Nutritional Deficiency May Breed Deadlier Viruses

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Poor nutrition leads to mutations that create more dangerous forms of the influenza virus and may contribute to newly virulent outbreaks of viral epidemics ranging from the common cold to AIDS and Ebola hemorrhagic fever, university researchers said on Friday.

Deficiencies of selenium allowed the human influenza virus to mutate into more virulent forms in mice, and a similar mutation is likely to occur in people, researchers said in a study in the FASEB Journal, published by the Federation of American Societies for Experimental Biology.

''Once the mutations have occurred, even mice with normal nutrition are more susceptible to the newly virulent strain,'' said researcher Melinda Beck of the University of North Carolina at Chapel Hill. ''Poor nutritional status
may contribute to the emergence of new viral strains and might promote epidemics.''

In the study, groups of mice with normal and selenium-deficient diets were exposed to Influenza A Bangkok, a mild strain of human influenza virus. Although researchers had expected the malnourished mice to be sicker than the well-fed ones, they confirmed that the virus also mutated to a greater degree in these mice.

Selenium, which is found in meat and grains like wheat and rice, is a component of an anti-oxidant enzyme that helps the body fight off infections. Most people in developed countries would not need to supplement their diet to maintain adequate levels of the mineral, the researchers said.

''It's in everyone's best interest to make sure that populations are well-fed -- both ethically and morally, and for public health concerns,'' Beck said. ''It's a two-sided coin. More virulent (viral) strains will affect healthy
populations as well.''

The study focused on the flu virus, which hospitalizes more than 100,000 people each year in the United States alone. The research also confirmed earlier studies into the causes of mutations of a virus, Coxsackie B3, linked to a heart disease known as Keshan disease.

The disease, once found in China among children and women of childbearing age with diets low in selenium, was largely eradicated by dietary supplements, the researchers said.

Insight

Putting It All Together: The New Orthomolecular Nutrition. Researchers writing in the July 15, 2000 issue of the British-based international medical journal, The Lancet , called attention to the importance of selenium to health, citing the trace mineral's potential to reduce the risk of thyroid problems, pregnancy and fertility problems, heart disease, and progression of HIV to AIDS, among other important
findings.

According to the review study, diet and geographic location can impact the amount of selenium you are getting. Selenium is an essential trace mineral found in the soil. Typically, crops will convert selenium into organic forms that can be absorbed nutritionally by humans. Getting sufficient quantities of selenium may increase thyroid hormone metabolism, improve fertility, help fight cancer, and reduce risk of cardiovascular disease and arthritis.

The author of the study, ("The importance of selenium to human health," The Lancet , Volume 356, Number 9225, 15 July 2000), Margaret Rayman, a professor of nutritional medicine at the University of Surrey in Guildford, England, began focusing on selenium several years ago, after her research into the condition known as preeclampsia showed that low
selenium levels were a common denominator in all the women in the study. Her research went on to discover that in the UK, and in Europe as well, selenium levels were abnormally low overall. Rayman found that dietary consumption of selenium had dropped 50% in the past two decades, a time period during which the UK had reduced it imports of selenium rich North American wheat in favor of selenium poor European wheat.

In addition to the relationship to early miscarriage, male infertility, mood problems, thyroid disorders, cardiovascular disease and arthritis, Rayman also discovered that selenium plays a key role in viral infections. In particular, higher selenium levels can help slow down the replication of the HIV virus. Her study actually found that "AIDS patients with low
levels of selenium were 20 times more likely to die from an AIDS-related illness than those with healthy levels of the mineral."

In addition to selenium supplements, selenium-rich foods such as kidney, liver, crab, other shellfish, and Brazil nuts can be eaten. North American soil is also selenium rich, and crops grown in this soil have higher levels of selenium. Researchers believe that most North Americans are probably getting enough selenium, and caution that too much selenium can be toxic. The maximum level of selenium recommended per day for adults is 400 micrograms per day. However, some studies have shown that certain areas of the U.S., including, for example, the Eastern Coastal plain of
the U.S., have selenium-deficient soil as well, so dietary exposure to selenium may be inconsistent.

Regarding the thyroid, selenium is a component of the enzyme that helps convert T4 to T3 peripherally, so deficiencies of selenium may impair thyroid function and promote hypothyroidism. According to the New England Journal, "selenium deficiency can result in thyroid injury and decreased extrathyroidal triiodothyronine production" (reduced peripheral T3
production.) Some experts believe that low T3 levels may be characteristic in areas with insufficient selenium. Studies also show that excess intake of selenium may also depress T3 levels . With some scientists suspecting that there may be a viral component or trigger to certain autoimmune conditions such as the common thyroid condition known as Hashimoto's Disease, the anti-viral properties of selenium also become more interesting, and further research into that connection as relates to thyroid disease particularly would be illuminating.

Implications for Patients: The key issue for thyroid patients is making sure you get enough, but not too much, selenium. Talking to a good nutritionist or holistic physician can help you determine if selenium might help your health and thyroid function.

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