Selenium is an essential micronutrient found in about 25 proteins. Most of these so-called selenoproteins are enzymes with antioxidant properties.
The main dietary sources of selenium are plant foods grown in selenium-rich soils and animals who graze on such plants.
According to Eurekalert:
“The researchers noted a significant protective effect of selenium, mainly among women, which they believe may result from gender-specific differences in the mineral's accumulation and excretion in women.”
Close to one-quarter of Americans over 40 take a selenium supplement or multivitamin that includes selenium – a direct response to positive press like this study, linking selenium to numerous beneficial health effects.
Selenium is a trace mineral that is incorporated into proteins to make selenoproteins, which act as strong antioxidants to help prevent free radical damage to your cells. It is because of its potent antioxidant properties that selenium may benefit:
- Heart disease
- Cognitive decline
- Cataracts and macular degeneration
- Cold sores and shingles
How Does Selenium Help Prevent Cancer?
According to the latest research, people with higher selenium intakes had a 39 percent reduced risk of bladder cancer, which is right in line with prior studies that have linked the mineral to lower rates of breast, prostate, lung, colorectal and skin cancer as well.
A 1996 study by Dr. Larry Clark of the University of Arizona also showed just how effective selenium can be in protecting against cancer.
In the study of 1,300 older people, the occurrence of cancer among those who took 200 micrograms of selenium daily for about seven years was reduced by 42 percent compared to those given a placebo.
Cancer deaths for those taking the selenium were cut almost in half, according to the study. In addition, the men who took selenium had 63 percent fewer prostate cancers, 58 percent fewer colorectal cancers, 46 percent fewer lung cancers and overall 37 percent fewer cancers.
Selenium was even found to reduce the risk of lung cancer to a greater degree than stopping smoking.
Some of the scientific explanations for selenium’s anti-cancer effect include:
- Increased antioxidant protection and immune system
- Regulation of cell proliferation and apoptosis (programmed cell death)
- Triggering DNA repair in damaged cells
- Suppression of growth of blood vessels supplying nutrients to the cancer
- Inhibition of tumor cell invasion
Selenium also plays a role in activating glutathione peroxidase, an enzyme that helps the liver detoxify harmful substances, thereby helping with cancer prevention.
With Selenium, the Dose Makes all the Difference
In the case of selenium, there is a fine line between the amount that is beneficial and the amount that is harmful. A daily dosage between 150-300mcg is generally safe for the average adult, but if your levels get too high it can increase your risk of diabetes and actually becomes cytotoxic (toxic to cells).
If you choose to take a selenium supplement for health maintenance, you should use it in a high-quality bioavailable form, in a low dose (such as 200mcg).
The lower doses are recommended for prevention of disease, including cancer, while higher doses are used for treatment only after cancer is diagnosed. The higher doses are for regulation of cell proliferation by inducing apoptosis (programmed cell death).
In cancer treatment, there is a good evidence base to support the use of significantly higher doses in the correct dosage form -- especially the selenium selenite in liquid drops -- as part of a well-designed integrative and complementary medicine cancer treatment protocol.
You should only take higher doses of selenium while under the supervision of a competent health care professional who understands the pathway stimulations being induced, and, again, the higher doses should be reserved for targeting cancer that has already been diagnosed.
With selenium it’s important to resist the typical American approach of concluding that if a little is good, even more is better, as this can frequently backfire.
Can You Get Enough Selenium from Food Alone?
Determining the selenium content of your food is tricky because levels are highly dependent on the level of selenium in the soil where the food was grown.
In the United States, selenium levels in soil tend to be relatively high (northern Nebraska and the Dakotas have soil that is especially high in selenium). However, in other areas such as China, Russia, Australia, New Zealand and Europe, soil levels of selenium tend to be much lower, and if you eat food primarily grown in these areas, a high-quality selenium supplement may be beneficial.
Even parts of the United States have been identified as selenium-deficient regions, including:
- The Pacific Northwest
- Parts of the Great Lakes region and east of it toward New England
- Parts of the Atlantic Coast
If you live in one of these areas and focus your diet on locally grown foods from the region, you may be low in selenium.
On the flipside, if you eat a diet from a variety of regions, including those rich in selenium, you can generally get plenty of selenium from your diet, and thereby get the benefits of the mineral without risking an overdose. Some excellent food sources of selenium include (again, assuming they are grown in ideal soil conditions):
- Brazil nuts (which average about 70-90 micrograms per nut)
- Button mushrooms and shitake mushrooms
- Sunflower seeds
- Mustard seeds
11 More Tips to Add to Your Cancer-Prevention Arsenal
Selenium has long been part of my guidelines to help avoid and treat cancer, particularly prostate and breast cancers, but this mineral is only part of my overall cancer prevention strategy. The natural strategies that follow will provide your body with the basic foundational elements necessary for disease and cancer prevention:
- Optimize your vitamin D levels. It's virtually impossible to discuss cancer prevention and treatment today without discussing vitamin D, as the scientific evidence of its anti-cancerous benefits is truly impressive.
Theories linking vitamin D to certain cancers have been tested and confirmed in more than 200 epidemiological studies, and understanding of its physiological basis stems from more than 2,500 laboratory studies, according to epidemiologist Cedric Garland, DrPH, professor of family and preventive medicine at the UC San Diego School of Medicine.
To find out the appropriate levels of vitamin D for cancer prevention and treatment, please watch my free one-hour vitamin D lecture.
- Control your insulin levels by limiting your intake of processed foods, fructose and sugars as much as possible.
- Get appropriate amounts of animal-based omega-3 fats, especially those from krill oil.
- Exercise. One of the primary reasons exercise works is that it drives your insulin levels down. Controlling insulin levels is one of the most powerful ways to reduce your cancer risks. Please carefully review the Peak Fitness Technique for more detailed information.
Exercise is also an important part of cancer treatment, as Harvard Medical School researchers found patients who exercise moderately -- 3-5 hours a week -- reduce their odds of dying from breast cancer by about half as compared to sedentary women.
- Have a tool to permanently erase the neurological short-circuiting that can activate cancer genes. Even the CDC states that 85 percent of disease is caused by emotions. It is likely that this factor may be more important than all the other physical ones listed here, so make sure this is addressed.
My particular favorite tool for this purpose, as you may know, is the Emotional Freedom Technique (EFT).
- Only about 24 percent of people eat enough vegetables, so by all means eat as many vegetables as you are comfortable with. Ideally, they should be fresh and organic.
However, please understand that, frequently, fresh conventionally grown vegetables are healthier than organic ones that are older and wilted in the grocery store. They are certainly better than no vegetables at all, so don't use that as an excuse. If you are a carb nutritional type you may need up to 300 percent more vegetables than a protein nutritional type.
- Eat according to your nutritional type. When we treat cancer patients in our clinic, this is in fact one of the most powerful anti-cancer strategies we have.
- Maintain an ideal body weight.
- Get enough high-quality sleep.
- Reduce your exposure to environmental toxins like pesticides, household chemical cleaners, synthetic air fresheners and air pollution.
- Boil, poach or steam your foods, rather than frying or charbroiling them. Better yet eat as many of your foods raw as you can.