Can Selenium Prevent Breast Cancer?

If you’re a woman, preventing breast cancer should always be on your mind. The ruthless disease affects 1 in 8 women, so there’s a good chance you know someone who has been diagnosed. It’s also the second leading cause of death in women in the US and the most common cancer in females. So, what are you doing to lower your chances?

Some risk factors like age, genetics, and having an early first period can’t be changed. But like most diseases, diet plays an enormous role. Drinking lots of alcohol and eating little to no fruits, vegetables, and whole grains are especially impactful.1 2 And it’s worth thinking about selenium. According to various studies, this nutrient has properties that may prevent certain types of cancer. The relationship isn’t clear, but it’s certainly worth looking into the science.


What Is Selenium?

Selenium is a trace element that is found in many natural foods

Selenium is a trace element that is found in many natural foods. In the body, it supports reproduction, DNA production, and thyroid gland function. You need it to survive!3


How Does Selenium Fight Breast Cancer?

Selenium might prevent breast cancer by fighting free radicals and reducing inflammation

1. Kills Free Radicals

Selenium is an antioxidant. This means it can protect healthy cells by finding and destroying free radicals, the harmful molecules behind chronic diseases.4 If free radicals build up, they can attack normal cells and induce cancer growth.


2. Disrupts Cancer Pathways

In order to grow and spread, cancer stem cells need to interact with tumor cells and normal immune cells. Stem cells also have the ability to avoid apoptosis, the process of self-destruction. But according to a 2017 study in Advances in Cancer Research, all of this may be suppressed with selenium.5 Therefore, stem cells won’t stand a chance.

3. Reduces Inflammation

It’s no secret that inflammation is the root of chronic diseases. In the case of cancer, the pathways between stem and tumor cells spark that inflammation.6 However, as selenium interrupts these pathways, inflammation will take a backseat.


Should You Take Selenium For Breast Cancer Prevention?

More evidence is required to make a solid connection between selenium and breast cancer

Aside from the above benefits, selenium has been found to induce cancer cell death and control gene expression.7 It seems promising, but know that other studies haven’t found much of a relationship. A 2008 review in Environmental Health and Preventive Medicine claims that there is no link between selenium levels and breast cancer.8


Clearly, more evidence is required to make a solid connection. Until then, taking a multivitamin and eating a well-rounded diet might give you all the selenium that you need.

Symptoms Of Too Much Selenium

Excess selenium may lead to stomach upset, muscle weakness, fatigue, or numbness


If you want to take selenium supplements, check with your doctor first. Taking more than 1,000 mcg a day may lead to stomach upset, muscle weakness, fatigue, or numbness. Peripheral neuropathy, or a tingling in the feet or hands, might also develop. High doses of selenium, about 200 micrograms or more, may also potentially increase the risk of type 2 diabetes.9

Food Sources Of Selenium

Natural sources of selenium include salmon, sunflower seeds, oysters, and shrimps.


When in doubt, get selenium from natural foods.10 Top sources include brazil nuts, tuna, oysters, clams, shrimp, salmon, crab, pork, chicken, sunflower seeds, whole-wheat bread, and fat-free or skim milk.