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Vegetarian Diet and Athletes



In dieser Rubrik werden „Position-Statements“ renommierter nationaler und internationaler Fachgesellschaften publiziert. Diesmal präsentieren wir Ihnen eine Publikation der FIMS (Fédération Internationale de Médecine du Sport - International Federation of Sports Medicine) - A balanced intake of macro- and micro nutrients is crucially important for conditioning, recovery from fatigue after exercise, as well as for injury prevention. An increasing number of athletes have adopted vegetarian diets for one or more reasons and actually there is no available evidence to support either a beneficial or a detrimental effect of a vegetarian diet on sport performance. Therefore, it is widely accepted that appropriately planned vegetarian diets can provide sufficient nutrient energy with an appropriate range of carbohydrate, fat, and protein intake to support performance and health. On the other hand, questions have been raised by some investigators regarding unique risks of the vegetarian diet, including oligomenorrhea and amenorrhea, iron deficiency, vitamin B12 deficiency, vitamin D deficiency, and impaired mineral status. In the present overview those items are described with the aim of identifying intervention warnings for vegetarian athletes.
Vegetarian diet and athletes International SportMed Journal, Vol. 10 No.1, 2009,
pp. 53-60,
International SportMed Journal
FIMS Position Statement 2009
Vegetarian diet and athletes
Dr Paolo Borrione, MD, Dr Loredana Grasso, SCD, Dr Federico Quaranta, MD,
*Professor Attilio Parisi, MD
Department of Health Sciences, University of Rome “Foro Italico”, Rome, Italy
A balanced intake of macro- and micro nutrients is crucially important for conditioning, recovery from
fatigue after exercise, as well as for injury prevention. An increasing number of athletes have adopted
vegetarian diets for one or more reasons and actually there is no available evidence to support either
a beneficial or a detrimental effect of a vegetarian diet on sport performance. Therefore, it is widely
accepted that appropriately planned vegetarian diets can provide sufficient nutrient energy with an
appropriate range of carbohydrate, fat, and protein intake to support performance and health. On the
other hand, questions have been raised by some investigators regarding unique risks of the
vegetarian diet, including oligomenorrhea and amenorrhea, iron deficiency, vitamin B12 deficiency,
vitamin D deficiency, and impaired mineral status. In the present overview those items are described
with the aim of identifying intervention warnings for vegetarian athletes. Keywords: vegetarian,
athletes, diet, nutrition, deficiency
Dr Paolo Borrione, MD
Dr Paolo Borrione is a physician specialising in haematology, researcher in Internal Medicine at the
University of Rome “Foro Italico”, member of the Italian anti-doping commission. His main fields of
research in the last years were focused on the effects of molecules on cell components and on the
effects of exercise on the cardio-vascular system.
Dr Loredana Grasso, SCD
Dr Loredana Grasso is a biologist specialised in the environment and working epidemiology. Her main
fields of research focus on the effects of exercise on the cardiovascular system and on health
screening and prevention strategies for youths.
Official Journal of FIMS (International Federation of Sports Medicine)
*Corresponding author. Address at the end of text.
Vegetarian diet and athletes International SportMed Journal, Vol. 10 No.1, 2009,
pp. 53-60,
Dr Federico Quaranta, MD
Dr Federico Quaranta is a physician specialised in Sports Medicine in the Department of Health
Science of the University of Rome “Foro Italico”. His main field of research is focused on the effect of
exercise on the cardiovascular system.
*Professor Attilio Parisi, MD
Professor Attilio Parisi is a physician specialising in Sports Medicine, assistant Professor of Methods
and Didactics of Movement Activities at the University of Rome “Foro Italico”, and physician to the
Italian Modern Pentathlon Federation. His main fields of research are sports nutrition, cardiological
responses to sport activities, and epidemiological and therapeutic aspects of physical activities.
Athletes require an adequate food intake to
meet the high level of energy expenditure, to
maintain the body homeostasis, to prevent
exercise-related stress disorders, to achieve
an appropriate body composition, and to
sustain athletic performance. Balanced
nutrition is critically important for conditioning,
recovery from fatigue after exercise, and injury
prevention 1. Food choice is a complex
product of multiple influences including culture,
family, and availability of specific foods, and
the nutritional value of each diet is reflected in
these variables and choices. An increasing
number of athletes have adopted vegetarian
diets for one or more reasons, including
ecological, economical, religious, health, or
ethical motivations.
There are several types of vegetarian diets
that have widely divergent nutritional contents
and require differentiation:
- The general vegetarian diet allows no
consumption of meat and fish are
consumed while eggs, milk, cheese and
honey are allowed.
- The lacto-vegetarian diet also excludes
- The vegan diet excludes the consumption
of all animal-related foods, including dairy
- The crudest diet is limited exclusively to
fruits and vegetables.
- The fruitarian diet includes only fruits and
- The eco-vegan diet is similar to vegan diet
that requires nourishment coming only
from biological cultivations 2; 3.
While vegetarian diets have been associated
with several health benefits 4 including lower
mortality and morbidity from diabetes, ischemic
heart disease, dyslipidemia, hypertension and
obesity 5-8, there are several nutrients which
are difficult to obtain from plant foods alone.
Moreover, the absence of some
micronutrients, such as vitamin B12
(cyanocobalamin) in plant-derived foods,
underscoring the fact that strict vegetarian
diets must rely on fortified foods or
supplements to obtain an adequate intake of
essential micronutrients 9.
With regard to physical activity, there is no
available evidence to support either a
beneficial or a detrimental effect of a
vegetarian diet on sports performance,
especially when carbohydrate intake is
adequate. Appropriately planned vegetarian
diets can provide sufficient nutrient energy with
an appropriate range of carbohydrate, fat, and
protein intake to support performance and
health. In fact, vegetarian athletes can meet
their protein needs from exclusively plant-
based sources when a variety of these foods
are consumed daily and food energy intake is
adequate 10-12.
