Vitamin D and Your Heart

It’s estimated that up to half of middle-aged to elderly Americans don’t get enough vitamin D. People with low levels of vitamin D have higher risks of developing breast, prostate and colon cancer, cognitive decline, osteoporosis and auto-immune diseases such as multiple sclerosis, rheumatoid arthritis and type 1 diabetes. And now recent studies suggest that a lack of vitamin D may be a new trigger for cardiovascular disease, especially in people who also have hypertension and diabetes.

Inadequate sun exposure from living in northern latitudes, darkly pigmented skin and eating foods low in vitamin D are thought to be the causes. Here in Connecticut, we spend most of our time indoors or in cars with clothes covering most of our body. When we do go outside, we apply sunscreen to protect our bodies from the threat of skin cancer.

Researchers are now paying attention again to the “sunshine vitamin” that had taken a backseat ever since rickets, a bone-crippling disease caused by low levels of vitamin D that was rampant in children 100 years ago, practically disappeared. Seems like our mothers and grandmothers were right when they insisted on us taking a teaspoon of that horrible tasting cod liver oil (high in vitamins D, A, and omega 3 fatty acids) and spending a half-hour in the sunshine every day! Our current lifestyles have moved most of us indoors, but our need for vitamin D still exists.

How do I know if I need more vitamin D?
Vitamin D deficiency (lack) is easy to screen for and treat through a routine blood test. Blood levels of vitamin D that are 30-40 nanograms per milliliter or higher are considered optimal (best). In the United States, Caucasians currently average 18-22 nanograms/ml and African Americans average 13-15 nanograms. Ask your physician if he or she thinks you should be tested. If your levels are low, your physician will recommend a supplement dosage based on your medical needs. While it is tempting to buy vitamin D over the counter, and self-prescribe, it is a fat soluble vitamin and can be toxic in large doses. It is best to ask your physician for guidance as he or she can monitor your levels as you take the supplement. The current recommended dosage from the Institute of Medicine is 400 IU for adults aged 50-70 and 600 IU for those older than 70. These recommended levels are being reevaluated and may soon be increased based on current research.

Why do I need vitamin D?
Every tissue in the body needs vitamin D. Your heart, brain, immune system and muscles all have receptors for vitamin D. In terms of heart health, the researchers who followed 1,739 Framingham Offspring Study participants concluded that moderate to severe vitamin D deficiency was associated with an increased risk for developing cardiovascular disease. This was especially true for those with hypertension. Another study found that calcium supplementation without vitamin D led to an increased incidence of heart attacks.

Where do we get vitamin D?

• Food: Very few foods naturally contain vitamin D. Out of those that do, the best sources of vitamin D include salmon (especially wild-caught), mackerel, cod, tuna canned in water, sardines canned in oil and the vitamin D-fortified foods such as milk, some orange juices and ready-to-eat cereals. Whole, low-fat and skim milk all contain the same amount of vitamin D, but skim milk is more heart-healthy as it is lower in saturated fats.
• Sun: The sun is considered the best natural source. Depending on the intensity and the time of year, it is estimated that anywhere from 5-30 minutes of exposure per day is adequate. The skin absorbs ultraviolet B rays from the sun and converts them into pre-vitamin D. The liver then changes this to 25-hydroxyvitamin D, which is the main form that circulates in the blood. The kidneys then take this form and convert it into a hormone called 1,25-dihydroxy-vitamin D.
• Supplements: Vitamin D is found in daily vitamins, calcium supplements and on its own. Your doctor can help you determine how much you should have daily. Prescription variations depend on your blood levels, lifestyle, medical problems, age and skin color.

What should I do?

• Ask your physician about having your vitamin D levels tested.
• Try to eat 10 ounces of fatty fish (such as salmon, tuna, sardines, mackerel and trout) per week.
• Drink 2-3 glasses of skim milk fortified with vitamin D per day.
• Continue to use sunscreen when in the sun. Apply liberally and often.