Recent research shows up to 50 percent of kids and adults in America are at high risk for vitamin D deficiency. A lack of vitamin D has been linked to a whole host of diseases. And now research continues to show it has a significant effect on cancer.

Dr. Donald Trump has been treating prostate cancer for 32 years. He's noticed something disturbing.

"Seventy percent of my patients have vitamin D deficiency," said Dr. Trump.

The sunshine vitamin is an emerging area of cancer research.

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READ: Vitamin D And Cancer

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"Low vitamin D levels are one of the factors that contributes to the development of a number of cancers," said Dr. Trump.

A study in post-menopausal women shows high doses of vitamin D cut the risk of cancer by 60-percent. Another study found 72-percent of lung cancer patients with high vitamin D levels who had a summer surgery were alive five years later, while just 29-percent of those with low vitamin D and winter surgeries were alive five years later.

"I am encouraged by that because we obviously need things that are useful in lung cancer," said Dr. Trump.

Five years ago, Susan Graham was diagnosed with lung cancer. The same cancer killed her mother and sister.

"I got past the 'poor me' and I said 'No, this is not going to get me.' Took my family, it's not going to get me."

She's cancer-free today and is grateful for every minute of her life. Now, she hopes to join a new study on vitamin D's effect in high risk lung cancer patients. A new government study found people with more vitamin D in their blood were 72-percent less likely to die of colorectal cancer than those with low vitamin D. But this study also found vitamin D levels in the blood played no role in the risk of dying of cancer in general. Is vitamin D a magic bullet for cancer? The issue is far from settled.

With more research, Dr. Trump believes the government will raise the recommended daily allowance of vitamin D.