With a well-balanced diet, it is certainly possible for a healthy person to obtain all of the vitamins and minerals he or she needs from foods alone. Dietary supplements are not a replacement for eating healthful foods; rather, they are intended to do just what their name implies—to supplement a diet.

There are circumstances, however, in which the foods we eat may not provide all of the important nutrients that our body needs, resulting in a nutrient deficiency. Here’s a quick rundown of five nutrient deficiencies that are more common than you might think.

Vitamin D: Calcium’s Best Buddy

When it comes to nutrient deficiencies, vitamin D is arguably the most common. A large majority (some reports estimate up to 95% of the U.S. population age 19 and older) does not meet recommended vitamin D intake levels. That is probably due to the fact that there aren’t a whole lot of naturally occurring food sources of vitamin D. Furthermore, the largest source of vitamin D—fortified dairy products like milk—tend to be foods that we eat less of as we grow older.

Vitamin D is a fat-soluble vitamin that plays a role in helping bones absorb calcium. It is found in fatty fish like salmon and mackerel, as well as certain types of mushrooms. Your body forms vitamin D naturally when skin is exposed to sunlight, but most of us don’t spend much time outside, so fortified dairy products such as milk and yogurt are going to be your best food sources of vitamin D. Adults aged 19-70 should aim to get 15 micrograms of vitamin D per day. If foods don't provide that amount, your healthcare provider may suggest a supplement.

Vitamin E: Get Yours From Foods Instead of Pills

Next up on the list of nutrients you may not be eating enough of is vitamin E. Like vitamin D, vitamin E is also a fat-soluble vitamin, but it is found in fatty foods such nuts, seeds and vegetable oils.

About 94% of adults over age 19 eat less than the estimated average requirement for vitamin E. Due to potential health risks associated with large doses of vitamin E pills, however, widespread supplementation is not routinely recommended. Instead, shift your food intake to make sure you are eating a variety of healthful fats that will help you bump up your vitamin E levels from food-based sources to meet your needs.

Make Magnesium Matter More in Your Diet

Magnesium is a mineral that plays a role in more than 300 enzymatic pathways in your body. It helps make proteins, controls blood sugar and blood pressure, bone health and is needed for making DNA, RNA and the antioxidant glutathione.

Despite its position of supreme importance in the body, more than 60% of adults older than 19 don’t meet the estimated average requirement for magnesium. One way you can increase your intake is to bump up your intake of dark green leafy vegetable and whole grains. Fortified foods such as breakfast cereals are also a good source of this important mineral.

Iron: This One’s for the Ladies

About 14-18% of Americans currently take a supplement containing iron; and iron supplement takers tend to be overwhelmingly female. That’s because women are at higher risk for iron deficiency and iron deficiency anemia due to biological factors such as menstruation and lower intakes of high heme-iron foods, such as meat, fish and poultry.

The Office of Dietary Supplements (ODS) states that those at high risk for insufficient iron intake include infants, young children, teenaged girls, pregnant women and premenopausal women. Animal foods such as meat, fish and poultry are good sources of the easily absorbed form of iron called heme iron.

Although plant foods contain iron, it is in the less readily absorbed non-heme iron form. The Recommended Dietary Allowance (RDA) for vegetarians is 1.8 times higher than for people who eat meat. If you’re concerned about iron status, check with your primary care provider who can test for deficiency and anemia before recommending you start a supplement.

Vitamin A is Important for More Than Just Your Eyes

Although vitamin A deficiency is not widespread in the North American population, slightly more than 50% percent of people still do not meet the estimated average requirement for this fat-soluble vitamin. Vitamin A is well known for the role it plays in vision, but it also impacts immune function, reproduction and your body’s cellular communication as well.

You can make sure you’re getting enough by consuming both preformed vitamin A (from animal foods, such as milk and eggs) and provitamin A, found in leafy green vegetables, orange and yellow vegetables, tomatoes and fruits. Increasing the variety of both the plant and animal foods you eat ensures you get adequate amounts of the all-important vitamin A.

Learn more about how to eat for better health with Nutrition for Sports, Exercise and Weight Management.