• Home
  • Blog
  • Can Eating Brazil Nuts Help Prevent Cancer?

April 28, 2017

Brazil Nuts may help keep cancer at bay!?

Should you eat Brazil nuts, a food with a high selenium content, on a regular basis to prevent some types of cancer, some types of auto-immune disease and some metabolic disorders?

 The evidence is growing, and it all points to the same answer: YES!

Brazil Nut

According to both the American Cancer Society, and the Canadian Cancer Society, over 45% of North Americans are expected to experience cancer growth in their lifetime. Many medical research experiments and lab tests have revealed that nutritional deficiencies may be one of the main factors contributing to cancer development. We are all aware of common cancer types such as breast cancer and prostate cancer, but did you know that primary liver cancer represents the sixth most commonly diagnosed cancer, with the second-highest cancer mortality rate!

How is Selenium relevant to Liver Cancer?

A study published in April 2017 suggested selenium as an important element (if not one of the most essential) to protect hepatocytes (cells that make up 80% of your liver) from damage. Medical scientists involved in this study emphasized the role of selenium in reducing the risk of liver cancer [1]. So, with high mortality rates from this type of cancer, would it not be wise to prevent liver cancer from developing in the first place?

If you believe in preventative measures, read on!! I will show you a few simple and safe ways to ensure an adequate level of selenium intake!

Is there a Correlation between Selenium and Risk of Cancer?

Selenium deficiency has been one of the main areas of focus of many cohort studies for various types of endocrine and metabolic diseases over the past few years.

In particular, many medical investigations have revealed a high correlation between the risk of cancer and low blood serum selenium levels [2]. In fact, with advances in medical technology, scientists have been experimenting with the use of colloidal selenium nanoparticles in pre-clinical trials for chemo-preventative and therapeutic cancer treatment [3]! What does this tell you about selenium? It is a crucial element for good health!

According to articles in many medical research journals, some of the other most common cancers may be prevented by maintaining adequate levels of nutrition. For example, it is known that there is a high correlation of selenium deficiency with thyroid cancer[4], breast cancer, ovarian cancer[5] and colon cancer[6]. Vitamin D deficiency also has a high correlation with prostate cancer, breast cancer, colorectal cancers and melanoma etc.[7][8]

Should I Take a Selenium Supplement?

So if nutritional deficiency in selenium is a key culprit in some cancer development, would it be wise to take a selenium supplement to prevent this nutritional deficiency?

Surprise, surprise! My answer to the above question is a “No”.

While there are various types of selenium supplements available in the market, selenium also works synergistically with micro-nutrients. It has been proven time and again that isolating certain nutrients in supplement form does not provide the same benefits as consuming these nutrients from a whole food source. Therefore, supplementing with selenium should be used only as a backup. Also, selenium should be in organic form for our body to absorb and effectively utilize. Therefore, eating a diet rich in selenium along with other plant-based foods could be a better solution than taking a selenium supplement in order to reverse or alleviate health problems caused by selenium deficiency!

Are Brazil nuts an excellent source of Selenium?

The short answer is, yes, Brazil nuts are an excellent source of selenium. In fact, they have the highest selenium content of all food known on earth. An average adult may be supplemented by up to 400mcg daily for up to 30 days to correct a low selenium problem. Recommended daily amounts of selenium are 55 mcg for both men and women, but during pregnancy, a woman requires approximately 60 mcg of selenium daily, and lactating women should take 70 mcg a day. Each Brazil nut (depending on the size) may contain between 50 and 90 mcg of selenium. Therefore, an intake of 2-3 brazil nuts every second day is all we need to meet our selenium requirements!

Why Does Our Body Need Selenium?

In case you are curious as to why our body needs selenium, I would like to give you a very quick overview of amino acids!

Do you recall from your high school biology class that there are 9 essential amino acids we must obtain thru our diet in order to create certain proteins for our body? You may also have learnt that the non-essential amino acids can be synthesized by our body even if you did not consume food that contains the amino acids. If you remember this, congratulations, you probably remember that the 9 essential amino acids are some of the crucial building blocks for our body’s protein synthesis. And proteins are the building blocks of life!

