Quarter of over-50s found to be low in vital 'sunshine' vitamin
Lack of exercise is linked to one in four adults over 50 being deficient in vitamin D which is needed to help keep bones, teeth and muscles healthy.
Vitamin D has a known role in strong bones, with growing evidence for beneficial effects on muscle strength and other non-skeletal conditions, said researchers at Trinity College Dublin. The findings showed the risk of being low in the so-called "sunshine vitamin" was higher among women and the over-80s.
Smokers, people who are obese and who have poor self-reported health were more likely to be deficient in the vitamin, the study published in the journal 'Nutrients' said.
People who had a healthy weight, were retired and taking regular vigorous physical activity had a better chance of having adequate levels.
It also helped if people took a vitamin D supplement and had travelled to the sun in the previous year.
Associate Professor in Nutrition at Trinity College Maria O'Sullivan commented: "Our study identified factors associated with vitamin D deficiency, including being aged more than 80 years, obesity and sedentary lifestyles, all of which are increasing traits in western populations.
"Furthermore, this is one of the few studies to highlight the importance of non-white ethnicity in vitamin D deficiency in a large study of ageing.
"The findings are valuable in developing targeted strategies to eliminate vitamin D deficiency in older populations."
Vitamin D helps to control the amount of calcium and phosphate in our bodies.
It is present naturally in a small number of foods, including oily fish, red meat, liver and egg yolks.
It's also found in fortified foods like breakfast cereals and fat spreads.
However, it's difficult to get the recommended amount of vitamin D from food alone.
The main source is from the action of sunlight on our skin.
Dr Niamh Aspell, who led the study, said: "Those who used a vitamin D supplement were less likely to be vitamin D deficient, as may be expected.
"But supplement use was low at 4.4pc and, therefore, food fortification and other strategies need to be considered at policy level for older populations."
Research Fellow Dr Eamon Laird pointed out more northern countries such as Finland have implemented a successful vitamin D fortification policy which has all but eliminated deficiency in the population, and this could happen Ireland.