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Effects of Whey Protein Isolate on Body Composition, Lipids, Insulin and Glucose in Overweight and Obese Individuals


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The health benefits currently associated with increased dairy intake may be attributable to the whey component of dairy proteins. The present study evaluated the effects of whey protein supplementation on body composition, lipids, insulin and glucose in comparison to casein and glucose (control) supplementation in overweight/obese individuals for 12 weeks. The subjects were randomised to whey protein, casein or glucose supplementation for 12 weeks according to a parallel design. Fasting blood samples and dual-energy X-ray absorptiometry measurements were taken. Seventy men and women with a mean age of 48.4 (SEM 0.86) years and a mean BMI of 31.3 (SEM 0.8) kg/m2 completed the study. Subjects supplemented with whey protein had no significant change in body composition or serum glucose at 12 weeks compared with the control or casein group. Fasting TAG levels were significantly lowered in the whey group compared with the control group at 6 weeks (P = 0.025) and 12 weeks (P = 0.035). There was a significant decrease in total cholesterol and LDL cholesterol at week 12 in the whey group compared with the casein (P = 0.026 and 0.045, respectively) and control groups (P < 0.001 and 0.003, respectively). Fasting insulin levels and homeostasis model assessment of insulin resistance scores were also significantly decreased in the whey group compared with the control group (P = 0.049 and P = 0.034, respectively). The present study demonstrated that supplementation with whey proteins improves fasting lipids and insulin levels in overweight and obese individuals.
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Effects of whey protein isolate on body composition, lipids, insulin and glucose
in overweight and obese individ uals
Sebely Pal*, Vanessa Ellis and Satvinder Dhaliwal
School of Public Health, Curtin Health Innovation Research Institute, ATN Centre for Metabolic Fitness, Curtin University
of Technology, GPO Box U1987, Perth, WA 6845, Australia
(Received 18 November 2009 Revised 23 February 2010 Accepted 24 February 2010 First published online 9 April 2010)
The health benefits currently associated with increased dairy intake may be attributable to the whey component of dairy proteins. The present study
evaluated the effects of whey protein supplementation on body composition, lipids, insulin and glucose in comparison to casein and glucose
(control) supplementation in overweight/obese individuals for 12 weeks. The subjects were randomised to whey protein, casein or glucose
supplementation for 12 weeks according to a parallel design. Fasting blood samples and dual-energy X-ray absorptiometry measurements were
taken. Seventy men and women with a mean age of 48·4 (
SEM 0·86) years and a mean BMI of 31·3 (SEM 0·8) kg/m
completed the study. Subjects
supplemented with whey protein had no significant change in body composition or serum glucose at 12 weeks compared with the control or casein
group. Fasting TAG levels were significantly lowered in the whey group compared with the control group at 6 weeks (P¼ 0·025) and 12 weeks
(P¼ 0·035). There was a significant decrease in total cholesterol and LDL cholesterol at week 12 in the whey group compared with the
casein (P¼ 0·026 and 0·045, respectively) and control groups (P, 0·001 and 0·003, respectively). Fasting insulin levels and homeostasis model
assessment of insulin resistance scores were also significantly decreased in the whey group compared with the control group (P¼ 0·049 and
P¼ 0·034, respectively). The present study demonstrated that supplementation with whey proteins improves fasting lipids and insulin levels in
overweight and obese individuals.
Metabolic syndrome: Whey protein: Lipid: Obesity: Cholesterol: Insulin: Glucose
It is now estimated that over 20 % of adults in many Western
countries have the metabolic syndrome with numbers continu-
ing to increase
. The metabolic syndrome is classified as a
combination of risk factors such as obesity, atherogenic
dyslipidaemia, hypertension, glucose intolerance and insulin
resistance, which significantly increases the risk of developing
CVD and type 2 diabetes mellitus
. Many studies, including
the National Health and Nutrition Examination Survey
(19992004), and the Coronary Artery Risk Development In
Young Adults study have suggested that higher dairy con-
sumption reduces the risk of obesity
. It has been proposed
that specific components of dairy, such as Ca, other minerals,
casein or whey proteins
, may have beneficial effects on
metabolic risk factors.
Milk contains two major protein groups: caseins and whey
proteins. Caseins account for almost 80 % and whey accounts
for 20 % of total protein in bovine milk
. Casein and whey
are both heterogeneous groups of proteins containing all the
common amino acids, and are especially rich in the essential
ones. Whey proteins contain globular proteins that can be
isolated from whey, a by-product of cheese manufactured
from cows’ milk
A study by Bowen et al.
suggested that the whey
and casein protein components of dairy appear to be more
important for weight loss than Ca in overweight adults due
to their high concentrations of branched-chain amino acids.
However, there is little evidence of beneficial effects of
casein beyond it being a good quality source of protein and
having a possible hypotensive effect
(10 12)
. In a separate
article, we have shown that both whey and casein proteins
consumed over 12 weeks significantly reduced diastolic and
systolic blood pressure from baseline in overweight individ-
uals; however, whey protein consumption also significantly
reduced arterial stiffness
. Some studies demonstrate that
dairy whey proteins have a better effect on appetite control
than other protein sources such as egg and casein
(13 15)
In addition, convincing evidence indicates that dairy whey
proteins and their bioactive components such as lactalbumin,
angiotensin-converting enzyme inhibitor and branched-chain
amino acids may have an insulinotrophic effect
(16 20)
, hypo-
triacylglycerolaemic effect
, muscle-sparing effect
(22 24)
and cholesterol-lowering effect
. However, most of these
studies using whey proteins have been conducted in healthy
individuals or animals, with limited studies in overweight/
obese individuals. Given the effect of whey proteins on appe-
tite control, muscle sparing and lipid metabolism demons-
trated previously in healthy adults, our hypothesis was that
whey protein consumption would also have a beneficial
* Corresponding author: Dr Sebely Pal, fax þ 61 8 9266 2258, email
Abbreviation: TC, total cholesterol.
British Journal of Nutrition (2010), 104, 716–723 doi:10.1017/S0007114510000991
q The Authors 2010
British Journal of Nutrition
effect on metabolic risk factors in overweight and obese
individuals, a population highly susceptible to the metabolic
syndrome. Therefore, the aim of the present study was to
compare the effect of whey and casein consumption on
lipids, insulin, glucose and body composition in overweight/
obese individuals.
Methods and procedure
Overweight and obese individuals between the ages of 1865
years with a BMI between 25 and 40 kg/m
were recruited
through advertisements in the local newspapers and television
exposure. Of the 380 who responded, 97 were eligible to
participate and 89 commenced the study. The suitability
assessments were conducted via telephone and online followed
by screenings in person. Exclusion criteria included taking
regular medications (such as lipid-lowering agents and hyper-
tensives), kidney and liver diseases, cancer within the last
5 years, smoking, pregnancy or lactation, over two standard
alcoholic drinks per day, type 1 or type 2 diabetes, liver or
kidney diseases, and cardiovascular events in the last 6 months.
Study design and methodology
This was a randomised, parallel design study conducted over a
12-week period where subjects were randomised to one of the
three groups, whey protein group, casein protein group or the
control group (glucose), using a simple randomisation table.
The subjects had no knowledge of the supplement type as
they were all closely matched for taste and appearance.
