Vitamin D May Prevent Influenza

Why Respiratory Infections Occur In Cold Months

Oct 26, 2008

Vitamin D is credited for strong bones. New evidence shows it also plays a pivotal role in the optimal functioning of the immune system.

As this year's cold and flu season approaches, government health agencies will be urging the public to get vaccinated. From November to April, some 10-25% Canadians get the flu and recover. Unfortunately, about 4,000-8,000 elderly people die from pneumonia or flu complications.

Should the Public Follow this Advice?

Szilagyi and his colleagues reported that vaccines were not effective in protecting children against the flu, and requires further investigation.Their study was published in the October 2008 issue of the Archives of Pediatric and Adolescent Medicine. In contrast, a growing number of Western health experts are recognizing the importance of increasing vitamin D intakes during the fall and winter months.

Protective Role of Vitamin D

Active vitamin D (1,25 dihydroxyvitamin D3) directly regulates and enhances the body's production of"antimicrobial peptides." These small proteins also called "bacteriocins", mount an attack against bacteria, fungus, or viruses by rapidly destroying or dissolving their cell walls.Vitamin D also prevents the immune system from releasing too many inflammatory agents called"chemokines" and "cytokines" into infected lung tissues.

Influenza's Seasonal Nature

In 1945, Dr. Hope-Simpson discovered that influenza outbreaks occurred in temperate regions during the fall and winter months, and during the rainy seasons in the tropics. He concluded that latitude, timing of the outbreaks and light intensity have positive and negative effects on the virus, and that populations get the flu when sunlight is at its lowest levels.In 2003, investigators confirmed that tropical flu epidemics occurred during the rainy season when vitamin D levels are falling.

Sunlight Intensity and Vitamin D

For most people, spending 10-15 minutes outdoors everyday, a few times weekly during summer is enough to ensure vitamin D levels. However, dark-skinned people need longer sunlight exposure than light-skinned persons to obtain the same benefit. So do people who are housebound, live in tall buildings, air-polluted neigborhoods, wear layers of clothing, and use sunscreens. For them, vitamin D supplementation may be necessary.

Vitamin D Requirements

The Adequate Intake (AI) for vitamin D for healthy persons ages 0-50 years is 5 micrograms per day.For people 51-70 years, the AI is 10 micrograms per day; and for persons over 71 years, the AI is 15 micrograms per day.

The Tolerable Upper Level (UL) for vitamin D for all ages is 15 micrograms per day. UL is the maximum safe amount that a person can take on a regular basis. * 400 International Units (IU) = 10 micrograms

Significant Food Sources of Vitamin D

Fatty fish and their oils: salmon, herring, tuna, sardines. Egg Yolk, liver, butter, cream, fortified milk, cereals & margarines, beef, veal.

The copyright of the article Vitamin D May Prevent Influenza in Healthcare Research is owned by Alicia Richardson. Permission to republish Vitamin D May Prevent Influenza in print or online must be granted by the author in writing.