Nicotinamide adenine dinucleotide phosphate is a coenzyme that can transfer electrons and hydrogen. It is involved in numerous rections in cell metabolism and is formed starting from vitamin B3 (nictoic acid amide or niacin).
What is nicotinamide adenine dinucleotide phosphate?
Nicotinamide adenine dinucleotide phosphate (proper name nicotinamide adenine dinucleotide phosphate) is also abbreviated as NADP (oxidized form without hydrogen) or NADPH (reduced form with hydrogen). It is an organic molecule and belongs to the coenzymes. These substances play an essential role in the function of enzymes. NADP plays a central role in many redox reactions in cellular energy metabolism: it can bind and transfer electrons and hydrogen in a reaction and serves as a reducing agent (accepting hydrogen and electrons) and an oxidizing agent (releasing hydrogen and electrons).
Function, action and tasks
In the construction of endogenous substances and tissues (anabolic metabolic pathways), nicotinamide adenine dinucleotide phosphate in its reduced form serves to transfer hydrogen ions and electrons. In the synthesis of fatty acids, NADPH transfers hydrogen to a reaction partner in a so-called condensation reaction. This results in the formation of saturated fatty acids. Fatty acids are formed when sufficient carbohydrates and energy are available to the body. Fatty acids are stored in fatty tissue and in the liver, among other places. They have a vital function for the body as energy stores and energy suppliers. NADPH/NADP also plays a central role in the breakdown of metabolic products for detoxification of the organism and for energy production (catabolic metabolic pathways). For example, it is oxidized during the breakdown of unsaturated fatty acids and releases hydrogen and electrons to a reaction partner. The degradation of amino acids as building blocks of proteins also takes place in catabolic metabolism with the participation of NADPH/NADP. Glucose (dextrose) is degraded during energy production in the cells to maintain metabolic and thus life processes: this is also only possible with the help of NADP. It serves here as an acceptor for hydrogen and electrons. Vitamin B3 (niacin) as a precursor of nicotinamide adenine dinucleotide phosphate can be formed by the body itself through the amino acid tryptophan, but in an unfavorable ratio of 60:1. Accordingly, a supply of vitamin B3 with food is indispensable to guarantee sufficient formation of NADP/NADPH in the body. The need for vitamin B3 depends on the body’s energy metabolism. Thus, the more energy the body consumes, the more niacin must be supplied with food.
Formation, occurrence, properties and optimal values
Vitamin B3 is found especially in meat (poultry), fish, eggs and dairy products. However, whole grain products, coffee and legumes are also sources of niacin. In general, the German Nutrition Society assumes an average daily requirement of vitamin B3 of about 13 mg for women and older people. Pregnant women and nursing mothers have an increased requirement of about 17 mg. Men require a daily intake of between 13 and 17 mg, depending on their age, and children require between 7 and 12 mg. The body’s energy requirements play a role here, as the requirement can increase in the short term during higher stress levels. With a normal diet, an overdose of niacin is very unlikely. However, this can occur if very high doses of supplements are ingested. Headaches, vomiting, skin symptoms and diarrhea are the first symptoms. Chronic and severe overdose can result in gastritis and liver damage. However, vitamin B3 is not toxic to humans even in high doses.
Diseases and disorders
If the intake of vitamin B3 is too low, there will be a long-term deficiency of nicotinamide adenine dinucleotide phosphate in the body, since tryptophan is not sufficient as the sole source of synthesis in the long term. Symptoms of deficiency with too little NADPH/NADP in the body show up in symptoms such as weight loss, insomnia, diarrhea and inflammation of the skin. Overall, when there is a niacin deficiency and thus NADPh/NADP deficiency, the digestive and nervous systems as well as the skin are affected. If the deficiency of vitamin B3 is severe and persists for a long time, the disease pellagra (pellagra = rough skin) may occur.This disease causes symptoms of the nervous system such as tremors, convulsions, paralysis and mental disorders up to dementia. Inflammatory skin changes, thickening, redness, itching and brown discoloration in areas exposed to sunlight (face, neck, forearms, hands) are also typical. Normally, the disease develops gradually over years, as the body can compensate for the niacin deficiency for a long time by breaking down tryptophan. In extreme cases, however, pellagra can lead to death within a few weeks. Today, the disease occurs only rarely. It is mainly found in regions where corn and millet are consumed as staple foods, as these do not contain vitamin B3. With a normal diet, a niacin deficiency and thus an insufficient level of nicotinamide adenine dinucleotide phosphate in the body is very rare. Treatment consists of direct administration of vitamin B3 and a diet rich in niacin. Alcoholism can also lead to a niacin deficiency and thus to a deficiency of NADPH/NADP in the organism. If alcohol consumption is high, a diet rich in vitamin B3 is accordingly advisable. Certain hereditary diseases such as Hartnup syndrome are another cause of niacin or NADPH/NADP deficiency in the body. In this case, vitamin B3 cannot be absorbed normally by the organism and drug therapy is essential.
