Nutrition
Many athletes take amino acid supplements before or after training with weights to increase their strength and muscle mass. The amino acids contained in proteins act as building blocks for protein synthesis and muscle growth. In addition, key amino acids such as leucine activate chemical pathways that promote protein synthesis. Casein is the main protein component of milk and cheese. Hydrolyzed casein contains protein hydrolysates, which are small packets of amino acids that are formed when milk protein is broken down by acid or enzymes with water.
A French study found that hydrolyzed casein was absorbed faster than intact casein. The body absorbs hydrolyzed casein better than intact casein, resulting in higher blood levels of specific amino acids (e.g. leucine and phenylalanine) and a greater potential for protein synthesis. The study showed that hydrolyzed casein supplements increased blood levels of amino acids and insulin (a highly anabolic hormone) faster and more than intact casein, with intact casein being the longer acting protein.
(American Journal of Clinical Nutrition, 90:1011-1022, 2009)
Extreme overtraining in bodybuilding and physical decline that occurs in diseases such as cancer, AIDS, chronic obstructive pulmonary disease and hydropic cardiac decompensation are typically accompanied by tissue and muscle breakdown, fatigue, weakness and reduced quality of life. Physical deterioration occurs even if the affected person is not actively trying to lose weight. Exercise is often not a suitable option for preventing such deterioration, as people lack the energy and motivation for physical activity. Dietary strategies can be effective to some extent in preventing physical decline, maintaining body weight and improving quality of life.
A literature review conducted by Greek scientists suggests that supplementation with creatine monohydrate may be helpful for physical decline. Creatine increases the levels of high-energy chemicals such as creatine phosphate (CP) and adenosine triphosphate (ATP) in cells during exercise. Creatine supplements also reduce inflammation, stimulate the formation of satellite cells (important for muscle growth) and increase gene activity that stimulates protein synthesis and cell repair. In the short term, its creatine supplementation appears to be safe and may prevent physical decline.
(Current Opinion in Clinical Nutrition and Metabolic Care, 12: 623-627, 2009)
High-intensity interval training (HIIT) causes rapid changes in endurance capacity, maximum oxygen consumption, muscle glycogen stores and oxidative enzyme activity. Creatine monohydrate supplements increase capacity for high-intensity training and promote recovery after repeated interval training sessions.
Kristina Kendall and colleagues from the University of Oklahoma in Norman found that the effects of HIIT and creatine may be more effective than either alone. Creatine plus interval training increased critical power (the theoretical power release that can be sustained indefinitely), but had no effect on maximal power release. The results were small and may not necessarily be significant in practice, but this technique may be more effective in highly trained athletes.
(Journal Strength Conditioning Research, 23: 1663-1669, 2009)
glutamine and citrulline are amino acids that are crucial for metabolic fitness. Citrulline is partially produced during reactions involving glutamine. Glutamine plays an important role in the function of the immune system. Many athletes take glutamine to prevent upper respiratory tract infections and influenza. Glutamine is the most abundant amino acid in the body, but its stores can be depleted by trauma, serious illness or intense training.
Citrulline is an important amino acid involved in the formation of urea. It is a popular component in sports supplementation as it is involved in key amino acid reactions and affects blood flow by increasing nitric oxide levels. Nitric oxide is an important chemical secreted by the endothelium, the inner lining of blood vessels.
Glutamine promoteswound healing and accelerates recovery from serious illness, injury, trauma and burns. Several studies have found a link between suppressed immune function and low glutamine levels.
A study conducted at Baylor University found that glutamine is not a significant amino acid for the production of citrulline. Good dietary sources of glutamine include beef, chicken, fish, eggs, milk, dairy products, wheat, cabbage, beets, beans, spinach and parsley, while watermelon rinds are an excellent source of citrulline.
(American Journal Physiology Endocrinology Metabolism, 299: E69-E79, 2010)
Capsaicin is the chemical that gives chili peppers their heat. It increases calorie consumption for several hours and could be helpful in a weight loss program. Capsaicin works by increasing levels of the "flight or fight" hormone epinephrine (adrenaline), which increases fat utilization and boosts metabolism.
A Korean study showed that supplementation with capsaicin (200 mg) 30 minutes before exercise (50 percent of maximum effort for 30 minutes) increased fat utilization after exercise and stabilized the electrocardiogram (measurement of the electrical activity of the heart). Capsaicin helps to bring the nervous system back to its resting state after exercise and promotes fat utilization.
A few years ago, Danish scientists found that supplementing with capsaicin 30 minutes before a meal reduced food intake by 8 percent. Taking capsaicin with tomato juice was even more effective, reducing food intake by 28 percent.
(Journal Sports Science and Medicine, 9: 253-261, 2010)
