Sebely Pal

Effects of whey protein isolate on body composition, lipids, insulin and glucose in overweight and obese individuals

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.

The chronic effects of whey proteins on blood pressure, vascular function, and inflammatory markers in overweight individuals.

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/m2) 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.

The effect of 12 weeks of aerobic, resistance or combination exercise training on cardiovascular risk factors in the overweight and obese in a randomized trial.

BackgroundEvidence suggests that exercise training improves CVD risk factors. However, it is unclear whether health benefits are limited to aerobic training or if other exercise modalities such as resistance training or a combination are as effective or more effective in the overweight and obese. The aim of this study is to investigate whether 12 weeks of moderate-intensity aerobic, resistance, or combined exercise training would induce and sustain improvements in cardiovascular risk profile, weight and fat loss in overweight and obese adults compared to no exercise.MethodsTwelve-week randomized parallel design examining the effects of different exercise regimes on fasting measures of lipids, glucose and insulin and changes in body weight, fat mass and dietary intake. Participants were randomized to either: Group 1 (Control, n = 16); Group 2 (Aerobic, n = 15); Group 3 (Resistance, n = 16); Group 4 (Combination, n = 17). Data was analysed using General Linear Model to assess the effects of the groups after adjusting for baseline values. Within-group data was analyzed with the paired t-test and between-group effects using post hoc comparisons.ResultsSignificant improvements in body weight (−1.6%, p = 0.044) for the Combination group compared to Control and Resistance groups and total body fat compared to Control (−4.4%, p = 0.003) and Resistance (−3%, p = 0.041). Significant improvements in body fat percentage (−2.6%, p = 0.008), abdominal fat percentage (−2.8%, p = 0.034) and cardio-respiratory fitness (13.3%, p = 0.006) were seen in the Combination group compared to Control. Levels of ApoB48 were 32% lower in the Resistance group compared to Control (p = 0.04).ConclusionA 12-week training program comprising of resistance or combination exercise, at moderate-intensity for 30 min, five days/week resulted in improvements in the cardiovascular risk profile in overweight and obese participants compared to no exercise. From our observations, combination exercise gave greater benefits for weight loss, fat loss and cardio-respiratory fitness than aerobic and resistance training modalities. Therefore, combination exercise training should be recommended for overweight and obese adults in National Physical Activity Guidelines.This clinical trial was registered with the Australian New Zealand Clinical Trials Registry (ANZCTR), registration number: ACTRN12609000684224.

The acute effects of four protein meals on insulin, glucose, appetite and energy intake in lean men

Different dietary proteins vary in their ability to influence satiety and reduce food intake. The present study compared the effects of four protein meals, whey, tuna, turkey and egg albumin, on postprandial glucose and insulin concentrations as well as on appetite measures and energy intake in twenty-two lean, healthy men. This was a randomised, cross-over design study where participants consumed four liquid test meals on separate occasions followed by the collection of regular blood samples (fasting, +30, 60, 90, 120, 180 and 240 min). They were then offered a buffet meal 4 h later. The blood glucose response after the consumption of the test meal, as an incremental area under the curve (AUC), was significantly lower with the whey meal than with the turkey (P < 0.023) and egg (P < 0.001) meals, but it was not lower than with the tuna meal (P < 0.34). The AUC blood insulin after the consumption of the test meal was significantly higher with the whey meal than with the tuna, turkey and egg meals (all P < 0.001). The AUC rating of hunger was significantly lower with the whey meal than with the tuna (P < 0.033), turkey (P < 0.001) and egg (P < 0.001) meals. Mean energy intake at the ad libitum meal was significantly lower (P < 0.001) with the whey meal than with the tuna, egg and turkey meals. There was a strong relationship between self-rated appetite, postprandial insulin response and energy intake at lunch. Whey protein meal produced a greater insulin response, reduced appetite and decreased ad libitum energy intake at a subsequent meal compared with the other protein meals, indicating a potential for appetite suppression and weight loss in overweight or obese individuals.

