source of high quality
protein, cow-based dairy is often consumed by athletes at or above the general population
recommendation of two to four servings per day. Coinciding high lactose intakes are likely
(Table 2) and should be investigated as a primary trigger for GI symptoms with appropriate high
protein substitutes made, such as lactose free milk if required. A low FODMAP diet should be
considered once typical GI symptom triggers have first been assessed, such as lactose (11, 12).
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D
ptoms
.
D
uture research sh
ner er
nipulation may be anipulation may be an
inno
nagement of exercise-assoagement of exercise-asso
unt when trialing short-chnt when trialing
re individual and unnecesindividual and unneces
appropriately planned,appropriately planned,
uu
can be matched for enerbe matched for ener
rotein and fat intake wereotein and fat intake were
espectively,tively
these findinge fin
in, cow-based d
n, cow-based d
air
y
airy
isis
ecommendation of two
mendation of two
2) and shouand s
Intakes of prebiotic fructooligosaccharides and galactooligosaccharides, found in high amounts
in wheat and legumes, are restricted with a low FODMAP diet, which is concerning. These
prebiotics stimulate healthy colonic Bifidobacterium. After 4-weeks of a restricted fermentable
carbohydrate diet Bifidobacteria populations were decreased in IBS patients (38). Immune health
may be compromised with lower Bifidobacterium count, which is an important consideration for
overall athlete immunity and health (39). In athletes, it is unclear if risk associated with
decreased healthy bacterial populations due to diet may be more or less apparent as exercise
further alters diet-microbe-host metabolic interactions and may support higher gut
microorganisms diversity (40). Exercise and an athletes diet could offer a protective element
against a decrease in healthy gut bacterial populations associated with FODMAP restriction.
Given the restrictive nature and novelty of this dietary approach a systematic and individualized
approach will be obligatory for successful and efficacious implementation of a low FODMAP
diet in an athletic setting.
Conclusions
Results from this study have shown that a short-term LFOD results in significantly lower daily
GI symptoms over the intervention period compared to a HFOD diet in athletes with a self-
reported history of persistent exercise-associated GI distress. Exercise-associated GI distress and
pathophysiology of IBS are multifactorial, but both conditions feature similar symptomatology.
Although, more work is needed to determine the effectiveness of a low FODMAP diet, our
preliminary findings suggest this dietary approach may be applicable beyond the clinical realm
and offer a novel strategy to reduce GI symptoms in some symptomatic but otherwise clinically
healthy athletes.
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associa
associa
ss apparent as apparent as
exerc
exe
may support higher
may support higher
couldcould
off
er a protec
offer a protec
tiviv
associated assoc
with FODMwith FODM
tary approach tary approach
aa
systematsys
nd efficacious implemennd efficacious implemen
y have shown that a shove shown that a sho
ver the intervention periver the intervention peri
story of persistent exerciof persistent ex
ophysiology of IBS are m
physiology of IBS are m
lthough, more work i
gh, more work i
nary findiny fin
Acknowledgments
The authors would like to thank Monash University, Department of Gastroenterology, for
assisting with FODMAP quantification. The King and Amy O’Malley Trust provided
scholarship support. Isabelle Goodwin and Sarah Weber assisted with data input and food
logistics. The results of this study are presented clearly, honestly, and without fabrication,
falsification, or inappropriate data manipulation. The results of the present study do not
constitute endorsement by ACSM.
Funding
This study was supported in part by the Canadian Sport Institute Pacific. No conflict of interest is
present.
