A different type of thiamin deficiency affecting brain function is sometimes seen in alcoholics. Thiamin is found in whole grains, nuts and meat, especially pork. In the UK, white and brown flour and many breakfast cereals are fortified. Riboflavin is required to release energy from protein, carbohydrate and fat. Although there is no specific deficiency disease, low intakes lead to dryness and cracking of the skin around the mouth and nose.
Excess riboflavin is excreted in the urine.
Deficiency results in a disease called pellagra . It may occur in communities where maize forms the staple diet. Maize contains very little tryptophan and the niacin that is present is in an unavailable form. If, however, the maize is cooked in a particular way, the niacin is released. Excess intakes from vitamin pills may be dangerous.