Also known as Vitamin B3, niacin has earned a reputation (in supplement form) as a natural cholesterol lowering agent. It may also help to prevent or treat a number of other disorders, from arthritis and depression to diabetes. This vitamin is also critical to releasing energy from carbohydrates and helping to control blood sugar levels. Interestingly, the body also synthesizes niacin from tryptophan, an amino acid found in eggs, milk and poultry. Although few people in the industrialized world are actually deficient in niacin, many may benefit from additional amounts in supplement form to help treat assorted complaints. Keep in mind that each of the three forms of niacin affects the body differently. Niacinamide has notable anti-inflammatory properties, for example, while nicotinic acid and inositol hexaniacinate affect blood lipid levels and circulation.