After randomisation, subjects were asked to consume one of
the following supplement sachets mixed with 250 ml water
twice a day for 12 weeks: whey protein isolate, sodium case-
inate (both containing 27 g protein) or glucose control (27 g
glucose; MG Nutritionals, Brunswick, Vic, Australia). The
protein supplement compositions are given in Table 1.
The kJ content of all supplement sachets was equal to
525 kJ per sachet. Subjects were instructed to take one
sachet within 30 min before breakfast and one within 30 min
before their evening meal. To monitor compliance, subjects
were asked to record their consumption of the supplements
by completing tailored calendar tick boxes and bringing
their empty sachets to their 6- and 12-week visits.
All subjects were asked to maintain their usual dietary intake
and physical activity levels during the study. Weighed food
records were completed by subjects before commencement of
the study to gain baseline intake data, and every 2 weeks of
the study (weeks 2, 4, 6, 8 and 12) on two weekdays and one
weekend day to assess compliance. To maintain isoenergetic
diets, subjects were given individual instruction by the study
dietitian to reduce their usual dietary intake by about 1050 kJ
per day (equal to two sachets of supplements) which they
recorded on the weighed food diary. This was monitored, and
subjects were contacted if they were under- or over-compensat-
ing. All subjects were instructed to maintain dairy intake at
one serve per day for 4 weeks leading up to and during the
study period, to limit alcohol to two or less standard drinks for
men and one or less standard drinks for women, and to not
take any multivitamins or herbal supplements during the study
period. All other aspects of their dietary intake were to remain
unchanged. Energy and nutrient compositions were calculated
using FoodWorks 2007 (Xyris Software, Highgate Hill, QLD,
Australia) based on the Australian food composition tables.
Subjects were assessed at baseline, 6 and 12 weeks. Body
weight (UM-018 Digital Scales; Tanita Corporation, Tokyo,
Japan) was recorded in light clothing without shoes. Height
was measured to the nearest 0·1 cm using a stadiometer
(26SM 200 cm SECA, Hamburg, Germany) without shoes.
Waist circumference was measured three times in the standing
position at the narrowest area between the lateral lower rib and
the iliac crest, and the measures were averaged. Total body
fat, lean mass, android fat (fat around the abdomen and
trunk) and gynoid fat (fat around the hips, thighs and buttocks)
as well as percentage fat were assessed by whole body dual-
energy X-ray absorptiometry (Lunar Prodigy; Lunar, Madison
WI, USA) at baseline and at 12 weeks.
Measurement of plasma lipids, insulin and homeostasis model
An 8·5 ml fasting blood sample was taken via venepuncture
from subjects in the fasting state, at baseline, 6 and 12
weeks, to measure circulating insulin, glucose and lipids
(TAG, NEFA, HDL, LDL and apo B). Serum was isolated
by centrifugation at 3000 rpm at 4 8C for 10 min, and was
stored at 2 80 8C until the end of the study. Serum TAG
and total cholesterol (TC) were measured using enzymatic
colorimetric kits (TRACE Scientific Limited, Noble Park,
Vic, Australia). Serum HDL cholesterol was determined
after precipitation of apo B-containing lipoproteins with
phosphotungstic acid and MgCl
; HDL cholesterol present in
the supernatant was determined by enzymatic colorimetry
(TRACE Scientific Limited). Serum LDL cholesterol was
determined using a modified version of the Friedewald
. NEFA were determined using WAKO NEFA C
kit. Apo B was analysed using an ELISA kit obtained from
Mabtech AB (Nacka Strand, Sweden). Plasma glucose levels
were measured using the Randox glucose GOD PAP kit
(Antrim, UK), and plasma insulin was measured using an
ELISA kit (Dako Diagnostic, Kyoto, Japan). The homoeo-
stasis model of assessment index 2 was used to assess insulin
resistance (homeostasis model assessment of insulin resistance)
from fasting glucose and insulin concentrations
Table 1. Protein supplement typical composition in two sachets per
day (60 g)
Component (g) Whey protein isolate Sodium caseinate
Protein (total N £ 6·38) 54·00 54·30
Fat 0·30 0·72
Carbohydrate lactose 0·30 0·12
Moisture 1·32 0·78
Ash 2·20 2·20
Sweetener (Sucralose) 0·04 0·04
Flavouring 1·80 1·80
Ca 0·09 0·06
P 0·18 0·46
Effect of whey on lipids, insulin and glucose 717
British Journal of Nutrition
Statistical analysis
All subjects who completed the study were included in
the data analysis. Statistical analysis was conducted using
SPSS 17 for Windows (SPSS, Inc., Chicago, IL, USA).
Data are expressed as mean values with their standard
errors, and were assessed for normality. Comparison of
baseline characteristics between each group was undertaken
by one-way ANOVA. Differences within groups were deter-
mined using a two-sided paired t test. Using one-way analysis
of covariance with the baseline data as the covariate,
differences between groups were determined at week 6 to
assess immediate effects of intervention and at week 12
to assess longer term effects of supplementation. Statistical
differences were analysed further by post hoc analysis
using the least square differences method. Percentage change
between groups was calculated based on raw values
of group means. Statistical significance was considered
at P, 0·05.
The present study was conducted according to the guide-
lines laid down in the Declaration of Helsinki, and all
procedures involving human subjects/patients were approved
by the Curtin University Human Research Ethics Committee
(Approval Number HR 149/2007). Written informed consent
was obtained from all subjects.
This clinical trial has been registered with the Australian
New Zealand Clinical Trials Registry. The registration
number is ACTRN12609000175279, and trial Web address
Eighty-nine individuals were randomly assigned to either a
control, casein or whey protein supplement for 12 weeks.
Nineteen subjects withdrew from the study within 4 weeks
after randomisation due to non-compliance for various reasons
as shown in Fig. 1. Seventy subjects completed the 12-week
Response to advertisement
Subjects screened
Eligible for participation
Week 0
Glucose supplement (control)
Week 0
Casein supplement
Week 0
Whey supplement
Week 12
Week 12
Week 12
Withdrawal before randomisation
9 due to work commitments
or personal reasons
after commencement
Personal reasons
unrelated to diet (
Struggled with
supplement or
protocol (
after commencement
Lost to follow up (
Personal reasons
unrelated to diet (
commitments (
Struggled with
supplement or
protocol (
after commencement
Lost to follow up (
Personal reasons
unrelated to diet (
Fig. 1. Details of subject recruitment and withdrawal.
S. Pal et al.718
British Journal of Nutrition
study (control group: n 25, twenty-two women and three men;
casein group: n 20, seventeen women and three men; whey
protein group: n 25, twenty-one women and four men).
Subject characteristics in the three treatment arms at baseline
were not significantly different.
The self-reported composition of the study diets consumed
during the 3-month study period is presented in Table 2. There
were no significant differences in total energy, total fat,
saturated fat, monounsaturated fat, polyunsaturated fat, Ca
and fibre between control, casein and whey protein groups
(Table 2). The contribution of carbohydrate to total energy
intake was lower in the casein group (P, 0·001) and
whey group (P, 0·001) compared with the control group.
The contribution of protein to total energy intake was higher
in subjects in the casein group (P, 0·001) and whey group
(P, 0·001) compared with the control group.
