For years, the medical community thought that vitamin D was something we generally all got enough of – available from the sunshine and in our food, there always seemed plenty around. However our modern indoor lifestyles, changes in nutritional intake and excessive sun safety advice have meant that vitamin D deficiency is very real and extremely more important to have enough of during stages of fertility and pregnancy.
Vitamin D in Fertility and Pregnancy
Maternal vitamin D levels have the ability to affect the baby significantly. Modern research has now linked vitamin D deficiency to increased risk of gestational diabetes in pregnancy and several immune function disorders in the children of deficient mothers. Prior to conception, the fertility focused mother-to-be needs good levels of vitamin D for proper implantation, immune balance, calcium absorption and insulin regulation also.
The link between vitamin D levels and correct glucose metabolism has been well established in recent years, with researchers looking at the development of diabetes type 2. This link also corresponds to gestational diabetes, a condition in pregnancy which has significantly increased in New Zealand and Australia in recent years. Recent studies have shown that as much as 40% of women with gestational diabetes are also vitamin D deficient, and the lower the vitamin D levels the poorer the glycaemic control.
Vitamin D in pregnancy is a key link in reducing the risk of autoimmune conditions in the offspring. In 2001, a study was published linking vitamin D deficiency in pregnancy to an increased risk of the autoimmune condition, multiple sclerosis. The study involving 35,794 women found that a higher vitamin D intake reduced the risk of multiple sclerosis in their children.
Multiple sclerosis is not the only autoimmune condition linked with inadequate vitamin D in pregnancy. In fact, researchers now believe that vitamin D plays a protective role against all autoimmune conditions (including diabetes type 1, asthma & atopic conditions) during pregnancy, as well as in the first 12 months of a baby’s life. Studies indicate that babies who receive 2000IU vitamin D daily for the first year of life reduced the risk of developing diabetes type 1 later in life by up to 80%.
Aside from the debilitating impact of autoimmune conditions, poor vitamin D levels increase the likelihood of childhood infections (particularly respiratory viruses) even in apparently healthy babies. Researchers are now suggesting that maternal supplementation of vitamin D during pregnancy may provide an effective strategy against neonatal infection.
So how much vitamin D is enough and what foods contain it? A recent clinical trial demonstrated that supplementation of 4000IU vitamin D daily was not associated with a single adverse effect, confirming its safety during pregnancy. Women who have darker skin, or who avoid sun exposure are at a greater risk of deficiency as well as vegetarians and vegans.
For this group, I would recommend 3000-4000IU daily. If you do not fall in this category, then supplementation of 2000IU daily would be recommended. Vitamin D is found in regular daily exposure to sunshine, as well as fatty fish (ie salmon and mackerel), eggs, whole milk and butter.
For more information on how your diet can influence your everyday health, fertility, pregnancy and children, contact Wellington Natural Fertility Nutrition specialist, Kimberly Taylor on 04 4991439.