B vitamins and Choline As many of the B vitamins are involved in the metabolism of carbohydrate, fat and protein, their ergogenic potential has been studied individually and in combination. In general, although a deficiency of the B vitamins may impair both aerobic and anaerobic exercise performance, supplementation has not been shown to enhance performance in well-nourished individuals. Niacin supplementation may influence fat metabolism, blocking the release of free fatty acids (FFA) from adipose tissue and increasing reliance on carbohydrate utilization, possibly leading to premature depletion of muscle glycogen. Some research has indicated that excess niacin supplementation may actually impair aerobic endurance performance [8]. Vitamins B1, B6 and B12 are believed to affect the formation of serotonin, an important neurotransmitter involved in relaxation. Some research with large doses (60–200 times the RDA) of these vitamins has shown increases in fine motor control and performance in pistol shooting. Others have suggested that the beneficial effect was related to the role of these vitamins in promoting the development of neurotransmitters that induce relaxation [9]. Additional research is merited to evaluate these effects on performance in precision sports dependent on fine motor control. However, it should be noted that such doses could exceed the Tolerable Upper Intake Level (UL) for vitamin B6.