Changes in body composition (Table 3) were assessed
by body weight, waist and hip circumference measurements
and body composition scans by dual-energy X-ray absorp-
tiometry. There was no overall effect of supplements on
body weight, BMI, waist, waist:hip ratio, total body fat,
android fat, gynoid fat and lean body mass between groups
at 6 or 12 weeks, with no difference within groups.
Table 4 shows the mean fasting levels of all blood measure-
ments from each intervention group at the three visits, and
summarises the significant within-group and between-group
differences. Fasting TAG concentrations decreased by 13 %
at week 6 (P¼ 0·008) and week 12 (P¼ 0·003) compared
with baseline in the whey protein group. Fasting TAG levels
were lowered by 22 % in the whey protein group compared
with the control group at 6 weeks (P¼ 0·025) and by 22 %
at 12 weeks (P¼ 0·035).
TC levels in plasma (Table 4) were decreased by 7 % at
week 12 in the whey group compared with baseline (P, 0·001).
There was a lowering in TC at week 6 in the whey protein
group compared with the control group (P¼ 0·044). There
was a decrease in TC by 9 % at week 12 in the whey protein
group compared with the casein group (P¼ 0·026) and by 11 %
compared with the control group (P, 0·001). Plasma LDL
was reduced by 7 % at week 12 in the whey group compared
with baseline (P¼ 0·007). There was an attenuation in plasma
LDL levels at week 12 in the whey protein group compared
with the casein (P¼ 0·045) and control groups (P¼ 0·003).
There was an 11 % reduction in plasma insulin levels
(Fig. 2(a)) in the whey protein group at 12 weeks (41·71
SEM 3·80) pmol/l) compared with baseline (46·96 (SEM 3·76)
pmol/l; P¼ 0·012). There was also a lowering in fasting insulin
levels in the whey protein group (41·71 (
SEM 3·80) pmol/l) com-
pared with the control group (54·77 (
SEM 5·185); P¼ 0·049)
at 12 weeks. There was a decrease in homeostasis model
Table 2. Nutritional data recorded in 3 d food diaries
(Mean values with their standard errors, n 70)
Baseline Week 6 Week 12
Total EI (kJ/d)
Control 7535·9 373·9 7385·0 1197·8 7244·9 337·9
Casein 7072·6 212·4 6564·7 263·3 6721·9 235·8
Whey 7770·4 415·5 7353·2 447·0 7507·0 385·1
Carbohydrate (% of EI)
Control 45·7 1·3 50·5*
0·9 51·5†
Casein 41·6 1·5 37·2*
1·2 35·3†
Whey 43·7 1·1 36·5*
0·9 34·9†
Protein intake (% of EI)
Control 18·3 0·7 16·4*
0·6 15·8†
Casein 20·5 0·8 33·4*
1·1 32·9†
Whey 19·9 0·8 31·3*
0·9 31·9†
Fat intake (% of EI)
Control 33·0 1·0 31·0 0·9 30·1 0·9
Casein 34·9 1·1 30·4 1·1 29·3 1·0
Whey 33·7 1·1 31·4 1·0 29·7 0·9
SFA (% of total fat)
Control 42·0 2·1 38·6 1·2 41·4 1·0
Casein 38·2 1·8 41·0 1·5 40·0 1·0
Whey 42·4 1·3 41·1 1·3 41·3 1·1
MUFA (% of total fat)
Control 41·1 0·7 41·2 0·8 40·0 0·5
Casein 42·0 1·1 40·3 1·0 41·6 0·9
Whey 40·0 0·8 41·3 1·0 41·3 0·8
PUFA (% of total fat)
Control 16·9 0·8 18·5 0·9 18·5 1·1
Casein 19·1 1·6 18·4 1·3 18·3 0·8
Whey 16·4 0·8 17·6 0·7 16·8 0·8
EI, energy intake.
Mean values with unlike superscript letters were significantly different between groups at 6 and
12 weeks (P, 0·05).
* Mean values were significantly different within group (time 0 v. time 6 weeks, P, 0·05).
Mean values were significantly different within group (time 0 v. time 12 weeks, P, 0·05).
Effect of whey on lipids, insulin and glucose 719
British Journal of Nutrition
assessment of insulin resistance scores at 12 weeks in the
whey protein group (0·82 (
SEM 0·08)) compared with baseline
(0·91 (
SEM 0·07); P¼ 0·046) (Fig. 2(b)). There was a decrease
in homeostasis model assessment of insulin resistance scores
in the whey treatment group (0·82 (
SEM 0·08)) compared with
the control group at 12 weeks (1·01 (
SEM 0·10); P¼ 0·034).
Previous studies have demonstrated the effect of whey pro-
teins on appetite control, muscle sparing and lipid metabolism
in healthy adults, but limited data are available for the effect
of whey protein consumption on metabolic risk factors in
overweight and obese individuals. In the present study, supple-
mentation with whey protein for 12 weeks decreased TC and
LDL cholesterol levels compared with the supplementation
with control and casein. Whey protein also decreased
plasma TAG, insulin and homeostasis model assessment of
insulin resistance scores compared with the control. There
was no effect of casein supplementation on any metabolic
risk parameter compared with control supplementation.
Overall, the present study demonstrated that whey protein
supplementation can significantly improve metabolic risk
factors associated with chronic diseases in overweight and
obese individuals.
Supplementation with whey protein significantly lowered
plasma TC and LDL cholesterol after 12 weeks compared
with the supplementation with casein and control. Interestingly,
a decrease in LDL cholesterol levels with whey protein was
observed without changes in apo B levels, indicating a change
in LDL particle size rather than in particle number. Lipid-
lowering agents such as statins, fibric acid and nicotinic acid
have been shown to lower LDL levels from 5 to 55 %, resulting
in a CHD risk reduction of 2545 % with 5 years of treatment
in randomised, placebo-controlled clinical trials
. A meta-
analysis by Baigent et al.
found that over 5 years, every
mmol/l reduction in LDL cholesterol by statin therapy resulted
in a 12 % reduction in all-cause mortality and a 19 % reduction
in coronary mortality. Similarly, a 20 24 % reduction in TAG
levels has been shown to reduce the progression of CHD
Therefore, a reduction in serum TC by 11 %, in LDL cholesterol
by 9·6 % and in TAG by 22 % after 12 weeks of whey
supplementation in the present study may also be clinically
significant. The effect of whey proteins on lipid levels in
the present study is consistent with earlier animal experi-
ments mostly undertaken in rats
and healthy men
Table 3. Body composition measurements*
(Mean values with their standard errors)
Baseline Week 6 Week 12 Change
SEM Mean SEM Mean SEM Mean SEM
Weight (kg)
Control 84·1 1·8 83·9 1·8 83·8 1·9 2 0·28 0·38
Casein 82·9 3·1 82·1 3·1 82·0 3·1 2 0·90 0·42
Whey 90·5 3·4 90·3 3·8 89·7 3·2 2 0·78 0·45
BMI (kg/m
Control 30·6 0·9 30·6 1·5 30·5 1·5 2 0·04 0·14
Casein 31·3 0·9 31·0 0·9 30·9 0·9 2 0·31 0·15
Whey 32·0 0·8 32·0 0·7 31·8 0·8 2 0·23 0·16
Waist (cm)
Control 93·7 1·5 95·1 1·7 93·7 1·6 2 0·02 0·46
Casein 92·1 2·1 93·7 2·6 91·2 2·1 2 0·93 0·52
Whey 95·9 1·7 97·6 2·0 95·5 1·9 2 0·03 0·42
Waist:hip ratio
Control 0·83 0·01 0·84 0·01 0·84 0·01 0·01 0·02
Casein 0·81 0·02 0·83 0·01 0·82 0·02 0·00 0·02
Whey 0·82 0·01 0·83 0·01 0·83 0·01 0·01 0·01
Total body fat (kg)
Control 35·4 1·1 35·1 1·1 2 0·36 0·2
Casein 35·1 2·1 34·1 2·1 2 0·90 0·35
Whey 37·6 1·9 37·6 1·8 2 0·04 0·31
Total lean (kg)
Control 44·5 1·7 44·7 1·8 0·14 0·26
Casein 43·9 1·7 43·7 1·6 2 0·26 0·21
Whey 48·3 2·3 48·6 2·4 2 0·30 0·45
Android fat (%)
Control 50·2 1·2 50·0 1·3 2 0·21 0·44
Casein 49·0 1·2 48·4 1·5 2 0·66 0·52
Whey 49·7 1·1 49·9 1·1 0·30 0·37
Gynoid fat (%)
Control 48·3 1·4 47·9 1·3 2 0·34 0·52
Casein 47·8 2·3 46·9 1·6 2 0·87 0·37
Whey 48·1 1·5 47·3 1·6 2 0·30 0·36
* There were no significant differences at baseline between diets. There were no significant differences
between groups.