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nt study
nt study
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nstitute Pacific. No conflnstitute Pacific. No confl
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List of Figures
Figure 1 Schematic showing participant selection and study design. LFOD=Low FODMAP
diet, HFOD=High FODMAP diet, GI=gastrointestinal, DALDA=Daily Analysis of Life
Demands for Athletes
Figure 2 (a) Individual area under the curve (AUC) for daily gastrointestinal (GI) symptom
scores over 6 days for LFOD vs HFOD (n=11). (b) Mean group AUC during LFOD compared to
HFOD for daily GI symptom scores. (c) Mean total daily GI symptom scores for each day (day
1-6) of the dietary period for all participants (error bars represent standard deviations) on LFOD
and HFOD (p=0.006). * Denotes significance (P=0.003)
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ntestinal (GI) sympto
testinal (GI) symp
C during LFOD compare
C during LFOD compar
symptom scores for eachsymptom scores for each
represent standard deviatrepresent standard deviat
.003) 003)
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Table 1. Example of high and low FODMAP diets
a low FODMAP muesli made with rice crispies, corn flakes, quinoa flakes, shredded coconut,
and pumpkin seeds
b low FODMAP pesto pasta made with: cherry tomatoes, eggplant, garlic infused oil, pine nuts,
basil, parsley
c high FODMAP pesto pasta made with: cauliflower, asparagus, pistachios nuts, basil, parsley,
garlic
d low FODMAP vegetables included: small portion sweet potato, red bell pepper, spinach
e high FODMAP vegetables included: larger portion of sweet potato, beetroot, garlic, red onion
Meal
Low FODMAP diet
High FODMAP diet
Breakfast
low FODMAP muesli
a
lactose-free milk
blueberries
coffee/tea with lactose-free milk
muesli with dried fruit and nuts
milk
apple
coffee/tea with milk
Snack
corn Cruskits
lactose-free yogurt
grapes
rye Cruskits
yogurt
nectarine
Lunch
maple glazed salmon on quinoa/rice
pesto pastab
honey glazed salmon on durum wheat
pesto pastac
Snack
gluten-free biscuits
cheddar cheese
tomato, cucumber
wheat biscuits
cheddar cheese
snap peas, cucumber
Dinner
grilled chicken and vegetables on
quinoad
grilled chicken and vegetables on
couscouse
Snack
lactose-free yogurt
strawberries
coffee/tea with lactose-free milk
yogurt
cantaloupe
coffee/tea with milk
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made with rice crispies, code with rice crispies, co
s
ACC
pesto pasta made wit
AC
AC
FODMAP pesto
A
A
MAP
glazed salmon on durum wglazed salmon on durum w
sto pastato pasta
cc
wheat biscuits wheat b
c
heddar chee
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cheddar che
snap peas, cucumsnap peas, cucu
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Table 2. Composition of dietary intake during the habitual and low FODMAP dietary periods
Dietary Component
HFOD
LFOD
P value
Total energy (kcal)
3181 ± 403
3198 ±429
0.724
Total carbohydrate (g)
323 ± 63
327 ± 67
0.569
Total protein (g)
158 ± 16
153 ± 20
0.030*
Fat (g)
130 ± 12
137 ± 15
0.003*
Fiber (g)
32 ± 5
30 ± 5
0.318
Total FODMAPs (g)
41.4 ± 7.9
8.1 ± 3.5
<0.0001*
Excess fructose (g)
1.9 ± 0.54
0.5 ± 0.4
<0.0001*
Lactose (g)
28.0 ± 8.6
0.9 ± 0.3
<0.0001*
Total oligosaccharides (g)
8.7 ± 1.9
5.5 ± 3.2
0.001*
Fructooligosaccarides (g)
7.3 ± 1.8
4.5 ± 2.7
<0.001*
Galactooligosaccarides (g)
1.4 ± 0.3
1.0 ± 0.5
0.006*
Total Polyols (g)
2.9 ± 0.9
1.3 ± 0.7
<0.0001*
Sorbitol (g)
1.8 ± 0.9
0.9 ± 0.4
0.001*
Mannitol (g)
1.1 ± 0.3
0.4 ± 0.5
<0.0001*
Energy, macronutrients and fiber were calculated using FoodWorks dietary software, which is
based on the Australian Food Composition tables. Total FODMAPs = excess fructose + lactose +
sorbitol + mannitol + fructans + galactooligosaccharides (GOS). Bold text indicates additive
constituents for total FODMAPs. Data is presented as group (n=11) mean ± standard deviation
(SD) for HFOD and LFOD. *Significance between HFOD and LFOD (P<0.05).
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... Athlete-specific data support the concept that FODMAPs affect exercise-associated gastrointestinal symptoms [88,89]. Gastrointestinal symptoms can occur after intense exercise, which can affect energy replenishment. ...
... Often athletes exclude foods high in FODMAPs such as lactose, fructose with excess glucose, galactooligosaccharides, polyols, and fructans) on their own [90]. Some studies have highlighted the effectiveness of using a low FODMAP diet to reduce the severity of gastrointestinal symptoms during and outside of exercise [89,91]. ...
