Impact of Whey Protein on Malnutrition Management in the Elderly
Overview of Whey Protein and Malnutrition
A recent study explores whether whey protein can influence energy intake in elderly individuals managing malnutrition. Whey protein, a natural supplement derived from milk, is commonly used to support lean muscle mass and address malnutrition in older adults. The prevalence of malnutrition, which includes both undernutrition and obesity, is increasing among older men and women, leading to significant mobility loss and a decline in quality of life. Therefore, it is crucial for older adults to restore skeletal muscle mass and function through supplemental support. Consuming whey protein offers a convenient and effective method for meeting daily protein requirements.
Understanding the Effects of Whey Protein
Despite its common use, the impact of whey protein on energy intake and gastrointestinal mechanisms in older adults remains poorly understood. Previous research indicated that oral whey protein loads suppressed subsequent energy intake by 12-17% in younger individuals, but did not show similar effects in healthy older men.
Study Design and Methodology
A new study published in the *American Journal of Clinical Nutrition* investigates the role of whey protein in addressing malnutrition among the elderly. The research focused on its effects on energy intake, appetite, gastric emptying, and gut hormones. The study involved eight men and eight women, with an average age of 72 years and a BMI of 25 kg/m². Participants received two oral whey protein doses of 30 g (120 kcal) and 70 g (280 kcal), alongside a flavored-water control drink, over three separate occasions spaced 3 to 14 days apart.
Participants consumed a standardized evening meal the night before each study day. On each study day, they ingested the designated drink, and measurements of total gastric volume, appetite perceptions, and gastrointestinal symptoms were taken before consumption, immediately after, and at 15-minute intervals up to 180 minutes. At that point, participants were allowed to eat from a buffet until they felt comfortably full, with food intake measured to calculate energy consumption. Blood samples were also taken to assess plasma concentrations of gastrointestinal hormones.
Results and Findings
The findings indicated that energy intake at the buffet meal was approximately 80% higher in older men compared to women. However, neither the whey protein nor the control drink significantly suppressed energy intake during the buffet meal. A dose-dependent effect of the protein load was observed, with total energy intake increasing from the control (843 ± 77 kcal) to the 30 g protein (923 ± 75 kcal) and 70 g protein (1073 ± 78 kcal).
The study also noted that whey protein consumption led to slower gastric emptying, with no significant difference between men and women. Additionally, the protein load resulted in increased plasma levels of insulin, glucagon, ghrelin, cholecystokinin, GIP, GLP-1, and PYY. However, the effects on hunger, desire to eat, fullness, nausea, and bloating were not statistically significant.
Overall, the protein drinks did not suppress subsequent food intake in older adults. Instead, a dose-dependent increase in total energy intake (from the preload drink plus subsequent meal) was observed when compared to the control drink. This suggests that protein doses adequate for muscle deposition can be safely consumed by elderly individuals without decreasing appetite or overall energy intake.
Limitations of the Study
The study faced limitations, including a small participant sample size, which may have impacted its power. Energy intake was evaluated only three hours post-protein intake and not throughout the rest of the day. Additionally, while older women typically have lower energy needs than older men, the study design maintained isocaloric drinks for both groups.
Conclusion and Implications
In conclusion, the consumption of whey protein drinks does not affect subsequent energy intake three hours post-consumption among the elderly. Instead, it contributes to an overall increase in total energy intake, indicating that whey protein drinks are an advantageous option for elderly individuals focusing on their protein needs.
Written by Preeti Paul, MS Biochemistry
Reference: Caroline Giezenaar, Laurence G Trahair et al. Effects of randomized whey-protein loads on energy intake, appetite, gastric emptying, and plasma gut-hormone concentrations in older men and women. *Am J Clin Nutr*, July 2017.
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