Like other yeasts, brewer's yeast is a fungus. The scientific names for the fungi in brewer's yeast are Saccharomyces cerevisiae and Saccharomyces boulardii. It is a bitter-tasting yeast product used in the beer-making process, and is also a popular nutritional supplement. Brewer's yeast contains many of the B-complex vitamins. The University of Maryland Medical Center warns of possible serious drug interactions with brewer's yeast, and difficulties for diabetics due to the presence of chromium. Your physician or pharmacist can help you decide if this is a good supplement for you.
Thiamine, or vitamin B1, is involved in the metabolism of carbohydrates, fats and amino acids, as well as alcohol and glucose. It supports nerve function, including that of the heart. Severe deficiency of thiamine causes beriberi, an often fatal disease with symptoms such as difficulty walking, loss of sensation in the hands and feet, paralysis of the lower legs and mental confusion. Thiamine, like all B-complex vitamins, is water soluble.
Riboflavin, or vitamin B2, plays an important role in the metabolism of carbohydrates and proteins. It also supports the integrity of the mucous membranes. Deficiency results in sores or lesions of the mouth, eyes, skin and genitalia.
Niacin, or vitamin B3, and its related compounds are vital in cell metabolism. A deficiency in either niacin or its precursor tryptophan can result in pellagra, a serious and debilitating condition that can cause a form of dementia as well as skin and digestive problems.
Pantothenic acid, or vitamin B5, is involved in many enzyme reactions. It is rare to have a deficiency, but symptoms of malaise, abdominal discomfort and a burning sensation in the feet can occur when the body does not have enough of this vitamin. The symptoms resolve when healthy vitamin levels are restored.
Pyridoxine and the related substances in the vitamin B6-complex are important to the central nervous system, the skin and the blood. In infants, a deficiency may cause convulsions; in adults, it can cause anemia. Large doses of pyridoxine can be toxic.
Biotin, or vitamin B7, is essential for fat and carbohydrate metabolism. A deficiency causes skin and tongue problems which resolve with replacement of the vitamin.
Folic acid, or vitamin B9, is essential for the development of the fetal nervous system, so it is a very important prenatal vitamin. It is also involved in the maturing of red blood cells at all stages of life.