Identification of Lipoproteins of Intestinal Origin in Human Atherosclerotic Plaque

Abstract Apolipoproteins (apo) B48 and B100 are exclusive markers of lipoproteins derived from the intestine and liver, respectively. Lipoproteins of hepatic origin are causally related to atherosclerosis and are found in plaque. However, lipoproteins of intestinal origin have not previously been reported in human atherosclerotic tissue, although studies in animal models suggest that chylomicrons may contribute to arterial cholesterol entrapment. In this study, we report on the relative distribution of both apoB48 and apoB100 in human atherosclerotic tissue. Lipoproteins were isolated from human femoral and carotid endarterectomy samples, from varicose vein and aortic aneurysms. ApoB was determined by Western blot analysis and quantified based on the signal to apoB48 and apoB100 protein standards of known mass. ApoB48 and apoB100 were found in human carotid and femoral endarterectomy samples, but not in varicose vein or aortic aneurysm tissue. The level of apoB48 relative to hepatic lipoproteins (B100) was found to be much greater than would be predicted based on the relative plasma concentration and arterial exposure of the two lipoprotein groups. Intimal association was substantially greater in carotid endarterectomy samples compared to femoral, however, the ratio of chylomicrons to hepatic lipoproteins was greater in the latter. On the basis that chylomicron apoB48 was found in human atherosclerotic tissue and that each chylomicron particle contains substantial quantities of cholesterol, it is possible that the contribution of intestinal lipoproteins to atherosclerosis may be significant.

Atopy, eczema and breast milk fatty acids in a high-risk cohort of children followed from birth to 5 yr

Background: The incidence of atopic diseases such as eczema is increasing in westernized societies. The suggestion that there is a ‘protective’ association between the unique fatty acid composition of breast milk, particularly the omega‐3 (n‐3) and omega‐6 (n‐6) essential polyunsaturated fatty acid content, and the development of atopic disease in children was investigated in a cohort study of 263 infants born into families with a history of allergy (one or both parents had asthma, hayfever, eczema). The objectives of this study were to determine the lipid profile [specifically in relation to long‐chain polyunsaturated fatty acid (LC‐PUFA) composition] in maternal breast milk samples collected at 6 wk and at 6 months following birth, and to investigate the potential role of these fatty acids in modulating the phenotype of children at high genetic risk of developing atopic disease. Method: Breast milk samples were available from 91 atopic mothers at their childs ages of 6 wk and 6 months. These samples were analysed for the fatty acid spectrum. Analysis of variance was used to detect differences between groups of outcomes (no atopy or eczema, non‐atopic eczema, atopy, atopic eczema) at ages 6 months and 5 yr, and a multiple comparisons procedure was conducted to isolate the parameters producing the different results (F‐test, LSD test). For the exposure variables, n‐3 and n‐6 fatty acids are expressed as weight percentage and as a ratio (at both time‐points). Results: The fatty acid profiles of maternal breast milk at 6 wk and 6 months were similar. An increased ratio of n‐6: n‐3 fatty acids in both 6 wk and 6 month milk samples was associated with non‐atopic eczema (p < 0.005) but not atopy alone or atopic eczema. Conclusion: We found milk fatty acids were a significant modulator of non‐atopic eczema but not atopy or atopic eczema in infants at 6 months. In mothers with a history of asthma, hayfever or eczema, their 6‐month‐old infants were more likely to develop non‐atopic eczema if their milk had a higher ratio of n‐6: n‐3 LC‐PUFA.

The effects of whey protein on cardiometabolic risk factors

Obesity has reached epidemic proportions worldwide. The health consequences of obesity are more dangerous when associated with the metabolic syndrome and its components. Studies show that whey protein and its bioactive components can promote greater benefits compared to other protein sources such as egg and casein. The aim of this paper is to review the effects of whey protein on cardiometabolic risk factors. Using PubMed as the database, a review was conducted to identify current scientific literature on whey protein and the components of the metabolic syndrome published between 1970 and 2012. Consumption of whey protein seems to play an anti‐obesity and muscle‐protective role during dieting by increasing thermogenesis and maintaining lean mass. In addition, whey protein has been shown to improve glucose levels and insulin response, promote a reduction in blood pressure and arterial stiffness, and improve lipid profile. The collective view of current scientific literature indicates that the consumption of whey protein may have beneficial effects on some symptoms of the metabolic syndrome as well as a reduction in cardiovascular risk factors.

