Vitamins are essential to life. Diseases such as scurvy occur when vitamin C intake is inadequate; bone disease such as rickets or osteoporosis occur when vitamin D intake is inadequate; anemias occur when vitamin B levels are inadequate; deficiency of folic acid during pregnancy can lead to fetal neural tube defects; and bleeding disorders occur when vitamin K levels or intake are inadequate.
Recently, daily dietary vitamin supplementation has been promoted for contributing to good health as well as to prevent disease. Scientific evidence to support many of the purported health benefits for dietary vitamin supplementation of a balanced diet is limited or non-existent.
Not everyone needs or ingests the same amount of food or liquid intake every day. There is overwhelming information from scientific investigations and clinical experience that demonstrates the needs for different doses of therapeutic medications for people of different ages, sizes, race, sex, diseases, and those taking combinations of medicines and eating different diets. One would therefore expect both the daily vitamin intake from food, and the total daily vitamin requirements to differ between individuals.
Daily iron and folate intake should be higher in menstruating women than men of similar age, while lower total intake of vitamins A, B, E, K, and zinc are based on body size and usually lower in women compared to men. Adequate daily intake can be achieved through a balanced diet for most nutrients and vitamins. Exceptions are the need for the supplementation of most vitamins and folate in pregnant women, and for vitamin D and calcium in older individuals.
From Schwartz, JB. Pharmacy Focus. Vitamin Intake, recommended intake, and gender differences. J Gender-specific Medicine 2001; 4(1), 11-15.