S. Pal et al.720
British Journal of Nutrition
In the present study, whey protein consumption did not
change body composition. Therefore, the beneficial changes
in TC, LDL cholesterol and TAG from whey supplementation
seem to have occurred independently of changes in body
weight or fat mass. The mechanisms behind the favourable
effects on lipids may be related to the effect of whey
proteins on de novo cholesterol biogenesis in the liver
the inhibition of cholesterol absorption in the intestine
mediated by b-lactoglobulin
, the inhibition of the
expression of genes involved in intestinal fatty acid and
cholesterol absorption and synthesis
and/or the increase
in faecal steroid excretion
The differential effects on lipid metabolism between whey
and casein may be related to their specific influence on
digestion and absorption and their amino acid content
Whey proteins have been shown to have a fast rate of diges-
tion and absorption producing a rapid peak in plasma amino
acids compared with casein. Whey also has a higher
branched-chain amino acids content compared with casein.
Unlike whey, casein is a coagulating protein and exhibits a
slower rate of gastric emptying and also mediates lower post-
prandial excursions of plasma amino acid concentrations
Casein has been shown numerous times to produce higher
levels of serum cholesterol and LDL when compared with
soya proteins, and this is thought to be due to its unusually
low content of cysteine
In the present study, whey protein supplementation
decreased plasma insulin levels by 11 % at 12 weeks and
improved insulin sensitivity. Insulin-resistant rats were fed a
high-protein diet for 6 weeks, either whey or red meat protein;
the whey protein concentrate reduced plasma insulin by 40 %
and increased insulin sensitivity
. These changes were
explained by the reduction in visceral fat in the rats fed the
whey protein diet, because visceral obesity is strongly corre-
lated with insulin resistance. However, in the present study,
there were no changes in body fat to explain changes in insulin
sensitivity. Interestingly, postprandial studies have demon-
strated that whey proteins have a stimulating effect on insulin
secretion in healthy subjects
and in diabetics
. In healthy
subjects, ingestion of a mixture of leucine, isoleucine, valine,
lysine and threonine resulted in glycaemic and insulinaemic
responses similar to those resulting after whey ingestion
suggesting that branched-chain amino acids are the major
determinants of insulinaemia as well as lowered glycaemia.
The key mechanism is not known, although elevated concen-
trations of specific insulinogenic amino acids as well as bio-
active peptides, either originally present in whey or formed
during digestion, are possible. The short-term insulinotrophic
Table 4. Concentration of plasma lipids, lipoproteins, glucose and NEFA*
(Mean values with their standard errors)
Baseline Week 6 Week 12 Change
SEM Mean SEM Mean SEM Mean SEM
TAG (mmol/l)
Control 1·21 0·08 1·21
0·08 1·20
0·09 0·00 0·06
Casein 1·10 0·11 1·00
0·10 1·00
0·10 2 0·10 20·10
Whey 1·07 0·08 0·93†
0·05 0·93‡
0·07 2 0·15 0·04
TC (mmol/l)
Control 5·43 0·17 5·53
0·18 5·58
0·18 0·15 0·13
Casein 5·34 0·23 5·38
0·23 5·30
0·23 2 0·04 0·12
Whey 5·36 0·17 5·18
0·18 4·97‡
0·16 2 0·38 0·08
HDL (mmol/l)
Control 1·61 0·07 1·61 0·07 1·61 0·06 0·00 0·04
Casein 1·65 0·08 1·54 0·08 1·62 0·08 2 0·03 0·03
Whey 1·56 0·07 1·51 0·06 1·53 0·06 2 0·03 0·43
LDL (mmol/l)
Control 3·25 0·15 3·36 0·16 3·41
0·16 0·16 0·10
Casein 3·32 0·24 3·27 0·25 3·36
0·22 0·03 0·09
Whey 3·31 0·17 3·20 0·15 3·08‡
0·12 2 0·22 0·08
NEFA (mmol/l)
Control 0·51 0·02 0·55 0·03 0·56 0·03 0·05 0·04
Casein 0·59 0·04 0·63 0·03 0·60 0·03 0·01 0·03
Whey 0·60 0·04 0·52 0·03 0·54 0·02 2 0·05 0·03
Glucose (mmol/l)
Control 5·46 0·11 5·57 0·09 5·65 0·09 0·19 0·11
Casein 5·49 0·13 5·50 0·15 5·56 0·12 0·07 0·07
Whey 5·56 0·12 5·54 0·11 5·70 0·13 0·14 0·09
Apo B (ng/ml)
Control 220·41 23·20 250·70 29·21 30·30 13·8
Casein 253·20 18·90 285·60 22·42 32·30 14·8
Whey 207·60 15·80 223·80 18·57 16·10 7·8
TC, total cholesterol.
Mean values with unlike superscript letters were significantly different between groups at 12 weeks (P, 0·05).
* There were no significant differences at baseline between diets.
Mean values were significantly different within group (time 0 v. time 6 weeks, P, 0·05).
Mean values were significantly different within group (time 0 v. time 12 weeks, P, 0·05).
Effect of whey on lipids, insulin and glucose 721
British Journal of Nutrition
effect of whey proteins may be a valuable tool in the
management of type 2 diabetes or the metabolic syndrome.
Today, sulphonylurea agents are commonly used to stimulate
insulin secretion and to attenuate postprandial blood glucose
for the purpose of facilitating normoglycaemia in diabetic
subjects. However, further studies are required to resolve
why whey proteins can have an insulinotrophic effect in
the short term, but can decrease plasma insulin levels and
improve insulin sensitivity in the long term.
A study limitation involved the self-reporting of energy
intake by the study participants. Mean intakes of about
7000 kJ as recorded in the present study would not represent
the true energy intake of overweight or obese individuals on
an isoenergetic diet. However, it is well established that under-
reporting of energy intake in this population is preva-
(39 41)
, and is an accepted study limitation. Despite the
underreporting, analysis of the weighed food records enabled
monitoring of any changes in energy intake and macronutrient
as well as dairy product intake.
