Seniors should spread protein intake throughout day, researchers flag

17 Mar 2020 --- Older people should be spreading their protein intake evenly across all meals to most effectively mitigate against age-related muscle loss. This is according to research from the University of Birmingham, UK, which found that in comparison to young and middle-aged people, older study participants were more likely to eat a lower-quality protein source, such as bread, at lunchtime. The researchers highlight that this offers evidence for revised nutritional guidelines and are calling for a “more sophisticated and individualized” approach.

“These findings contribute to a growing body of evidence suggesting that dietary protein guidelines should be altered for older adults. While many older adults consume more than the current recommendations for dietary protein, it is clear that their protein is consumed in an uneven fashion. This means very little with breakfast and lunch and most of the daily protein coming at dinner time,” Dr. Leigh Breen, Senior Lecturer in Exercise Physiology and Metabolism at the University of Birmingham and an author of the study, tells NutritionInsight.

He continues that to support muscle mass and strength in older age, the researchers believe that sufficient protein (at least 30 g on average) needs to be consumed at each main meal throughout the day. Evenly distributing protein helps to ensure that each meal provides sufficient amino acids to support muscle mass in older age.

“The muscle growth response to food intake is relatively short-lived, no more than several hours. Therefore, there is a need to ensure that sufficient protein is consumed around four hours after the previous meal. Even spreading of protein intake helps to ensure muscle benefit repeatedly across the day, as opposed to an uneven protein distribution that would support muscle growth responses on just one occasion in the day,” Dr. Breen details.

Influencing guidelines
The research was inspired by a drive to generate evidence to support the idea that dietary protein recommendations need to be reconsidered in older adults. “We know that older muscles need more dietary protein than younger muscles, but this is not reflected in the current guidelines, where recommendations are broadly similar for all adults. Hence, we wanted to characterize the eating habits of healthy older adults in our local population,” explains Dr. Breen. 

The results show that a one-size-fits-all guideline for protein intake isn’t appropriate across all age groups. Meanwhile, Dr. Benoit Smeuninx, first author of the study, states that the 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.”

Dr. Breen further adds that certain aspects of the findings were surprising, while others were not. Previous research had established that dietary protein intake alters with advancing age for a number of reasons, including but not limited to changes in taste perception, chewing efficiency and socio-economic factors, for example cost and eating out less.

“While we were encouraged that many of our healthy older population consumed protein above the current recommended level, we were surprised to see how low protein intake was at breakfast and lunch. Even more concerning was that the quality of protein at these meals was often quite low, meaning that these protein sources would not provide all the amino acids that our muscles need,” he continues.

Protein for seniors has been a key focus for many companies in recent years as people are living longer lives than ever before. NutritionInsight has previously reported on how companies are rapidly innovating to address a range of needs, with muscle mass-protecting protein being a particular emphasis.

Younger people to benefit from spreading protein?
The study divided 120 participants into three groups, with average ages of 23, 51 and 77. The participants completed a food diary over a three-day period, weighing out every single food item consumed. This allowed the researchers to identify 18 different patterns of protein intake throughout the day, showing a wide variety of eating habits.

Dr. Breen says that it is currently unclear if younger people would also benefit from spreading their protein. “Younger adults need less protein to support their muscle mass, so it is easier for younger adults to consume sufficient amounts with each main meal. However, younger athletic populations may benefit from higher and more regular protein intakes and this strategy should be considered in order to support the training goals of this population.”

Looking forward, future areas of research include studying how protein needs in hospitalized individuals could aid the maintenance of muscle mass. Another avenue of exploration is the interaction between physical activity protein consumption in the fight against age-related muscle loss.

By Katherine Durrell