Timing is everything: What older populations need to know about protein intake
Recent research from the School of Sport, Exercise and Rehabilitation Sciences at the University of Birmingham, found that dietary protein consumption may play a role in sarcopenia, the loss of age-related muscle mass and function.
Due to the lack of evidence on dietary protein habits across the adult lifespan, researchers examined the dietary intakes of healthy young, middle-aged and older community-dwelling individuals living in the United Kingdom. The research team specifically wanted to study the participant’s amount, source and pattern of protein intake.
The study involved 120 participants, who were divided into three groups of 40 based on age. The youngest group included participants who were 23 years of age on average; the second group averaged 51 years of age; and the older group was 77 years old on average.
Participants' height and body mass were assessed in light clothing using a stadiometer and digital scales. Participants were given a 3-day food diary to be completed over two days during the week and one day over the weekend. The food diary required participants to provide the time, preparation method, brand and weight of all food ingredients and drinks consumed.
The primary focus was patterns in the dietary behavior of participants, with protein intake evaluated across the different age groups. The researchers identified 18 different patterns of protein intake throughout the day, illustrating a wide variety of eating habits.
Most noticeably, the team found that older people, compared to young and middle-aged individuals, were more likely to eat a lower-quality protein source at lunchtime.
In order for the body to produce new muscle, it needs stimulation, which occurs when we eat protein. The process becomes less efficient the older we get, so older populations require more protein intake in order to see the same results as younger people.
The results suggest that dose, timing, source and distribution of dietary protein across the day impacts muscle building across all ages.
“Although total daily protein intake was sufficient in the majority of participants, per-meal protein intake and protein distribution contend the current knowledge regarding optimal protein intakes. Increasing protein intake, especially at breakfast and lunch, could mitigate age-related muscle loss,” the report concludes.
No one-size-fits-all approach
The authors note that despite strong evidence to suggest a benefit and need for higher protein intakes to support muscle mass and strength in older individuals, no Recommended Dietary Allowance (RDA) guidelines exist in this population.
"Most people are reaching the Recommended Daily Allowance of protein, but our results show that a one-size-fits-all guideline for protein intake isn't appropriate across all age groups. Simply saying older people should eat more protein isn't really enough either. We need a more sophisticated and individualized approach that can help people understand when and how much protein to consume to support muscle mass,” said Dr. Benoit Smeuninx, first author on the study.
The results could have implications on future revisions to nutritional guidelines, offering direction to older people who may need to adopt eating habits that include more balanced protein consumption.
Source: Frontiers in Nutrition
16 March 2020 DOI: 10.3389/fnut.2020.00025
“Amount, Source and Pattern of Dietary Protein Intake Across the Adult Lifespan: A Cross-Sectional Study”
Authors: B. Smeuninx et al.