Chromium is an important trace mineral in human nutrition. chromium deficiency leads to insulin resistance in mammals, and this may relate to the role that chromium plays in the function of the insulin system. Originally it was thought that chromium was involved in the binding of insulin to its receptor forming a chromium-insulin-receptor complex on cell membranes. More recent evidence however suggest that chromium may be involved in insulin release from the pancreas and in the production of the insulin receptor, or amplification of its signal intracellularly. With respect to this latter mechanism, chromium bound to transferrin in the blood is believed to be taken into the cell through transferrin receptors, where four chromium atoms bind to a peptide called apochromodulin, in the process forming chromodulin (also called holochromodulin). Chromodulin then binds to the cytosolic beta subunit of the insulin receptor and potentiates the effects of insulin by enhancing the kinase activity of the receptor.
Whatever the mechanism of action, chromium is now considered to be integral to the correct function of the insulin system. Low intakes of chromium have been reported in developed nations due to the consumption of too much overly refined grains and other processed foods devoid of chromium. Hair mineral analysis is a useful tool to assess chromium function as the hair accumulates minerals such as chromium over time and the content of hair can therefore be a reasonable estimate of mineral intake. During pregnancy, the foetus is reliant on the mother for its mineral supply, and as such the mineral status of the mother tends to fall during pregnancy unless dietary intake is optimal. A number of studies have shown mineral deteriorations over the course of pregnancy and this is also true for chromium. Such a deterioration in chromium status could have implications for the development of the growing foetus or the health of the mother, especially as the exact role of chromium in the function of the insulin system is still unknown.
For example, in one study1, the chromium content of women who had given birth was compared to a control group of women who had not born children. The childbearing women has significantly lower chromium concentrations in their hair samples compared to the non childbearing women. However, there was no significant difference amongst the nulliparous and multiparous women in terms of hair mineral chromium concentrations. When the same authors analysed longitudinal samples of hair from women taken throughout the course of pregnancy, they found that chromium concentrations decreased from an initial concentrations of below 200 ng/g in the third trimester of pregnancy. This was in comparison to the 221 ng/g in the women that had never given birth. Therefore the concentrations of chromium in pregnant women are low and fall further with advancing pregnancy. This suggest that if chromium intakes are not optimal during pregnancy, chromium deficiencies may develop in the mothers.
Dr Robert Barrington’s Nutritional Recommendation: Hair mineral analysis is a useful tool to determine the medium and long term mineral status of certain minerals. In this regard it can be a useful tool in determining chromium status. Pregnancy may take a toll on the mineral stores of the mothers, because the foetus is in need of essential elements for growth and development and often these are parasitised from the maternal stores if dietary intake falls short. Ensuring optimal chromium intakes is important during pregnancy so that the foetus can be supplied with chromium without negatively affecting the chromium stores of the mother. As chromium is difficult to include even in a healthy diet, it is one mineral that is recommended in supplemental form. Doses of around 200 micrograms per day for a healthy adult are recommended. The picolinate form of the vitamin appears to be well absorbed and is not toxic even at high intakes.
RdB
