Which of the following statements about niacin is false?
1) Participates in energy metabolism (ATP production) of every cell and its absence causes serious illness.
2) The niacin-deficiency disease is called pellagra and its symptoms are known as the four "Ds": diarrhea, dermatitis, dementia, and death.
3) Symptoms of toxicity include ________. liver injury, vision disturbances, impaired glucose tolerance, and niacin flush, which can be very painful.
4) A good food source is corn.
5) Tryptophan (an amino acid found in proteins) can be converted to niacin in the body.