Nutrition and Exercise for Sarcopenia
| Status: | Active, not recruiting |
|---|---|
| Conditions: | Orthopedic |
| Therapuetic Areas: | Orthopedics / Podiatry |
| Healthy: | No |
| Age Range: | 65 - 85 |
| Updated: | 4/21/2016 |
| Start Date: | March 2009 |
| End Date: | August 2017 |
Nutrition and Exercise to Improve Protein Metabolism and Prevent Sarcopenia in Aging
The investigators' general hypothesis is that nutritional factors, including protein/energy
malnutrition and/or an impaired response of muscle to nutrition, and inactivity play
significant roles in developing sarcopenia, the involuntary loss of muscle mass and function
with age. Therefore, age-specific prolonged interventions including nutritional
manipulations and/or exercise may help to reduce, stabilize, or even reverse sarcopenia.
malnutrition and/or an impaired response of muscle to nutrition, and inactivity play
significant roles in developing sarcopenia, the involuntary loss of muscle mass and function
with age. Therefore, age-specific prolonged interventions including nutritional
manipulations and/or exercise may help to reduce, stabilize, or even reverse sarcopenia.
Our preliminary studies indicate that, in older adults, muscle protein anabolism is normally
stimulated by amino acids alone, but impaired when nutritional stimuli contain carbohydrate
due to a relative insulin resistance of muscle protein synthesis. We have also found that
amino acids are the most efficient nutrients for the acute stimulation of muscle protein
anabolism and our pilot data suggest that they can also increase muscle mass in healthy
older adults.
Inactivity is another likely contributor to sarcopenia. Exercise increases not only muscle
protein synthesis,mass and strength, but also energy expenditure. Hence, exercise may
improve the response of muscle to nutritional interventions in older subjects via increased
energy requirements and food consumption, thereby allowing for achievement of true
supplementation.
We will test the following specific hypotheses in older, community indwelling, sedentary
subjects:
Using a factorial design we will address in older, community-indwelling, sedentary subjects
the following hypotheses:
1. Nutritional supplementation with amino acids will improve muscle mass, strength,
function, quality, and protein synthesis.
2. Progressive exercise training for 24 weeks will improve muscle mass strength,function,
quality, perfusion, and protein metabolism.
3. Combined treatment with nutritional supplementation and progressive exercise training
for 24 weeks will improve muscle mass, strength, function, quality, perfusion, and
protein metabolism more than either intervention alone.
Our goal is to establish if specific interventions that can acutely increase muscle protein
synthesis can also effectively translate into increased muscle mass and/or performance in
older sedentary people, thus preventing frailty and promoting physical independence. To this
end we will use stable isotope methodologies to measure muscle protein metabolism and
contrast enhanced ultrasound to measure muscle perfusion, in order to determine if the
treatments' acute effects can predict their chronic impact on muscle mass and function. We
will also determine if chronic treatment leads to metabolic and/or vascular adaptations that
may explain the measured changes in muscle mass and function.
stimulated by amino acids alone, but impaired when nutritional stimuli contain carbohydrate
due to a relative insulin resistance of muscle protein synthesis. We have also found that
amino acids are the most efficient nutrients for the acute stimulation of muscle protein
anabolism and our pilot data suggest that they can also increase muscle mass in healthy
older adults.
Inactivity is another likely contributor to sarcopenia. Exercise increases not only muscle
protein synthesis,mass and strength, but also energy expenditure. Hence, exercise may
improve the response of muscle to nutritional interventions in older subjects via increased
energy requirements and food consumption, thereby allowing for achievement of true
supplementation.
We will test the following specific hypotheses in older, community indwelling, sedentary
subjects:
Using a factorial design we will address in older, community-indwelling, sedentary subjects
the following hypotheses:
1. Nutritional supplementation with amino acids will improve muscle mass, strength,
function, quality, and protein synthesis.
2. Progressive exercise training for 24 weeks will improve muscle mass strength,function,
quality, perfusion, and protein metabolism.
3. Combined treatment with nutritional supplementation and progressive exercise training
for 24 weeks will improve muscle mass, strength, function, quality, perfusion, and
protein metabolism more than either intervention alone.
Our goal is to establish if specific interventions that can acutely increase muscle protein
synthesis can also effectively translate into increased muscle mass and/or performance in
older sedentary people, thus preventing frailty and promoting physical independence. To this
end we will use stable isotope methodologies to measure muscle protein metabolism and
contrast enhanced ultrasound to measure muscle perfusion, in order to determine if the
treatments' acute effects can predict their chronic impact on muscle mass and function. We
will also determine if chronic treatment leads to metabolic and/or vascular adaptations that
may explain the measured changes in muscle mass and function.
Inclusion Criteria:
1. age 65-85 yrs
2. ability to sign consent form (score >25 on the 30 item Mini Mental State Examination,
MMSE)
3. stable body weight for at least 1 year (verified via medical records).
Exclusion Criteria:
1. physical dependence or frailty (impairment in any of the Activities of Daily Living
(ADL), history of falls (≥2/year) or significant weight loss in the past year)
2. exercise training (≥2 weekly sessions of moderate-to-high intensity aerobic or
resistance exercise)
3. significant heart, liver, kidney, blood or respiratory disease
4. peripheral vascular disease
5. diabetes or other untreated endocrine disease
6. active cancer
7. recent (within 6 months) treatment with anabolic steroids, or corticosteroids
8. alcohol or drug abuse
9. tobacco use (smoking or chewing, verified via medical records)
10. depression (>5 on the 15-item Geriatric Depression Scale (GDS))
11. malnutrition (BMI <20 kg/m2; hypoalbuminemia or hypotransferrenemia; protein
intake<0.66 g/kg/day at run-in)
12. obesity (BMI>30 kg/m2).
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