In the present study, most subjects had a waist circum-
ference greater than that specified by the ATP III Clinical
Identification of Metabolic Syndrome
. In addition, most
subjects already had at least one or two other metabolic
syndrome risk factors or were borderline candidates. Many
in this group will eventually progress to establish the
metabolic syndrome if their obesity continues. As the
consumption of whey proteins in this group has beneficial
effects on serum lipids and insulin, regular whey protein
supplementation may, at the very least, slow down the
progression to the metabolic syndrome, CVD or diabetes,
and/or may delay the need for medications. Collectively,
whey protein has the potential to be used as an added
component in dietary plans and in functional foods aimed at
the management of chronic diseases in overweight and
obese individuals.
The present study is a Dairy Australia initiative funded by
the Dairy Service Levy and the Australian Government
(grant no. CUT11913). We thank Murray Goulburn Nutritionals
(Vic, Australia) for providing the supplements. The authors
declare that they have no competing interests. The authors’
responsibilities were as follows: V. E. coordinated the trial,
data collection and input for the manuscript. S. P. conceived
and designed the study, wrote the manuscript, and supervised
the study and the statistical analysis; S. D. provided support
with the statistical analysis and input for the manuscript.
All authors have read and approved the final manuscript.
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6 weeks 12 weeks
6 weeks 12 weeks
Insulin change
HOMA-IR change
Fig. 2. Changes in insulin (a) and homeostasis model assessment of insulin
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, Control;
, casein; , whey.
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Effect of whey on lipids, insulin and glucose 723
British Journal of Nutrition
... The impact of short term, energy-balanced HPDs on glucose and insulin homeostasis in overweight and obese subjects has been shown to augment insulin sensitivity, but not overall glucose homeostasis. Pal et al. (2010) found a significant decrease in fasting insulin levels and insulin resistance with a HPD supplemented with whey protein (Pal et al., 2010). Seventy non-diabetic, overweight, and obese individuals (BMI of 25 to 40 kg/m 2 ) were randomized to either a whey protein-supplemented HPD or a glucose-supplemented control diet, which was consumed twice daily over a period of 12 weeks. ...
... The impact of short term, energy-balanced HPDs on glucose and insulin homeostasis in overweight and obese subjects has been shown to augment insulin sensitivity, but not overall glucose homeostasis. Pal et al. (2010) found a significant decrease in fasting insulin levels and insulin resistance with a HPD supplemented with whey protein (Pal et al., 2010). Seventy non-diabetic, overweight, and obese individuals (BMI of 25 to 40 kg/m 2 ) were randomized to either a whey protein-supplemented HPD or a glucose-supplemented control diet, which was consumed twice daily over a period of 12 weeks. ...
... Short-term (1 week to 6 months), energy balanced, high protein diet No significant change in serum insulin levels in healthy individuals (Rietman, Schwarz, Blokker, et al., 2014;Warland et al., 2008) Reduced insulin resistance in overweight and obese subjects (Pal et al., 2010) Short-term (1 week to 6 months, energy restricted, high protein diet) ...
Full-text available
Glucose homeostasis is the maintenance and regulation of blood glucose concentration within a tight physiological range, essential for the functioning of most tissues and organs. This is primarily achieved by pancreatic secretion of insulin and glucagon. Deficient pancreatic endocrine function, coupled with or without peripheral insulin resistance leads to prolonged hyperglycemia with chronic impairment of glucose homeostasis, most commonly seen in diabetes mellitus. High protein diets (HPDs) are thought to modulate glucose homeostasis through various metabolic pathways. Insulin secretion can be directly modulated by the amino acid products of protein digestion, which activate nutrient receptors and nutrient transporters expressed by the endocrine pancreas. Insulin secretion can also be modulated indirectly, through incretin release from enteroendocrine cells, and via vagal neuronal pathways. Additionally, glucose homeostasis can be promoted by the satiating effects of anorectic hormones released following HPD consumption. This review summarizes the insulinotropic mechanisms by which amino acids and HPDs may influence glucose homeostasis, with a particular focus on their applicability in the management of Type 2 diabetes mellitus.
... When the data were considered as a whole, the authors reported that protein intakes above the RDA benefitted changes in lean body mass relative to consuming the RDA for protein. However, when the authors separated out the 5 studies (7 treatment groups) [66][67][68][69][70] having neither an anabolic nor catabolic stressor, they reported that the protein RDA was adequate for supporting lean mass in these individuals. There are several interesting points to make regarding the interpretation of these data. ...
... For example, one of these studies [66] showed significant benefits of higher protein intake (2 X RDA vs. RDA) on lean body mass and leg power in elderly men. In each of the other 4 studies showing the protein RDA to be adequate for support of lean body mass, other ancillary benefits of protein intakes above the RDA were reported, including lower body fat mass/better weight maintenance following weight loss [67][68][69], reductions in blood lipids (triacylglycerols, total-and LDL-cholesterol) when the additional protein source was whey [70], and improved appetite control, again when whey protein was the additional protein source [69]. Finally, in 3 of these studies, the mean age was under 50 years, so these ancillary benefits of higher protein intake may not be restricted to older adults. ...
Full-text available
Since the U.S. Institute of Medicine’s recommendations on protein and amino acid intake in 2005, new information supports the need to re-evaluate these recommendations. New lines of evidence include: (1) re-analysis/re-interpretation of nitrogen balance data; (2) results from indicator amino acid oxidation studies; (3) studies of positive functional outcomes associated with protein intakes higher than recommended; (4) dietary guidance and protein recommendations from some professional nutrition societies; and (5) recognition that the synthesis of certain dispensable amino acids may be insufficient to meet physiological requirements more often than previously understood. The empirical estimates, theoretical calculations and clinical functional outcomes converge on a similar theme, that recommendations for intake of protein and some amino acids may be too low in several populations, including for older adults (≥65 years), pregnant and lactating women, and healthy children older than 3 years. Additional influential factors that should be considered are protein quality that meets operational sufficiency (adequate intake to support healthy functional outcomes), interactions between protein and energy intake, and functional roles of amino acids which could impact the pool of available amino acids for use in protein synthesis. Going forward, the definition of “adequacy” as it pertains to protein and amino acid intake recommendations must take into consideration these critical factors.
... However, it remains to fully elucidate the compounds underlying these effects, milk-derived proteins and bioactive peptides may be responsible for the observed activities (10) . Amongst these proteins, milk-derived whey protein (WP), as a biologically active protein which may counteract cardiomatabolic disorders such as hypertension, diabetes mellitus, dyslipidemia, obesity, and oxidative stress, has attracted a great deal of attention (11)(12)(13) . As evidence shows, WP exerts the angiotensin-convertingenzyme (ACE)-inhibitory behaviors and thereby modulates blood pressure and vascular reactivity (14,15) . ...