On the other hand, questions have been raised
by some investigators regarding unique risks
of the vegetarian diet, including
oligomenorrhea and amenorrhea 13;14, iron
deficiency 15, vitamin B12 deficiency 16;17,
vitamin D (cholecalciferol) deficiency 18, and
impaired mineral status 19. Of particular
concern is the issue of amenorrhea among
competitive female athletes 13;14. It is well
known that the prevalence of oligomenorrhea
and amenorrhea among athletes is about 20%
and that can increase to almost 50% in some
competitive athlete groups. The cause is not
fully understood, but low dietary energy intake
is considered to be one of the major factors in
the suppression of the hypothalamic-pituitary-
ovarian axis 20. Several authors have shown
that amenorrheic athletes typically have low
concentrations of estradiol and progesterone,
Official Journal of FIMS (International Federation of Sports Medicine)
Vegetarian diet and athletes International SportMed Journal, Vol. 10 No.1, 2009,
pp. 53-60,
and some investigator have noted that a
significant proportion of female athletes with
amenorrhea were vegetarians 20. Since some
authors demonstrated lower circulating
oestrogen levels in vegetarians when
compared to non-vegetarians and showed that
these hormonal differences were associated
with higher fibre and lower fat intakes, it could
be argued that the nutrient composition of
some vegetarian diets maybe predisposed to
amenorrhea 20;21. However, these studies were
not able to clearly determine whether the
cause was the vegetarian diet per se or other
factors, such as a heavy exercise training
programme coupled with a lower energy
intake. In this regard, certain authors observed
that when vegetarian athletes are properly
nourished their menstrual cycle function is
normal, suggesting that a low energy intake,
not diet quality, is the major cause of
amenorrhea, and that when brought into a
positive energy balance, hormonal profiles
return to normal and menstruation is restored
22. Certainly, more research is needed in this
area. Moreover, some studies have come to
very different conclusions regarding the protein
requirements of physically active individuals
based on a lack of consensus as to whether
protein requirements are influenced by
physical activity 23;24.
Athletes must understand that a balanced diet
is essential to meet their individual energy
requirements and it must suit the specific
needs of the physical exercise demands. Even
if a vegetarian diet per se does not seem to be
associated with detrimental effects on athletes,
vegetarians must achieve an optimal nutrient
intake through careful planning 25;26. Diet
intake quality can be evaluated in several
different ways. One of the easiest ways is to
determine the proportion of specific nutrient
types supplied by the diet itself. Nutrients are
generally classified as either macronutrients or
micronutrients. The former include
carbohydrates, proteins, fats, macro minerals,
and water. Micronutrients, which include
vitamins, minerals, and phytochemicals, derive
their name from the fact that they are needed
in relatively small amounts. When planning a
diet for athletes all of those nutrients should be
taken into consideration.
Carbohydrates should represent the largest
portion of the athlete’s diet, and endurance
athletes should ensure adequate
carbohydrates in their diet to optimise
glycogen stores. Indeed, several studies
showed that a large carbohydrate intake may
optimise muscle and liver glycogen stores with
a positive impact on physical performances
27;28. Sports nutrition guidelines recommend
that 60-65% of total energy should come from
carbohydrates 24;29. Carbohydrate intake is not
usually an issue for vegetarian athletes since
most carbohydrates are of plant origin. There
are two main types of carbohydrates: simple
carbohydrates and complex carbohydrates.
Fruits and milk are rich in simple
carbohydrates. Usually, refined sugars, such
as table sugar, sweets, and syrups, are not
considered a good source of carbohydrates for
vegetarians since they do not provide sufficient
fibre, vitamins, or minerals beneficial to
vegetarians. Complex carbohydrates can be
easily derived from cereals and root
vegetables. Less refined food, such as brown
rice and wholewheat breads and pastas, are
preferred carbohydrate sources for their higher
content of essential dietary fibre and B
Even if several recent studies suggest that
highly trained athletes may perform better on
"high-fat" diets, it is still recommended that
<30% of total energy intake should come from
fats 30; 31. In fact, previous studies highlighting
the beneficial effects of low-fat diets showed
methodological biases, such as small sample
sizes or non-randomised samples 33;33.
Vegetarian athletes may easily meet their
energy and nutrient needs consuming high-fat
foods, such as nuts and seeds, olives, olive oil,
sesame oil, canola oil, and avocado. On the
other hand, it is still possible to find vegetarian
athletes with diets too rich in saturated fats
mainly from full-cream dairy products. In more
restrictive vegetarian diets with a <10% fat
intake, these may have some benefit to the
overall health of subjects with a known
personal or family history of cardiovascular
disease, while the severe fat restriction will be
detrimental for optimal athletic performance,
particularly for those athletes engaged in
heavy training.
Protein requirements in physically active
subjects are still a matter of debate. As
summarised in different reviews, there is no
universal consensus that protein requirements
are influenced by physical activity 23;24;34, but it
Official Journal of FIMS (International Federation of Sports Medicine)
Vegetarian diet and athletes International SportMed Journal, Vol. 10 No.1, 2009,
pp. 53-60,
is accepted by many that the protein
requirements of athletes vary according to the
practised discipline, the level of training and
the total energy intake derived from
carbohydrates. On average, it is recommended
that athletes consume 1.5g of protein/kg/d 25.
However, some authors suggest that protein
requirements are approximately 1.2- to
1.6g/kg/d for athletes practising endurance
disciplines and approximately 1.6- to 1.7g/kg/d
for strength athletes 35. Despite this
controversy over protein requirements, it has
to be noted that an inadequate intake of
carbohydrates increases the utilisation of
protein for energy needs and as a result, the
total dietary protein requirements. In fact,
during prolonged physical activity, athletes with
low glycogen stores metabolise twice as much
protein as those with adequate stores as result
of the increased gluconeogenesis 36.
Vegetarian athletes can easily achieve
adequate protein intake from plant-protein
foods, such as legumes, grains, nuts and
seeds, as well as all the essential and non-
essential amino acids if a variety of foods is
consumed. A well-planned vegetarian diet
should contain, on average, 12.5% of energy
from protein 37. It has to be underlined that
strength-trained athletes or those with high
training levels or low carbohydrate energy
intakes may need to include more protein-rich
When considering athletic performance, it
should be remembered that creatine
concentrations have been found to be lower in
vegetarian athletes when compared to non-
vegetarians 38. The estimated daily
requirement of creatine is 2g. Non vegetarians
typically get 1g creatine/d from meat, the rest
is synthesised, mainly in the liver, using the
amino acids arginine, methionine and glycine
as precursors. It has also been demonstrated
that inadequate dietary creatine intake from
meat sources is not compensated by increased
endogenous creatine production 39; 40.
Currently, little is reported with regard to the
long-term effects of creatine supplementation
in vegetarian athletes. Different studies have
demonstrated that creatine supplementation
increases muscle concentrations of creatine
and improves performance during repeated
bouts of high-intensity activity 38-40. Other
studies failed to show any effects of creatine
on power performances 41. Almost all studies
demonstrated that creatine supplementation
has no effect on aerobic performances.
