Potential effects of low vitamin D: Are you at risk?

The best way to get adequate vitamin D is to eat fish, fortified milk, eggs and other foods.

Are you getting enough vitamin D? Studies show that as many as 1 in 4 Americans have low vitamin D levels, which can contribute to a range of health issues. Here's some information on the importance of vitamin D, the potential effects of low vitamin D levels, and how to ensure you're getting enough vitamin D.

What is vitamin D?

Vitamin D is a fat soluble vitamin that helps your body absorb calcium to build strong bones throughout life. Vitamin D also supports muscle and nerve function, helps your immune system fight off infections and viruses, and helps to control blood sugar levels.

Vitamin D is sometimes called the "sunshine vitamin" because the body makes it in response to ultraviolet rays. In most climates, it takes only a few minutes of sun exposure for your body to make vitamin D. However, since ultraviolet rays can also cause cancer, the best way to get vitamin D is typically through food and sometimes supplements. Some of the best food sources of vitamin D are fatty fish (including salmon, tuna and trout) and fish liver oil. Egg yolks, cheese and beef liver supply some vitamin D too. Many foods are also intentionally fortified with vitamin D, including breakfast cereals, milk and nondairy milks.

The potential risks of low vitamin D

Some people, such as babies who are breastfed and individuals with food intolerances, may have trouble getting enough vitamin D through their diet, which can put them at risk of experiencing the negative effects of low vitamin D levels . Older people and people who have darker skin sometimes don't make vitamin D efficiently enough to maintain optimal levels either. Because vitamin D is a fat‐soluble vitamin, people who have disorders that prevent them from digesting fat also may not absorb enough vitamin D from their diet. Some people need more vitamin D than others, including people who are obese, people who have had gastric bypass surgery and people over the age of 71.

People who have low levels of vitamin D may be at higher risk of experiencing the following conditions:

Bones breaking more easily: Vitamin D helps the body absorb the calcium it needs to develop and maintain strong bones. Without enough vitamin D, bones can bend and break more easily. In older people, low vitamin D can contribute to osteoporosis (weak or brittle bones) and increase the risk of fractures. In younger people, especially children, it can lead to osteomalacia (also called rickets), a condition in which bones and muscles become weak and cause pain.

Increased likelihood of contracting infections and viruses: Vitamin D helps to activate T cells that fight infections. One of the potential effects of low vitamin D levels is that the immune system may not react effectively to invading bacteria and viruses, which can lead to a person becoming sick more often or with more severe symptoms.

Potential increased risk of high blood pressure, heart disease and cancer: Vitamin D also helps control cell growth and inflammation, especially in veins and arteries. Low vitamin D levels can lead to stiffening of the arteries and higher cholesterol, raising the risk of high blood pressure and heart disease, which could lead to heart attack or stroke. Cancer is caused by an overgrowth of cells, and some studies show a link between low vitamin D levels and elevated cancer risk.

Increased risk of diabetes: Because vitamin D helps control blood sugar levels, another potential effect of low vitamin D is a greater risk of developing diabetes, a condition in which the body doesn't process sugars and starches properly and blood sugar levels go too high.

How to get enough vitamin D

In most cases, the best way to get vitamin D is from food, because your body absorbs it best in combination with other nutrients. Foods that provide vitamin D often provide other important vitamins and minerals as well, such as calcium and phosphorus.

Should you take a supplement? That's a great question for your health care provider. Providers often recommend supplements for breastfed babies, older people and people with certain other conditions.

Depending on your situation and any symptoms you may be experiencing, your provider may order a blood test to determine whether you are at increased risk of facing negative effects of low vitamin D levels.