Research shows that vitamin D is important for heart health, but most Americans are not getting enough of this vital vitamin.

“We have found that over 50% of people out there are deficient in vitamin D,” says Dr. Chauncey Crandall, world-renowned cardiologist and director of preventive medicine at the Palm Beach Cardiovascular Clinic in Florida. And this is not ideal because vitamin D can reduce the incidence of heart attack by almost 20%, Crandall tells Newsmax’s “Newsline.”

Editor’s Note: Top Doctors Warn: This Common Deficiency Affects Every Organ in Your Body

Our skin produces vitamin D when exposed to the sun and we can get the vitamin in our diet from dairy products, such as milk, yogurt, egg yolks and cheese, and fatty fish, like salmon, halibut, and mackerel.

However, most people are not getting outside enough and if they do go out, they are wearing sunscreen and clothes that block the sun’s rays, so they are not able to make enough vitamin D, according to Crandall. And they don’t get enough dairy products or fatty fish in the diet.

Special: Doctor: All Multivitamins Are Not the Same

The study that found a reduction in heart disease from vitamin D was published in The BMJ. For the study, more than 20,000 men and women, ages 60 to 84, took 60,000 international units (IU) of vitamin D or a placebo monthly. After five years, the rate of heart attack was 19% lower and the rate of coronary revascularization (treatment to restore normal blood flow to the heart) was 11% lower in the vitamin D group compared to the placebo group.

Because most people don’t get outside enough and may be deficient in vitamin D, Crandall recommends supplementing with vitamin D daily. “We recommend around 2,000 to 5,000 IUs of vitamin D,” explains Crandall, editor of the popular newsletter Dr. Crandall's Heart Health Report. Crandall says you can also take a tablespoon of cod liver oil every day. And he recommends eating fatty fish, like salmon, mackerel or sardines.

Editor’s Note: Doctor: 4 Signs Your Heart Is Quietly Failing

Vitamin D is also important when it comes to depression. “Higher doses of vitamin D are associated with less depression in many people, and people that live in countries where there isn't a lot of sun have a higher incidence of depression,” says Crandall. By taking vitamin D you may be able to reverse depression, says Crandall.