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An athlete’s diet is influenced by external and internal factors that can reduce or exacerbate exercise-induced food intolerance/allergy symptoms. This review highlights many factors that influence food choices. However, it is important to remember that these food choices are dynamic, and their effectiveness varies with the time, location, and environmental factors in which the athlete chooses the food. Therefore, before training and competition, athletes should follow the recommendations of physicians and nutritionists. It is important to study and understand the nutritional strategies and trends that athletes use before and during training or competitions. This will identify future clinical trials that can be conducted to identify specific foods that athletes can consume to minimize negative symptoms associated with their consumption and optimize training outcomes.
... Foram selecionados 33 artigos, dentre eles dois estudos de coorte, 10 estudos transversais, nove estudos de caso-controle e 12 ensaios clínicos. Dos estudos, os de coorte avaliaram entre 38 e 90 pacientes adultos 8,9 nos estudos transversais inclusos, a amostra variou de 16 a 3362 adultos e crianças 10-18 nos estudos de caso-controle participaram de 15 a 960 adultos e crianças [19][20][21][22][23][24][25][26][27] , e os ensaios clínicos com uma amostra de 11 a 110 indivíduos adultos [28][29][30][31][32][33][34][35][36][37][38][39] . ...
... Segundo Pedersen 34 a dieta reduzida em FODMAPs tem efeito benéfi co para pacientes dinamarqueses com DII, com redução de sintomas e melhora da qualidade de vida. A restrição de FODMAPs mostrou redução e alívio de SGI em pacientes com DII e em grupos que apresentam sintomas semelhantes 9,31,33,35 . ...
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Objetivo: reunir informações sobre o efeito da dieta com baixo teor de carboidratos fermentáveis sobre sintomas gastrointestinais, assim como sua aplicação nos transtornos do espectro autista.Método: revisão sistemática de literatura, utilizando-se descritores em inglês e português, das bases de dados Biblioteca Nacional de Medicina dos Estados Unidos, Biblioteca Virtual da Saúde e Portal de Periódicos Capes.Resultados: encontrou-se 33 artigos, dos quais dois eram coorte, 10 transversais, nove caso-controle e 12 ensaios clínicos. Os objetivos foram investigar a melhora dos sintomas gastrointestinais a partir da dieta com baixo teor de FODMAPs em pacientes com Síndrome do Intestino Irritável e Doença Inflamatória Intestinal. Na população com transtorno do espectro autista os objetivos foram avaliar a incidência de sintomas gastrointestinais e o impacto da restrição de FODMAPs nos mesmos. Os estudos mostraram melhoras de sintomas gastrointestinais, com alívio após implementação da dieta, em especial em pacientes com síndrome do intestino inflamatório e doença inflamatória intestinal.Conclusões: a dieta com baixo teor de FODMAPs mostrou melhora de sintomas gastrointestinais quando aplicada a indivíduos com alterações intestinais. Contudo são necessárias maiores evidências cientificas para indicar sua aplicação como medida de rotina no transtorno do espectro autista.
... FODMAP are nondigestible short-chain carbohydrates that increase the osmotic load within the gastrointestinal tract. Intestinal microbes can ferment these dietary components to form gas, which results in bloating and gastrointestinal distress in certain individuals (203). A recent study investigating FODMAP intake in endurance athletes reported high intake, both habitually and surrounding exercise, contributing to gastrointestinal symptoms (204). ...
... A recent study investigating FODMAP intake in endurance athletes reported high intake, both habitually and surrounding exercise, contributing to gastrointestinal symptoms (204). Preliminary results indicate that a low-FODMAP diet alleviates gastrointestinal symptoms in athletes (203,205,206). However, FODMAP also act as fuel for the gut microbiota, and their restriction may impact the composition and function of the community (207). ...
