Vitamins

Firstly – what are micronutrients?

Vitamins and minerals are micronutrients and just like carbohydrates, dietary fibre, protein, fat and fluids (the macronutrients) they are not food groups.  Rather they are nutrients that are found within the various food groups.

Micronutrients are nutrients the body requires in very small quantities.  If followed, your national nutritional guidelines for daily consumption of the major food groups should ensure that the daily requirements for micronutrient intakes are easily achieved, without the need for supplementation.

Information from many national nutrition bodies suggests that vitamin and mineral deficiency is very rare in the western world.  Often deficiency is closely associated with poverty, so as it appears that more people living in the western world are living in, or close to the poverty line we may see deficiency start to increase.

In spite of the evidence that vitamin and mineral deficiency is very rare, vitamin and mineral supplements are heavily promoted and marketed and many people regularly consume these supplements.   It appears that the vitamin and mineral supplementation business is a profitable business to be in, but the questions begs asking – is it providing a necessary, valuable product to consumers or is it simply lining the pockets of the manufacturers?

To help answer this question lets first look at vitamins in a little more depth.

Vitamin deficiency & excess

If your national nutrition guidelines are adhered to then vitamin deficiency is highly unlikely, so as a personal trainer helping your clients adhere or at least move closer to adhering to your national guidelines should always be your first port of call (as opposed to suggesting a trip to the local ‘health food’ store or pharmacy).

If deficiency does occur it is most likely to occur with the water-soluble vitamins (C & the B-complex) as the body can only store a limited amount of them and food preparation can easily damage them.  Prolonged cooking, storage and processing all take their toll by destroying vitamins so it is best to use fresh, raw or lightly cooked (steamed) foods. 

It is estimated that boiling vegetables can destroy between 50-80% of the foods vitamin C content.  Frozen fruit and vegetables tend to retain higher levels of vitamins than their stored counterparts as the maturation (and death essentially) of the food is slowed.

A mild deficiency of vitamin C may cause weakness and general aches and pains.  A deficiency of the B-complex may expose people to a greater risk of illness due to a weakened immune system.  For people deprived of sunshine then a vitamin D deficiency is linked to depression (seasonal affective disorder ‘SAD’) and in the absolute worst cases rickets and osteomalacia (softening of the bones).

Generally high intakes of vitamins are not associated with causing harm in humans (except to the pocket if buying lots of expensive supplements).  In most cases excessive intakes are simply excreted (check out the colour of your pee after taking a vitamin B supplement – it can appear almost fluorescent).  In order for any potential harm to occur the intake needs to be extremely excessive, i.e. high dosages of supplements on top of a sufficient dietary intake.  For example grossly excessive intakes of vitamin A and E may result in nausea, loss of appetite, stomach cramps, abdominal pain and diarrhoea.

There is some evidence that some people benefit from higher intakes of certain vitamins than others.  Some recent research suggests that high doses of vitamin C in particular are beneficial in combating cancer.  Other research indicates that some of the B-complex vitamins namely B6, B12 and folic acid help protect against heart disease and stroke.   People who smoke, have high alcohol intakes and are highly stressed and/or frequently ill will have a higher demand for the B-complex. 

While such research is promising it must be pointed out that as personal trainers our role is not to diagnose vitamin and or mineral deficiency and promote excessive supplementation.  This is the domain of medical professionals.  If we help all our clients to adhere to national nutritional guidelines then 99 times out of 100 we’ll be ensuring all their vitamin and mineral needs are being accounted for.