The study, published in the Journal of the American Geriatrics Society, investigated the potential associations between protein intake and the risk of higher-level functional decline in older adults - finding that higher protein, particularly animal protein, was associated with lower risk of decline in higher-level functional capacity in older men.
Led by Dr Megumi Tsubota-Utsugi from the National Institute of Health and Nutrition in Japan, the team explained that increasing life expectancies in many countries is leading to an higher number of elderly people living with functional declines, such as declines in cognitive ability and activities of daily living. These functional declines can have profound effects on health and the economy.
"Identifying nutritional factors that contribute to maintaining higher-level functional capacity is important for prevention of future deterioration of activities of daily living," said Tsubota-Utsugi. "Along with other modifiable health behaviours, keeping higher protein intake could contribute to maintain elderly functional capacity."
Tsubota-Utsugi and her colleagues from Tohoku University and Teikyo University, Japan, noted that previous research suggests that aging may reduce the body's ability to absorb or process proteins, which could mean that protein requirements increase with age.
As a result, they wondered whether protein intake might affect the functional capabilities of the elderly. They designed a study to investigate the relationship between protein intake and future decline in higher-level functional capacity in older community-dwelling adults in the Japanese general population.
Their analysis included 1,007 individuals with an average age of 67.4 years who completed food questionnaires at the start of the study and seven years later. Participants were divided into quartiles according to intake levels of total, animal, and plant protein. Tests of higher-level functional capacity included social and intellectual aspects as well as measures related to activities of daily living.
"During the study period, 24.4% of eligible participants reported declines in higher-level functional capacity," explained the team.
It was found that men in the highest quartile of animal protein intake had a 39% decreased odds of experiencing higher-level functional decline than those in the lowest quartile. The Japanese team noted that these associations were not seen in women and no consistent association was observed between plant protein intake and future higher-level functional decline in either sex.
Source: Journal of the American Geriatrics Society
Published online ahead of print, doi: 10.1111/jgs.12690
"Animal Protein Intake Is Associated with Higher-Level Functional Capacity in Elderly Adults: The Ohasama Study"
Authors: Eri Imai, Megumi Tsubota-Utsugi, et al