If better bone health, silky skin and the prevention of a slew of diseases from osteoporosis to schizophrenia, aren’t enough of a sell, here’s one more reason women should be sure to get enough vitamin D in their diet: It can help keep off the pounds post-menopause, when weight seems to creep up no matter how much you sweat at the gym.

A study published in the Journal of Women’s Health found that in women 65 and older, those with low levels of vitamin D gained about two pounds per year compared with women getting sufficient amounts of the stuff. About 78 percent of the women who participated in the study did not have enough vitamin D in their systems. These women also weighed more to begin with.

Low levels are defined as less than 30 nanograms of vitamin D per milliliter of blood, while less than 25 nanograms counts as a deficiency. It’s not clear whether insufficient vitamin D contributes to weight gain or just reveals it, but one clue is the fact that fat cells have vitamin D receptors. Fat cells could inflate or shrink depending on vitamin D levels.

More research is needed, but doctors know this: Getting enough vitamin D is essential for overall health. Anyone from ages 1 to 70 needs 800 I-Us of the vitamin, while people over 70 need about 600 I-Us. Good diet sources of D include fatty fish like salmon and tuna, cheese, yogurt, milk and egg yolks.

But sometimes food is not enough. For some people, a supplement might be necessary to sufficiently ward off the slew of ailments associated with low vitamin D, such as heart disease, some cancers, diabetes, Alzheimer’s disease and of course, osteoporosis. And if you’re a woman over 65, it might just help you keep those post-menopausal pounds off. So don’t forget your vitamin D.