"Older" vegans should double-check they get all the key nutrients for vegans - just like all other vegans
A new 12-week study from Wageningen University in the Netherlands (don't call it Holland) included 72 adults presumably Dutch and omnivores, age 65+, who were randomised to three groups:
- continue their omni diet
- go on a self-selected vegan diet (n = 23)
- go on a self-selected vegan diet + do some resistance exercise (n = 23)
The results show that:
"A self-selected vegan diet reduces protein intake, skeletal muscle mass, and MPS [muscle protein synthesis] in older adults. The negative [unfavourable = muscle mass decrease] impact of a vegan diet on skeletal muscle mass can be mitigated by RE [resistance exercise]."
Fat-free thigh muscle volume also decrease in the vegan group without resistance exercise.
No significant differences were found between all three groups in terms of maximum knee extension strength of the dominant leg or of maximum knee flexion strength of the dominant leg. Although this seems to be the more relevant parameter (?) - muscle strength versus volume - this was not reported in the abstract.
The vegan diet group were educated about vegan protein sources and vegan diets in general by a registered dietitian.
It was not disclosed whether this dietitian was a vegan.
So, if we hypothetically think of a scenario in which "older" Dutch adults - who likely are used to eating very few to no legumes and who are very likely "culturally allergic" to meat alternatives and who may prefer the taste of "milks" such as oat milk (which is low in protein) - and these adults know nothing about vegan diets or veganism and they are taught how to be vegan by someone who does not know much about vegan diets ... it may explain why many of the people in the vegan group chose low protein foods. Add to this that many meat alternatives in supermarkets are low in protein. Tofu or tempeh is something that "younger" people are very open to, but - my guess - older Dutch adults (unless they were Indonesians - there are relatively many in the Netherlands - which was not disclosed) are not very open to cooking with tofu and tempeh on a daily basis.
Add to this that (weirdly?) the vegan groups were not given vitamin B12 or multivitamin supplements. All three groups were given vitamin D supplements only.
The abstract report that protein intake went down and muscle mass went down - that does not mean that one lead to the other, or that protein was the only or main factor.
Plus, fibre intake in the vegan groups was estimated to have gone up, which is highly relevant to health.
Key nutrients for vegans, including vitamin B12, iodine, zinc, and selenium were not discussed by the author.
Now someone once said - it surely wasn't me - that the ASN (American Society of Nutrition) journals, such as the American Journal of Clinical Nutrition, are a tiny bit biased to the extent that they are totally anti-vegan.
The present publication by Domic et al. certainly would not confirm such conspiracy theories, but it does not exactly weaken (pun intended) such hypotheses of anti-vegan bias.
The present paper was published in mid-August 2026, but only occurred in my PubMed update on 2 September 2026.
Conincidentally, the "ODS Digest: News & Insights – September Edition" newsletter by the National Institutes of Health (USA) start with a "Director's Message" that states:"[...] September also brings Healthy Aging Month—a good time to think about steps we can take to support our health now and in the future. One important step is getting enough essential nutrients, including vitamin B12. Vitamin B12 helps keep our red blood cells and nerve cells healthy, as well as support our DNA synthesis, energy levels, and metabolism. Importantly, as people age, their bodies may not absorb enough vitamin B12 from food. For many adults aged 50 and older, fortified foods or dietary supplements can help them get enough vitamin B12. [...]"
Additionally, the "Supplements in the News" section starts with an article on the Reports and Proceedings of the American Society for Nutrition: A daily multivitamin may help older adults maintain functional health.
This view on supplementation is not very widely accepted in Europe (maybe in the UK).
Side note: The study participants were a pretty selective sample, as they all had to be willing to be randomised to a vegan diet.
Take home message: Protein is important. Eating more protein - whatever is the optimal amount for you, surely no protein powders or crazy amounts are needed - can strengthen your muscles (and bones - not shown in this paper). Also: Eating more protein can help reduce body fat, especially if eating protein means legumes, which are low in fat and calories and relatively high in protein. These views are relatively well-established in present-day nutritional epidemiology - although nothing is nutrition science is fully established.
Reference
Jacintha Domić, Pol Grootswagers, Philippe Jm Pinckaers, Max Melchers, Luc Jc van Loon, Lisette Cpgm de Groot: A self-selected vegan diet reduces skeletal muscle mass in healthy older adults: a randomized controlled trial. Am J Clin Nutr . 2026 Sep;124(3):101416. Epub 2026 Aug 14.
PMID: 42680254 DOI: 10.1016/j.ajcnut.2026.101416, https://pubmed.ncbi.nlm.nih.gov/42680254/
