Purified egg protein supplementation has beneficial effects on body composition, metabolism and eating behavior and results in a more sustained weight loss than low fat diet

Abstract Background: An increasing body of literature emphasizes the interest of moderate enrichment in protein for treating obesity and its metabolic consequences. However, egg proteins that are known to have the highest biological value have not been studied in this context. We investigated in self-restricted obese individuals with low Protein Intake (PI) (< 0.7 g.kg-1.d-1) the effects of increasing PI up to 1.5 g.kg-1.d–1 on body weight, body composition, eating behavior, Resting Metabolic Rate (RMR) and kidney function. Randomized controlled trial over 2 months: Twelve subjects were given daily supplements of a formula of Purified high biological value Egg Protein (PEP) (Ovamine® Nuvia laboratories, Paris) to achieve this level of PI while ten matched controls were given a simple Low-Fat High Protein Diet (LFHPD). Subjects were tested before and after 2 months. PEP resulted in increased PI (1.39 ± 0.07 vs 0.65 ± 0.07 g.kg-1.d-1 p < 0.01), higher percentage of protein (+9.6%, p < 0.01) and lower percentage of lipids (-13,6%, p < 0.01) in diet, while these values were not significantly modified with LFHPD. Analogic-numeric scales indicated that appetite increased under LFHPD and decreased under PEP (p = 0.006) with a subjective feeling of eating less (p < 0.01), yet in both groups, total calculated energy intake was not decreased. Under PEP (but not LFHPD) there was a decrease in weight (-1.97 ± 0.5 kg p < 0.01) and body mass index (-0.74 ± 0,18%, p < 0.01) due to a decrease in fat mass only (-3.2 ± 1.3 kg p < 0,05). There was in both groups a nonsignificant tendency to reduce RMR with no change in RER. Creatinine clearance increased by 10% under PEP (before: 149 ± 19; after: 162 ± 22 ml.min-1, p = 0.05) but not under LFHPD. Microalbuminuria was unchanged. Controlled follow-up trial over 18 months: 337 subjects divided into three matched groups followed over 18 months: no change in diet or lifestyle (n = 69); LFD (n = 171), and PEP (n = 97) targeting 1.2 g.kg-1.d-1 protein with the same purified egg protein preparation of high biological value. In the group of control subjects (n = 58) there was a gradual weight increase up to +8.58 ± 0.56 % of initial weight on the 18th month, while subjects on low fat diet had lost -5.55 ± 1.31 and those receiving moderate enrichment in protein had lost -8.07 ± 1.58. The initial drop-out at 1 month is -19% with low fat diet and -15% with moderate enrichment in protein. After 6 months it is -57% with low fat diet and -47% with moderate enrichment in protein. During the first 6 months the curves of low-fat diet and protein supplementation are almost overlapped but after 8 months the difference becomes significant. At 18 months, subjects on low fat diet have lost -5.95 ± 1.82 and those receiving moderate enrichment in protein have lost -8.05 ± 1.87 (p = 0.023). On the whole moderate enrichment in protein induces a weight loss > 10% in 18% of the subjects and a weight loss > 5-10 in 22% of them. Visual analogic scales evidence in receiving egg protein a decrease in appetite (p < 0.01) and nibbling (p < 0.01) and an increase in satiety (p < 0.01). Conclusion: This study is thus the first to demonstrate a fair efficacy of purified egg protein over the long term together with positive effects on body composition and eating behavior. PEP supplements are an easy means for increasing PI and reducing fat intake, while this goal remains difficult to achieve with simple diet. Despite no advice of caloric restriction and no increase in RMR, PEP induces a slight loss in body fat, with preservation of lean mass, and only marginal changes in glomerular filtration. Over 18 months it results in a significant weight loss, which is significantly more pronounced (+38%) and continues over a longer period under PEP compared to LFD (p = 0.003). In addition, we observe that the effect of this procedure on body weight is more pronounced in three categories of subjects: those with marked excess calorie intake, those with initial low protein intake, and those whose phase 2 insulin response is higher. Since egg proteins are the variety of proteins that possess the greatest biological value and have additional biological properties beneficial for cardiovascular and metabolic health, they are likely to represent a new promising tool for the management of obesity and metabolic syndrome. Further controlled studies are in progress to better assess this issue.