While it is widely accepted that calcium is good for bone health, and bodily functions such as muscle contractions and blood clotting, it is the first time the nutrient has been linked to extended fertility.
A 30 year study of nearly 120,000 women who were recruited when they were aged 25 and 49, found those with highest intake of calcium in their diets were 13 per cent less likely to undergo menopause by the age of 45 compared to women with the least intake.
Milk is the best source of calcium, but the nutrient is also abundant in leafy greens such as kale and broccoli, and oily fish like sardines. Dietary sources of vitamin d include fatty fish such as tuna, mackerel and salmon, cheese and egg yolks.
“We found that after adjusting for a variety of different factors, vitamin D from food sources, such as fortified dairy and fatty fish, was associated with a 17 per cent lower risk of early menopause when comparing the highest intake group to the lowest intake group.”
Early menopause affects about 10 percent of women and is associated with higher risk of cardiovascular disease, osteoporosis and early cognitive decline.
The women in the study with the highest intake of calcium and vitamin D drank around one pint of fortified milk a day.
Because higher intake of vitamin D and calcium from foods may simply act as a marker for better nutrition and overall health the researchers took into account other factors such as intake of vegetable protein and alcohol, as well as body mass index and smoking.
“The large size of this study allowed us to consider a variety of potential correlates of a healthy lifestyle that might explain our findings, however, adjusting for these factors made almost no difference in our estimates,” added Dr Purdue-Smith.
Calcium and vitamin d deficiencies have previously been implicated in polycystic ovary syndrome, endometriosis, and premenstrual syndrome so may boost fertility overall.
The researchers said the outcome was important because women are increasingly delaying motherhood into their late 30s and early 40s.
“Fertility declines dramatically during the 10 years leading up to menopause, so early menopause can have profound psychological and financial implications for couples who are unable to conceive as they wish,” the authors concluded.