Whey protein (WP) has been heavily appreciated as a rich source of bioactive peptides, with potential benefits for cardiovascular health. This study constitutes a systematic review and meta-analysis summarizing the effects of WP consumption on vascular reactivity, arterial stiffness, and circulatory biomarkers of vascular function. We searched electronic databases, including PubMed, SCOPUS, and Web of science for relevant articles from inception to July 2020. Original clinical trials published in English-language journals that investigated the effects of WP on vascular function were eligible. A total of 720 records were identified in the initial search; from these, 16 were included in our systematic review and 13 in meta-analysis. The pooled analysis of 6 studies showed a significant increase in flow-mediated dilation (FMD) after WP consumption (WMD: 1.09%, 95% CI: 0.17, 2.01, P=0.01). Meta-analysis of available data didn't show any significant reduction in arterial stiffness measures including augmentation index (effect sizes: 7, WMD:-0.29%, 95% CI:-1.58, 0.98, P=0.64) and pulse wave velocity (effect sizes: 4, WMD:-0.72 m/s, 95% CI:-1.47, 0.03, P=0.06). Moreover, the pooled analysis of 6 effect sizes showed no significant effects on plasma levels of nitric oxide following WP supplementation (WMD: 0.42 μmol/L, 95% CI:-0.52 to 1.36, P=0.38). The overall results provided evidence supporting a protective effect of WP on endothelial function measured by FMD, but not for arterial stiffness measures and circulatory biomarker of vascular function. Further research is required to substantiate the benefits of WP on vascular function.
... Although most of the recent evidence in systematic reviews and meta-analysis show beneficial effects of whey protein supplementation on postprandial and short-term glycemic response, as well as blood lipid profile, other long-term clinical data are needed for better understanding the benefits of whey intake on postprandial and baseline glycemia after several weeks/months [42,[124][125][126]. Increasingly more studies have investigated the effects of whey and its bioactive peptides and biochemical and biological pathways, especially on longer periods on glucose and lipid metabolism, hypertension, oxidative stress and inflammation, and vascular health [127,128]. Some studies suggest that regular whey intake may positively affect long-term glycemic control [129,130]. ...
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Type 2 diabetes mellitus (T2DM) is a major cause of morbidity and mortality, and it is a major risk factor for the early onset of cardiovascular diseases (CVDs). More than genetics, food, physical activity, walkability, and air pollution are lifestyle factors, which have the greatest impact on T2DM. Certain diets have been shown to be associated with lower T2DM and cardiovascular risk. Diminishing added sugar and processed fats and increasing antioxidant-rich vegetable and fruit intake has often been highlighted, as in the Mediterranean diet. However, less is known about the interest of proteins in low-fat dairy and whey in particular, which have great potential to improve T2DM and could be used safely as a part of a multi-target strategy. This review discusses all the biochemical and clinical aspects of the benefits of high-quality whey, which is now considered a functional food, for prevention and improvement of T2DM and CVDs by insulin- and non-insulin-dependent mechanisms.
... In longer-term studies, we also find this difference between the effect of the global protein intake and the effect of BCAAs. The type of proteins administered is involved; indeed, Pal et al. [90] compared the effects of a 12-week supplementation with 27 g of casein, whey (rich in BCAAs), or glucose (control) in overweight patients and observed an improvement of the insulin sensitivity with the whey supplementation. More specifically, essential amino acids do not seem to affect insulin sensitivity by themselves [91]. ...
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For more than a decade, there has been a wide debate about the branched-chain amino acids (BCAA) leucine, valine, and isoleucine, with, on the one hand, the supporters of their anabolic effects and, on the other hand, those who suspect them of promoting insulin resistance. Indeed, the role of leucine in the postprandial activation of protein synthesis has been clearly established, even though supplementation studies aimed at taking advantage of this property are rather disappointing. Furthermore, there is ample evidence of an association between the elevation of their plasma concentrations and insulin resistance or the risk of developing type 2 diabetes, although there are many confounding factors, starting with the level of animal protein consumption. After a summary of their metabolism and anabolic properties, we analyze in this review the factors likely to increase the plasma concentrations of BCAAs, including insulin-resistance. After an analysis of supplementation or restriction studies in search of a direct role of BCAAs in insulin resistance, we discuss an indirect role through some of their metabolites: branched-chain keto acids, C3 and C5 acylcarnitines, and hydroxyisobutyrate. Overall, given the importance of insulin in the metabolism of these amino acids, it is very likely that small alterations in insulin sensitivity are responsible for a reduction in their catabolism long before the onset of impaired glucose tolerance.
Functional foods are defined as foods and ingredients that exhibit health benefits beyond their nutritional value. Research on functional foods is increasing rapidly as they may help prevent and manage some non-communicable diseases. Whey proteins are recognized as a high-quality nutrient source and known to contain some bioactive components. They are rich in essential amino acids such as cysteine, branched-chain amino acids such as leucine, valine, and isoleucine, and bioactive peptides. Whey proteins look promising as a potential functional food, given its antioxidant, anti-inflammatory, blood pressure lowering, anti-obesity, and appetite suppressing effects that is discussed in the literature. Whey proteins also show functional properties that play an essential role in food processing as an emulsifier, fat-replacer, gelling and encapsulating agent and are known to improve sensory and textural characteristics of food. This review focuses on the functional food aspects of whey proteins, associated health effects, and current food applications.
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Background:Creatine is a nutritional supplement used to increase strength and muscle mass and is helpful for delaying fatigue in high-intensity and short-term exercises. Wrestling is a heavy and severe activity that it needs to certain physical and physiological such as anaerobic and it is a power-speed exercise that doing strength training is necessary to improve the performance of the athlete. The aim of the present investigation was to explore the effect of creatine supplementation during strength training on the development of physical performance and hypertrophy in wrestlers. Materials and Methods: Thirty men freestyle wrestler randomly were divided into three groups: Experimental group 1: (Creatine + 8 weeks strength training), Experimental group 2: (Creatine+ without training) and Control group. We measured factors of physical performances (Weight, BMI, Speed, Vo2max, BF%, IRM, Muscular Strength, Power) and Hypertrophy (Volume of muscles). Duration strength training was 8 weeks; 3 sessions per week, and each session last 55-70 minutes with the intensity of 60-75 percent of one Repetition maximum. Data analysis for pre and posttest that measured by repeated ANOVA with post hoc test and IBM SPSS Statistics 22. Significance level of p≤0.05 considered. Results: ANOVA showed a significant effect for Weight, BMI, 1RM and no significant for Speed, Vo2max, BF% in both experimental groups compare to pretest and control group. We observed a significant increase in Muscular Strength, Power and Hypertrophy only in experimental group 1 compared to the pre-test and control group (p<0.05). Conclusion:Strength training could increase power, but for increase in strength, weight and hypertrophy in wrestling, creatine is necessary. Creatine is a dietary supplement that increases muscle performance in short-duration, high-intensity resistance exercises, which rely on the phosphocreatine shuttle for adenosine triphosphate in wrestlers.
This study aimed to investigate the effects of administration of xanthan gum-based fluid thickener on the regulation of postprandial blood glucose level, gene expression in the gastrointestinal tract, and gut microbiome. Six-week-old Sprague-Dawley rats were divided into two groups: with (Th group) and without (Co group) the administration of a xanthan gum-based fluid thickener for 5 wks. Blood glucose levels at 60 and 90 min after glucose administration were substantially decreased in the Th group. Glp1 and Glp1r expression in the ileum was significantly upregulated after continuous administration of thickener. RNA-seq analysis revealed that the cholesterol homeostasis, fatty acid metabolism, and glycolysis gene sets were enriched in the ileum of Th group. Microbial composition in the gut was altered after administrating the fluid thickener, and relative abundance in Erysipelotrichales and Christensenellaceae showed positive correlation with Glp1 and Glp1r expression in the ileum. Xanthan gum-based fluid thickener may ameliorate glucose/lipid metabolism.
