(Family Features) At a time when the country is facing an obesity epidemic, the problem of nutrition inadequacy is often overlooked. Many people are falling short on key nutrients - shortages that could put their health at risk.

A new study, called "What America's Missing," which analyzed government food consumption survey data, indicates that nine out of 10 Americans fall short of key nutrients in their diet. The report identifies a total of 11 "gap nutrients," including calcium, vitamin D and potassium - three of the "nutrients of concern" identified in the 2010 Dietary Guidelines Advisory Committee's report.

"The nation's nutrient shortages are directly linked to the under-consumption of the specific foods and beverages that supply these nutrients, such as fruits, vegetables, whole grains and lowfat milk," said registered dietitian Elisa Zied, MS, RD, CDN author of "Feed Your Family Right!" and "Nutrition at Your Fingertips." What's so important about these three nutrients of concern?

Calcium: Helps build and maintain strong bones and teeth

Vitamin D: Promotes the absorption of calcium for healthy bones

Potassium: Helps regulate the balance of fluids in your body

A serving of milk offers nine essential nutrients and is the single greatest source of calcium, vitamin D and potassium in the American diet - no other food contributes more of these essential nutrients. Yet, on average, Americans today are drinking only about a single serving of milk each day - falling far short of the recommended three 8- ounce servings (or 2 servings for children ages 8 and younger). The milk gap starts around age nine and continually gets wider, especially among adolescent girls and women.

"Milk, in particular, is something that's likely already in your refrigerator," Zied said. "So it's not too difficult to think about adding just one more serving a day.

Visit WhyMilk.com for recipes and tips to pour one more for your entire family, and help fill the nutrient gap.