níacín

Niacin, also known as vitamin B3, is an essential nutrient that plays a crucial role in the body's metabolism. It is a water-soluble vitamin, meaning the body does not store it and requires a regular intake through diet or supplements. Niacin exists in two primary forms: nicotinic acid and niacinamide. Both forms are converted in the body into its active coenzyme forms, NAD (nicotinamide adenine dinucleotide) and NADP (nicotinamide adenine dinucleotide phosphate).

These coenzymes are vital for hundreds of enzymatic reactions involved in energy production, DNA repair, and the synthesis of fatty acids and steroids. A deficiency in niacin can lead to pellagra, a disease characterized by dermatitis, diarrhea, and dementia. Severe cases can be fatal if left untreated.

Dietary sources of niacin are abundant. It can be found in foods such as lean meats, poultry, fish, nuts, legumes, and fortified cereals. The recommended daily intake of niacin varies based on age, sex, and life stage, but is generally measured in milligrams (mg).

While niacin is essential, high doses of nicotinic acid, particularly when taken as a supplement, can cause side effects such as flushing, itching, and gastrointestinal upset. Niacinamide generally does not cause flushing. Niacin is also used therapeutically in higher doses to help manage cholesterol levels, although its use for this purpose is often accompanied by careful medical supervision due to potential side effects.