Research brief · 2026-09-09
How Much Protein Do Older Adults Actually Need?
The recommended dietary allowance for protein is 0.8 grams per kilogram of body weight per day. Whether older adults need more than that is one of the most argued questions in nutrition, and the answer from the trials depends on who is being measured.
The tightest test came from Bhasin's 2018 randomized trial in JAMA Internal Medicine. Ninety-two men aged 65 and older with physical function limitations ate controlled meals for six months at either 0.8 or 1.3 grams per kilogram per day. Lean body mass did not differ between groups, and neither did strength or physical function. In that population, the standard allowance appeared sufficient.
A different picture emerged in adults who already had sarcopenia. Lin's 2020 trial in Clinical Nutrition set a target of 1.2 to 1.5 grams per kilogram for 56 sarcopenic older adults, reached either through dietary counseling or a leucine and vitamin D enriched whey supplement. Appendicular muscle mass index improved in both groups over 12 weeks, with no difference between them. The authors' reading was that hitting the target mattered, not how people got there.
Above baseline, the source of protein also seemed to matter. McKendry's 2024 trial in the American Journal of Clinical Nutrition had 31 healthy older men eat at the RDA for a week, then add whey, pea or collagen protein for a second week. Muscle protein synthesis rose significantly with whey and pea, but did not change with collagen at the identical amount.
The limits are real. Every trial here enrolled people younger than 85, and a 2018 review in Nutrients flagged protein needs in the very old as a major evidence gap. None measured falls, hospitalizations or mortality, only intermediate markers like lean mass. Questions about protein in older age belong in a conversation with a physician or dietitian.
Sources
- Bhasin S et al. Effect of Protein Intake on Lean Body Mass in Functionally Limited Older Men: A Randomized Clinical Trial
- JAMA Internal Medicine 2018
- Lin CC et al. Effects of adequate dietary protein with whey protein, leucine, and vitamin D supplementation on sarcopenia in older adults
- Clinical Nutrition 2020
- McKendry J et al. The effects of whey, pea, and collagen protein supplementation beyond the RDA on myofibrillar protein synthesis in older males
- American Journal of Clinical Nutrition 2024
- Granic A et al. Nutrition in the Very Old
- Nutrients 2018
Peptide Proof reports what studies found. We do not give medical advice, dosing guidance, or treatment recommendations.