Vitamin D, a hormone produced by the body through exposure to sunshine or obtained from foods such as fatty fish and egg yolk, helps the body control calcium and phosphate levels. Previous studies have linked vitamin D levels with a range of health problems including cardiovascular disease and cancer.
Up to 80% of the population in Europe are affected by low vitamin D levels. As this is particularly common amongst people who lead unhealthy, sedentary lifestyles, low vitamin D levels have been associated with obesity; at the same time as obesity is rising, vitamin D levels are falling. In addition, female fertility and semen quality have deteriorated in the recent years due to largely unknown causes. Infertility rates amongst couples who want to have children are at 10-15%, and up to 10% of women of reproductive age suffer from polycystic ovary syndrome (PCOS), a condition which may hinder fertility.
Dr Elisabeth Lerchbaum, from the Medical University of Graz, has led much research on the effects of vitamin D supplementation in different aspects of male and female fertility. Research from her group and others suggests vitamin D affects many aspects of fertility in both genders, including influencing production and maturation of sperm cells in men, egg cell and uterine lining maturation in women, and sex hormone production in both sexes. Vitamin D levels have been associated with in-vitro fertilisation (IVF) outcome, some features of PCOS and endometriosis in women. In men, levels of vitamin D have been linked to semen quality and male hormone levels in both fertile and infertile men.