Researchers wanted to find out whether increasing protein intake could aid obese older adults in losing weight and maintain muscle mass whilst improving physical limitations.
Older adults can find exercising and losing weight difficult due to physical limitations. Improper dieting can also diminish muscle mass in addition to fat.
Study parameters
Researchers from the Duke University Medical Centre in North Carolina enrolled 67 obese adults aged 60 years and older. They had a Short Physical Performance Battery (SPPB) assessment, which evaluated balance, gait, strength, and endurance.
The SPPB assessment score ranges from zero (worst performance) to 12 (best performance). Those who scored between four and 10 were selected for the study
Individuals were then placed in one of two groups: a control group that stuck to a traditional weight loss programme, and the other increased protein intake at each meal.
Researchers made a note of physical performance scores and BMI at baseline, at three months, and after six months.
At the 6-month follow-up, researchers found that the protein group lost more weight (-8.7±7.4 kg) than the control group (-7.5±6.2 kg), and the protein group had higher improved physical function scores (+2.4±1.7 units) than the control group (+0.9±1.7 units).
“Obese, functionally limited older adults undergoing a 6-month weight loss intervention with a meal-based enhancement of protein quantity and quality lost similar amounts of weight but had greater functional improvements relative to the control group,” commented the research paper.
“If confirmed, this dietary approach could have important implications for improving the functional status of this vulnerable population.”
Protein-centric diets
High-protein diets have been the focus of an ongoing trend in recent years, where the addition of protein-rich foods in a dietary regimen has yielded a number of health benefits, including strength gains, greater fat loss and improved feelings of satiety.
These benefits are of particular advantage to older individuals, in which physical limitations manifest and additional diet and exercise is needed to keep fit and healthy. To complicate matter further, the muscle building capabilities of older individuals further diminish with age.
The potential value of protein supplements and/or protein-centric meals and the importance of complete (animal source) protein for maintaining muscle quality have been well-documented, particularly in older participants.
Protein supplementation amongst the obese elderly are represented by a trio of noted studies.
One study evaluated a whey protein supplement (25 g twice daily for six months, plus exercise) and found no differential effects on physical function or lean muscle.
Likewise, in a small (n =11), short-term (8-weeks) study using whey protein plus essential amino acids and no exercise intervention, researchers found no protein effect on lean muscle; functional outcomes were not reported.
In contrast to these findings, another piece of research compared a combination supplement (daily 20.7 g leucine-rich whey protein, vitamin D, other nutrients; 13 weeks) to an isocaloric control (with resistance training in both groups) and reported a protein benefit for appendicular muscle mass.
This result could relate in part to resistance training, which is well known to enhance the effect of protein supplementation on muscle building. However, while function improved in this trial, there was no group difference.
Source: The Journals of Gerontology
Published online ahead of print, doi: 10.1093/gerona/glv210
“Improved Function With Enhanced Protein Intake per Meal: A Pilot Study of Weight Reduction in Frail, Obese Older Adults.”
Authors: Kathryn Porter Starr, Carl Pieper, Melissa Orenduff, Shelley McDonald, Luisa McClure, Run Zhou, Martha Payne and Connie Bales