Taking vitamin E separately may be more cost effective. Blood clotting and calcium-binding in bone. High doses of niacin can cause flushing, itching skin, stomach irritation and liver damage. Toxicity is rare, but over 500 mg taken regularly can damage the nervous system. Deficiency in pregnant women can cause infant birth defects.
Gastrointestinal disorders can inhibit absorption and result in pernicious anemia.
High doses can exacerbate depression symptoms. Healthy bone and joint function. Women at risk of or suffering from osteoporosis may need a higher dosage. 600 mcg daily dosage recommended for diabetics. Proper iron absorption and use.