Guest Post by Jaime Martinez, MS, RD of Nutrition CPR
Improved body composition and aesthetics are often primary goals for those who work with fitness professionals.
Though body composition is often a primary goal, what is far less
appreciated 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
Muscle mass improves strength, exercise ability and metabolic function. More importantly, it affects the aging process as well.
Low levels of muscle and excess body fat 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. 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, which can lead to unwanted, extra body fat.
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.
[i]
Building and maintaining adequate lean mass is fundamental for
activities of daily living and quality of life. Individuals tend to
build muscle mass over the first two decades of life, lose muscle mass
and strength between the third and fourth decade, and the decline
accelerates during the sixth decade.[i]
In addition to age, decreased physical activity, changes in sex
hormone levels, increased inflammation as well as increased cortisol
will accelerate the loss of lean mass. Men see a sharper decline in lean
mass with age as a result of hormonal factors, specifically declines in
growth hormone and testosterone levels.
Disease and Lean Mass
As lean mass declines, it can be replaced with fat mass and
connective tissue. The losses of lean mass and gain in fat mass present
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.
[ii]
Specifically, type 2 diabetes has reached epidemic proportions in the
US. Research reveals type 2 diabetic subjects maintained on a high
protein intake had improved glycemic control and lower HbA1c’s.
[iii] Both of these parameters directly influence morbidity and mortality risk.
Strength Training and Lean Mass
The pre-diabetic and diabetic patient can improve their health and
quality of life through exercise, reduced carbohydrate intake and
increased consumption of protein and healthy fats. Strength training and
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
intake, 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 impairs 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 break
down.
Adequate dietary protein prior, during and post workout helps avoid
increases in protein breakdown and decreases in protein synthesis during
exercise.
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.
[iv]
The anabolic effect of exercise is amplified by the presence of
protein in the diet. 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.
[v]
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.
[vi]
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.
[vii]
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, are directly involved with the regulation of
protein synthesis.[iv],[vi]
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.
[viii]
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.
[i]
Lushaj EB, Johnson JK, McKenzie D, Aiken JM : Sarcopenia accelerates at
advanced ages in Fisher 344xBrown Norway rats. J Gerontol A Biol Sci
Med Sci 2008;63:921– 927
[ii]
Anderson RN, Smith BL. Deaths: leading causes for 2002. National Vital
Statistics reports. Vol 53. Hyattsville, MD: National Center for Health
Statistics, 2005. (No. 17.)
[iii]
Gannon MC, Nuttall FQ, Saeed A, Jordan K, Hoover H. An increase in
dietary protein improves the blood glucose response in persons with type
2 diabetes. Am J Clin Nutr 2003; 78: 671–2.
[iv]
Paddon-Jones D, Sheffield-Moore M, Zhang XJ, et al. Amino acid
ingestion improves muscle protein synthesis in the young and elderly. Am
J Physiol Endocrinol Metab. 2004;286:E321-E328.
[v]
Paddon-Jones D, Short KR, Campbell WW, Volpi E, Wolfe RR : Role of
dietary protein in the sarcopenia of aging. Am J Clin Nutr 2008; 87:
1562S– 1566S
[vi]
Stark, M., Lukaszu, J. Prawit, A., Salacinski, A. Protein timing and
its effects on muscular hypertrophy and strength in individuals engaged
in weight-training Journal of the International Society of Sports
Nutrition 2012, 9:54 doi:10.1186/1550-2783-9-54
[vii]
Solerte SB, Gazzaruso C, Schifino N, et al. Metabolic effects of orally
administered amino acid mixture in elderly subjects with poorly
controlled type 2 diabetes mellitus. Am J Cardiol 2004; 93: 23A–9A
[viii]
Nisoli, Enzo, MD, PhD, Cozzi, Valeria, PhD, Carruba, Michele, O. MD,
PhD, Amino Acids and Mitochondrial Biogenesis. Am J Cardiol 2008:
101[suppl]:22E-25E.
