Weight loss and improving body composition is a primary goal for many, but what is far less appreciated and addressed is the correlation between optimal body composition and overall health. Lean mass plays an important role in preventing obesity and illness and can provide optimal health and overall improved quality of life.
Health and Lean Mass
It is no secret that muscle mass is tied to strength, exercise ability and metabolic function, however the relationship between body composition, and strength, is also closely associated with health, aging, and disease. Low lean mass resulting in increased fat mass, are predictors of disability, obesity and mortality. Basal metabolic rate (the amount of calories one burns at rest) accounts for almost 70% of the total daily calories burned, and the amount of lean muscle mass can account for almost half of an individual’s basal metabolic rate. Simply put, if you have low lean muscle mass, you will have a lower basal metabolic rate, and the result is weight gain, specifically in fat mass. Additionally, low muscle mass often leads to diminished strength and can contribute to mobility issues, osteoporosis, falls and fractures, frailty, and loss of physical function and independence (2). Building and maintaining adequate lean mass is therefore fundamental for activities of daily living and quality of life.
Individuals tend to build muscle mass over the first two decades of life, then lose muscle mass and strength between the third and fourth decade, and the decline accelerates during the sixth decade (2). In addition to age, decreased physical activity, changes in sex hormone levels, increased cytokines as well as increased cortisol will accelerate the loss of lean mass. Men as compared to women see a sharper decline in lean mass with age as a result of hormonal factors, specifically declines in growth hormone and testosterone levels. As lean mass declines in men and women, fat mass and connective tissue mass will subsequently increase.
The losses of lean mass and gain in fat mass presents health and survivability risks. The maintenance of protein content of specific tissues and organs, such as the skin, brain, heart, and liver, is essential for survival. As lean mass declines, the risk of chronic disease increases. These diseases include: congestive heart failure, obstructive pulmonary disease, autoimmune diseases, diabetes, peripheral artery disease, and cancer. Chronic diseases related to poor lifestyle behaviors account for more than two-thirds of deaths in the United States (3). Specifically, type 2 Diabetes has reached epidemic proportions in the US due to poor lifestyle behaviors to include being sedentary and improper macronutrient balances. Research reveals type 2 diabetic subjects maintained on a high protein intake had improved glycemic control and lower HbA1c’s (4). Both of these parameters directly influence morbidity and mortality risk. The pre diabetic and diabetic patient can improve their health and quality of life by making behavioral changes to include increased exercise activity as well as decreasing carbohydrate intake and conversely increasing dietary protein and healthy fats.
Exercise and Lean Mass
Strength training in combination with the right balance of dietary protein and antioxidants is critical in achieving an increase in lean mass. Without the inclusion of resistance training and adequate protein via diet, wasting of muscle mass and the increase of adipose mass will occur.
A sedentary lifestyle is a strong risk factor for accelerated decline of lean body mass. Inactivity will impair mitochondrial oxidative capacity, the balance of protein synthesis and degradation, and influences the ability of muscle-cell regeneration. While inactivity results in the decline of lean mass, exercise without proper protein intake can have similar disruptions. Exercise causes an increase in catabolic hormone release. These catabolic hormones include cortisol, epinephrine, glucagon, and norepinephrine and muscle contains most of the receptors for insulin, cortisol and glucagon. Catabolic hormones cause protein stores to breakdown, therefore having adequate protein prior, during and post workout is key in order to keep the body in protein synthesis, minimize injury and avoid immune issues.
Diet and Lean Mass
Muscle protein or percent of lean mass is strongly influenced by protein intake in the diet. High dietary protein intakes increase protein synthesis by increasing systemic amino acid availability (5). The anabolic effect of exercise is amplified by the presence of protein in the diet as amino acid availability increases muscle protein turnover. Dietary protein recommendations for influencing muscle protein turnover range between 1.0-2.0g/kg, dependent on sport specific training goals. Despite variances in recommendations, experts agree the current recommendation of 0.8g/kg of protein falls short in achieving gains in lean mass and decreasing fat mass. As we age, older individuals struggle to eat enough protein to even meet the low recommendations of 0.8g/kg and thus they are at increased risk of sarcopenia/muscle wasting.
The good news is that for people who want to stay strong in their older age, older bodies are just as good as young ones in turning protein- rich food into muscle as indicated in the August 2013 issue of the American Journal of Clinical Nutrition (6). The unfortunate news is that all too often the amount of protein consumed by older adults falls short to sustain lean muscle mass and thus negatively influences health and quality of life. Protein supplementation for many groups, i.e. elderly, immune compromised and athletes, becomes necessary to avoid muscle degradation.
Supplementation and Lean Mass
The supplementation of protein both pre- and post-workout increases physical performance, training session recovery, lean mass, muscle hypertrophy, and strength (7). More specifically whey protein is beneficial as it delivers the correct amino acids in proportion to the ratio of skeletal muscle. Whey protein supplementation preserves muscle mass by creating and maintaining a high concentration of essential amino acids (EAA) in the blood. These EAA’s improve the physical function and strength of an individual by stimulating the synthesis of myofibrillar proteins (8). EAA’s are also necessary for energy production in the Kreb’s cycle within the mitochondria and can influence the number of mitochondria. Of the 9 EAA’s, specifically the branched chain amino acids, (BCAA’s) and even more specific leucine is directly involved with the regulation of protein synthesis (5,7). BCAA’s have the strongest influence in increasing lean mass by stimulating mitochondrial biogenesis and triggering growth and repair. Supplementation with BCAA’s can also reduce time to fatigue by increasing ATP production in the myocardium and may be useful for the treatment of metabolic syndrome and the prevention of cardiovascular risk in aging. (9).
Research supports the benefits of amino acid supplementation for various subpopulations to positively influence health and quality of life. The benefits are documented for those diagnosed with diabetes, insulin resistance, cardiovascular disease, COPD, sarcopenia, cancer and cancer cachexia. Amino Acid supplementation is beneficial for many to promote a proper balance between anabolic and catabolic muscle stimuli.
Bottom Line: Optimal health and quality of life are directly related to body composition characterized by increased amounts of lean mass and low fat mass. It is important to emphasize the health benefits associated with lean mass and the role exercise, macronutrient balance, and proper supplementation play in order to achieve optimal body composition.
The information provided in this post is for education only and is not intended for the treatment or prevention of disease, nor should it be used as a replacement for seeking medical treatment.
Copyright © Jaime Coffey Martinez, Nutrition CPR, LLC
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