Women's Heart Advisor October 2008 Issue

A-B-Cs of Heart Health: Know Which Vitamins You Need Most

Eat a variety of whole foods to boost your vitamin intake and help protect against cardiovascular disease.

A heart-healthy diet involves more than reducing your intake of saturated fats and trans fats, both of which increase the levels of artery-clogging cholesterol. Certain vitamins play key roles in protecting your heart. If you have heart diseaseóor hope to prevent itóeating foods that contain these beneficial vitamins is an easy way to give your heart a natural boost.

"You donít have to obsess over whether youíre eating enough of specific foods to get the vitamins you need. Itís all about eating a variety of whole foods," says Cleveland Clinic dietitian Melissa Ohlson, MS, RD, LD.

Hereís what the latest research says about vitamins and your heart:

Vitamin A

Vitamin A is an antioxidant, but impacts mostly the eyes, skin and immune system. The recommended daily allowance (RDA) of vitamin A for adult women is 700 micrograms (mcg) or 2,333 international units (IU). This amount is easily obtained by eating eggs, milk, fortified cereals, dark-orange and red vegetables, and non-citrus fruits. Studies have shown that beta-carotene supplements are not generally beneficial, and they also have been associated with increased risk of lung cancer in smokers.

Folic acid, a B vitamin

High levels of homocysteine are associated with increased risk of coronary artery disease (CAD), and a form of vitamin B known as folic acid reduces homocysteine levels. For unknown reasons, however, folic acid supplements do not reduce the risk of CAD and may increase the risk of restenosis (re-narrowing of an artery) in people who have undergone revascularization (a procedure to restore blood flow to the heart or other organs).

"In addition to being safer, whole foods are a better source of B vitamins than supplements, because they also provide other heart-friendly nutrients, such as dietary fiber and antioxidants," says Ohlson.

The RDA for folic acid for adult women is 400 mcg. You can get this vitamin from dark leafy greens, lentils, split peas, enriched breads and cereals, and citrus fruits, such as oranges and orange juice. There is reason to get plenty of B: although the vitamin does not lower cardiovascular risk, it may help preserve cognitive function and prevent macular degeneration (a disease that causes central vision loss).

Vitamin C

No randomized clinical trials have been performed to gauge the effects of vitamin C supplements on cardiovascular disease. However, in the large Nurses Health Study, women with the highest consumption of vitamin C had the lowest risk of cardiovascular disease and nonfatal heart attack.

"The current consensus does not recommend vitamin C supplementation," says Ohlson. "Itís better to eat citrus, tomatoes, broccoli, bell peppers, leafy greens, kiwi and cantaloupe."

The RDA for vitamin C for adult women is 75 mg, which can be found in 6 oz. of orange juice.

Vitamin D

When it comes to heart health, vitamin D is the clear leader. If you get too little vitamin D, you are more likely to have risk factors for heart disease, such as hypertension, diabetes, high triglycerides and obesity. Studies also have shown that having low levels of vitamin D can double the risk of heart disease, heart attack, heart failure, stroke or peripheral arterial disease in five years, particularly in people with hypertension.

In animal studies, a powerful form of activated vitamin D has been shown to slow the progression of heart failure and may prevent its development. In this case, vitamin D acts more like a hormone than a vitamin.

Just how much vitamin D we need is under debate. The RDA is 200 to 600 IU, but some researchers recommend 1,000 to 2,000 IU. More than 2,0000 IU may be dangerous, since excess vitamin D is stored in the body, and large amounts can be toxic.

The best sources of vitamin D are oily fishes such as herring, salmon and eel; egg yolks; liver; and fortified breads, cereals and milk. Vitamin D is found in a few plant foods, but the body does not absorb this form as well.

"If you are vegetarian, talk with your doctor about vitamin D supplements and fortified foods," Ohlson advises.

Depending on where you live, exposing your skin to the sun for five to 30 minutes twice a week (without sun block) will provide you with plenty of vitamin D. People who are bedridden or live in less-sunny climates may need to obtain sufficient vitamin D through foods and supplements.

Vitamin E

The antioxidant qualities of vitamin E looked promising, but supplementation with this vitamin failed to reduce CAD risk in clinical trials. Moreover, there was some evidence that vitamin E supplements may slightly increase the risk of death among people with CAD. Fortunately, foods containing vitamin E are safe and good for you. The best sources of vitamin E for obtaining the RDA of 15 mg for adults are olive oil, nuts, seeds and dark greens.

Vitamin K

This vitamin plays a key role in blood clotting. It is found primarily in cheese and green vegetables. The RDA is 65 mcg for adult women, and you can get five times that amount in one serving of broccoli or spinach. People who take anticoagulants ("blood thinners") should not take vitamin K supplements.

"What it all boils down to is that our bodies generally prefer the vitamins from foods than those from supplements, although we donít know why. We should try to protect our heart health with a balanced diet of fresh, whole foods and only use supplements if we fall short," says Ohlson.