"....Vitamins are potent, essential nutrients which have effects that can precipitate harm as well as provide benefit.
---Margo Denke, MD, Center for Human Nutrition

Dr. Denke's remarks were in reference to a study on vitamin A intake and hip fractures in postmenopausal women. Osteoporosis and hip fracture are associated with chronic over-consumption of this essential nutrient at levels just twice the current recommended RDA.

There is growing concern among experts about this 'subtoxicity' of too much vitamin A, particularly in developed countries where food is fortified with A and there is a high level of use of vitamin supplements.