There’s a new reason for the elderly to drink another glass of milk or go outside to get some sun.

A study appearing in the Journal of the American Geriatrics Society finds older Americans with a vitamin D deficiency are three times more likely to die from heart disease and two and a half times more likely to die from another cause compared to those with optimum levels of the vitamin.

"Given the aging population and the simplicity of increasing a person’s level of vitamin D, a small improvement in death rates could have a substantial impact on public health," said the study’s lead author Dr. Adit Ginde from the University of Colorado Denver School of Medicine’s Division of Emergency Medicine.

Vitamin D deficiencies are believed to be common among those 65 and older due to less exposure to the sun and a reduced ability for the body to produce the vitamin.

The vitamin is available as a nutritional supplement. It can also be found in dietary sources like milk, fish, eggs and cod liver oil.

Health experts say as little as 10 minutes of daily sun exposure can prevent insufficient levels of the vitamin.