The Question Of Supplements

There ar many millions of people out there taking high dose vitamin pills daily, especially beta carotene and vitamins C and E, the antoxidant nutrients that they recieved has gotten so much media attention in recent years. But these supplements are really no substitute for plain old good eating habits, and the majority of these people can fill their nutrition needs by following a good diet regimine.

These megadose vitamins can actually be harmful. When taken in very large amounts, vitamins and minerals, like all drugs carry the risk of adverse side effects and interactions. Many minerals, and vitamins A and D are stored in the body and can build to toxic levels when taken in large doses. The presence of large quantities of a particular vitamin or mineral in the intestinal tract invariably interferes with the body's ability to absorbtion of other nutrients and can lead to deficiency diseases.

Where supplements are needed, they should only be prescribed by a doctor. For example a woman planning to concieve or who is already pregnant needs extra folate to protect the baby from neurological problems. Pregnancy also increases the demand for iron beyond what can be obtained from an ordinary diet. An older woman may need additional calcium and vitamin D to help prevent Osteoporosis.

RECOMMENDED NUTRIENT INTAKE (RNIs)

In order to meet the recommended nutritional needs of most people, the Nutrition Research Division of Health and Welfare Canada established the Recommended Nutrient Intakes or RNIs, for 9 vitamins, 6 minerals, protein, and energy.

Also the Nutrition Reasearch Division lists all the estimated safe and adequate intakes of two other vitamins and five minerals. To determine a specificRNI, nutritio scientists established a minimum value, below which deficiency develops, and the maximum amount, above which harm might occur. The RNI is set between these two values, with a margin of safety to ensure a reserve to carry a person through weeks or even months of inadequate intake.

Many people mistakenly assume that they must consume the full RNI of each nutrient daily. This of course is not true because each RNI is actually more than one person needs. For example the RNI for vitamin C (40mg) is really four times what the average person needs to prevent scurvy. It should be noted that in Canada, deficiency diseases are rare, occuring mostly among people with other disorders, for example, thiamine deficiency is common among long term alcoholics and seniors.