It has been shown that vitamin and mineral requirements increase during pregnancy. The reason for this is the obvious one, in that the growing foetus has a large requirements for essential nutrients and these can only be derived from the mother through her diet. Therefore the mother must fulfill her own requirement for essential nutrients and those of the growing foetus. This is particularly true of those essential nutrients that are not stored in body tissues to any great extent, as there are no reserves of these essential nutrients for the foetus to cannibalise. In this regard the water soluble vitamins, particularly the B vitamins, are required in daily amounts in excess of normal intake during pregnancy. Animals studies attest to the detrimental effects on offspring when this intake is not adequate. Further, evidence from observational studies also suggests that poor pregnancy outcomes are apparent when intakes of vitamin B6 are not adequate in humans, which can lead to low birth weight and other complications.
To investigate the effects of vitamin B6 intakes on the outcomes of pregnancy, one group of researchers followed a group of 127 low income women and assessed their vitamin B6 intakes1. The mean dietary intake of the women was just 1.37 mg per day, which is below the recommended intake (2.6 mg per day at the time) for pregnant women in the United States (where the study was conducted). The researchers then measured the activity of the enzyme alanine aminotransferase in a subset of the subjects. Alanine aminotransferase is an enzyme which requires the active form of vitamin B6, pyridoxal 5’-phosphate, for activity. Alanine aminotransferase activity was measured by addition of pyridoxal 5’-phosphate to blood samples. Increases in the activity of alanine aminotransferase were indicative of low plasma levels of pyridoxal 5’-phosphate. The mean stimulation of the alanine aminotransferase enzyme was 34.8 % and 29.4 % at baseline and week 30, respectively.
Apgar scores (a measure of a baby’s health that includes appearance, pulse, grimace, activity and respiration) in those mothers with high erythrocyte alanine aminotransferase stimulation values were significantly lower than those with normal alanine aminotransferase stimulation values. Therefore these results suggest that the pregnancy outcomes for this sample of low income women were worse if they had poor vitamin B6 status. However, this is not surprising, because vitamin B6 is a water soluble essential nutrient that is required for health. It should be no surprise that low intakes therefore inhibit the health of both the mother and the growing foetus during pregnancy. More worrying is the likelihood that these women had multiple vitamin and mineral deficiencies that were almost certainly inhibiting the complete and healthy development of their offspring. More recent evidence suggests that such impairments of growth and development during pregnancy are a contributory factor in the development of adult disease.
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