Chromium is one of the lesser known of the trace minerals which are essential to human health, but there are two types you need to know about.
Hexavalent chromium has wide applications for industry, but is toxic to humans both on external skin contact and through internal consumption. Trivalent chromium, however, appears to be not only completely safe, but potentially highly beneficial to health, and all mentions of chromium in the remainder of this article will relate only to this type.
Perhaps the most important function of chromium lies in its interaction with other key nutrients, particularly niacin (vitamin B3) and certain amino acids, to form what is known as the “glucose tolerance factor” (GTF), which enhances the action of insulin and consequent metabolism of glucose to produce energy within the body. The correct metabolism of glucose, of course, is also crucial in regulating blood sugar levels; and a lack of insulin or a decrease in the body’s sensitivity to it may give rise to the increased blood sugar levels characteristic of diabetes. Less well known, perhaps, is that insulin is also important in the metabolism of dietary protein and fat.
Although the mechanism by which chromium enhances insulin action is not fully understood there is evidence that supplements of up to 200 mcg a day may have some effect in reducing the need for additional insulin in diabetics. This evidence, however, is based on Chinese research which orthodox medical opinion remains reluctant to accept as necessarily applicable to Western diets and obesity patterns; insisting that more research is needed. But whilst from the strictly scientifc point of view this may be true, it is worth noting that the benefits were observed at relatively low and harmless levels of supplementation. So, as ever, regard must be had to the likely balance of risk and reward.
Moreover, but perhaps logically enough, it has also been suggested that a deficiency of chromium may be a factor pre-disposing an individual towards the development of type 2, ie late onset, or non-insulin dependent, diabetes. There is also some evidence that similar deficiencies in chromium may be implicated in increased levels of blood cholesterol, although orthodox opinion maintains that this does not necessarily imply that supplementation in non-deficient individuals will serve to reduce these levels.
Chromium’s role in the metabolism of glucose, protein and fat has led to a widespread belief that it may help not only in the reduction of body fat but in the acquisition of lean muscle mass. But sadly, although there is some research to support this idea, there is at least as much which showed no such benefits, and chromium supplements should not therefore be marketed or regarded either as a bodybuilding or diet product.
Owing to the supposed paucity of information on the action of chromium within the body, neither the US nor European authorities have currently proposed a Recommended Dietary Allowance (RDA). But the US Food and Nutrition Board has suggested an Adequate Intake (AI) level of 35 mcg daily for men and 25 mcg for women. Slightly higher levels are suggested for pregnant or breast-feeding women; slightly lower for children, adolescents and the over fifties.
Chromium in foods is commonly found in small, in fact minute, quantities. Moreover these amounts have been found to vary considerably even within batches of the same food. For these reasons it is difficult to give accurate indications of the amounts which may be expected in servings of common foodstuffs. As a generalisation, however, it may be stated that lean meats such as beef and turkey (especially when processed), fresh vegetables, particularly, broccoli and green beans, are probably the richest readily available sources.
Even these, however, will seldom provide more than around 10 mcg per serving at most, and often considerably less. It’s also important to note that the foods high in refined sugars which are so common in the modern Western diet are not only themselves low in chromium but also appear to increase the excretion of chromium from the body. Unsurprisingly, therefore, it is estimated that the average adult daily intake of chromium may be as little as 20 – 40 mcg a day, of which only around 2% may be successfully absorbed and utilised by the body, and that deficiencies of the mineral are consequently quite common.
But if supplements of chromium are to be taken, regard must be had as always to the holistic functioning of the body. Chromium is absorbed best, for example, when taken in the presence of adequate vitamin C; whereas an excessive intake of calcium by contrast, will further restrict chromium absorption. But taking too much chromium is likewise to be avoided because any excess may restrict the body’s absorption of the essential minerals zinc and iron.
Happily, however, none of this need be as confusing as it may sound. Supplementing with between 50 and 200 mcg of chromium a day appears to be both safe and potentially beneficial provided it is obtained as part of a comprehensive multi-mineral supplement. But for best results, as always, this multi-mineral should be taken in conjunction with a quality multi-vitamin preparation.
