Vitamin amino acids. Most vitamins are not single molecules, but groups of related molecules called vitamers. For example, vitamin E consists of four tocopherols and four tocotrienols. The thirteen vitamins required by human metabolism are: vitamin A (retinols and carotenoids), vitamin B (thiamine), vitamin B (riboflavin), vitamin B (niacin), vitamin B (pantothenic acid), vitamin B (pyridoxine), vitamin B (biotin), vitamin B (folic acid or folate), vitamin B (cobalamins), vitamin C (ascorbic acid), vitamin D (calciferols), vitamin E (tocopherols and tocotrienols), and vitamin K (quinones). Vitamins have diverse biochemical functions. Some forms of vitamin A function as regulators of cell and tissue
Vitamin B3 paresthesia, and headache. Liver toxicity is the most serious toxic reaction and it occurs at doses >2 grams/day. Fulminant hepatitis has been reported at doses between 3-9 grams/day with needs for liver transplantation. Other reactions include: Vitamin B deficiency can cause pellagra, a disease found in many alcoholics in North America. Symptoms include vomiting, loss of appetite, abdominal pain, and general fatigue. Vitamin B3 Vitamin B is a vitamin that includes three forms: nicotinamide (niacinamide), niacin (nicotinic acid), and nicotinamide riboside. All three forms of vitamin B are converted within the body to nicotinamide adenine dinucleotide (NAD). NAD is required