Research Communications

From the comfort of a living area in their Lubbock home, faculty researchers Julian Spallholz and Mallory Boylan graciously share a story of selenium. Both are researchers in the Department of Food and Nutrition in the College of Human Sciences at Texas Tech University. They have collaborated on a number of research projects involving the trace mineral, selenium, and they have made some interesting contributions toward informing the public of its benefits. Although their work with selenium is highly varied, it is their recent suggestions regarding selenium and the avian flu that have garnered much media attention.

Photos by Jerod Foster
Julian Spallholz and Mallory Boylan study selenium.

Spallholz and Boylan have visited Thailand twice to recommend that selenium supplements be used in animals as an effort to keep the avian flu from mutating into a form that is transmittable among humans. “What Mallory and I have been is the messenger at this point. We have taken the message through some colleagues and friends into Thailand, particularly through people who do business in the animal supplement business there, to try to explain to the animal science and the public health people that they need to check what their selenium status is,” Spallholz says. The researchers’ message includes recommendations that are based on the work of Melinda Beck at the University of North Carolina at Chapel Hill and Orville Levander at the United States Department of Agriculture (USDA) in Beltsville, Maryland, who have found that selenium helps prevent mutations in the coxakie and human flu viruses.

This research has shown that in mice, a diet poor in selenium causes mutations to occur in the influenza virus, making it more dangerous. Once viral mutations occurred, even mice whose diets included adequate amounts of selenium were more vulnerable to the more dangerous strain. Mutations create new strains of the influenza virus that affect humans every year. “People have pointed out that all of these annual flu viruses, the Hong Kong flu, the Chinese flu, these cold flu viruses that come to North America, generally are emerging from Southeast Asia and emerging from parts of the world that are low in selenium,” Spallholz explains.

The avian flu virus, also known as H5N1 or the "bird flu," is an infection caused by an influenza virus carried by birds. Noted in birds since 1997, the virus has killed millions of birds, and more than 70 human deaths have been reported since 2003. The avian flu primarily is transmittable among birds, and the few cases found in humans represent instances in which those individuals have lived in very close proximity to different birds. No direct human-to-human spread has been reported, but scientists believe that the virus will develop that propensity if it mutates.

Scientists have linked the H5N1 virus to the devastating 1918 Spanish flu outbreak that killed more than 50 million people across the world. Spallholz and Boylan are working with governments in Southeast Asia to help ensure the avian flu does not mutate into a form that can be transmitted from one human to another. They believe that fortifying feed for chickens, pigs, cattle and other animals in Southeast Asia with selenium can help prevent an outbreak like the Spanish flu outbreak. Selenium can be added easily and inexpensively to animal feed as a supplement, and Spallholz assures that, “In this country, most commercial feed, for almost every species of animals, is fortified. The reason that is done is because the animals do better, grow better, and they’re healthier if they have adequate selenium.”

Selenium is an essential trace mineral that helps protect cells against damage caused by free radicals produced during infection. It is a component of the antioxidant enzyme glutathione peroxidase and it stimulates immune functioning. The daily recommended dose of selenium for adults is 55 micrograms, an amount that is most often adequately met by the U.S. diet. “You probably get 50 percent more than the official recommended amount in the American diet because the animal diets are fortified, and that raises the general health prospects of Americans,” Spallholz says. Selenium is found in Brazil nuts and whole grain cereals, as well as in some meats and seafood. The selenium content of foods is related to the selenium content in the soil in which the foods are grown or the animals graze. Some areas of the world contain soil that is severely deficient in selenium, and selenium deficiency weakens an organism’s immune system, preventing effective T-cell lymphocyte or antibody activity.

While selenium deficiency is harmful, high levels of selenium can result in toxicity. Spallholz refers to this as the paradox of selenium: that it is essential, yet toxic. In fact, selenium first gained attention because of its toxic properties. In the early 1900s livestock growers in the Southwest noticed that some of their animals were presenting adverse symptoms after consuming what is locally known as loco weed. Such plants contain an unusually high amount of selenium. In humans, selenium toxicity occurs at high doses (more than 400 micrograms a day) and is characterized by dermatitis, hair loss, diseased nails and peripheral neuropathy.

Selenium toxicity in livestock experimentally has been reversed by the use of arsenic, and this knowledge has fueled one of Spallholz and Boylan’s latest projects. Along with a number of researchers from around the world, Spallholz and Boylan have set out to reduce the incidence of arsenic poisoning in Bangladesh and West Bengal, India. The drinking water in large parts of this area of Asia contains arsenic levels that exceed the World Health Organization’s limit. Spallholz and Boylan have suggested that dietary supplements of selenium may ameliorate arsenic toxicity. This suggestion is based on the belief that the region may be suffering from selenium deficiency because arsenic accelerates excretion of selenium, lowering the selenium content in the human body. People in the area also have diets that are low in animal protein, a good source of selenium, and the soil in the area contains low levels of selenium. Spallholz and Boylan have measured selenium in samples of soils from the affected region and they have found that the levels of selenium in these samples are strikingly low and classify as deficient.

Spallholz has been working with selenium since he was a graduate student at Colorado State University, in the department of biochemistry. His adviser was investigating the toxic properties of selenium, and one of Spallholz’s first studies involved chickens. Spallholz became interested in the nutritional aspects of selenium from his observations of the effects of selenium content in the chickens’ diet, and he has since continued research in this area.

Forty years later, Spallholz continues to be an advocate for the benefits of selenium supplements, but his research interests have turned to finding ways to harness the toxic power of this trace nutrient. Supplements can ward off disease by boosting the immune system, but toxic doses of selenium can directly destroy harmful cells, such as cancer, bacteria and viruses. Spallholz and Ted Reid, at the Texas Tech University Health Sciences Center, have developed the technology to covalently attach selenium to materials and substances, so that it targets these harmful cells. For instance, Spallholz and Reid, along with Dr. Steven Mathews, have used the technology to coat contact lenses with selenium to prevent the growth of bacteria. They are hoping that this will eliminate the need to regularly clean lenses. Testing on rabbits in the laboratory has shown selenium’s effectiveness in keeping bacteria from growing on the surface of contact lenses for up to two months. Recently, the researchers have been given approval to test the coatings in human participants’ eyes at the Institute for Eye Research at the University of New South Wales in Sydney, Australia. The technology also may be used to coat interventional catheters to inhibit bacteria, viruses, cellular and biofilm growth and formation.

Spallholz also hopes to employ the technology to attach selenium to different antibiotics, anti-viral, and anti-cancer medications, in the tradition of the “magic bullet” idea for the use of antibodies to treat cancer. The unique properties of selenium allow it to target only those cells that are harmful to the organism and leave surrounding cells untouched. Spallholz has written on how the biochemistry of selenium works to combat cancer, and he suggests that the free radical generation by selenium constitutes its carcinostatic activity. This technology easily could be used with medications that treat the avian flu virus, as well. A therapeutic dose of selenium is half of the recommended daily allowance and much less than the amount taken as a nutritional supplement.

While they certainly celebrate the potential of selenium, Spallholz and Boylan caution that it is not an absolute solution, especially when it comes to the avian flu. People must keep in mind that too much selenium is harmful, but they should also remember that it is an inexpensive and accessible way to reduce certain health risks. Boylan reminds us, “All you are doing is reducing risk. You are not making it zero; you’re not eliminating it.”