Published on October 12, 2021

Study shows selenium status may be a better predictor of breast cancer mortality than several important tumor characteristics

Key Points

  • Selenium (Se) is an essential mineral with antioxidant properties, and higher levels of selenium have been associated with lower risk of cancer, cognitive decline, cardiovascular disease, and COVID-19
  • One analysis from the study below found that patients with the highest serum Se concentrations had a 58% lower risk of death compared to patients with the lowest serum Se concentrations
  • When considered together, the three different biomarkers used to measure Se status were better at predicting mortality than three of the most important tumor characteristics (Nottingham histologic grade, tumor size, and number of lymph nodes involved)
  • Both selenium and vitamin D have been shown to be important factors in predicting breast cancer outcomes

Selenium is an essential nutrient with antioxidant properties that plays a key role in thyroid function, reproduction, immune health, and DNA synthesis. Selenium also influences the production of cytokines and eicosanoids — chemical messengers that regulate inflammation and immune cell function. Studies have found an association between higher selenium status and a lower risk of cancer, cognitive decline, cardiovascular disease, and COVID-19. In fact, one study found significant correlations between the cure rate for COVID-19 and selenium status within particular regions of China, indicating that higher levels of selenium led to improvement in COVID-19 outcome.

Selenium Status Linked to Breast Cancer Outcomes

Cancer studies have shown that selenium also influences tumor growth and cell proliferation, with intake and levels showing potential effects on cancer development. With this in mind, Demircan et al. looked at breast cancer outcomes among 1996 patients with primary invasive breast cancer and correlated them to selenium status. Three different biomarkers of selenium (Se) were utilized: total serum Se concentration, selenoprotein P (SELENOP), and the glutathione peroxidase GPx3. Including all three measures allowed for a robust assessment of the relationship between selenium intake and status and breast cancer outcomes, compared to using blood Se concentration alone.

What did the study find?

Selenium status was divided into quintiles for each of the three biomarkers. A significant inverse correlation was seen between the lowest quintile (those with the lowest selenium status) and overall survival from breast cancer (p trend < 0.001). This means that the highest risk of mortality was seen among those with the lowest selenium status, and the relationship was strongest when selenium status was lowest according to all three measurements combined.  For example, as illustrated in the chart below, patients with the highest serum Se concentrations had a 58% lower risk of death compared to patients with the lowest serum Se concentrations.

Click to Enlarge & Print

The associations remained significant even after adjusting for variables such as treatment method, age, gender, menopausal status, tumor size, and other variables. In fact, when considered together, all three selenium biomarkers were better at predicting mortality than three of the most important tumor characteristics (Nottingham histologic grade, tumor size, and number of lymph nodes involved).

As stated by the authors,

“We conclude that the Se status constitutes and important prognostic parameter in breast cancer,” and that their finding “supports the notion on the essential importance of a sufficiently high Se status for human health.”

Check Your Selenium Status Today!

Test your selenium levels today as part of the Elements Panel, which includes testing your vitamin D level along with essential elements magnesium, selenium, zinc, copper, and copper:zinc ratio, and toxic heavy metals cadmium, lead, and mercury.

Vitamin D Status Can Also be Predictive of Breast Cancer Outcomes

There is overwhelming evidence showing a significant relationship between higher vitamin D levels and a lower risk of getting breast cancer, as well as a lower risk of death among breast cancer patients.  Both are especially important for improving breast cancer outcomes.

Having and maintaining healthy vitamin D, selenium, and other nutrient levels can help improve your health now and for your future. Choose which to measure, such as your vitamin D, selenium with other essential minerals including magnesium and zinc, by creating your custom home test kit today. Take steps to improve the status of each of these measurements to benefit your overall health. You can also track your own intakes, symptoms and results to see what works best for YOU.

Enroll and test your levels today, learn what steps to take to improve your status of vitamin D (see below) and other nutrients and blood markers, and take action! By enrolling in the GrassrootsHealth projects, you are not only contributing valuable information to everyone, you are also gaining knowledge about how you could improve your own health through measuring and tracking your nutrient status, and educating yourself on how to improve it.

Help everyone Move Research into Practice with vitamin D and other nutrients! As a special birthday gift to everyone, in honor of the science, we have created a special scholarship fund for anyone to donate to that will go towards helping others participate. Your donation will allow anyone to get help with funding their participation when they need it.

Text-to-give: Text Daction to 44321 to add to our Scholarship Fund.

What Does it Take YOU to Get Your D to 40 ng/ml (100 nmol/L)?

Did you know your health could be greatly affected by making sure you have a vitamin D level of at least 40 ng/ml (100 nmol/L)? Help us help you.

STEP 1 - Do you know what your vitamin D level is? If not, be sure to test today to find out.

STEP 2 – Determine your target level. Are you at your target level? Experts recommend a level of at least 40-60 ng/ml (100-150 nmol/L).

STEP 3 – Need to boost your level? Use the D*calculator to see how much vitamin D it may take to reach your target. Opt for the Loading Dose for a quicker boost.

STEP 4 – Optimize how your body absorbs and utilizes vitamin D with co-nutrients and these simple steps.

STEP 5 – Re-Test! This is an important step to make sure you have reached your target level, and to ensure you are not taking too much! Re-testing after 3-4 months is recommended.

STEP 6 – Adjust, Repeat…

Give your immune system the nutrients it needs to support a healthy you and protect yourself from unnecessary diseases, especially COVID-19.


The first Randomized Controlled Trial on vitamin D and COVID-19 has shown a 96% lower risk of ICU admission for those receiving vitamin D (as 25(OH)D to quickly boost vitamin D blood levels) along with the standard treatment, compared to those receiving standard treatment alone.

These results support many previous observational studies showing a relationship between vitamin D levels and intake and COVID-19 severity.

Review the Latest Nutrient Research for COVID-19

GrassrootsHealth Nutrient Research Institute has launched the new Immune Boost project with the use of our myData-myAnswers nutrient health system that nearly 15,000 people are already using for their health. Specific markers that influence immune health are suggested for testing as part of this project including:

  • Vitamin D
  • Omega-3 Index
  • Essential elements magnesium, selenium, and zinc
  • hsCRP

Our goal is to demonstrate how one can use the Nutrient Research Model established by Dr. Robert Heaney to show the effect of vitamin D serum levels of at least 40 ng/ml (100 nmol/L) on risk reduction for all ethnicities in the population. Status and intake of other nutrients will also be analyzed for any type of relationship to immune status and symptom severity. Join the project today!

Please let us know if you're interested in helping sponsor this project.

CLICK HERE for updates and new information about the project.

Through GrassrootsHealth Nutrient Research Institute, you can also test your essential elements magnesium, copper, zinc and selenium, toxins such as lead, mercury and cadmium, as well as your omega-3 levels, inflammation levels and thyroid stimulating hormone (TSH) level. Find out your levels today! Log on to the test selection page (click the link below) to get your tests and see for yourself if your levels can be improved.

Make sure you track your results before and after, about every 6 months!

Click Here to Access the Test Page

How can I track my nutrient intake and levels over time?

To help you track your supplement use and nutrient levels, GrassrootsHealth has created the Personal Health Nutrient Decision System called

For each specific supplement, you can track what days you take it, how much, and many other details.  This will help you know your true supplemental intake and what patterns of use work for you to reach and maintain optimum nutrient levels. Check it out today!