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The athlete's goal is to optimize their performance. Towards this end, nutrition has been used to improve the health of athletes' brains, bones, muscles, and cardiovascular system. However, recent research suggests that the gut and its resident microbiota may also play a role in athlete health and performance. Therefore, athletes should consider dietary strategies in the context of their potential effects on the gut microbiota, including the impact of sports-centric dietary strategies (e.g., protein supplements, carbohydrate loading) on the gut microbiota as well as the effects of gut-centric dietary strategies (e.g., probiotics, prebiotics) on performance. This review provides an overview of the interaction between diet, exercise, and the gut microbiota, focusing on dietary strategies that may impact both the gut microbiota and athletic performance. Current evidence suggests that the gut microbiota could, in theory, contribute to the effects of dietary intake on athletic performance by influencing microbial metabolite production, gastrointestinal physiology, and immune modulation. Common dietary strategies such as high protein and simple carbohydrate intake, low fiber intake, and food avoidance may adversely impact the gut microbiota and, in turn, performance. Conversely, intake of adequate dietary fiber, a variety of protein sources, and emphasis on unsaturated fats, especially omega-3 (ɷ-3) fatty acids, in addition to consumption of prebiotics, probiotics, and synbiotics, have shown promising results in optimizing athlete health and performance. Ultimately, while this is an emerging and promising area of research, more studies are needed that incorporate, control, and manipulate all 3 of these elements (i.e., diet, exercise, and gut microbiome) to provide recommendations for athletes on how to "fuel their microbes."
... Meanwhile, the MAX group consumed a CHO loading diet that was higher in CHO (12 g·kg BM −1 ·day −1 ) and based on low-residue (low-fibre) food choices [2], while consuming CHO during the session at higher rates of intake (90 g·h −1 ) ( Figure 1). Although there is growing evidence that dietary fermentable oligo-di-mono-saccharide and polyols (FODMAP) affect markers of gastrointestinal function, integrity, and symptoms [30][31][32], we decided not to control FODMAP intake to allow "real-world" dietary habits. We note that tests of body composition and maximal aerobic capacity were undertaken at the commencement and completion of the training camp in which this study was embedded; these results have been reported elsewhere [9]. ...
Article
Full-text available
We implemented a multi-pronged strategy (MAX) involving chronic (2 weeks high carbohydrate [CHO] diet + gut-training) and acute (CHO loading + 90 g·h −1 CHO during exercise) strategies to promote endogenous and exogenous CHO availability, compared with strategies reflecting lower ranges of current guidelines (CON) in two groups of athletes. Nineteen elite male race walkers (MAX: 9; CON:10) undertook a 26 km race-walking session before and after the respective interventions to investigate gastrointestinal function (absorption capacity), integrity (epithelial injury), and symptoms (GIS). We observed considerable individual variability in responses, resulting in a statistically significant (p < 0.001) yet likely clinically insignificant increase (∆ 736 pg·mL −1) in I-FABP after exercise across all trials, with no significant differences in breath H 2 across exercise (p = 0.970). MAX was associated with increased GIS in the second half of the exercise, especially in upper GIS (p < 0.01). Eighteen highly trained male and female distance runners (MAX: 10; CON: 8) then completed a 35 km run (28 km steady-state + 7 km time-trial) supported by either a slightly modified MAX or CON strategy. Inter-individual variability was observed, without major differences in epithelial cell intestinal fatty acid binding protein (I-FABP) or GIS, due to exercise, trial, or group, despite the 3-fold increase in exercise CHO intake in MAX post-intervention. The tight-junction (claudin-3) response decreased in both groups from pre-to post-intervention. Groups achieved a similar performance improvement from pre-to post-intervention (CON = 39 s [95 CI 15-63 s]; MAX = 36 s [13-59 s]; p = 0.002). Although this suggests that further increases in CHO availability above current guidelines do not confer additional advantages, limitations in our study execution (e.g., confounding loss of BM in several individuals despite a live-in training camp environment and significant increases in aerobic capacity due to intensified training) may have masked small differences. Therefore, athletes should meet the minimum CHO guidelines for training and competition goals, noting that, with practice, increased CHO intake can be tolerated, and may contribute to performance outcomes.
... The fiber and fat content may slow gastric emptying and increase nausea, and the fiber load may also precipitate diarrhea (Staudacher & Whelan, 2017). Increasingly, athletes report using a low-fiber diet (Burke et al., 2019) or foods with low volumes of fermentable oligo-, di-, mono-saccharides and polyols (Lis et al., 2018) to limit GI disturbances. However, the picture is not consistent, as intake of low to moderate glycemic index foods have been shown, in some studies, to help reduce GI symptoms during exercise (Kaviani et al., 2019). ...
