Are you getting enough vitamin D? Chances are, you may not be, even if you spend a lot of time in the sun. New research shows that many Americans are woefully deficient in this key nutrient, a deficiency that’s linked to a host of ailments, including type 2 diabetes, high cholesterol, hypertension, and —yes — obesity. In fact, studies have found that a deficiency in vitamin D can hamper a person’s ability to lose weight effectively. So how do you know if you’re deficient? And if you are, what should you do about it? Here are some suggestions.
- Get tested. Ask your doctor if you can have a vitamin D analysis done as part of your routine blood test. If you have a 25-hydroxyvitamin D level below 20 ng/ml (nanograms per milliliter), you are considered deficient in D. Optimal levels are 30 to 40 ng/ml. Some doctors, however, feel that a level above 50 ng/ml is more desirable.
- Catch some rays. Vitamin D is known as the sunshine vitamin because the body produces it after being exposed to sunlight. Studies show that spending 10 to 15 minutes in the sun while unprotected (that is, without sunscreen) two to three times a week can boost your vitamin D levels. If you’re planning to be out in the sun for more than 15 minutes, however, be sure to apply the appropriate amount of sunscreen.
- Eat vitamin D–rich foods. Eating a healthy diet can help increase your vitamin D levels. Foods that are natural sources of vitamin D are sardines, mackerel, herring, and salmon. Vitamin D–fortified foods, such as low-fat or fat-free milk, reduced-fat cheese, and some whole-grain cereals, can also help you get more of this vitamin into your body.
- Consider a supplement. Consult with your doctor about taking a daily vitamin D supplement if you cannot get adequate amounts of vitamin D from foods and/or sun exposure and especially if you are pregnant or considering pregnancy. The recommended intake by the Institute of Medicine in 2010 is 600 IU daily if you are 19 to 70, and 800 IU if you are older. Many researchers, however, suggest that 1,000 IU of vitamin D a day is a better goal for everyone. While vitamin D supplementation is safe up to 10,000 IU a day, make sure you consult with your doctor about taking the appropriate dose. Recently, the US Preventive Services Task Force (USPSTF) proposed that postmenopausal women not take low-dose calcium and vitamin D supplements daily to ward off bone fractures. The USPSTF said there was no evidence to support using the low-dose supplements — defined as 400 IU of vitamin D with 1,000 milligrams of calcium carbonate — as protection against fractures. There was "inadequate evidence" as to how higher doses — meaning more than 400 IU of vitamin D paired with 1,000 milligrams of calcium — might affect bone fracture risk, the task force noted. To make better use of a vitamin D supplement, take it with your largest meal. Researchers believe that the nutrient, which is fat-based, is absorbed better with food that also has some fat content.