Protein helps maintain muscle, but ageing muscles can respond less strongly to it. This reduced muscle-building response, known as anabolic resistance, is one reason some experts suggest higher protein intakes for older adults. BBC Science Focus Magazine (source, opens in new tab)
BBC Science Focus Magazine'You need double as you age': Why you’re (probably) eating the wrong amount of protein, according to expertsOpen source (opens in new tab)
Expert recommendations reported by BBC Science Focus suggest about 1.0–1.2 grams of protein per kilogram of body weight each day for older adults, rising to as much as 1.5 grams for some people at risk of or experiencing muscle loss. These are weight-adjusted targets: the daily amount depends on the person’s body weight. The upper figure is not a general instruction for everyone to double their intake as they age.
A 2020 Birmingham study examined a related question: how much protein people of different ages actually ate, and how they spread it across meals. The researchers compared 120 healthy adults, each of whom weighed and recorded their food for three days. Frontiers in Nutrition (source, opens in new tab)
Frontiers in NutritionAmount, Source and Pattern of Dietary Protein Intake Across the Adult Lifespan: A Cross-Sectional StudyOpen source (opens in new tab)
The older participants ate less protein overall than the youngest group. Yet almost everyone in the study met the comparison threshold of 0.8 grams per kilogram of body weight per day. Older adults could therefore be eating less than younger adults without falling below that threshold, which was lower than the expert targets described above.
Protein intake was unevenly distributed across meals in all three age groups. The researchers suggested that increasing protein, particularly at breakfast and lunch, could potentially help limit age-related muscle loss. Their study recorded existing diets; it did not test whether changing those meals or increasing the daily total preserved muscle.
The study included 40 young, 40 middle-aged and 40 older adults, with average ages of about 24, 52 and 77. Their average daily protein intakes were 105.1 grams, 97.0 grams and 83.4 grams respectively. The difference between the oldest and youngest groups was statistically significant; the difference between the older and middle-aged groups was not.
These were comparisons between different people at one point in time, rather than measurements of the same people as they aged. The findings therefore cannot show that ageing itself caused the differences in intake. Three days of food diaries also provide only a short snapshot of eating habits, and the study did not measure the muscle-building response used to explain the higher expert targets.
The participants were healthy adults living in the community who were able to walk. The authors cautioned that their findings offered little insight into protein requirements for older people who were frail, living in institutions or receiving hospital care. The study helps describe eating patterns in a healthy population; it cannot establish the intake needed by people whose circumstances and health differ.
- BBC Science Focus Magazine · News report'You need double as you age': Why you’re (probably) eating the wrong amount of protein, according to expertssciencefocus.com · opens in new tab
- Frontiers in Nutrition · Peer-reviewed studyAmount, Source and Pattern of Dietary Protein Intake Across the Adult Lifespan: A Cross-Sectional Studyfrontiersin.org · opens in new tab