Article
This systematic review analyzed whether carbohydrate source (food vs. supplement) influenced performance and gastrointestinal (GI) symptoms during endurance exercise. Medline, SPORTDiscus, and citations were searched from inception to July 2021. Inclusion criteria were healthy, active males and females aged >18 years, investigating endurance performance, and GI symptoms after ingestion of carbohydrate from a food or supplement, <60 min before or during endurance exercise. The van Rosendale scale was used to determine risk of bias, with seven studies having low risk of bias. A total of 151 participants from 15 studies were included in the review. Three studies provided 0.6–1 g carbohydrate/kg body mass during 5–45 min precycling exercise (duration 60–70 min) while 12 studies provided 24–80 g/hr carbohydrate during exercise (60–330 min). Except one study that suggested a likely harmful effect (magnitude-based inferences) of a bar compared to a gel consumed during exercise on cycling performance, there were no differences in running ( n = 1) or cycling ( n = 13) performance/capacity between food and supplemental sources. Greater GI symptoms were reported with food compared with supplemental sources. Highly heterogenous study designs for carbohydrate dose and timing, as well as exercise protocol and duration, make it difficult to compare findings between studies. A further limitation results from only one study assessing running performance. Food choices of carbohydrate consumed immediately before and during endurance exercise result in similar exercise performance/capacity responses to supplemental carbohydrate sources, but may slightly increase GI symptoms in some athletes, particularly with exercise >2 hr.
... 28 The impact of the type of supplements (BCAA or glycine) on each continuous parameter was analysed by multiple mixed linear regression models, as suggested by Dwan et al. 29 and others. [30][31][32][33] These analyses take into account the crossover design of the study and include all values assessed at all time points. Analyses were performed according to the latest CONSORT statement for randomized crossover trials, 29 which recommends to include only the patients who have completed the trial, thus to perform a per-protocol analysis, and not to test for the carry-over effect. ...
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Full-text available
Background Protein energy wasting is associated with negative outcome in patients under chronic haemodialysis (HD). Branched-chain amino acids (BCAAs) may increase the muscle mass. This post hoc analysis of a controlled double-blind randomized crossover study assessed the impact of BCAAs on nutritional status, physical function, and quality of life. Methods We included 36 chronic HD patient features of protein energy wasting as plasma albumin <38 g/L, and dietary intakes <30 kcal/kg/day and <1 g protein/kg/day. Patients received either oral BCAA (2 × 7 g/day) or glycine (2 × 7 g/day) for 4 months (Period 1), followed by a washout period of 1 month, and then received the opposite supplement (Period 2). The outcomes were lean body mass measured by dual-energy X-ray absorptiometry, fat-free mass index measured by bioelectrical impedance, resting energy expenditure, dietary intake and appetite rating, physical activity and function, quality of life, and blood parameters. Analyses were performed by multiple mixed linear regressions including type of supplementation, months, period, sex, and age as fixed effects and subjects as random intercepts. Results Twenty-seven patients (61.2 ± 13.7 years, 41% women) were compliant to the supplementations (consumption >80% of packs) and completed the study. BCAA did not affect lean body mass index and body weight, but significantly decreased fat-free mass index, as compared with glycine (coeff −0.27, 95% confidence interval −0.43 to −0.10, P = 0.002, respectively). BCAA and glycine intake had no effect on the other clinical parameters, blood chemistry tests, or plasma amino acids. Conclusions Branched-chain amino acid did not improve lean body mass as compared with glycine. Unexpectedly, glycine improved fat-free mass index in HD patients, as compared with BCAA. Whether long-term supplementation with glycine improves the clinical outcome remains to be demonstrated.
... These include monosaccharides, disaccharides oligosaccharides, and intestinal fermenting polyols, such as fructose, lactose, or xylitol [43]. The low-FODMAP diet has been proven to minimize gastrointestinal disorders, such as abdominal pain and bloating in IBS or IBDs [44][45][46]. A low intake of saccharides fermenting in the intestines reduces the frequency of diarrhea, but it was shown that this diet does not provide similar effects in minimizing constipation [47]. ...
