Vitamin D, otherwise known as the sunshine vitamin, is chronically lacking in the Irish population. Ireland has a very northerly latitude and therefore we do not get sufficient sunshine.  The world health organisation recommends 15 minutes arms and legs exposure per day to get the amount of Vitamin D necessary for good health.  Vitamin D is a fat soluble vitamin which is needed for every cell in the body to function properly.  It can be stored in the body for up to 60 days.  Food sources of Vitamin D include oily fish such as mackerel and salmon, egg yolk, liver, butter and dairy products.  Mushrooms are a weak plant source of vitamin D and the vitamin is very poorly absorbed from them.  

Vitamin D deficiency has been linked with several reproductive disorders, including miscarriage, preterm birth and reduced production of the sex hormones.  In fact, research has discovered that vitamin D may play a regulatory role in female reproductive physiology, since vitamin D receptors and enzymes are expressed in the ovaries and the placenta.  According to a study carried out in the National Maternity hospital in Dublin, pregnant women in Ireland have vitamin D intakes far below those recommended for the normal development of a child’s bones.  Research, found that the average dietary intake of vitamin D among pregnant women in Ireland was 80 per cent below the Food Safety Authority’s recommendation for an average adult. 

Conceiving a baby is wonderful. Enjoying a healthy pregnancy and having a healthy child is every parents wish.  Research is now focusing on the lack of maternal vitamin D and the mother’s health.  One such recent study from University College Cork has shown that expecting mothers with high levels of vitamin D are less likely to have serious pregnancy complications such as gestational diabetes and pre-eclampsia.  Researchers also found that High vitamin D status is associated with lower risk of complications such as small-for-gestational age (SGA) at birth.

The female uterus acts as a vessel to accept, grow and nurture the unborn foetus.  As the foetus develops it is entirely dependent on the nutrients that its mother takes in.  Having sufficient nutrients during pregnancy decreases the risk of nutritional deficiencies. Vitamin D is a hormone in the body and is responsible for regulating the functions of 100's of genes.  It is absolutely essential for the growth and development of the growing baby. It works with calcium to help the body build strong bones and to continue to maintain them.

Deficiency during pregnancy can lead to reduced bone grown in the unborn baby and in severe cases it can cause childhood rickets.  It is involved in healthy brain development and supports muscle functions which may be stretched during pregnancy.

RECENT RESEARCH

Until recently most of the vitamin D research has been focused on its impact on female fertility issues.   Despite the prevalence of male infertility, as well as the established link between vitamin D status and male fertility, there is a lack of research regarding vitamin D in male partners of couples attempting pregnancy.   In animal models, vitamin D deficiency in males has been found to result in low sperm count, impaired sperm motility and decreased pregnancy rates. 

Since vitamin D receptors and enzymes are expressed in the testis and male reproductive tract, it is clear that Vitamin D has a role to play in male reproductive physiology.   A recent study has concluded that there is a direct relationship between higher Vitamin D levels in male semen and increased rates of conception.

 Gaye Godkin, Health Nutritionist, MPH Nutrition (Hons) DipNT cNLP