We all know that excessive sun exposure increases the risk for skin cancer and premature aging of the skin—but being too vigilant about blocking (or avoiding) the sun’s rays can have serious health consequences as well. When your skin can’t absorb UVB rays from sunlight, your body can’t produce the vitamin D it needs. And as many as 70% of people in North America are deficient in vitamin D.

Why that’s a big problem: Vitamin D deficiency has been linked with increased risk for osteoporosis and bone fractures…high blood pressure, heart attack and stroke…diabetes and obesity…postoperation infection…colorectal and breast cancers…rheumatoid arthritis…multiple sclerosis…and dementia, among other health problems.

What to do: Ask your doctor to check your vitamin D level. If it’s below 100 nanomoles per liter (nmol/L) or below 40 nanograms per milliliter (ng/mL)—two ways of expressing the same level—you might benefit tremendously from spending more time in the sun without sunscreen. The health benefits of doing this tend to outweigh the risks as long as you do not spend so much time in the sun that you sunburn.

If spending more time exposed to the sun makes you too fearful of skin damage or if you live in the northern US where it’s hard to get enough vitamin D from sun exposure in the winter, taking vitamin D-3 supplements can boost your vitamin D level. Daily dosages of 600 international units (IU) or 800 IU of D-3 traditionally have been recommended, but for some people, two to three times those amounts are beneficial. Dosages as high as 4,000 IU per day have been shown to be safe for adults—but be sure to get your dosage recommendation from your doctor.

Also ask your doctor to check your calcium, magnesium and iron levels when you have your vitamin D tested. If any of these are low, add foods rich in them to your diet (or take supplements that include them). One reason vitamin D provides so many health benefits is that it improves the digestive tract’s ability to absorb these necessary minerals. Examples: Milk, cheese, yogurt and leafy, green vegetables are rich in calcium…many nuts and seeds are rich in magnesium…and red meat, shellfish and spinach are rich in iron.