People fighting off winter colds and bouts of the flu typically reach for a glass vitamin C-packed orange juice, but new research suggests that vitamin D may be a better protector. People with low levels of the vitamin, which is often called the sunshine vitamin because sun exposure triggers its production in the body, are more likely to catch colds, the flu, and even pneumonia, a broad new study reports. The effect was magnified in people with asthma or other lung diseases. Vitamin D deficiency