Does eating enough protein help my immune system as I get older?
Eating enough protein helps your immune system in later life. Aim for at least 1.0-1.2 grams per kilogram of body weight per day, spread across your meals, and preferably obtain this from ordinary food rather than supplements.
Eating enough protein helps your immune system in later life. Multiple human studies support the view that older adults need at least 1.0 to 1.2 grams of protein per kilogram of body weight per day. This helps slow the ageing of the immune system. In chronic illness that requirement rises to 1.2-1.5 grams per kilogram, and in serious illness or malnutrition to as much as 2.0 grams.1
In practice, a large proportion of older adults eat too little protein. Among Americans over the age of 71, 30% of men and 50% of women fail to reach the recommended amount. Reduced appetite, tooth loss, changes in gut function, financial difficulties and loneliness all play a role. A poor nutritional status increases the risk of frailty and sustains low-grade, chronic inflammation.2
Not only the total daily amount matters, but also how you spread it throughout the day. Around 25-30 grams of protein per meal is enough for older adults to maximise muscle protein synthesis. Those who want to optimise this further can eat an additional 40 grams just before going to sleep; this improves amino acid utilisation slightly.
Individual amino acid supplements are not a safe substitute for ordinary protein-rich food. Higher doses can put a strain on the kidneys, increase ammonia production and cause gastrointestinal complaints. In people with diabetes or liver conditions the risks may be greater. Research into the long-term consequences of high doses is still at an early stage.3
All claims are based on PMID 40806046 (guidelines and population data on protein intake in older adults), PMID 35219904 (nutritional status and immunity/frailty) and PMID 35043647 (risks of amino acid supplements). No large independent trials that directly measure the immune effect were provided; the strength of evidence for most claims is 'moderate'.