The amount of vitamins and minerals needed for good health does not change much with age after early childhood, but several factors determine proper vitamin and mineral intake in older people, pregnant and lactating women and those with serious illness, according to health professionals at New York University Medical Center.

"Growing older does not increase or decrease the recommended daily amount of vitamins and minerals," said Tracy Melnick, a registered dietitian, "but their delivery may be affected."An article in an upcoming issue of the center's Health Letter explains vitamins are organic substances found in small amounts in many foods. They help in many of the body's chemical reactions, including turning carbohydrates into energy and converting other nutrients into body tissue.

Minerals are inorganic substances found in the earth, in many foods and in the body. They help transmit nerve impulses, release energy from carbohydrates, build bones and balance body fluids. Among the most important are iron, calcium, phosphorus and potassium.

"As people age, their ability to metabolize excess nutrients decreases, which increases the chance for vitamin toxicity," said Kathy Feld, a registered dietitian. She noted that vitamin toxicity is more likely with fat-soluble vitamins such as A and E, which are stored in the body; excess water-soluble vitamins, such as B and C, are excreted.

"Older people may fail to get enough calcium because of milk intolerance or a poor diet, and they have an increased need for the mineral because of calcium loss," Feld noted. If calcium-rich foods are not tolerated, a physician may recommend calcium supplementation. "For older people who do not drink milk and spend little time in the sun, vitamin D supplements should also be considered."

Pregnant women have increased requirements for all vitamins and minerals, notably iron, calcium, phosphorus and folacin, a B vitamin, and usually require supplementation. "This reflects increased blood volume and metabolic rate, the need to prevent anemia and provide for fetal skeletal growth and teeth formation," said Robin Goldberg, a registered dietitian specializing in prenatal nutrition.

Lactating women have increased needs as well. "Maternal diet is an important factor for the nutritive content of human milk. Women who breast feed may need supplementation, since vitamins and minerals they take in are incorporated in their milk," Goldberg added.

"In newborns, the risk of iron deficiency is greatest after four to six months, at which time iron supplementation may be necessary," said dietitian Chrystyna Hankewicz, a specialist in pediatrics.