Nutrition and Metabolism Level 3 PDF

# Dairy Department ## Dietetic Program ### Level 3 ## Course: Nutrition and metabolism **By:** Dr/ Esraa Mohamed Al-Amir **Lesson 4:** Nutritional Ergogenic Aids ### Amino Acids - **Arginine:** In large oral doses has been reported to elicit the release of somatotropin. Somatotropin, which has...

# Dairy Department ## Dietetic Program ### Level 3 ## Course: Nutrition and metabolism **By:** Dr/ Esraa Mohamed Al-Amir **Lesson 4:** Nutritional Ergogenic Aids ### Amino Acids - **Arginine:** In large oral doses has been reported to elicit the release of somatotropin. Somatotropin, which has been called insulin-like growth factor, stimulates protein synthesis. Arginine has also been reported to increase the secretion of growth hormone. - **Ornithine:** Oral doses of ornithine have also been shown to stimulate the release of somatotropin. However, at the levels required for somatotropin release, osmotic diarrhea is common. Both arginine and ornithine are purported to be beneficial in resistance training and to increase growth hormone release. - **Aspartate Salts:** The potassium-magnesium salts of aspartate have been marketed as an antifatigue agent. However, their use has been questioned and the benefit is more likely a placebo effect. The aspartate salts may have some benefits in endurance events if taken in high doses. Time to exhaustion has been reported to be increased. - **Branched-Chain Amino Acids (BCAAs)**: BCAAs (isoleucine, leucine, and valine) have been hypothesized to benefit endurance activities by influencing the level of serum tryptophan. BCAAs compete with tryptophan for entry into the brain. One theory about fatigue is that brain tryptophan is converted to serotonin, which causes fatigue. This conversion may be one of several factors that bring about fatigue. BCAAs are also used by muscle for energy near the end of very long endurance events. ### Antioxidants Endurance exercise increases the amount of oxygen moving into the muscle. Increased exposure to large volumes of oxygen in turn increases the generation of free radicals, which are involved in fatigue and damage to the muscle cell membrane. This information provides the rationale for using antioxidants to prevent muscle damage and delay fatigue. Many antioxidants have been used, including vitamin C, vitamin E, and selenium. Coenzyme Q10 also has antioxidant activity, though its use as an ergogenic aid is based on other properties. ### Herbs Much interest has recently been directed toward herbal preparations. Evaluating and comparing studies of these preparations is difficult, because the way herbs are collected, processed, and grown influences the active components. One class of herb, ephedra, was previously used for its ephedrine content. The risk of harmful side effects or death has discouraged its use and caused it to be banned in most sports. The FDA banned the sale of ephedra-containing supplements in 2004. The ban was later removed after the FDA lost a court challenge. The most widely used and studied herbs are the ginsengs. Some purported ergogenic benefits of Panax (Chinese/Korean) ginseng include: - increased run time to exhaustion (three out of seven studies) - increased muscle strength (one out of two studies) - improved recovery from exercise (three out of four studies) - improved oxygen metabolism during exercise (seven out of nine studies) - reduced exercise-induced lactate (five out of nine studies) - improved auditory and visual reaction times (six out of seven studies) - improved vitality and feelings of well-being (six out of nine studies) These benefits have most consistently been reported following supplementation over more than 8 weeks. ### Caffeine Ergogenic effects of caffeine are seen in endurance events. The greatest effect is seen in people who do not consume caffeine on a regular basis. Caffeine is a CNS stimulant that increases blood flow to the kidneys (thus acting as a diuretic) and stimulates the release of fatty acids from adipose. Sport regulatory bodies have changed their position on caffeine use several times. It was banned for a period before 1972 and then removed from the banned list. Regulators then set an upper limit for its use. Caffeine was removed from the banned list of stimulants before the 2004 Olympics. The use of caffeine is now being reconsidered once again.