To have a healthy heart, you know it’s important to do things like exercise regularly, eat healthfully and not smoke. But what about take a vitamin?
In recent years, research has found a possible link between certain cardiovascular problems and a lack of vitamin D. And guess who’s at high risk for vitamin D deficiency. Winter-dwelling Alaskans.
How does vitamin D affect your heart?
Vitamin D may be involved in all sorts of disorders, including the following cardiovascular-related conditions:
• Hypertension (high blood pressure): Vitamin D deficiency causes increased activity of the hormone system that regulates blood pressure.
• Inflammation: Atherosclerotic heart disease (hardening of the arteries) is an inflammatory illness. Taking vitamin D has been shown to reduce a protein in your blood associated with inflammation.
• Hyperparathyroidism (overactive parathyroid glands): Vitamin D deficiency can cause this disorder because the nutrient helps you absorb calcium. If you don’t absorb enough, your parathyroid glands kick in to help get it elsewhere (including from your bones). People with hyperparathyroidism are at risk for cardiovascular diseases.
• Type 2 diabetes: Vitamin D affects mechanisms related to both insulin resistance and production.
• Depression: Vitamin D levels are low in people with depression. Depression is a major risk factor for cardiovascular disease.
Do you have vitamin D deficiency?
We need more research to know whether taking a supplement will help prevent or fix all these disorders. For now, supplements are recommended for many people but should be taken under the guidance of a health-care provider because vitamin D may have adverse effects if you have certain conditions or take certain medications.
Vitamin D deficiency is prevalent worldwide. Your risk increases as you move farther from the equator, and deficiency is most common in the winter months. So as an Alaskan, you’re likely to be deficient if you’re not supplementing.
Other risk factors include:
• Having darkly pigmented skin
• Wearing sunscreen or cover-up clothing (though those are important for skin cancer prevention)
• Being obese
• Being physically inactive
• Being housebound or living in a long-term care facility
• Living in a place with air pollution
• Having certain genetic factors or a decreased ability to absorb vitamin D
• Having renal or liver disease
• Taking certain medications, including glucocorticoids, antirejection medications, HIV medications and certain antiepileptic drugs
Where do you get vitamin D?
When you take a vitamin D supplement, it’s important to choose the most effective one.
There are two major forms of vitamin D: D2 and D3. Vitamin D2 is found in plants. You get D3 from the sun or your diet — in particular fatty fish (wild salmon, mackerel, tuna fish, sardines and cod liver oil).
The best source of vitamin D is sunlight. You should try to obtain vitamin D naturally rather than through artificial supplements. However, how much you get from the sun depends on a few factors, including your skin tone. If you’re a light-skinned Caucasian and it’s the middle of the year, five to 10 minutes of midday exposure on your arms and legs will give you about 3,000 international units of vitamin D. A sub-Saharan African needs 60 to 90 minutes to produce an equivalent amount.
Most people living north of the 34th parallel — north of Atlanta, Ga. — require vitamin D supplementation during the winter months. But keep in mind that vitamin D can interact with certain medications and make some disorders worse, so talk to your health-care provider for a personal recommendation (again, guided by a health-care provider).
With supplements, you absorb D3 (which is from animal sources) more easily than D2 (synthetic), so that’s what I recommend to my patients. But how much to take is debatable. Some sources suggest up to 10,000 international units daily. The Institute of Medicine recommends no more than 4,000 because of concern about potential toxicity.
I generally recommend 2,000 to 5,000 international units of vitamin D3 per day unless I’ve done a special blood test that tells me you need more or less.
Now, here’s a twist: Magnesium is key here too. A deficiency in this mineral reduces your ability to absorb and use the vitamin D. So remember to get enough magnesium as well.
Foods rich in magnesium include:
• Plantains, raw
• Seeds, especially pumpkin and toasted sesame
• Beans, especially pinto and black
• Nuts, especially Brazil nuts, almonds and peanuts
A study sponsored by the National Institutes of Health is underway to see whether 2,000 international units of vitamin D3 or 1 gram of omega-3 fatty acids can reduce the risk of heart disease, stroke and cancer in 20,000 people. Results are expected in 2016. In the meantime, consider talking to your health-care provider about whether taking a vitamin D supplement could benefit you.
Dr. Romel Wrenn, M.D., FACC, is a board certified interventional cardiologist with the Porter Heart Center at Fairbanks Memorial Hospital.