Acute effects of whey protein isolate on cardiovascular risk factors in overweight, post-menopausal women.

OBJECTIVE The purpose of this study was to investigate the acute effects of dietary whey proteins on lipids, glucose and insulin, and resting energy expenditure in overweight and obese post-menopausal women, a population highly susceptible to cardiovascular disease. METHODS A three-way crossover design study was conducted where 20 overweight or obese, post-menopausal women were randomised to consume either 45 g whey protein isolate, 45 g sodium caseinate or 45 g of a glucose control in conjunction with a breakfast meal. Blood samples were taken for up to 6 h. RESULTS There was no significant change in postprandial incremental area under the curve (AUC) for total cholesterol, low density lipoprotein, high density lipoprotein, non-esterified fatty acids, Apo B48, insulin and leptin between groups. However, there was a significant decrease in the appearance of triglycerides (TG) in the blood by 21% and 27% after consuming the whey meal compared to control and casein meals, respectively, as measured by AUC. There was also a significant reduction by 27% and 32% in the AUC for TG:ApoB48 ratio in the whey group compared to the glucose and casein groups, respectively. There was a significantly lower AUC for blood glucose after the consumption of the whey and casein meal compared to glucose meal. CONCLUSION These findings suggest that a single dose of whey protein can decrease arterial exposure to smaller TG-enriched lipoprotein particles compared to the glucose and casein meals in the postprandial period in overweight and obese, post-menopausal women.

Acute effects of whey protein isolate on blood pressure, vascular function and inflammatory markers in overweight postmenopausal women.

Previous evidence indicates that chronic consumption of dairy whey proteins has beneficial effects on CVD risk factors. The present study investigated the postprandial effects of whey protein isolate on blood pressure, vascular function and inflammatory markers in overweight and obese postmenopausal women. This was a randomised, three-way cross-over design study where twenty overweight and obese postmenopausal women consumed a breakfast meal in conjunction with one of three supplements: 45 g whey protein isolate, 45 g sodium caseinate or 45 g of a glucose control. Fasting and postprandial blood samples, blood pressure and pulse wave analysis readings were taken for up to 6 h. After consumption of the meal, both systolic and diastolic blood pressure, and augmentation index (AI) decreased initially for all interventions and gradually returned to baseline levels by 6 h. However, there were no significant differences in AI, systolic or diastolic blood pressure within or between the glucose control, casein or whey groups. There were also no significant group effects on plasma inflammatory markers (IL-6, TNF-α and C-reactive protein). The health effects previously seen with chronic whey protein ingestion were not seen in the acute 6 h postprandial period in relation to blood pressure, vascular function or inflammatory markers when compared with casein and a glucose control. This suggests that such effects are better observed from the long-term consumption of whey proteins.

The acute effects of psyllium on postprandial lipaemia and thermogenesis in overweight and obese men

Overweight and obesity is one of the risk factors for developing CVD. At present, very little is known about the acute effects of dietary fibre on lipids, glucose and insulin, resting energy expenditure and diet-induced thermogenesis in overweight and obese individuals. This study examined the postprandial metabolic effects of dietary fibre in overweight and obese men. Ten overweight and obese men consumed a mixed meal accompanied by either a high-fibre or low-fibre supplement on two separate visits, in a random order, 1 week apart. Two isoenergetic breakfast meals with similar composition were consumed by ten overweight/obese men. The meals contained either a low (3 g) or high (15 g) amount of fibre, low-fibre meal (LFM) and high-fibre meal (HFM) respectively. Analysis was carried out using paired t test and ANOVA. Serum TAG incremental area under the curve during 6 h of the postprandial period was significantly lower after the consumption of HFM compared with LFM. At the first hour of the postprandial period, plasma apo B48 concentration after consumption of HFM was significantly lower compared with LFM. The resting energy expenditure and diet-induced thermogenesis after both meals was similar during 6 h of the postprandial period. Collectively, these findings suggest that a single acute dose of dietary fibre in the form of psyllium supplement can decrease arterial exposure to TAG and modify chylomicron responses in the postprandial period.