By Dr David Smallbone, Academic Director, IINH.

Form determines function

Vitamins and minerals are vital for health, but the different forms they come in can determine how well they work in the body – if at all. The bioavailability of a nutrient – from food or supplement – is a measure of how much of it is actually usable by the body.

All the nutrients we require, apart from oxygen, have to be obtained from food. Nutrients come in various forms and compounds. Many nutrients have different functions to perform around the body, and each function will determine the best form of nutrient for that purpose. Many nutrients thus need to be consumed in a variety of forms to achieveoptimal effectiveness for the body. Bioavailability alsodepends on the individual’s ability to process the nutrient and get the best from it. So here are the two key aspects of bioavailability:

  • Not all nutrients in our food are in equally bioavailable forms.
  • Not all nutrients are equally bioavailable to everyone.

Some nutrients have different bioavailable forms even within the same food. For example,Vitamin E comes in eight distinct forms, all with differing bioavailability depending on what they are used for in the body. Very few nutrients occur only in a single format; most have several.

Chalk is not cheese

The commonest nutrients are not necessarily the most bioavailable. Take calcium. The most abundant source of calcium – often used in cheaper supplements for treating osteoporosis – is simply white chalk, like that found in the iconic white cliffs of Dover, UK. But calcium in this form (carbonate) is almost totally non-bioavailable to humans and animals. However, many soil bacteria and plants can use it.

Better together

Combining a mineral with other elements can change its bioavailability quite dramatically. Iron is a good example. Iron in the usual form of ferrous sulphate, is only very minimally absorbed, but as ferrous citrate or fumarate, it is much better absorbed and probably has superior bioavailability. However, the best bioavailability form of iron is animal source, from blood or muscle (meat).

When it comes to vitamins, there is a different problem. Very few occur alone in foods, and even fewer are bioavailable when isolated. Unfortunately, many vitamins in supplements come in isolated form and consequently have little or no bioavailability – or use.

Also, most nutrients need co-factors in order to function or be absorbed efficiently. Most supplements do not contain these co-factors, which therefore have to be consumed in other food materials for the vitamin to be usefully bioavailable.

Superior supplements

In general, look for ‘food-form’ vitamins and minerals, which will either be food– identical or extracted from actual foods. It is important to ensure that the nutrient level is known and standardized. Generally, food-form vitamins and minerals also contain the required cofactors for optimum results and thus do not have to be taken with food, whereas most ‘chemical’ isolated formats need to be taken with meals or snacks.

With regard to minerals, the semi-organic forms made from combining the mineral with an acid base are better than the pure isolated chemical forms. Superior forms include citrates, fumarates, glycuronates, etc. However, some mineral formats, e.g. picolinates, are not recommended as they are so tightly bonded to the mineral that they don’t readily release it, or else they need another mineral to bind to, thus robbing the body of the other nutrient.

Nutrient forms in food

Not all nutrients found as part of food are equally available – it depends on the bonding mechanisms involved. For instance, milk is a good source of calcium but because it is firmly bonded to a protein, casein, it is not very bioavailable in many people. However, the calcium in some fermented milk products becomes less attached to the casein protein and thereforemore bioavailable. Yoghurts, many cheeses and kefir would be examples.

Other important supplements

Several important substances in food are neither vitamins nor minerals. Examples would be Co-enzyme Q10, betaine hydrochloride (or trimethyl glycine) and various amino acids.

Coenzyme Q10 is an antioxidant found mainly in mitochondria, the ‘power station’ structures of each cell. Apart from assisting energy production, this vitally important material helps prevent cell and genetic damage and slows the ageing process. There are several forms of Coenzyme Q but the human version is Q10. As we age, we become less able to manufacture it and to convert other forms of Coenzyme Q into Q10. So, we lack adequate amounts and deteriorate and age faster.

To supplement – or not?

Levels of almost all the essential minerals in our food have declined alarmingly in recent decades. So how do we resolve this conundrum?

Unless you grow your own food and trust the source of the other components of your diet, or only use organically grown food, it is quite probable that you will not be consuming sufficient amounts of some nutrients needed to support optimal health.

You may therefore decide to supplement with vitamins, minerals and other nutrients. A good place to start is with a food-form multivitamin and mineral product, and then perhaps other supplements as necessary and appropriate. If you wish to do this yourself, you need in-depth knowledge of nutrient requirements and forms – without which you may end up wasting money. Alternatively, you could consult a qualified Nutritional Therapist at the Irish Institute of Nutrition and Health (

My suggestion as a starter is to use a food-form multivitamin and mineral such as Higher Nature’s True Food Supernutrition Plus, once or twice a day.

For more about the best supplements to use, please follow my series on Vitamins, Minerals and other supplements, to follow shortly.

Dr. D. F. Smallbone M.B.,Ch.B.,L.R.C.P.,M.R.C.S.,M.F.Hom., F.C.O.H.