Can Plant-Based Diet Deliver Ample Protein for Older Adults?

TOPLINE:
Replacing animal-based protein sources with plant-based alternatives in older adults reduced both the quality and quantity of protein intake only when all animal-based foods were eliminated for a vegan scenario, finds a simulation study that suggests a switch to 60% plant-based protein seems to be safe.
METHODOLOGY:
For environmental and health reasons, the Dutch Health Council advises a switch to an animal-based to plant-based protein ratio of 40:60, but older adults also need adequate protein intake to prevent muscle loss and maintain health, and it’s uncertain if they can meet their protein requirements through a more sustainable diet.
This simulation study evaluated the impact of more sustainable eating patterns on protein quantity and quality by using data of 607 community-dwelling older adults aged 65-79 years from the Dutch National Food Consumption Survey 2019-2021.
Data on food consumption were collected via two 24-hour dietary recalls per participant on nonconsecutive days and calculated as three main meals and four in-between moments each day.
In the simulation, certain food products in the original diet were replaced from a list of similar plant-based alternatives, using a random number generator, to create scenarios for two flexitarian diets (40% and 80% meat and fish were replaced), one pescetarian diet (meat was replaced, but not fish and other animal-based products), one vegetarian diet (meat and fish were replaced, but not other animal-based products), and one vegan diet (fish, meat, and animal-based products were replaced).
Protein intake was calculated in three ways for each meal moment, including by total protein intake (quantity) and by the proportion of indispensable amino acids that must be eaten together within a limited timeframe (quality).
TAKEAWAY:
In the reference diet, the total daily plant-based protein intake was 39.0% in men and 37.7% in women, while in the vegetarian scenario, it was 59.1% in men and 54.2% in women.
In the flexitarian, pescetarian, and vegetarian scenarios, the usable protein intake was comparable; in the vegan scenario, both total protein intake and usable protein intake were lower, leading to nearly 50% less usable protein than in the original diet.
In the original diet, 7.5% of men and 11.1% of women did not meet the estimated average requirements (EARs) for utilizable protein; in the vegan scenario, 83.3% of both sexes had a protein intake below the EAR.
The loss in protein intake (quantity) in all scenarios was mainly observed at dinner; the loss in protein quality was greatest at breakfast and lunch, especially in lysine (found in beans or soy milk).
IN PRACTICE:
“Changing protein intake to 60% plant-based protein seems to be safe for older adults in terms of protein intake. In contrast, a vegan pattern was associated with a substantial decline in protein availability, leading to a majority of older adults not reaching the recommended protein levels,” the authors wrote.
SOURCE:
The study was led by Jos W. Borkent, HAN University of Applied Sciences, Nijmegen, the Netherlands. It was published online in The Journal of Nutrition, Health and Aging.
LIMITATIONS:
Study limitations included the use of a simulation model, which may not fully reflect real-life dietary practices. The strict timeframe for assessing protein quality (optimal combinations of indispensible amino acids) within one meal moment may have led to an underestimation of protein availability, especially in the vegan scenario. Additionally, the choice of processed meat replacements in the vegan scenario may not have represented protein sources of the highest quality available. Higher protein quality per meal in the vegan scenario is possible when smart combinations are made in multiple meal components.
DISCLOSURES:
The study was partly funded by a grant from the Taskforce for Applied Research SIA, which is part of the Netherlands Organisation for Scientific Research and financed by the Dutch Ministry of Education, Culture and Science and by a fund of the Dutch Dairy Association. The authors declared that they had no conflicts of interest.
This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.
 
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