Muscle mass decreases markedly with aging, compromising overall fitness and contributing to frailty, disability, and falls. Findings from a recent study suggest that dietary fiber helps reduce muscle mass losses associated with aging.
Dietary fiber refers to the indigestible components of plant-based foods. It is classified as either soluble or insoluble. Soluble fiber, which is found in grains, nuts, seeds, legumes, and some vegetables and fruits, dissolves in water and may reduce blood glucose and cholesterol levels. Insoluble fiber, which is found in wheat bran, vegetables, and whole grains, does not dissolve in water. It promotes digestive health. Processed foods are typically low in fiber.
According to the Dietary Guidelines for Americans, the recommendations for combined fiber intake vary according to age and sex. Women need between 22 and 28 grams of fiber per day, and men need between 28 and 34 grams per day. Most people living in the United States only get about half of the recommended amounts of fiber daily.
The authors of the study drew on data collected over a seven-year period via the National Health and Nutrition Examination Survey. Study participants, which included more than 5,000 adults aged 40 years and older, provided information about their dietary intake and underwent physical exams (including the collection of blood and urine samples) to assess body composition, grip strength (a predictor of functional impairment and premature death), and metabolic health.
They found that people whose diets were rich in dietary fiber had greater lean body mass, bone mineral content, and grip strength compared to those with low intake. People whose diets were rich in dietary fiber were also more likely to have lower body mass index, body fat, fasting glucose, fasting insulin, and HOMA-IR (a measure of insulin resistance) than those with low intake.
These findings suggest that higher dietary fiber intake helps maintain muscle mass in older adults. Evidence indicates that sauna use improves muscle and bone mass, as well. Learn more about the health benefits of sauna use in this article by Dr. Rhonda Patrick.
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