Vegetarian athletes should be aware of the
potential to have lower body creatine pools
when compared to non-vegetarian
counterparts. It seems reasonable to suggest
creatine supplementation for vegetarian
athletes engaged in repeated bouts of short-
term high-intensity exercise, but this may not
be necessary for endurance athletes.
Iron and Zinc
Concerns have been raised about
micronutrient availability in vegetarian athletes.
It has been suggested that the increase of
dietary fibres and phytic acids may reduce the
bioavailability of zinc, iron, and some trace
minerals 42. The increased iron loss in some
sport disciplines is well known, mainly due to
gastrointestinal bleeding 43, heavy sweating,
haemolysis, and in women, menstruation. For
this reason, some athletes engaged in
endurance disciplines are at increased risk of
iron depletion and even iron deficiency
anaemia 44. Even if mild iron deficiency seems
not to affect health or athletic performances, it
has to be taken into consideration that low iron
stores, even without anaemia, have been
associated with decreased endurance
capabilities 45.
In the vegetarian diet, iron is consumed in the
non-heme state which has a relatively low
absorption rate (2-20%) when compared with
the heme iron (15-35%) 46. Moreover, several
plant-derived substances, such as tea tannins,
bran, polyphenols, egg yolk, soy bean
products, and phytic acid may interfere with
iron absorption 47. Low iron intake and reduced
absorption taken together may reduce the
body’s iron stores in some athletes. Indeed, it
has been demonstrated that female vegetarian
runners had a lower iron status when
compared to non-vegetarian runners 48. In
most cases, vegetarian athletes can achieve
proper iron status without iron supplementation
if they avoid foods that interfere with iron
absorption and increase the intake of those
substances known to optimise the absorption
of non-heme iron, such as vitamin C, citric
acid, malic acid, tartaric acid, fructose, and
Zinc is another micronutrient of concern in
vegetarian athletes. Some authors highlighted
that exercise increases zinc urinary excretion
49. This observation is of particular interest
Official Journal of FIMS (International Federation of Sports Medicine)
Vegetarian diet and athletes International SportMed Journal, Vol. 10 No.1, 2009,
pp. 53-60,
when considering vegetarian athletes with low
zinc intake or bioavailability. In fact, the high
phytate concentrations of some plant-derived
foods may reduce zinc absorption even when
known plant-derived sources of zinc, such as
dried beans, soy products, nuts and seeds are
consumed. Other known inhibitors of zinc
absorption include oxalate, fibre and
polyphenols, such as tannins 42;50. Based on
those observations, concerns have been
raised that vegetarian athletes, especially
during adolescence, may have difficulty
maintaining adequate zinc levels.
Although more research is needed, vegetarian
athletes should be aware of the potential iron
and zinc deficiency linked to their diet choices
and that iron and/or zinc supplementation may
be necessary, particularly in athletes who
follow the stricter nutritional regimens. It is
important to emphasise that the zinc and iron
supplements should include no more than
100% of the recommended dietary allowance
to avoid negative interactions with the
absorption of other nutrients 51.
Vegetarian diets can fulfil most of the vitamin
requirements, except for vitamin B12
(cyanocobalamin), vitamin D (cholecalciferol)
and vitamin B2 (riboflavin). Riboflavin is
required for a wide variety of cellular
processes and like the other B group vitamins,
it plays a key role in energy metabolism.
Riboflavin is, in fact, important for the
conversion of proteins, fats and carbohydrates
into energy, as well as for the synthesis and
repair of various tissues 52. Riboflavin is
normally present in a number of foods and the
amount needed is directly linked to the total
energy intake. For all of those reasons,
riboflavin plays an important role when
considering both the athlete’s overall health
and performance. Dietary intake of riboflavin
may be limited in vegetarian diets, in particular
in those subjects who avoid the consumption
of soy milk and soy milk products. As a matter
of fact, several studies showed that subjects
with marginal riboflavin status may have
increased requirements when they begin to be
physical active 53. Vegetarian athletes, and in
particular those who avoid dairy products,
should be instructed to increase their intake of
plant sources of riboflavin, such as whole grain
cereal, soybeans, soymilk, almonds,
asparagus, bananas, sweet potatoes and
wheat germ.
Vitamin D is essential for promoting calcium
absorption and maintaining adequate serum
calcium and phosphate concentrations to
enable normal bone mineralisation. Vitamin D
is needed for bone growth and remodelling. It
also plays other roles, including the modulation
of the immune system and neuromuscular
function 54;55. Vitamin D is found in very few
foods, all of animal origin including fish, liver,
eggs and dairy products; Vitamin D is not
present in plant foods. Vitamin D is
synthesised in skin exposed to sunlight and
this synthesis is usually adequate to supply the
overall requirements in the summer months in
temperate regions and year-round in equatorial
regions. Vegetarian athletes without sufficient
sunlight exposure, including those who may be
required to keep their skin covered for religious
or cultural reasons or who are dark-skinned,
are at risk of vitamin D deficiency. In these
cases, fortified foods or supplements should
be taken to assure adequate body levels of the
Vitamin B12 plays a key role in the normal
function of the nervous system and in
erythropoiesis 56, is involved in the cellular
metabolism affecting DNA synthesis and
regulation 57, and also plays an important role
in fatty acid synthesis and energy production
58. Since vitamin B12 is found exclusively in
animal products, vegetarians consuming eggs,
cheese, milk or yoghurt receive an adequate
supply of this vitamin. On the contrary,
vegetarian athletes following stricter dietary
regimens need to regularly consume B12
fortified foods or supplements.
A vitamin B12 deficiency can cause serious
health damage. In adults, both anaemia-
related symptoms and neurologic signs are
usually recognisable and can be treated. It
should be emphasised that maternal vitamin
B12 deficiency during pregnancy and lactation
in vegetarians can cause irreversible
neurologic damage in the infant and it is critical
to provide appropriate vitamin B12
supplementation to prevent this disorder 59;60.
A well planned and controlled
vegetarian diet appears to effectively
support physical activities.
The control of the nutritional status of
vegetarian athletes can allow proper
supplementation or the use of fortified
foods when needed.
Official Journal of FIMS (International Federation of Sports Medicine)
Vegetarian diet and athletes International SportMed Journal, Vol. 10 No.1, 2009,
pp. 53-60,
Plant and animal protein sources
seem to provide equivalent support to
physical activities.
Since vegetarians have lower creatine
concentrations when compared to
omnivores, they may experience
performance increases following
creatine supplementation.
