Women with a higher dietary intake of vitamin D are less likely to experience early menopause, according to a new study published in the American Journal of Clinical Nutrition.
The researchers, from the University of Massachusetts, looked at the association between calcium levels, vitamin D consumption and the age at which menopause occurs.
Approximately 116,000 women were followed for 20 years. In that period, 2041 of the participants were diagnosed with menopause at 45 years old or younger. Using dietary questionnaires, the consumption of vitamin D and calcium was measured.
The normal timing of menopause varies by ethnic group. It usually occurs between the ages of 48 and 55. Ten per cent of women will enter menopause between the ages of 40 and 45, and those entering menopause before 40 are considered to be doing so prematurely.
The results were interesting; those who consumed the most vitamin D via dietary means – particularly dairy products – were 18 per cent less likely to experience early menopause. The ideal daily intake appeared to be two-and-a-half servings (a single serving is 230ml) of fortified milk.
The effect of consuming more calcium via diet was minimal. However, from the age of 40 onwards, increased intake of calcium via supplement appeared to increase the risk of early menopause. Consuming vitamin D supplements was not found to be associated with any change in the likelihood of early menopause.
Supplements may not be necessary at all. For years calcium supplements have been recommended for bone health, but there is accumulating evidence that they could be doing more harm than good. Although full fat dairy gets a lot of bad press, a new study suggests that it’s perfectly safe to consume.
The observations in this study prove association, but not causation. Having said that, the findings seem biologically plausible; vitamin D receptors are found in abundance in ovarian tissue. Vitamin D is also known to protect the ovaries from the effects of ageing.
Early menopause is associated with several health problems, including increased risk of cardiovascular disease and osteoporosis. The condition is usually genetically predetermined, though there are a few exceptions. For example, when it is caused by autoimmune disease, surgery, chemotherapy or radiation.
Although further studies will be needed before a definitive statement can be made, it now appears that they may increase the risk of early menopause too.