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Full-text available
Gastrointestinal symptoms in Crohn’s disease (CD) are common and affect the quality of life of patients; consequently, a growing number of studies have been published on diet interventions in this group. The role of the gut microbiota in the pathogenesis and the progression of inflammatory bowel diseases (IBD), including CD, has been widely discussed. Mainly, a decreased abundance of Firmicutes, species of the Bifidobacterium genus, and the Faecalibacterium prausnitzii species as well as a reduced general diversity have been described. In this review article, we summarize available data on the influence of reduction diets on the microbiome of patients with CD. One of the most frequently used elimination diets in CD patients is the low-FODMAP (Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols) diet. Although many papers show it may reduce abdominal pain, diarrhea, or bloating, it also reduces the intake of prebiotic substances, which can negatively affect the gut microbiota composition, decreasing the abundance of Bifidobacterium species and Faecalibacterium prausnitzii. Other elimination diets used by IBD patients, such as lactose-free or gluten-free diets, have also been shown to disturb the microbial diversity. On the other hand, CDED (Crohn’s disease exclusion diet) with partial enteral nutrition not only induces the remission of CD but also has a positive influence on the microbiota. The impact of diet interventions on the microbiota and, potentially, on the future course of the disease should be considered when nutritional guidelines for IBD patients are designed. Dietetic recommendations should be based not only on the regulation of the symptoms but also on the long-term development of the disease.
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Athletes employ various dietary strategies in attempts to attenuate exercise-induced gastrointestinal (GI) symptoms to ensure optimal performance. This case-study outlines one of these GI-targeted approaches via the implementation of a short-term low FODMAP (Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols) diet, with the aim to attenuate persistent running specific GI symptoms in a recreationally competitive multisport athlete (male, 86 kg, 57.9 ml.kg.min-1 VO2max, 10-15 hrs.week-1 training, with no diagnosed GI disorder). Using a single-blinded approach a habitual diet was compared to a 6-day low FODMAP intervention diet (81 ± 5g vs 7.2 ± 5.7g FODMAPs.day-1) for their effect on GI symptoms and perceptual wellbeing. Training was similar during the habitual and dietary intervention periods. Post-exercise (During) GI symptom ratings were recorded immediately following training. Daily GI symptoms and the Daily Analysis of Life Demands for Athletes (DALDA) were recorded at the end of each day. Daily and During GI symptom scores (scale 0-9) ranged from 0-4 during the habitual dietary period while during the low FODMAP dietary period all scores were 0 (no symptoms at all). DALDA scores for 'worse than normal' ranged from 3-10 vs 0-8 in the habitual and low FODMAP dietary periods, respectively, indicating improvement. This intervention was effective for this GI symptom prone athlete; however, randomized-controlled trials are required to assess the suitability of low FODMAP diets for reducing GI distress in other symptomatic athletes.
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Purpose of review: Runner's diarrhea is an acute exercise-induced diarrhea. Usually, this is not a pathological situation but it can affect performance. This review focuses on the discussion of the main causes of runner's diarrhea and nutritional recommendations to prevent it. Recent findings: Although based on limited data, multiple transportable carbohydrate intake during exercise instead of glucose alone can be recommended for preventing the urge to defecate and (possibly) diarrhea. Additionally, avoiding ingestion of fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) is related to a lower incidence of reported gastrointestinal problems. There is, however, still no study that associates FODMAPs and runner's diarrhea. Gluten-free diets seem to have no impact on exercise-induced intestinal damage and there is no evidence to recommend this diet for the prevention of diarrhea in nonceliac athletes. Summary: The main causes of diarrhea in runners are ischemic, mechanical, and nutritional factors. For the prevention of diarrhea, it has been recommended that dehydration and the ingestion of fiber, fat, protein, high concentrated carbohydrate beverages, FODMAPs, caffeine, bicarbonate, and nonsteroidal anti-inflammatory drugs be avoided. However, the causes of diarrhea and nutritional strategies to prevent it are based on limited research and more studies are definitely needed.
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Recent explosion in the prevalence of gluten-free athletes, exacerbated by unsubstantiated commercial health claims, has led to some professional athletes touting gluten-free diet as the secret to their success. Forty-one percent of athletes report adhering to a gluten-free diet (GFD), which is four-fold higher than the population-based clinical requirements. Many nonceliac athletes believe that gluten avoidance improves gastrointestinal well-being, reduces inflammation, and provides an ergogenic edge, despite the fact that limited data yet exist to support any of these benefits. There are several plausible associations between endurance-based exercise and gastrointestinal permeability whereby a GFD may be beneficial. However, the implications of confounding factors, including the risks of unnecessary dietary restriction, financial burden, food availability, psychosocial implications, alterations in short-chain carbohydrates (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols), and other wheat constituents emphasize the need for further evaluation.