Appropriate planning and programmed
follow-up are needed to monitor
vitamin B12, iron, zinc, vitamin D,
riboflavin, and protein status.
Oligomenorrhea and amenorrhea
should be monitored in the light of a
possible influence of the vegetarian
Address for correspondence
Professor Attilio Parisi, Department of Health
Science, University of Rome “Foro Italico”,
Piazza Lauro de Bosis 15 00194 Rome, Italy
Tel: +39 06 36733333
Fax: +39 06 36733344
Official Journal of FIMS (International Federation of Sports Medicine)
1. Maughan R. The athlete's diet:
nutritional goals and dietary strategies.
Proc Nutr Soc 2002; 61: 87-96.
2. Dwyer J. Convergence of plant-rich
and plant-only diets. Am J Clin Nutr
1999; 70(3 Suppl): 620S-622S.
3. American Dietetic Association;
Dietitians of Canada. Position of the
American Dietetic Association and
Dietitians of Canada: Vegetarian diets.
J Am Diet Assoc 2003; 103: 748-765.
4. Key TJ, Appleby PN, Rosell MS.
Health effects of vegetarian and vegan
diets. Proc Nutr Soc 2006; 65: 35-41.
5. Appleby PN, Davey GK, Key TJ.
Hypertension and blood pressure
among meat eaters, fish eaters,
vegetarians and vegans in EPIC-
Oxford. Public Health Nutr 2002; 5:
6. Kontogianni MD, Panagiotakos DB,
Pitsavos C, et al. Relationship
between meat intake and the
development of acute coronary
syndromes: the CARDIO2000 case-
control study. Eur J Clin Nutr 2008; 62:
7. Berkow SE, Barnard N. Vegetarian
diets and weight status. Nutr Rev
2006; 64: 175-188.
8. Vang A, Singh PN, Lee JW, et al.
Meats, processed meats, obesity,
weight gain and occurrence of
diabetes among adults: findings from
Adventist Health Studies. Ann Nutr
Metab 2008; 52: 96-104.
9. Murphy SP, Allen LHJ. Nutritional
importance of animal source foods.
Nutrition 2003; 133(11 Suppl 2):
10. Barr SI, Rideout CA. Nutritional
considerations for vegetarian athletes.
Nutrition 2004; 20: 696-703.
11. Venderley AM, Campbell WW.
Vegetarian diets: Nutritional
considerations for athletes. Sports
Med 2006; 36: 293-305.
12. Nieman DC. Physical fitness and
vegetarian diets: Is there a relation?
Am J Clin Nutr 1999; 70(3 Suppl):
13. Barr SI. Vegetarianism and menstrual
cycle disturbances: Is there an
association? Am J Clin Nutr 1999 Sep;
70(3 Suppl): 549S-54S.
14. Benson JE, Engelbert-Fenton KA,
Eisenman PA. Nutritional aspects of
amenorrhea in the female athlete triad.
Int J Sport Nutr 1996; 6: 134-145.
15. Waldmann A, Koschizke JW,
Leitzmann C, et al. Dietary iron intake
and iron status of German female
vegans: Results of the German vegan
study. Ann Nutr Metab 2004; 48: 103-
16. Allen LH. Causes of vitamin B12 and
folate deficiency. Food Nutr Bull 2008;
29(2 Suppl): S20-34.
17. Kwok T, Cheng G, Woo J, et al.
Independent effect of vitamin B12
deficiency on hematological status in
older Chinese vegetarian women. Am
J Hematol 2002; 70: 186-190.
18. Willis KS, Peterson NJ, Larson-Meyer
DE. Should we be concerned about
the vitamin D status of athletes? Int J
Sport Nutr Exerc Metab 2008; 18: 204-
19. Kleiner SM. The role of meat in an
athlete's diet: Its effect on key macro-
and micronutrients. Sports Sci Exch
1995; 8: 1-6.
20. Loucks AB, Laughlin GA, Mortola JF,
et al. Hypothalamic-pituitary-thyroidal
function in eumenorrheic and
amenorrheic athletes. J Clin
Endocrinol Metab 1992; 75: 514-518.
Vegetarian diet and athletes International SportMed Journal, Vol. 10 No.1, 2009,
pp. 53-60,
21. Mitsuzono R, Ube M. Effects of
endurance training on blood lipid
profiles in adolescent female distance
runners. Kurume Med J 2006; 53: 29-
22. Hanne N, Dlin R, Rotstein A. Physical
fitness, anthropometric and metabolic
parameters in vegetarian athletes. J
Sports Med Phys Fitness 1986; 26:
23. Millward DJ, Bowtell JL, Pacy P, et al.
Physical activity, protein metabolism
and protein requirements. Proc Nutr
Soc 1994; 53: 223-240.
24. Lemon PW. Do athletes need more
dietary protein and amino acids? Int J
Sport Nutr 1995; 5 Suppl: S39-61.
25. Position of the American Dietetic
Association, Dietitians of Canada, and
the American College of Sports
Medicine: Nutrition and athletic
performance. J Am Diet Assoc 2000;
100: 1543-1556.
26. Position of the American Dietetic
Association and the Canadian Dietetic
Association, nutrition for physical
fitness and athletic performance for
adults. J Am Diet Assoc 1993; 93:
27. Sedlock DA. The latest on
carbohydrate loading: A practical
approach. Curr Sports Med Rep 2008;
7: 209-213.
28. Burke LM. Nutritional needs for
exercise in the heat. Comp Biochem
Physiol A Mol Integr Physiol 2001;
128: 735-748.
29. Williams C. Macronutrients and
performance. J Sports Sci 1995; 13
Spec No: S1-10.
30. Lambert EV, Speechly DP, Dennis SC,
et al. Enhanced endurance in trained
cyclists during moderate intensity
exercise following 2 weeks adaptation
to a high fat diet. Eur J Appl Physiol
1994; 69: 287-293.
31. Muoio DM, Leddy JJ, Horvath PJ, et
al. Effect of dietary fat on metabolic
adjustments to maximal VO2 and
endurance in runners. Med Sci Sports
Exerc 1994; 26: 81-88.
32. Brown RC, Cox CM. Effects of high fat
versus high carbohydrate diets on
plasma lipids and lipoproteins in
endurance athletes. Med Sci Sports
Exerc 1998; 30: 1677-1683.
33. Brown RC, Cox CM, Goulding A. High-
carbohydrate versus high-fat diets:
Effect on body composition in trained
cyclists. Med Sci Sports Exerc 2000;
32: 690-694.
34. Tipton KD, Wolfe RR. Protein and
amino acids for athletes. J Sports Sci
2004; 22: 65-79.
