Selenium Heart Health and Cancer Prevention

By Bonnie Jenkins, Advanced Natural Medicine

When we think about antioxidants, we usually think of the big three – Vitamins A, C and E. Selenium, on the other hand, often slips by almost unnoticed. But selenium’s relatively low profile belies this mineral’s important role in optimizing your health. Selenium is a part of 25 different compounds known as selenoproteins that are produced by the body – and they are necessary to regulate thyroid function, thwart cell damage, bolster immunity and tamp down inflammation. In fact, taking a moderate amount of supplemental selenium shows promise for helping to ward off certain illnesses, including many types of cancer.

Battling the Big Stuff

Perhaps the most exciting roles selenium plays in human health are its impact on heart health and cancer prevention. As part of powerful antioxidant compounds, selenium is capable of preventing the conversion of LDL (“bad”) cholesterol to a form that is more likely to clog arteries. And population studies suggest that low blood levels increase the likelihood of having a heart attack or stroke. In one multi-center study in Europe, toenail selenium levels were linked to risk of heart attack in participants whose levels were the lowest.

And then there’s cancer. Experts are unsure exactly how selenium works to ward off tumors, but it may protect DNA from damage, trigger the self-destruction of cancer cells—dubbed apoptosis by scientists—and boost immunity. As part of the Nutritional Prevention of Cancer Trial, researchers from the Arizona Cancer Center in Tucson studied the effects of selenium supplements on 1,312 men and women with a history of non-melanoma skin cancers. Half the people received 200 mcg. of selenium daily for an average of four and a half years while the other half received placebos. The group taking the supplements developed 54 percent fewer cases of colorectal cancers, 52 percent fewer prostate cancers and 26 percent fewer lung cancers. But, as impressive as these statistics are, they may just scratch the surface. Animal studies have confirmed the relationship between selenium and virtually every type of cancer studied.

Several population studies also support a strong selenium-cancer connection. One review pooled the results of 20 population studies and concluded that the higher the selenium levels in the body, the lower the risk for prostate cancer. In addition to helping prevent prostate cancer, selenium may also slow its progression. In another study, Harvard School of Public Health researchers compared blood samples from healthy men diagnosed with prostate cancer to men who remained cancer-free. The results? Those with the most selenium in their blood were only about half as likely to develop advanced prostate cancer during the 13-year study period when compared to men with the lowest selenium levels.

Fixing Up the Joint

Selenium’s antioxidant properties may also help prevent arthritis and reduce its symptoms by quashing the free radicals that can harm healthy joint tissue. University of North Carolina researchers have discovered that low blood levels of selenium are associated with an increased risk of osteoarthritis (OA), especially in women and African-Americans. Their study analyzed the levels of selenium in the toenails of 940 older men and women. (Toenails reflect selenium intake over several years.) People with the highest selenium concentrations were half as likely to suffer from OA as those with the lowest levels.

A Little Goes A Long Way

So how much selenium should you be getting? Adults need 55 mcg. of selenium each day to maximize selenoprotein production. While a selenium deficiency is uncommon in healthy people, severe gastrointestinal disorders like Crohn’s disease can result in selenium deficiency. Prolonged infections and inflammation can also lead to lower blood levels of selenium.

Most of us get all the selenium we need simply by eating a nutritious, well-balanced diet. But if your diet isn’t what it should be or if you’re at high risk for cancer or heart disease, consider taking 200 mcg. of supplemental selenium each day. But don’t overdo it. Like all minerals, selenium is toxic in large doses. Don’t exceed 400 mcg. a day from a combination of food and supplements. If you do so for a long period, you can develop selenium toxicity which can result in loss of fingernails, skin rash and changes in the nervous system.

One Last Thing ...

The amount of selenium in food depends on the amount in the soil, which varies widely from region to region. Early studies observed that there are fewer cancer deaths in areas where there’s more selenium in food, and that people with low blood selenium levels are at higher risk for several cancers.

Because our food comes from all over the world, it’s hard to know how much selenium is in a particular food and thus exactly how much we are getting. Nevertheless, it’s still important to include selenium-rich foods in your diet. The best sources are whole grains, nuts (particularly Brazil nuts) and seafood. Poultry and red meats are other good sources. Eating foods rich in vitamin E – think nuts, seeds and fortified cereals – increases the effectiveness of selenium in the body.

This Just In ...

Last week, Vice President Cheney’s doctors discovered a blood clot in his leg. The condition, known as deep vein thrombosis (DVT), developed after the VP had spent 65 hours on an airplane. Although this was the first time many people have heard of DVT, it’s actually fairly common.

The combination of dehydration and cramped seating on a long flight can result in blood pooling in the legs, which can trigger the formation of blood clots. And the longer the flight, the greater the risk. If you’re planning air travel in the near future, there are steps you can take to reduce the risk of DVT. Take a stroll to the bathroom or around the cabin every half-hour or so. You can also do some simple stretches while in your seat. It doesn't have to be anything fancy. Try a few sets of ankle circles, alternate foot and knee lifts, and then bring your knees to your chest.

You can also lower your chances of DVT before you ever step foot on the plane. A team at the University of Arizona Medical School have discovered that taking 125 mg. of pyconogenol before your flight can keep the blood flowing while you’re in the air.

If you are at high risk for these types of blood clots during long flights, you might also consider trying nattokinase, a supplement which is derived from the soyfood natto. Although the research is still in its early stages, this safe supplement may also reduce the chances of DVT.

Happy landings!

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References:

Cesarone MR, Belcaro G, Nicolaides AN, et al. “Prevention of venous thrombosis in long-haul flights with Flite Tabs: the LONFLIT-FLITE randomized, controlled trial.” Angiology. 2003;54: 531-539. de Lorgeril M, Salen P. “Selenium and antioxidant defenses as major mediators in the development of chronic heart failure.” Heart Failure Review. 2006;11:13-17. Li H, Stampfer MJ, Giovannucci EL, et al. “A prospective study of plasma selenium levels and prostate cancer risk.” Journal of the National Cancer Institute. 2004;96:696-703.

Putter M, et al. “Inhibition of smoking-induced platelet aggregation by aspirin and pycnogenol.” Thrombosis Research. 1999;95:155-161.

Williamson D. “Study links low selenium levels with higher risk of osteoarthritis.” University of North Carolina, Chapel Hill.