Dr. Oz: 4 Warning Signs You Should Never Ignore
For some diseases, the red flags are changing. Here's what to watch out for now.
By Dr. Mehmet Oz
Vitamin D
While doctors have thought for years that a D deficiency can increase the risk of respiratory infections, a 2013 Finnish study found that people with the lowest vitamin D levels were 2.6 times more likely to develop pneumonia than those with the highest, suggesting that the vitamin is essential to a strong immune system. All it takes to reach your daily quota of D is ten to 15 minutes in the sun three times per week. Note that simply opening the curtains isn't enough—the UVB rays your body needs can't penetrate windows.
From the February 2014 issue of O, The Oprah Magazine