Patricia Thompson - NUTRITION TALK ONE OF the most prolific products at pharmacies is nutritional supplements. Some are single nutrient supplements and others are multi-nutrient supplements, all promoted as being just right for you.
Most multi-nutrient supplements will contain the same vitamins and minerals and some add extras in the form of herbals and non-nutrient chemicals found in foods. The main variation is in the quantity of each nutrient or other constituent. Have you ever examined the label of these supplements and assessed whether they meet your needs or not?
Levels are stated relative to the US Recommended Dietary Allowance (RDA), a level that is considered adequate for nearly all 'healthy' persons in the society. A level of 100% the RDA is an assurance that the supplement would provide enough intake to ward off any deficiency of that nutrient even if the diet should contain none of this substance. Some supplements have levels way above the RDA with the rationale that if a little is good, then more is even better to avoid the degenerative chronic disorders that are currently plaguing our society.
NUTRIENT DEFICIENCY
If you already have a frank nutrient deficiency such as iron deficiency anaemia, your doctor will probably prescribe a single nutrient supplement at high potency doses to correct the problem. For instance, for anaemia, iron at a level of 60mg daily may be prescribed for a period of about three to six months. It is not the intention however for you to continue taking this supplement consistently beyond the prescribed period. If you do so, you may now be putting yourself at risk for iron poisoning.
Nutrition scientists have identified levels known as the tolerable upper intake levels, above which you increase your risk for nutrient toxicity. For some nutrients like manganese, calcium and fluoride this level may be as low as two to three times the RDA. For others like most of the vitamins, this may be as high as ten times the RDA.
Tolerable levels of iron are exceeded when 45mg per day or more is taken consistently compared to the RDA of 15-18 mg for menstruating females and 8-10 for males. Vitamin C has an RDA of 60-90mg daily and toxic levels are attained when this is taken consistently at levels greater than 2000mg daily for adults but at only 400-600mg for young children. Children are therefore more likely than adults to suffer the ill effects of diarrhoea and rash with high potency vitamin C supplements.
Nearly all general supplements have appreciable vitamin D at the level of 400IU. This is stated as 100% the RDA, but in the Caribbean, our RDA for adults is only 100IU, in recognition that we have abundant sunshine and can make our own vitamin D.Once our skins are adequately exposed to the UV rays of sunshine as obtains with children playing outside in the sun, there would be no need for any additional vitamin D. Toxic levels of vitamin D are 5 times the RDA for children.
Moreover, nutrients are interrelated. Vitamin D works with calcium, which in turn works with phosphorus and magnesium. Supplements should have a calcium: phosphorus ratio of 1:1 and a calcium: magnesium ratio of 2:1. Also, make sure that the levels stated will meet your individual needs. Calcium at a level of 150mg or less will have minimal effect if you are worried about osteoporosis and potassium at 25 mg will not do much for a diet lacking plant foods, including fruits and vegetables.
For regular every day use, high potency supplements are not appropriate. A general multi vitamin, multi mineral supplement may be all that is needed if you are a person who does not pay enough attention to eating healthily.
Patricia Thompson, M.Sc., Registered Nutritionist; The Nutrition Centre, Eden Gardens.