Aims The aim of this review was to analyze the evidence of whey protein supplementation on body weight, fat mass, lean mass and glycemic parameters in subjects with overweight or T2DM undergoing calorie restriction or with ad libitum intake. Data synthesis: Overweight and obesity are considered risk factors for the development of chronic noncommunicable diseases such as type 2 diabetes mellitus. Caloric restriction, used as a strategy for reducing weight and fat mass, may promote the improvement of glycemic parameters, but simultaneously decrease muscle mass. The maintenance of muscle mass during weight loss is necessary in view of its implication in preventing chronic diseases, improving functional capacity and quality of life. The effects of increased protein consumption on attenuating muscle loss and reducing body fat during caloric restriction or ad libitum intake in overweight individuals are discussed. In short-term, some studies have demonstrated positive effects of whey protein supplementation on improving satiety and postprandial glycemic control, although it is still unclear whether long-term whey protein can positively affect glycemic parameters. Conclusions Despite whey protein is considered a protein with a high nutritional quality, its effects in the treatment of overweight, obese individuals and type 2 diabetes mellitus submitted to calorie restriction or ad libitum intake are still inconclusive.
The milk-based high protein (HP) ready-to-drink (RTD) beverages have increasingly gained popularity over the past years as they are currently used by consumers looking to improve their nutritional status such as athletes and sick people at risk for nutrient deficiencies. Heat treatments are commonly applied during processing to ensure the safety and the longer shelf life of HP beverages. However, the heat treatment can compromise the final nutritional, organoleptic and technological product properties (aggregation, apparent viscosity and sedimentation). In situations where heat exchangers are used, considerable fouling accumulates on surface and often reaches a point where the efficiency of heat exchange systems becomes critical. This instability to heat treatment and the fouling formation are highly dependent on the nature of the used-protein, mineral content, pH and the presence of sensory attributes. In this context, this review will explore the impact of formulation conditions on the fouling of heat exchangers at high temperatures (UHT) and on the stability of dairy-based products, during and after heat treatments, with more focus on caseins at neutral pH. The aim of this review is to have one document which characterizes and understand the impact of heat treatment and formulation conditions on modifications at molecular and structural levels of casein, in order to improve the stability of casein-based RTD beverages and to reduce the fouling of heat exchangers and associated losses.
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Context Components of the insulin resistance syndrome (IRS), including obesity, glucose intolerance, hypertension, and dyslipidemia, are major risk factors for type 2 diabetes and heart disease. Although diet has been postulated to influence IRS, the independent effects of dairy consumption on development of this syndrome have not been investigated.Objective To examine associations between dairy intake and incidence of IRS, adjusting for confounding lifestyle and dietary factors.Design The Coronary Artery Risk Development in Young Adults (CARDIA) study, a population-based prospective study.Setting and Participants General community sample from 4 US metropolitan areas of 3157 black and white adults aged 18 to 30 years who were followed up from 1985-1986 to 1995-1996.Main Outcome Measure Ten-year cumulative incidence of IRS and its association with dairy consumption, measured by diet history interview.Results Dairy consumption was inversely associated with the incidence of all IRS components among individuals who were overweight (body mass index ≥25 kg/m2) at baseline but not among leaner individuals (body mass index <25 kg/m2). The adjusted odds of developing IRS (2 or more components) were 72% lower (odds ratio, 0.28; 95% confidence interval, 0.14-0.58) among overweight individuals in the highest (≥35 times per week, 24/102 individuals) compared with the lowest (<10 times per week, 85/190 individuals) category of dairy consumption. Each daily occasion of dairy consumption was associated with a 21% lower odds of IRS (odds ratio, 0.79; 95% confidence interval, 0.70-0.88). These associations were similar for blacks and whites and for men and women. Other dietary factors, including macronutrients and micronutrients, did not explain the association between dairy intake and IRS.Conclusions Dietary patterns characterized by increased dairy consumption have a strong inverse association with IRS among overweight adults and may reduce risk of type 2 diabetes and cardiovascular disease. Figures in this Article Risk of type 2 diabetes and cardiovascular disease is affected by a number of medical and lifestyle factors. In recent years, increasing attention has been focused on a constellation of risk factors termed the insulin resistance syndrome (IRS), also known as the metabolic syndrome or syndrome X.1- 2 In this syndrome, obesity, insulin resistance, and hyperinsulinemia are thought to cause glucose intolerance, dyslipidemia (low serum high-density lipoprotein cholesterol (HDL-C), and high serum triglyceride concentrations), hypertension, and impaired fibrinolytic capacity.3 An increasing incidence of IRS in all racial, ethnic, and social class groups in the United States can be inferred from the increasing prevalence of obesity4- 5 and type 2 diabetes6- 8 over the last 3 decades. Recently, this syndrome has been observed in youth,9- 11 and age-adjusted prevalence among adults has been estimated at 24%.12 An increase in the prevalence of IRS may partly explain the recent plateau or increase in cardiovascular disease rates, after several decades of decline.13 Although various environmental influences, including smoking and physical inactivity, are known to promote insulin resistance, the effect of dietary composition on IRS is poorly understood. For most of the past 3 decades, the US Department of Agriculture and the American Heart Association have recommended low-fat diets in the prevention and treatment of cardiovascular disease. Recently, however, some have questioned these recommendations out of concern that high-carbohydrate consumption might promote IRS.14- 17 Other dietary factors that have been linked to components of IRS include the ratios of monounsaturated or polyunsaturated to saturated fatty acids,15,18- 19 dietary fiber,20- 21 and glycemic index.22- 24 Dairy consumption is another dietary factor that might affect IRS. Milk intake has decreased significantly over the past 3 decades25- 27 as the prevalence of obesity and type 2 diabetes has increased. Epidemiologic and experimental studies suggest that dairy products may have favorable effects on body weight in children28 and adults.29- 31 In addition, dairy and/or calcium may decrease the risk for hypertension,32- 33 coagulopathy,34 coronary artery disease,35- 36 and stroke.37- 38 An inverse cross-sectional association between dairy intake and IRS was observed in men but not in women although the influence of physical activity, fruit and vegetable intake, and other lifestyle factors was not considered.39 The purpose of this study was to examine, in a prospective fashion, the independent association between dairy consumption and IRS, after taking into account physical activity level, macronutrient and fiber intake, and other potentially confounding variables.
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The speed of absorption of dietary amino acids by the gut varies according to the type of ingested dietary protein. This could affect postprandial protein synthesis, breakdown, and deposition. To test this hypothesis, two intrinsically 13C-leucine-labeled milk proteins, casein (CAS) and whey protein (WP), of different physicochemical properties were ingested as one single meal by healthy adults. Postprandial whole body leucine kinetics were assessed by using a dual tracer methodology. WP induced a dramatic but short increase of plasma amino acids. CAS induced a prolonged plateau of moderate hyperaminoacidemia, probably because of a slow gastric emptying. Whole body protein breakdown was inhibited by 34% after CAS ingestion but not after WP ingestion. Postprandial protein synthesis was stimulated by 68% with the WP meal and to a lesser extent (+31%) with the CAS meal. Postprandial whole body leucine oxidation over 7 h was lower with CAS (272 ± 91 μmol⋅kg−1) than with WP (373 ± 56 μmol⋅kg−1). Leucine intake was identical in both meals (380 μmol⋅kg−1). Therefore, net leucine balance over the 7 h after the meal was more positive with CAS than with WP (P < 0.05, WP vs. CAS). In conclusion, the speed of protein digestion and amino acid absorption from the gut has a major effect on whole body protein anabolism after one single meal. By analogy with carbohydrate metabolism, slow and fast proteins modulate the postprandial metabolic response, a concept to be applied to wasting situations.
