Well-known for its role in keeping bones strong, vitamin D is now being hailed for much more—from normal muscle function to a healthy immune system. Yet despite the growing research on the power of vitamin D, seven out of 10 Americans still fall short of recommended amounts in their diets, according to the recent Dietary Guidelines Committee Advisory report. In fact, vitamin D is one of the four nutrients of concern identified in the 2010 Dietary Guidelines for Americans, which means low intake is a public health concern for children and adults.

Even with warmer spring weather on the horizon and more time outdoors soaking up the sun’s rays, the sun can’t be counted on to supply all the vitamin D Americans need, especially if sunscreen blocks the ultraviolet rays that our bodies use to make vitamin D. Doctor of public health, registered dietitian and well-known author Dr. Wendy Bazilian (“The SuperFoodsRx Diet”) encourages Americans to look to their diets for vitamin D.

“Vitamin D is a true super nutrient and Americans can help close the vitamin D gap by taking simple steps like pouring one more serving of low-fat or fat-free milk each day for their families,” said Dr. Bazilian. “Milk is the leading source of vitamin D in our diets, supplying more than half of the nation’s vitamin D, along with a unique combination of key vitamins and minerals we all need each day. And, of course, it tastes great.”

Despite the “super” status for vitamin D, Americans of all ages still appear to be coming up short. A new research report called “What America’s Missing,” which analyzed government food consumption survey data, identifies a total of 11 “gap nutrients,” including vitamin D, along with calcium and potassium, which make up three of the “nutrients of concern” identified in the 2010 Dietary Guidelines Advisory Committee’s report.

Nearly 70% of Americans ages 2 and older fall short of the recommended vitamin D in their diets. The problem could be even worse as Americans get older. And with diet alone, less than 10% of men and women older than 50 years meet the recommendation, according to the recent 2010 Dietary Guidelines Advisory Committee report. Experts even suggest the chronic low intake of vitamin D has been behind the resurgence of rickets—a severe vitamin D deficiency that results in bone deformities.

With the average American falling short of the recommended three 8-oz. servings of low-fat or fat-free milk and milk products, it’s no wonder there is a significant vitamin D gap. The recommended three glasses of low-fat or fat-free milk a day provide 75% of the Daily Value of vitamin D. In fact, milk is the single greatest contributor of vitamin D in the American diet—no other food contributes more of this essential nutrient.