35. Lemon PW. Effects of exercise on
dietary protein requirements. Int J
Sport Nutr 1998; 8: 426-447.
36. Maughan R. The athlete's diet:
Nutritional goals and dietary
strategies. Proc Nutr Soc 2002; 61:
37. Venti CA, Johnston CS. Modified food
guide pyramid for lactovegetarians and
vegans. J Nutr 2002; 132: 1050-1054.
38. Lukaszuk JM, Robertson RJ, Arch JE,
et al. Effect of a defined lacto-ovo-
vegetarian diet and oral creatine
monohydrate supplementation on
plasma creatine concentration. J
Strength Cond Res 2005; 19: 735-740.
39. Williams MH, Branch JD. Creatine
supplementation and exercise
performance: An update. J Am Coll
Nutr 1998; 17: 216-234.
40. Bemben MG, Lamont HS. Creatine
supplementation and exercise
performance: recent findings. Sports
Med 2005; 35:107-125.
41. Izquierdo M, Ibañez J, González-
Badillo JJ, et al. Effects of creatine
supplementation on muscle power,
endurance, and sprint performance.
Med Sci Sports Exerc 2002; 34: 332-
42. Chiplonkar SA, Agte VV. Predicting
bioavailable zinc from lower phytate
forms, folic acid and their interactions
with zinc in vegetarian meals. J Am
Coll Nutr 2006; 25: 26-33.
43. Peters HP, De Vries WR, Vanberge-
Henegouwen GP, et al. Potential
benefits and hazards of physical
activity and exercise on the
gastrointestinal tract. Gut 2001; 48:
44. Hunt JR, Roughead ZK. Non heme-
iron absorption, fecal ferritin excretion,
and blood indexes of iron status in
women consuming controlled
lactoovovegetarian diets for 8 wk. Am
J Clin Nutr 1999; 69: 944-952.
45. Lamanca J, Haymes E. Effects of low
ferritin concentrations on endurance
performance. Int J Sports Med 1992;
2: 376-385.
Official Journal of FIMS (International Federation of Sports Medicine)
Vegetarian diet and athletes International SportMed Journal, Vol. 10 No.1, 2009,
pp. 53-60,
46. Chiplonkar SA, Agte VV. Statistical
model for predicting non-heme iron
bioavailability from vegetarian meals.
Int J Food Sci Nutr 2006; 57: 434-450.
47. Hunt JR. . Bioavailability of iron, zinc,
and other trace minerals from
vegetarian diets. Am J Clin Nutr 2003;
78(3 Suppl): 633S-639S.
48. Snyder AC, Dvorak LL, Roepke JB.
Influence of dietary iron source on
measures of iron status among female
runners. Med Sci Sports Exerc 1989;
21: 7-10.
49. Nuviala RJ, Lapieza MG, Bernal E.
Magnesium, zinc, and copper status in
women involved in different sports. Int
J Sport Nutr 1999; 9: 295-309.
50. Lukaski HC. Magnesium, zinc, and
chromium nutriture and physical
activity. Am J Clin Nutr 2000; 72(2
Suppl): 585S-93S.
51. Maret W, Sandstead HH. Zinc
requirements and the risks and
benefits of zinc supplementation. J
Trace Elem Med Biol 2006; 20: 3-18.
52. Woolf K, Manore MM. B-vitamins and
exercise: Does exercise alter
requirements? Int J Sport Nutr Exerc
Metab 2006; 16: 453-484.
53. Lukaski HC. Vitamin and mineral
status: Effects on physical
performance. Nutrition 2004; 20):632-
54. Holick MF, Chen TC. Vitamin D
deficiency: A worldwide problem with
health consequences. Am J Clin Nutr
2008; 87: 1080S-6S.
55. Smolders J, Damoiseaux J, Menheere
P, et al. Vitamin D as an immune
modulator in multiple sclerosis: A
review. J Neuroimmunol 2008; 194: 7-
56. Ryan-Harshman M, Aldoori W. Vitamin
B12 and health. Can Fam Physician
2008; 54: 536-541.
57. Sharp L, Little J, Brockton NT, et al.
Polymorphisms in the
methylenetetrahydrofolate reductase
(MTHFR) gene, intakes of folate and
related B vitamins and colorectal
cancer: A case-control study in a
population with relatively low folate
intake. Br J Nutr 2008; 99: 379-389.
58. Woolf K, Manore MM. B-vitamins and
exercise: Does exercise alter
requirements? Int J Sport Nutr Exerc
Metab 2006; 16: 453-484.
59. Weiss R, Fogelman Y, Bennett M.
Severe vitamin B12 deficiency in an
infant associated with maternal
deficiency and a strict vegetarian diet.
J Pediatr Hematol Oncol 2004; 24:
60. Dror DK, Allen LH. Effect of vitamin
B12 deficiency on neurodevelopment
in infants: Current knowledge and
possible mechanisms. Nutr Rev 2008;
66: 250-255.
Official Journal of FIMS (International Federation of Sports Medicine)
... (25) Os idosos vegetarianos podem ingerir estas quantidades de vitamina D recorrendo a alimentos enriquecidos/fortificados como bebida de soja ou arroz, sumo de laranja, cereais de pequeno-almoço e margarinas, todos eles enriquecidos nesta vitamina, e leite de vaca para os lactoovo-vegetarianos, (2,(7)(8)25) se não forem alcançadas as necessidades através da ingestão alimentar é recomendado um suplemento de vitamina D. (2) Os idosos podem ter dificuldade em absorver vitamina B 12 , muitas vezes devido à gastrite atrófica (2,25) que pode estar presente em mais de 50% dos indivíduos com mais de 60 anos, (25) por isso devem ser utilizados alimentos fortificados/enriquecidos ou suplementos de vitamina B 12 , já que estes são geralmente são bem absorvidos. (2) (26) Não é necessária uma recomendação diferente no que concerne ao consumo de proteína para os desportistas vegetarianos que consomem ovos ou lacticínios e misturas complementar de proteínas vegetais de elevada qualidade. ...
... A ingestão inadequada de proteína total e de aminoácidos essenciais não é susceptível de ser uma preocupação para os desportistas vegetarianos, (2,11) já que as necessidades proteicas podem ser suprimidas através da ingestão de leguminosas, cereais, frutos oleaginosos e sementes, (2,26) a única excepção possível são os desportistas veganos que também limitam o consumo de energia. (11) Os hidratos de carbono devem representar a maior percentagem da alimentação dos desportistas e os de endurance deve enfatizar este macronutrimento na sua alimentação de modo a optimizar as suas reservas de glicogénio. ...
