Why do I need vitamin D?

Marjorie Nolan Cohn
Nutrition & Dietetics

Vitamin D deficiency is more common than you might expect. People who don’t get enough sun, especially people living northern climates, are at risk. Vitamin D deficiency also occurs in sunny climates, possibly because people are staying indoors more, covering up when outside, or using sunscreen more consistently these days to reduce skin cancer risk. Vitamin D is crucial for the absorption and metabolism of calcium and phosphorous, which have various functions, especially the maintenance of healthy bones. It supports the immune system, and adequate vitamin D levels are linked with healthy weight.


Dr. Michael Roizen, MD
Internal Medicine
It's vital for you to get enough vitamin D3. If you're chronically short, your risk goes up for a passel of nastiness: several cancers (including breast, colon, and ovarian), heart disease, osteoporosis, asthma, type 1 diabetes, multiple sclerosis, and high blood pressure. New studies are also turning up links between low D and obesity in kids, injuries among pro football players, digestive diseases, pneumonia, and anemia.

On the upside, researchers have recently found that having healthy amounts of D3 relaxes your blood vessels, helps bone-building drugs work better, makes weight loss faster and easier, and even transforms slow sperm into speedy swimmers (think dog paddlers versus Michael Phelps).

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.