In ageing societies such as Japan, more attention is paid to geriatric syndromes like frailty and sarcopenia, as such conditions compromise one's independence and overall quality of life.
The prevalence of frailty in Japan has been reported at 11.6% among those deemed frail, and 60.4% among those deemed pre-frail.
Experts have recommended a minimum of 1g/kg of body weight of daily protein intake in healthy older adults in order to maintain muscle mass.
Enough protein for prevention?
Researchers at Tokyo's National Institutes of Biomedical Innovation therefore set out to evaluate protein and amino acid intake and distribution among the Japanese, in terms of how their consumption might help prevent frailty or sarcopenia.
Using data from Japan's 2012 National Health and Nutrition Survey (NHNS), they recruited respondents aged 30 and above who were neither pregnant nor lactating, and whose dietary intake, weight and height data were available.
They then calculated the participants' consumption of protein and amino acids.
They subsequently reported that although over 95% of the participants' protein intake met the levels recommended by Japan's Dietary Reference Intake, almost 50% did not consume enough protein to help prevent sarcopenia.
Additionally, leucine intake was insufficient across all the age and sex groups, possibly due to lower consumption of animal protein, particularly protein from milk and other dairy goods.
Distribution-wise, the participants tended to have protein and leucine mostly during dinner.
The researchers stated that the limitations of the study included the lack of NHNS data for muscle strength and body composition, which prevented them from examining the link between protein intake and the prevalence of sarcopenia and frailty.
At the same time, the survey only covered one day of dietary record for each household that participated, and individual consumption was proportionally divided based on household intake.
The survey did, however, cover all areas of Japan, thereby presenting data representative of dietary intake for the Japanese population.
The researchers concluded: "Although optimal protein intake to prevent sarcopenia or frailty remains unclear, the protein intake among the Japanese population might be insufﬁcient in quality, quantity and distribution."
Source: Geriatrics Gerontology International
"Current protein and amino acid intakes among Japanese people: Analysis of the 2012 National Health and Nutrition Survey"
Authors: Kazuko Ishikawa-Takata, Hidemi Takimoto