Background:Whey proteins have insulinotropic effects and reduce the postprandial glycemia in healthy subjects. The mechanism is not known, but insulinogenic amino acids and the incretin hormones seem to be involved. Objective:The aim was to evaluate whether supplementation of meals with a high glycemic index (GI) with whey proteins may increase insulin secretion and improve blood glucose control in type 2 diabetic subjects. Design:Fourteen diet-treated subjects with type 2 diabetes were served a high-GI breakfast (white bread) and subsequent high-GI lunch (mashed potatoes with meatballs). The breakfast and lunch meals were supplemented with whey on one day; whey was exchanged for lean ham and lactose on another day. Venous blood samples were drawn before and during 4 h after breakfast and 3 h after lunch for the measurement of blood glucose, serum insulin, glucose-dependent insulinotropic polypeptide (GIP), and glucagon-like peptide 1 (GLP-1). Results:The insulin responses were higher after both breakfast (31%) and lunch (57%) when whey was included in the meal than when whey was not included. After lunch, the blood glucose response was significantly reduced [−21%; 120 min area under the curve (AUC)] after whey ingestion. Postprandial GIP responses were higher after whey ingestion, whereas no differences were found in GLP-1 between the reference and test meals. Conclusions:It can be concluded that the addition of whey to meals with rapidly digested and absorbed carbohydrates stimulates insulin release and reduces postprandial blood glucose excursion after a lunch meal consisting of mashed potatoes and meatballs in type 2 diabetic subjects.
The National Cholesterol Education Program’s Adult Treatment Panel III report (ATP III)1 identified the metabolic syndrome as a multiplex risk factor for cardiovascular disease (CVD) that is deserving of more clinical attention. The cardiovascular community has responded with heightened awareness and interest. ATP III criteria for metabolic syndrome differ somewhat from those of other organizations. Consequently, the National Heart, Lung, and Blood Institute, in collaboration with the American Heart Association, convened a conference to examine scientific issues related to definition of the metabolic syndrome. The scientific evidence related to definition was reviewed and considered from several perspectives: (1) major clinical outcomes, (2) metabolic components, (3) pathogenesis, (4) clinical criteria for diagnosis, (5) risk for clinical outcomes, and (6) therapeutic interventions. ATP III viewed CVD as the primary clinical outcome of metabolic syndrome. Most individuals who develop CVD have multiple risk factors. In 1988, Reaven2 noted that several risk factors (eg, dyslipidemia, hypertension, hyperglycemia) commonly cluster together. This clustering he called Syndrome X , and he recognized it as a multiplex risk factor for CVD. Reaven and subsequently others postulated that insulin resistance underlies Syndrome X (hence the commonly used term insulin resistance syndrome ). Other researchers use the term metabolic syndrome for this clustering of metabolic risk factors. ATP III used this alternative term. It avoids the implication that insulin resistance is the primary or only cause of associated risk factors. Although ATP III identified CVD as the primary clinical outcome of the metabolic syndrome, most people with this syndrome have insulin resistance, which confers increased risk for type 2 diabetes. When diabetes becomes clinically apparent, CVD risk rises sharply. Beyond CVD and type 2 diabetes, individuals with metabolic syndrome seemingly are susceptible to other conditions, notably polycystic ovary syndrome, fatty liver, cholesterol gallstones, asthma, sleep disturbances, and some …
LR: 20061115; JID: 7501160; 0 (Antilipemic Agents); 0 (Cholesterol, HDL); 0 (Cholesterol, LDL); 57-88-5 (Cholesterol); CIN: JAMA. 2001 Nov 21;286(19):2401; author reply 2401-2. PMID: 11712930; CIN: JAMA. 2001 Nov 21;286(19):2400-1; author reply 2401-2. PMID: 11712929; CIN: JAMA. 2001 Nov 21;286(19):2400; author reply 2401-2. PMID: 11712928; CIN: JAMA. 2001 Nov 21;286(19):2400; author reply 2401-2. PMID: 11712927; CIN: JAMA. 2001 May 16;285(19):2508-9. PMID: 11368705; CIN: JAMA. 2003 Apr 16;289(15):1928; author reply 1929. PMID: 12697793; CIN: JAMA. 2001 Aug 1;286(5):533-5. PMID: 11476650; CIN: JAMA. 2001 Nov 21;286(19):2401-2. PMID: 11712931; ppublish
The objective of these 4 studies was to describe the effects of protein source, time of consumption, quantity, and composition of protein preloads on food intake in young men. Young men were fed isolates of whey, soy protein, or egg albumen in sweet and flavored beverages (400 mL) and provided a pizza meal 1-2 h later. Compared with the water control, preloads (45-50 g) of whey and soy protein, but not egg albumen, suppressed food intake at a pizza meal consumed 1 h later. Meal energy intake after egg albumen and soy, but not after control or whey treatments, was greater when the treatments were given in the late morning (1100 h) compared with earlier (0830-0910 h). Suppression of food intake after whey protein, consumed as either the intact protein or as peptides, extended to 2 h. Altering the composition of the soy preload (50 g) by reducing the soy protein content to 25 g and by adding 25 g of either glucose or amylose led to a loss in suppression of food intake by the preload. Egg albumen, in contrast to whey and soy preloads, increased cumulative energy intake (sum of the energy content of the preload plus that in the test meal) relative to the control. We conclude that protein source, time of consumption, quantity, and composition are all factors determining the effect of protein preloads on short-term food intake in young men.
Limited evidence suggests that dairy whey protein may be the major dairy component that is responsible for health benefits currently associated with increased dairy consumption. Whey proteins may reduce blood pressure and improve cardiovascular health. This study evaluated the effects of whey protein supplementation on blood pressure, vascular function and inflammatory markers compared to casein and glucose (control) supplementation in overweight/obese individuals. The subjects were randomized to either whey protein, casein or glucose supplementation for 12 weeks according to a parallel design. In all, 70 men and women with a mean (+/-s.e.m.) BMI (kg/m(2)) of 31.3 +/- 0.8 completed the study. Systolic blood pressure (SBP) decreased significantly at week 6 compared to baseline in the whey and casein groups, (P = 0.028 and P = 0.020, respectively) and at week 12 (P = 0.020, and P = 0.017, respectively). Diastolic blood pressure (DBP) decreased significantly compared to baseline in the whey and casein groups (P = 0.038 and P = 0.042, respectively) at week 12. DBP decreased significantly in the whey and casein groups (P = 0.025, P = 0.038, respectively) at week 12 compared to the control group. Augmentation index (AI) was significantly lower from baseline at 12 weeks (P = 0.021) in the whey group. AI decreased significantly in the whey group at 12 weeks compared to control (P = 0.006) and casein (P = 0.006). There were no significant changes in inflammatory markers within or between groups. This study demonstrated that supplementation with whey protein improves blood pressure and vascular function in overweight and obese individuals.