A woman smiles outdoors in sun
A woman smiles outdoors in sun
A woman smiles outdoors in sun

How Does Vitamin D Affect Women’s Health?

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Sometimes a little bit of sunshine is the best medicine. A walk in the park or a bike ride probably puts you in a good mood, and a moderate amount of sun is also good for your physical health. While you’re outside soaking up rays, your body is busy making vitamin D. That’s good news, because this hormone that’s boosted by exposure to sunlight plays an important role in women’s health.

woman in sunglasses looking towards sun

We have known for a long time about vitamin D’s critical role in bone health. (Did your mom tell you to drink vitamin D-rich milk to build strong bones and teeth?) More recently, though, vitamin D has been linked to having a potential role in a number of chronic diseases, including heart diseasecancer, inflammation and autoimmune disease

Erin Michos, M.D., associate director of preventive cardiology at the Johns Hopkins Ciccarone Center for the Prevention of Heart Disease, explains why vitamin D is important for women’s health and how to make sure you’re getting enough.

Q: Why is vitamin D important?

A: Research I have done in this area has found that people with low blood levels of vitamin D have a greater risk of a heart attack, heart failure, stroke, diabetes or high blood pressure later in life. In pregnant women, low vitamin D levels are linked to pre-eclampsia, gestational diabetes and adverse pregnancy outcomes. No matter your age or stage of life, having adequate vitamin D levels is important.

Q: What’s the link between vitamin D and heart health?

A: That isn’t entirely clear. We know that low vitamin D levels are a risk factor for heart disease, but at this time, we do not know whether treating low vitamin D with supplements can prevent a heart attack. There are a number of large clinical trials studying this now. Part of the problem with finding the answer is accounting for the many factors involved in heart disease. For example, maybe people who develop heart disease are also getting less physical activity outdoors. It may not be low vitamin D levels causing the heart disease.

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Q: Should people consider vitamin D supplements?

A: If the level of vitamin D in your blood is less than 20 nanograms per milliliter, your doctor may recommend taking a supplement. Many women already take calcium and vitamin D supplements together for bone health because vitamin D can help in calcium absorption, and they work best when taken together. Ask your doctor if supplements are right for you.

Q: Is it possible to take too much vitamin D?

A: The upper tolerable limit is 4,000 international units (IU) daily, and the recommended amount for women 14 to 70 is 600 IU per day. Women 71 and older should aim for 800 IU per day. 

Q: How can women maintain healthy vitamin D levels naturally?

A: I encourage women to get regular physical activity indoors and outdoors to maintain a healthy weight (because obesity is linked with low vitamin D), get modest exposure to sunlight (10 to 15 minutes of summer sun exposure per day), and eat a healthy diet, including vitamin D-rich foods, like fatty fish (salmon or tuna) and moderate amounts of fortified, low-fat dairy.

Q: Do some people naturally have lower vitamin D levels than others?

A: People with darker skin pigmentation tend to have lower levels, as do people who use sunscreen, don’t spend much time outdoors, or are overweight or obese. This is because vitamin D is fat soluble, so it gets trapped in fatty tissue and can’t be used by the body as it should be. Gastrointestinal surgery, like gastric bypass, makes it difficult to absorb vitamin D. And as we age, we don’t absorb vitamin D well, and we produce less.

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