The study: 70 women, 12 weeks, clear results
A randomized controlled trial published in PMC (reference PMC12179993) tested the effect of 15g per day protein supplementation on muscle function in 70 healthy women aged 50–80. The intervention lasted 12 weeks.
The supplemented group showed significant improvement in muscle strength and functional performance compared to the placebo group. The primary result confirms what literature already suggested — but with new precision about the conditions that determine how large the benefit is.
What the study reveals beyond the headline
The most interesting finding isn't the confirmation that protein helps. It's the difference in effect between women who combined supplementation with light physical activity and those who didn't: outcomes were 2x greater in the active group.
This isn't biologically surprising — muscle protein synthesis requires a mechanical signal (exercise) to be optimally activated. But it's an important practical data point: protein supplementation without associated physical activity produces limited results. The combination is what works.
Second key finding: protein timing. Women who concentrated their highest protein intake at the main daily meal retained significantly more nitrogen (a marker of protein synthesis) than those who distributed the same total intake across three small equal doses. This "concentrated intake" goes against the common advice to "spread your protein" — and suggests that for women over 50, a substantial protein serving at one or two main meals is superior to small regular doses.
The real protein deficit in women over 50
Current recommendations for active women over 50 are 1.2–1.6g of protein per kilogram of body weight per day. For a 65 kg woman, that's 78–104g of daily protein.
Food survey data in Western countries shows actual consumption among women in this age group sits between 0.7–0.9g/kg/day — roughly half the recommendation for active women. This isn't lack of appetite or wrong food choices: it's simply that high-protein sources (meats, fish, eggs, legumes in significant quantity) aren't naturally present at every meal in a standard eating pattern.
The practical approach: track protein intake for 3 days using a food logging app. If the average is below 1.2g/kg, an increase strategy is needed — through food first (eggs at breakfast, legumes at lunch, fish at dinner), with protein supplementation if dietary intake remains insufficient.