ABSTRACT
Americans spend more than $1.5 billion annually on vitamin and other nutritional supplements. The B vitamins, separately or combined with other products such as protein powders, are touted to provide performance boosts because of their physiological role in energy and red blood production. Nutritional status of a micronutrient must involve both assessments of dietary intake and biochemical measurements. The most accurate way to assess dietary intake is to biochemically analyze duplicate meals. The richest dietary sources of thiamin are whole grains, pork, legumes, followed by other meats, fish, green vegetables, fruit, and milk. Dairy products are the richest source of riboflavin, but riboflavin is also found in meat, cereals, and vegetables. The beginning of an exercise program in previously sedentary men and women has been found to decrease riboflavin status. Niacin is a general term to describe two compounds that act as vitamins, nicotinic acid and nicotinamide.
