Nicotinic acid/nicotinic acid and nicotinamide are also known as niacin or vitamin B3. Both substances convert into each other in the body. As vitamin B3, nicotinic acid performs many important functions in energy metabolism.
What is nicotinic acid?
Both nicotinic acid and nicotinamide are called niacin or vitamin B3. In the organism, they undergo constant mutual transformation. Niacin is often taken in with food as nicotinamide and converted into nicotinic acid in the intestine. Nicotinic acid is then also stored in the liver. Nicotinic acid used to be called pellagra-preventing factor (PPF) because a deficiency of vitamin B3 leads to the disease pellagra. Today, however, this designation is outdated. It is a chemical compound belonging to the heterocycles. The basic skeleton consists of a pyridine ring with a nitrogen atom in the aromatic ring, to which a carboxyl group is attached. Nicotinic acid is a solid which forms colorless crystals. The melting point is 236.6 degrees Celsius. Like the other vitamins of the B complex, nicotinic acid is water soluble. As a component of the coenzymes NAD and NADP, it is a hydrogen carrier and in this function very important for energy metabolism. Vitamin B3 must be ingested with food. The body can also produce small amounts of nicotinic acid from the amino acid tryptophan.
Function, effect and tasks
Nicotinic acid performs important functions in the body. Its most important function is to be responsible for reduction reactions by hydrogen transfer in the form of NAD and NADP. It is one of the most important reducing agents in the citric acid cycle and the respiratory chain. Furthermore, nicotinic acid is involved in the regeneration of muscles, nerves, skin or DNA. It also has an antioxidant effect, allowing it to participate in many enzymatic reactions. Nicotinic acid or nicotinamide is also responsible for reducing blood lipids in the body. The need for vitamin B3 depends on the physical load. The higher the energy consumption in the organism, the more nicotinic acid it also needs. Vitamin B3 also has a great influence on the ability to remember and concentrate, as it positively stimulates nerve function.
Formation, occurrence, properties and optimal values
Most vitamin B3 is absorbed through food. In the process, it often enters the body as nicotinamide. After absorption through the intestines, nicotinamide is converted to nicotinic acid and stored in the liver. Nicotinic acid can also be produced in low concentrations in the organism itself. This occurs via the breakdown of the amino acid tryptophan. Most foods contain niacin, although absorption is easier via animal products than via plant foods. Nicotinic acid is found in relatively high concentrations in game, poultry, fish, mushrooms, eggs or dairy products. High concentrations are also found in liver, whole grain products, cashews or coffee. Fruits and vegetables also contain nicotinic acid, although its utilization is somewhat more difficult than from animal foods. Thus, vegans have a little more difficulty supplying the body with sufficient niacin, but by consuming peanuts, mushrooms, brewer’s yeast, wheat bran, dates, dried apricots or legumes, they too can meet their vitamin B3 needs well. Some of these foods also contain a lot of tryptophan, from which niacin can then be synthesized in the body. As already mentioned, the need for niacin also depends on the body’s energy requirements. During greater physical activity, the energy metabolism is also increased. This causes the greater need for nicotinic acid during physical activity, breastfeeding or pregnant women. The average daily niacin requirement for the conversion of 1000 kilocalories in adults is about 6.6 milligrams. This gives women an average daily requirement of between 13 and 15 milligrams and men a daily requirement of between 15 and 20 milligrams. Children need between 5 and 6 milligrams of vitamin B3 per day. Vitamin B3 deficiency is only significant for populations that eat a one-sided diet of corn and millet products. In these plant foods, niacin is released only through a special processing method so that it can be absorbed by the body.
Diseases and disorders
Serious symptoms may occur in association with vitamin B3 deficiency.In extreme cases, this is referred to as pellagra. Although vitamin B3 deficiency is rare in our latitudes, vitamin B3 deficiency can occur in countries where the population mainly feeds on corn and millet products. Pellagra disease was particularly common in southern Europe, Africa, and North America after the Spanish conquest of Central America and the export of corn. The elaborate processing, which the natives of Central America still carried out, were not adopted by the Spaniards. It was not until the beginning of the twentieth century that the connection between the main diet of corn and the disease was discovered. Pellagra manifests itself through severe skin changes, diarrhea, depression, mucosal inflammation of the mouth and gastrointestinal tract, as well as memory problems that can lead to dementia. Of course, resorption disorders in the intestine due to chronic intestinal diseases can also lead to vitamin B3 deficiency. However, this also results in the deficiency of other vitamins. No toxic effects occur with an overdose of vitamin B3. In individual cases, however, a vasodilatory flush may occur, which at very high doses above 2500 milligrams per day leads to dizziness, a drop in blood pressure and an increase in the uric acid content of the blood. In medications, nicotinic acid is often used in combination with other drugs to lower blood lipid levels.
