Niacin
Niacin is one of the eight B complex vitamins including vitamins B1, B2, B6, B12, folate, biotin, and pantothenic acid. Niacin works closely with vitamin B1, B2, B6, pantothenic acid, and biotin to break the carbohydrates, fats, and proteins in food down into energy. Without niacin, the body would not be able to convert the food we eat into energy. Niacin has been used with some success to treat people with high cholesterol levels.
Niacin deficiency symptoms include:
weakness, loss of appetite, digestive upsets, insomnia, skin and gastrointestinal lesions, diarrhea, dementia, headaches, irritability, a sore, swollen, purple-red tongue.