My office is super dark. Am I going to suffer from a sunlight-vitamin deficiency?

–Haley Morris, East Village

While it seems lately the sun has become public enemy No. 1 and that venturing outside in anything less than SPF 800 is tantamount to suicide, rays play an important role in human nutrition. “Lack of sunlight lowers the chances that a person is synthesizing enough vitamin D,” says Susan Kraus, R.D., a clinical dietitian at New Jersey’s Hackensack University Medical Center. UV radiation, besides causing melanoma, also triggers the production of vitamin D beneath our skin. How important is this chemical reaction? Well, a serious lack of the delightful D can cause a host of medical problems including osteomalacia (weak muscles and bones— or, in piratespeak, rickets). The preventative means are easy: Pop a vitamin supplement or, better yet, adopt a diet rich in our fishy friends. “The recommended daily intake of vitamin D is 50 to 100 micrograms,” adds Kraus. “Eating a 3.5-ounce piece of tuna, salmon or mackerel will easily cover that requirement.” And yes, a teaspoon of cod-liver oil will do the trick as well—though we’d rather have rickets.