... (11) Os hidratos de carbono devem representar a maior percentagem da alimentação dos desportistas e os de endurance deve enfatizar este macronutrimento na sua alimentação de modo a optimizar as suas reservas de glicogénio. (11,26) A ingestão de hidratos de carbono, em geral, não é um problema para os desportistas vegetarianos, pois a maioria é de origem vegetal. (26) Os vezes superior para os vegetarianos (2,11) ) para que não haja interferência com a absorção de outros minerais. ...
... In addition to these aforementioned benefits, vegetarian diets may also provide advantages for exercise capacity by increasing muscle glycogen levels [71], and delaying fatigue [74]. As for increasing glycogen stores, carbohydrate intake is considered the cornerstone of a better endurance performance by enhancing muscle glycogen stores, delaying fatigue, and providing athletes to compete at better and higher levels during prolonged periods [75]. ...
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Endurance athletes need a regular and well-detailed nutrition program in order to fill their energy stores before training/racing, to provide nutritional support that will allow them to endure the harsh conditions during training/race, and to provide effective recovery after training/racing. Since exercise-related gastrointestinal symptoms can significantly affect performance, they also need to develop strategies to address these issues. All these factors force endurance athletes to constantly seek a better nutritional strategy. Therefore, several new dietary approaches have gained interest among endurance athletes in recent decades. This review provides a current perspective to five popular diet approaches: (a) vegetarian diets, (b) high-fat diets, (c) intermittent fasting diets, (d) gluten-free diet, and (e) low fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) diets. We reviewed scientific studies published from 1983 to January 2021 investigating the impact of these popular diets on the endurance performance and health aspects of endurance athletes. We also discuss all the beneficial and harmful aspects of these diets, and offer key suggestions for endurance athletes to consider when following these diets.
... Quando adequadamente planeado, o PAV pode ser seguido por atletas, já que pode fornecer a energia e os nutrientes necessários para manter um bom desempenho desportivo (5). O aumento da atenção mediática do PAV no contexto desportivo justifica-se também pela sua adoção por parte de alguns atletas como Dave Scott (seis vezes vencedor do Ironman), Andreas Cahling (fisioculturista), Surya Bonaly (patinadora olímpica), Pavo Nurmi (corredor de longa distância com 20 recordes mundiais) e Billy Jean King (tenista) (4). ...
There has been a growing adoption of the vegetarian dietary pattern, four times higher than ten years ago. Nowadays, the benefits of vegetable food consumption and its role in the prevention of several highly prevalent diseases in the population are known, such as type 2 diabetes mellitus, hypertension and cardiovascular diseases. When a large amount of food is included daily in the diet and the energy intake is adequate, vegetarian athletes can meet their protein needs through vegetable sources. Nutrients to consider avoiding nutritional deficiencies in vegetarians include proteins, n-3 fatty acids, iron, zinc, calcium, iodine, vitamin D and vitamin B12. With the increase of the number of athletes who follow the vegetarian diet, it is pertinent to question its effect on sports performance. This work brings together an existent proof of a nutritional approach in vegetarian athletes, identifying scientific studies from 1997 to 2019. The purpose of this paper is to examine and discuss the possible impacts of the vegetarian dietary pattern on sports performance. Current scientific evidence demonstrates that the adoption of this dietary pattern does not positively or negatively affect athletes' performance. Thus, it will be necessary to conduct further studies to examine the effects of the vegetarian dietary pattern on athletes to ensure the optimization of health and performance.
... Athletes require an adequate food intake to meet the high level of energy expenditure, to maintain the homeostasis, to prevent exercise -related stress disorders, to achieve an appropriate body composition, and to sustain athletic performance [1]. When activity is to be done, fuel is required. ...
Zusammenfassung. Ein Mangel an Vitamin D ist in der allgemeinen Bevölkerung wie auch bei Sportlerinnen und Sportlern sehr häufig. Ziel dieser Übersicht ist, den Stand des Wissens um die Bedeutung von Vitamin D für den sportlich aktiven Menschen zusammenzustellen. Ein Vitamin-D-Mangel liegt bei Sportlerinnen und Sportlern in bis zu 90 % vor. Risikogruppen bzw. -faktoren sind junge Sportler/innen, weibliches Geschlecht, Sportler/innen mit einer Einschränkung wie z.B. Querschnittgelähmte, Vegetarier/innen, Sportler/innen mit einer Resorptionsstörung wie Zöliakie, diejenigen, die in Hallen trainieren und dort auch Wettkämpfe durchführen (Eishockey, Basketball, Boxen, Rhythmische Sportgymnastik), ältere Sportler/innen, dunkle Hautpigmentation, der Gebrauch von Sonnenschutz, die Tageszeit des Trainings (früher Morgen, später Abend) sowie die geografische Lage. Sonnenexposition sowie eine ausgewogene Ernährung reichen oft nicht aus, um einen Vitamin-D-Mangel zu verhindern.
Western countries have greatly increased the number of people who adhere to a vegetarian or vegan diet for health reasons or animal right causes. This diet is presented as a balanced and healthy diet, however recommendations for a vegetarian and vegan diet remain controversial in the world of nutrition because of possible nutritional deficits. The aim of this study was to show recent evidence of protective and risk factors of these diets for chronic noncommunicable diseases associated with nutrition, as well as their use during the life cycle. We also considered the critical nutrients necessary to obtain a vegetarian/vegan diet without nutritional risks. In general, these diets were rich in dietary fibers, magnesium, phytochemicals, antioxidants, vitamins C and E, iron, folic acid and polyunsaturated fatty acids (n-6), but low in cholesterol, total fat and saturated fat, iron, zinc, vitamin A, B12 and D, and especially the omega 3 fatty acids EPA and DHA.
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Soccer is one of the most widely played and complex sports in the world, where success depends on technical, tactical and physical skills of the players.Studies to improve performance in soccer have often focused on technique and tactics. But nutrition is one of the most important factors influencing athletic performance of the players. The duration of matches is long and the training is intense for a soccer player.This leads to increased requirement for energy and nutrients as well as increased reactive oxygen radicals and hence increased muscle damage. Vitamins are micronutrients that a living organism requires in trace quantities for health. As these assume crucial functions in the body, the performance of the player is negatively affected particularly during long-term deficiency. Beta carotene, C and E vitamins are antioxidants that protect against oxygen radicals. In case of their deficiency, oxidant stress and muscle fatigue increases in the body. Vitamin D is involved in maintaining mineral balance, and it increases absorption of dietary calcium and phosphorus.In case of vitamin D deficiency, the injuries resulting from musculoskeletal system might increase. Vitamins B (B1, B2, Niacin, B6, B12, biotin, folic acid and pantothenic acid) perform duties such as energy production, absorption and transport of iron and blood cell production. Athletes who follow an energy-restricted and imbalanced diet might develop vitamin deficiency. In such a case, supplements can be used upon the recommendation of the doctor/dietician.It is reported that supplement use by athletes who have adequate and balanced nutrition does not increase performance.