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We surveyed 910 athletes to assess behaviours towards self-selected food/ingredient avoidance to minimize gastrointestinal distress. Fifty-five percent eliminated at least 1 high fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) food/category, with up to 82.6% reporting symptom improvement. In athletes indicating that high FODMAP foods trigger gastrointestinal symptoms, lactose (86.5%) was most frequently eliminated, followed by galactooligosaccharides (23.9%), fructose (23.0%), fructans (6.2%), and polyols (5.4%). Athletes avoid predominantly lactose and to a lesser extent other high FODMAP foods to reduce gastrointestinal distress.
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Probiotics and prebiotics, mainly commercialised as food ingredients and also as supplements, are considered highly profitable niche markets. However, in recent years, the food industry has suffered from a series of health claim restrictions on probiotics and prebiotics in many parts of the world, including those made by the European Food Safety Authority. Therefore, we reviewed the core benefits of probiotic and prebiotic consumption on health. A number of studies have examined the prevention and/or management of intestinal infections, respiratory tract infections, CVD, osteoporosis, urogenital infections, cavities, periodontal disease and halitosis, allergic reactions, inflammatory bowel disease and irritable bowel syndrome and Helicobacter pylori gastric infections. In fact, a deeper understanding of the mechanisms involved in human microbiota and immune system modulation by probiotics and prebiotics relies on continuous efforts to establish suitable biomarkers of health and diseases risk factors for the design of clinical trials required for health claim approval. In spite of the promising results, the performance of large, long-term, well-planned, well-aligned clinical studies is crucial to provide more reliability and a more solid basis for the outcomes achieved and to support the potential use of probiotics and prebiotics in clinical practice.
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IBS is one of the most common types of functional bowel disorder. Increasing attention has been paid to the causative role of food in IBS. Food ingestion precipitates or exacerbates symptoms, such as abdominal pain and bloating in patients with IBS through different hypothesised mechanisms including immune and mast cell activation, mechanoreceptor stimulation and chemosensory activation. Wheat is regarded as one of the most relevant IBS triggers, although which component(s) of this cereal is/are involved remain(s) unknown. Gluten, other wheat proteins, for example, amylase-trypsin inhibitors, and fructans (the latter belonging to fermentable oligo-di-mono-saccharides and polyols (FODMAPs)), have been identified as possible factors for symptom generation/exacerbation. This uncertainty on the true culprit(s) opened a scenario of semantic definitions favoured by the discordant results of double-blind placebo-controlled trials, which have generated various terms ranging from non-coeliac gluten sensitivity to the broader one of non-coeliac wheat or wheat protein sensitivity or, even, FODMAP sensitivity. The role of FODMAPs in eliciting the clinical picture of IBS goes further since these short-chain carbohydrates are found in many other dietary components, including vegetables and fruits. In this review, we assessed current literature in order to unravel whether gluten/wheat/FODMAP sensitivity represent 'facts' and not 'fiction' in IBS symptoms. This knowledge is expected to promote standardisation in dietary strategies (gluten/wheat-free and low FODMAP) as effective measures for the management of IBS symptoms. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.
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While it is well documented and widely appreciated that ingestion of wheat (and less so rye and barley) is associated with gastrointestinal symptoms such as bloating or abdominal pain, the component of wheat to which such an effect is attributed is less well established. Key Messages: Wheat is a complex of proteins (80% gluten, 20% metabolic proteins), carbohydrates (starch, non-starch polysaccharides, fructans), lipids and other components. The majority of attention has focused on gluten as the culprit in triggering symptoms, but re-challenge studies have nearly all used wheat flour-related products (such as bread) as the stimulus. When carbohydrate-deplete gluten was used as the challenge agent, gluten-specific feelings of depression and not gut symptoms were observed in those who fulfilled strict criteria of 'non-coeliac gluten sensitivity', thereby underlining the complexity of cereals and of undertaking research in this area. Candidate components other than gluten include poorly absorbed oligosaccharides (mainly fructans), non-gluten wheat proteins such as amylase-trypsin inhibitors or wheat germ agglutinin, and exorphins released during the digestion of gluten. Specific biological and/or clinical effects associated with gluten-free diets or wheat ingestion need to be carefully dissected before attribution to gluten can be claimed. Currently, coeliac disease is the only common condition that has been unequivocally linked to gluten. Inaccurate attribution will be associated with suboptimal therapeutic advice and at least partly underlies the current gluten-free epidemic gripping the Western world. © 2015 S. Karger AG, Basel.