A new study has shown that Vitamin D is much required in America and its best source is from milk.
Using the latest national data (NHANES 2003-2006) on what more than 16,000 Americans ages two and older eat, researchers investigated the contribution of each food group to the total vitamin D intake.
No other food item came close to the vitamin D contribution of milk.
In fact, for kids ages 2 to eighteen, milk provided nearly two-thirds of all vitamin D in the diet.
Dr. Keith Ayoob, a registered dietician and paediatric nutrition expert, said: "There are few true replacements for the nutrient package you find in one glass of fat free or lowfat milk.
"Without milk in the diet, it's hard to meet a number of nutrient needs - most notably vitamin D."
Many Americans are not getting enough vitamin D, and this D-ficiency may put their health at risk.
Well known for its role in keeping bones strong, vitamin D is now being hailed for so much more.
Emerging science suggests vitamin D may also help protect against diabetes, hypertension, heart disease and certain cancers. It also supports a healthy immune system.
Despite a potential upside of boosting vitamin D levels, Americans of all ages still fall short of their vitamin D needs.
In fact, current deficiency levels prompted the American Academy of Pediatrics to double the vitamin D recommendations for children and teens.
The Academy estimates that up to half of adolescents have low vitamin D levels.
Experts recommend 400IU of vitamin D each day - the amount in four glasses of fat free or lowfat milk.
The study was presented at the Experimental Biology conference in Anaheim, California.