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Vitamin B(12) is essential for DNA synthesis and for cellular energy production.This review aims to outline the metabolism of vitamin B(12), and to evaluate the causes and consequences of sub-clinical vitamin B(12) deficiency. Vitamin B(12) deficiency is common, mainly due to limited dietary intake of animal foods or malabsorption of the vitamin. Vegetarians are at risk of vitamin B(12) deficiency as are other groups with low intakes of animal foods or those with restrictive dietary patterns. Malabsorption of vitamin B(12) is most commonly seen in the elderly, secondary to gastric achlorhydria. The symptoms of sub-clinical deficiency are subtle and often not recognized. The long-term consequences of sub-clinical deficiency are not fully known but may include adverse effects on pregnancy outcomes, vascular, cognitive, bone and eye health.
Vitamin D deficiency is now recognized as a pandemic. The major cause of vitamin D deficiency is the lack of appreciation that sun exposure in moderation is the major source of vitamin D for most humans. Very few foods naturally contain vitamin D, and foods that are fortified with vitamin D are often inadequate to satisfy either a child's or an adult's vitamin D requirement. Vitamin D deficiency causes rickets in children and will precipitate and exacerbate osteopenia, osteoporosis, and fractures in adults. Vitamin D deficiency has been associated with increased risk of common cancers, autoimmune diseases, hypertension, and infectious diseases. A circulating level of 25-hydroxyvitamin D of >75 nmol/L, or 30 ng/mL, is required to maximize vitamin D's beneficial effects for health. In the absence of adequate sun exposure, at least 800–1000 IU vitamin D3/d may be needed to achieve this in children and adults. Vitamin D2 may be equally effective for maintaining circulating concentrations of 25-hydroxyvitamin D when given in physiologic concentrations.
The impact of chronic high volume athletic training on thyroid hormone economy has not been defined. We investigated the status of the hypothalamic-pituitary-thyroid axis (H-P-T) in women athletes with regular menstrual cycles (CA) and with amenorrhea (AA). Their data were compared with each other and with those derived from cyclic sedentary women (CS) matched for a variety of confounding factors including the intensity of exercise, caloric intake, and body weight. Alterations of the H-P-T axis were observed in women athletes compared to CS. While serum levels of T4, T3, free T4, free T3 and rT3 were substantially reduced (P less than 0.01) in AA, only serum T4 levels were significantly decreased in CA. Further, remarkable differences were found between CA and AA in that serum levels of free T4 (P less than 0.01), free T3 (P less than 0.01), and rT3 (P less than 0.05) were significantly lower in AA than in CA. Thyroid binding globulin and sex-hormone binding globulin concentrations were within their norma...
It is the position of the American Dietetic Association and Dietitians of Canada that appropriately planned vegetarian diets are healthful, nutritionally adequate, and provide health benefits in the prevention and treatment of certain diseases. Approximately 2.5% of adults in the United States and 4% of adults in Canada follow vegetarian diets. A vegetarian diet is defined as one that does not include meat, fish, or fowl. Interest in vegetarianism appears to be increasing, with many restaurants and college foodservices offering vegetarian meals routinely. Substantial growth in sales of foods attractive to vegetarians has occurred, and these foods appear in many supermarkets. This position paper reviews the current scientific data related to key nutrients for vegetarians, including protein, iron, zinc, calcium, vitamin D, riboflavin, vitamin B-12, vitamin A, n-3 fatty acids, and iodine. A vegetarian, including vegan, diet can meet current recommendations for all of these nutrients. In some cases, use of fortified foods or supplements can be helpful in meeting recommendations for individual nutrients. Well-planned vegan and other types of vegetarian diets are appropriate for all stages of the life cycle, including during pregnancy, lactation, infancy, childhood, and adolescence. Vegetarian diets offer a number of nutritional benefits, including lower levels of saturated fat, cholesterol, and animal protein as well as higher levels of carbohydrates, fiber, magnesium, potassium, folate, and antioxidants such as vitamins C and E and phytochemicals. Vegetarians have been reported to have lower body mass indices than nonvegetarians, as well as lower rates of death from ischemic heart disease; vegetarians also show lower blood cholesterol levels; lower blood pressure; and lower rates of hypertension, type 2 diabetes, and prostate and colon cancer. Although a number of federally funded and institutional feeding programs can accommodate vegetarians, few have foods suitable for vegans at this time. Because of the variability of dietary practices among vegetarians, individual assessment of dietary intakes of vegetarians is required. Dietetics professionals have a responsibility to support and encourage those who express an interest in consuming a vegetarian diet. They can play key roles in educating vegetarian clients about food sources of specific nutrients, food purchase and preparation, and any dietary modifications that may be necessary to meet individual needs. Menu planning for vegetarians can be simplified by use of a food guide that specifies food groups and serving sizes. J Am Diet Assoc. 2003;103:748-765.
The quality of vegetarian diets to meet nutritional needs and support peak performance among athletes continues to be questioned. Appropriately planned vegetarian diets can provide sufficient energy and an appropriate range of carbohydrate, fat and protein intakes to support performance and health. The acceptable macronutrient distribution ranges for carbohydrate, fat and protein of 45–65%, 20–35% and 10–35%, respectively, are appropriate for vegetarian and non-vegetarian athletes alike, especially those who perform endurance events. Vegetarian athletes can meet their protein needs from predominantly or exclusively plant-based sources when a variety of these foods are consumed daily and energy intake is adequate. Muscle creatine stores are lower in vegetarians than non-vegetarians. Creatine supplementation provides ergogenic responses in both vegetarian and non-vegetarian athletes, with limited data supporting greater ergogenic effects on lean body mass accretion and work performance for vegetarians. The potential adverse effect of a vegetarian diet on iron status is based on the bioavailability of iron from plant foods rather than the amount of total iron present in the diet. Vegetarian and non-vegetarian athletes alike must consume sufficient iron to prevent deficiency, which will adversely affect performance. Other nutrients of concern for vegetarian athletes include zinc, vitamin B12 (cyanocobalamin), vitamin D (cholecalciferol) and calcium. The main sources of these nutrients are animal products; however, they can be found in many food sources suitable for vegetarians, including fortified soy milk and whole grain cereals. Vegetarians have higher antioxidant status for vitamin C (ascorbic acid), vitamin E (tocopherol), and ß-carotene than omnivores, which might help reduce exercise-induced oxidative stress. Research is needed comparing antioxidant defences in vegetarian and non-vegetarian athletes.
