The risk of suffering from flu can be reduced by 50% if they take vitamin D, doctors in Japan have found. The finding has implications for flu epidemics since vitamin D, which is naturally produced by the human body when exposed to direct sunlight, has no significant side effects, costs little and can be several times more effective than anti-viral drugs or vaccines according to research in the American Journal of Clinical Nutrition.

Fatty fish can be a good source of vitamin D. Common options include salmon, trout, mackerel, tuna, and eel.A 3-ounce sockeye salmon fillet contains about 450 international units (IUs) of vitamin D—a good portion of the 600 IUs that is the Institute of Medicine's recommended dietary allowance (800 IUs if you're over 70).And you get a bonus—heart-healthy omega-3 fatty acids!

 Just like humans, mushrooms have the capacity to produce vitamin D when exposed to ultraviolet light.Mushrooms, however, are usually grown in the dark and don't contain the vitamin. Specific brands, however, are grown in ultraviolet light to spur vitamin D production.Check to see if vitamin D–rich 'shrooms, like Dole's Portobello Mushrooms, are available at a store near you. They're perfect for vegetarians looking for plant-based foods that contain the vitamin. Dole's portobellos will give you 400 IUs of vitamin D per 3-ounce serving (about 1 cup of diced mushrooms).

One 8-ounce glass of fortified orange juice usually has around 100 IUs of vitamin D, but the amount varies from brand to brand. Not all brands are fortified, so check the label.Two fortified brands, Florida Natural Orange Juice and Minute Maid Kids+ Orange Juice, contain 100 IUs per 8-ounce serving.

Eggs are a convenient way to get vitamin D. They're popular in many breakfast, lunch, dinner, and dessert recipes.Since the vitamin D in an egg comes from its yolk, it's important to use the whole egg—not just the whites. One yolk will give you about 40 IUs, but don't try to get your daily vitamin D just from eggs.One egg contains about 200 milligrams of cholesterol, and the American Heart Association recommends consuming no more than 300 milligrams a day for heart health. Always, buy organic eggs.

While its name might suggest a less-than-savory flavor, cod liver oil is often flavored with mint or citrus, or comes in capsule form.One tablespoon contains about 1,300 IUs of vitamin D, which is more than twice the recommended dietary allowance of 600 IUs per day.That amount doesn't exceed the maximum upper-level intake of 4,000 IUs for people over 8 years old, but it exceeds the daily maximum for infants (1,000 IUs).

For adults, at high risk of vitamin D deficiency may resort to UV-emitting lamps and bulbs. This includes people unable to absorb the vitamin (malabsorption) or those who can't get enough in winter months, says Michael F. Holick, MD, a professor of medicine, sociology, and biophysics at Boston University Medical Center.Personally, I feel the sun is our best source.  Leave off the sunglasses for at least 20 minutes for the vitamin D to be absorbed well.  Many holistic doctors will tell you sunglasses are a no-no and prevent us from obaining many benefits from the sun.  I never wear them.

Have a blessed day and goooo peek at some sun!