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Antioxidant intake associated with maintenance of physical strength in older individuals
Data obtained from the Invecchiare in Chianti study (InCHIANTI), which involved over a thousand Italians between the ages of 65 and 102, has revealed an association between dietary intake and plasma levels of antioxidant vitamins and levels of strength and physical performance. The purpose of InCHIANTI was to identify risk factors for the onset of disability in an older population.
Recent research has suggested that the decline in physical strength and abilities that occurs with age could be related to oxidative damage caused by free radicals to the skeletal muscles. In order to investigate the hypothesis that dietary antioxidants could prevent such a decline, the current study’s research team analyzed data from 986 InCHIANTI participants. To determine daily nutritional intakes, questionnaires were administered to each participant and evaluaed for levels of beta-carotene and vitamins A, E and C. Blood samples were analyzed for the alpha and gamma-tocopherol forms of vitamin E. Physical performance was assessed by tests of walking speed, ability to stand from a chair and standing balance, and strength was evaluated by knee extension testing.
Adjusted analysis of the data found that plasma alpha-tocopherol levels were associated with both strength and physical performance, while gamma-tocopherol was associated only with strength. Dietary vitamin C was found to be correlated with physical performance, and both vitamin C and beta-carotene were correlated with strength.
To the authors’ knowledge, this is the first study to evaluate the effects of dietary and plasma antioxidants on physical performance and strength in older persons. The report was published in the February 2004 issue of The American Journal of Clinical Nutrition (http://www.ajcn.org/).
Muscle loss can result from the combined effects of many age-related changes. Insulin-like growth factor-1 (IGF-1) is a growth hormone responsible for cell growth, maintenance, and repair in a variety of different tissues including muscle, GI (gastrointestinal) tract, and skin. Reduced IGF-1 signaling is implicated in muscle atrophy resulting from reduced growth hormone and treatment with drugs such as corticosteroids, dexamethasone, and cyclosporin. Under-nutrition resulting in a lack of vitamin D and physical inactivity are also factors in age-related muscle loss. In addition, elevated levels of inflammatory cytokines like TNF-alpha and IL-6 can cause muscle wasting (cachexia), although this is usually associated with disease (Visser et al. 2002). TNF-alpha may also act (at least in part) by inhibiting IGF-I signaling (Grounds 2002). In aging males, muscle loss can also be the result of the down-regulation of the hypothalamic-anterior pituitary-testicular axis (see the Male Hormone Modulation Therapy protocol).
As aging progresses, there are relative increases in body fat and decreases in muscle mass. The increase in adipose tissue is connected to an increase in the enzyme aromatase which converts testosterone to estradiol and leads to diminished testosterone levels and the deposition of visceral fat. As the total body fat mass increases, hormone resistance for insulin ultimately develops (Cohen 2001). For women, it is now well established that the decline in testosterone and the adrenal preandrogens also plays a significant role in affecting perimenopausal and menopausal symptomatology and quality of life. Loss of circulating levels of androgens affects libido, vasomotor symptoms, mood and well being, bone structure, and muscle mass (Burd et al. 2001).
Anyone interested in muscle building needs to be aware of the importance of maintaining a positive nitrogen balance. A positive nitrogen balance indicates that the body is receiving the optimum amount of protein that's required for muscle growth. Whey protein has the highest biological value of any protein yet studied. Its other health benefits include boosting immune function and protecting against muscle wasting. A daily dose of 3-4 scoops of Enhanced Life Extension Protein (containing whey and lactoferrin) will ensure that one is obtaining a highly bioavailable and digestible source of protein. In addition, 6-10 grams of the amino acid glutamine can also help the muscle-building process. Research shows that levels of glutamine are closely associated with muscle protein synthesis (Hammarqvist et al. 1989; Vinnars et al. 1990; Darmaun 1994; Roth et al. 1996).
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Skeletal muscle, heart, brain, and other tissues metabolize creatine and use it as a major energy storage form. Creatine boosts levels of ATP in the mitochondria, the cell’s energy powerhouse.
While studies have shown that creatine may indeed help build muscle and strength in explosive short duration activities, other research has demonstrated the supplement’s role in improving lean muscle mass.
Whey protein isolate can build lean muscle and prevent protein breakdown. It has also been shown to enhance the production of glutathione, the body’s natural antioxidant.
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- When brain cells (neurons) are exposed to known neurotoxic agents, creatine administration guards against damage by creating larger energy reserves. Other findings suggest that creatine may help the brain to recover from injury resulting from trauma, such as stroke.
- Creatine may help in the treatment of neuromuscular conditions, marked by impaired energy production and accelerated muscle atrophy, such as ALS, Huntington's Parkinson's and muscular dystrophies. Research shows that creatine helps by notably increasing muscle strength.
- Creatine increases physical strength and endurance in people with chronic heart failure by restoring cardiac creatine concentrations to meet the organ's high energy requirements.
- Creatine can increase strength and endurance in healthy aging individuals, by increasing cellular energy levels and their ability to repair DNA damage from cumulative oxidative stress.
- Many creatine products are sold on the American market, but the most absorbable form is micronized creatine monohydrate imported from Germany. Life Extension now offers three different micronized creatine supplements to provide this energy-booster to cells throughout the body.
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