The present study examined the effects of dietary manipulations on six trained runners. The percent energy contributions from carbohydrate, fat, and protein were 61/24/14,50/38/12, and 73/15/12 for the normal (N), fat (F), and carbohydrate (C) diets, respectively. Expiratory gases and blood responses to a maximum ([latin capital V with dot above]O2max) and a prolonged treadmill run were determined following 7 d on each diet. Free fatty acids (FFA), triglycerides, glycerol, glucose, and lactate were measured. Dietary assessment of subjects' N diet indicated that they were consuming approximately 700 kcal[middle dot]d-1 less than estimated daily expenditures. Running time to exhaustion was greatest after the F diet (91.2 +/- 9.5 min, P < 0.05) as compared with the C (75.8 +/- 7.6 min, P < 0.05) and N (69.3 +/- 7.2 min, P < 0.05) diets. [latin capital V with dot above]O2max was also higher on the F diet (66.4 +/- 2.7ml[middle dot]kg-1[middle dot]min-1, P < 0.05) as compared with the C (59.6 +/- 2.8 ml[middle dot]kg-1[middle dot]min-1, P < 0.05) and N (63.7 +/- 2.6 ml[middle dot]kg-1[middle dot]min-1, P < 0.05) diets. Plasma FFA levels were higher P < 0.05) and glycerol levels were lower (P < 0.05) during the F diet than during the C and N diets. Other biochemical measures did not differ significantly among diets. These data suggest that increased availability of FFA, consequent to the F diet, may provide for enhanced oxidative potential as evidenced by an increase in [latin capital V with dot above]O2max and running time. This implies that restriction of dietary fat may be detrimental to endurance performance. (C)1994The American College of Sports Medicine
When talented, motivated and highly trained athletes meet for competition the margin between victory and defeat is usually small. When everything else is equal, nutrition can make the difference between winning and losing. Although the primary concern of many athletes is to supplement the diet with protein, vitamins and minerals, and a range of more exotic compounds, key dietary issues are often neglected. Athletes must establish their nutritional goals, and must also be able to translate them into dietary strategies that will meet these goals. Athletes are often concerned with dietary manipulations in the period around competition, but the main role of nutrition may be to support consistent intensive training which will lead to improved performance. Meeting energy demand and maintaining body mass and body fat at appropriate levels are key goals. An adequate intake of carbohydrate is crucial for maintaining muscle glycogen stores during hard training, but the types of food and the timing of intake are also important. Protein ingestion may stimulate muscle protein synthesis in the post-exercise period, promoting the process of adaptation in the muscles. Restoration of fluid and electrolyte balance after exercise is essential. If energy intake is high and a varied diet is consumed, supplementation of the diet with vitamins and minerals is not warranted, unless a specific deficiency is identified. Specific strategies before competition may be necessary, but this requirement depends on the demands of the sport. Generally, it is important to ensure high pre-competition glycogen stores and to maintain fluid balance. There is limited evidence to support the use of dietary supplements, but some, including perhaps creatine and caffeine, may be beneficial.
These studies investigated the effects of 2 weeks of either a high-fat (HIGH-FAT: 70% fat, 7% CHO) or a high-carbohydrate (HIGH-CHO: 74% CHO, 12% fat) diet on exercise performance in trained cyclists (n = 5) during consecutive periods of cycle exercise including a Wingate test of muscle power, cycle exercise to exhaustion at 85% of peak power output [90% maximal oxygen uptake ( [(V)\dot]\dot V O2max), high-intensity exercise (HIE)] and 50% of peak power output [60% [(V)\dot]\dot V O2max, moderate intensity exercise (MIE)]. Exercise time to exhaustion during HIE was not significantly different between trials: nor were the rates of muscle glycogen utilization during HIE different between trials, although starting muscle glycogen content was lower [68.1 (SEM 3.9) vs 120.6 (SEM 3.8) mmol kg –1 wet mass, P < 0.01] after the HIGH-FAT diet. Despite a lower muscle glycogen content at the onset of MIE [32 (SEM 7) vs 73 (SEM 6) mmol kg –1 wet mass, HIGH-FAT vs HIGH-CHO, P < 0.01], exercise time to exhaustion during subsequent MIE was significantly longer after the HIGH-FAT diet [79.7 (SEM 7.6) vs 42.5 (SEM 6.8) min, HIGH-FAT vs HIGH-CHO, P<0.01]. Enhanced endurance during MIE after the HIGH-FAT diet was associated with a lower respiratory exchange ratio [0.87 (SEM 0.03) vs 0.92 (SEM 0.02), P<0.05], and a decreased rate of carbohydrate oxidation [1.41 (SEM 0.70) vs 2.23 (SEM 0.40) g CHO min–1, P<0.05]. These results would suggest that 2 weeks of adaptation to a high-fat diet would result in an enhanced resistance to fatigue and a significant sparing of endogenous carbohydrate during low to moderate intensity exercise in a relatively glycogen-depleted state and unimpaired performance during high intensity exercise.
This review describes current knowledge of the main causes of vitamin B12 and folate deficiency. The most common explanations for poor vitamin B12 status are a low dietary intake of the vitamin (i.e., a low intake of animal-source foods) and malabsorption. Although it has long been known that strict vegetarians (vegans) are at risk for vitamin B12 deficiency, evidence now indicates that low intakes of animal-source foods, such as occur in some lacto-ovo vegetarians and many less-industrialized countries, cause vitamin B12 depletion. Malabsorption of the vitamin is most commonly observed as food-bound cobalamin malabsorption due to gastric atrophy in the elderly, and probably as a result of Helicobacter pylori infection. There is growing evidence that gene polymorphisms in transcobalamins affect plasma vitamin B12 concentrations. The primary cause of folate deficiency is low intake of sources rich in the vitamin, such as legumes and green leafy vegetables, and the consumption of these foods may explain why folate status can be adequate in relatively poor populations. Other situations in which the risk of folate deficiency increases include lactation and alcoholism.