People
Whey protein and vitamin D may lower some inflammation markers in heart rehab patients
Heart rehab patients took a whey protein and vitamin D drink for two weeks, and some inflammation markers dropped. The study was small and exploratory, so it cannot show that the supplement caused these changes.
Summary of earlier studies
Comparative Effectiveness of Nutritional Strategies for Sarcopenia-Related Outcomes in Older Adults: A Systematic Review and Network Meta-Analysis.
Objective: This study compared the relative effects of distinct nutritional strategies on muscle mass, muscle strength, and physical performance in older adults with sarcopenia or at high risk of sarcopenia.
People
Protein and leucine add-ons did not beat diet alone for older men losing weight
Sixty-one older men followed a fasting diet for four weeks and took protein, leucine, or a placebo. All groups lost weight and improved in several health measures. The extra protein and leucine did not add measurable benefit beyond that.