The ability of older adults to improve their muscle strength through exercise training appears related to how well their immune system functions. Thus, a nutritional supplement which improves immune function could theoretically boost strength gained for older adults from exercise. The purpose of this pilot study is to determine if a nutritional supplement has any effect on immune function.

Veterans (age 60-80 yrs, N=12) be randomized in a double-blind placebo-controlled fashion to consume supplement or placebo for four weeks. After two weeks of consumption, subjects will be treated with a vaccine for tetanus, diphtheria, and pertussis. Blood will be drawn from each subject before and after vaccination to determine the effects of the supplement on immune response to vaccination. Additionally, subjects will undergo blood draw and muscle biopsy before and after two weeks of supplementation to determine the effects of supplementation on other measures of immune function (e.g. cytokine and growth factor levels). This is an important issue due to the serious health consequences associated with muscle loss in older adults and the need for improved strategies for rehabilitation.

Inclusion Criteria:

• Veteran
• Age 60-80 years
• Body Mass Index of 18.5 - 29.9 kg/m2

Exclusion Criteria:

• Participating in any other research study involving an intervention
• Smokes tobacco products
• Pains, tightness or pressure in chest during physical activity
• Participated in a weight-lifting targeting the thighs in last 3 months
• Problems walking or exercising with both legs
• Taking heparin, plavix / clopidogrel, or coumadin / warfarin
• Allergic to lidocaine
• Significant problem with fainting
• Allergic to vaccination
• Tetanus/diptheria/pertussis vaccine in previous two years
• Seizure in past 3 months
• Guillain-Barre Syndrome in past 3 months
• Enrolled in another interventional study
• Metastatic cancer or undergoing chemotherapy
• Cerebral aneurysm or intracranial bleed in past year
• End-stage congestive heart failure
• Unstable abdominal or thoracic aortic aneurysm
• Renal disease requiring dialysis
• Acute retinal hemorrhage or ophthalmologic surgery in past 3 months
• Bone fractures in the pelvis, legs, or feet in the last 3 months
• Hernia that causes pain during physical activity
• Myocardial infarction or cardiac surgery in past 3 months
• Pulmonary embolism or deep venous thrombosis in past 3 months
• Proliferative diabetic retinopathy or severe nonproliferative retinopathy
• Active suicidality or suicidal ideation
• Systemic bacterial infection
• Taking aspirin (in any form) and unable/unwilling to discontinue
• Unwilling to halt concurrent use of amino acid or protein supplements
• Unwilling to halt new use of nutritional supplements
• Unwilling to maintain current normal diet
• Encephalopathy in past 7 days
• Active oral or genital herpes
• Current use of appetite stimulants
• Current treatment for mania or bipolar disorder or taking lithium
• Diagnosis of a significant cognitive deficit
• Untreated severe aortic stenosis
• Uncontrolled diabetes mellitus
• Uncontrolled hypertension or hypotension (>160/100, <100 systolic)
• Uncontrolled malignant cardiac arrhythmia
• Unstable angina (at rest or increased pattern in past month)
• Allergic to latex or tape
• Bleeding or clotting disorders
• Taking any nonsteroidal anti-inflammatories and unable to discontinue use
• Taking certain supplements and unable or unwilling to discontinue use
• Significant problems with chronic pain
• Uncontrolled asthma or allergies
• Taking lactulose, nitrates plus hypertension medications, or Viagra
• Liver cirrhosis or other severe liver disease
• History of peripheral artery disease
• Steroid or androgen use in past 3 months
• Other physician judgment