What you likely did not learn is that the non-essential amino acids are also crucial for creating certain proteins for our body. However, in order for these proteins to be produced, some essential trace minerals must also be present, and one of these trace minerals is selenium.

In fact, our body synthesizes approximately 25 types of selenoproteins to maintain our normal body functions. Selenium is a “must-have” element our body needs to create these proteins. When there is a selenium deficiency, certain specific selenoproteins may not be able to produce. Many health issues can be worsened as a result!

What are some examples of Low Selenium Levels and Disease?

Let me give you a specific example: a very low level of blood serum selenium may allow the alcoholic liver disease to progress into cirrhosis (the end stage of liver disease which causes death)[9]. Supplementing with selenium can, in some cases, be used to reverse or control this disease’s progression.

In another example, clinical research reveals that increasing the intake of selenium in our diet to an optimal level can reduce insulin resistance[10]. While some cohort studies show that adequate selenium intake during pregnancy may provide protection to children up to the age of 3 against asthma, wheezing, allergic rhinitis and atopic dermatitis[11], other medical case studies show that asthmatic children with an adequate daily selenium intake have an improved quality of life.[12]

Selenium deficiency takes years to develop. This is why many chronic diseases such as autoimmune thyroiditis (Hashimoto’s thyroiditis)[13], benign prostatic hyperplasia (BHP)[14], cardiovascular disease[15], age-related macular degeneration (AMD)[16] and infertility[17] do not show up until after early adulthood. However, these diseases, according to various medical studies, may be reversed or alleviated with adequate intake levels of selenium when they are detected early.

Another very interesting finding from a cancer study published in March 2017 proved that selenium supplementation during radiation therapy for thyroid cancer patients is effective in reducing salivary gland damage[18]. More generally, because of its antioxidant properties, and its effects on repairing DNA damage, selenium may play a role in the prevention of cancer. A review of selenium and cancer prevention studies identified that subjects who consumed the highest amounts of selenium had a 31% lower cancer risk. a 45% lower risk of cancer death, and 33% lower risk of bladder cancer and, in men, a 22% lower risk of prostate cancer occurring. 

In a study of 77,446 men and women aged between 50 to 76 years, an inverse association was observed between dietary selenium and the risk of pancreatic cancer. In another study with 1312 participants, selenium was linked to a substantial reduction in lung, colon, esophageal, and prostate cancer deaths; the risk of prostate cancer death, in particular, was substantially reduced, with 63% fewer deaths in the men who took selenium. 

Broadly speaking, we can surmise that selenium plays an essential role in reducing the risk of some types of cancer.

How Does Selenium Deficiency Affect You Personally?

Up until now, I have been talking about diseases that may arise due to selenium deficiency. You may ask how does this affect you personally?

If you are one of those who have been suffering from a combination of the following health issues: unexplained pain such as Fibromyalgia; severe lethargy such as chronic fatigue, unexplained infertility, chronic diarrhea, abdominal pain, enlarged prostate, enlarged thyroid, artery hardening (atherosclerosis), high cholesterol, fatty liver, non-alcoholic and alcoholic liver diseases, cirrhosis, high blood pressure, or cancer, and you have not been eating a nutritious diet on a regular basis, there is a chance that your body is running low on selenium. Therefore, eating a selenium-rich diet may help you to alleviate or reverse these medical conditions when they are caused by a selenium deficiency.

Selenium plays a crucial role in many types of metabolic enzyme functions. It is one of the key elements needed to ignite our body’s defence system against free radical damage, support our immune function, maintain normal bone mineral density and glandular functioning. Without an adequate level of selenium, many types of metabolic and auto-immune diseases may arise.

What food sources have a high level of selenium?

Other than Brazil nuts, foods rich in selenium include organ meats, yellowfin tuna and oysters, all relatively common foods and easy for you to find. These are all good dietary sources of selenium. Brazil nuts have the highest amount of selenium, and also contain high amounts of magnesium (which is helpful for maintaining healthy blood pressure and good cardiovascular health). Therefore, to correct health issues due to a selenium deficiency, the quickest and simplest way would be to eat 4-6 pieces per day for 2-4 weeks. Then continue to eat 1-3 pieces of brazil nut every other day on a regular basis. This regime may be helpful to reverse some of the diseases caused by selenium deficiency and will also prevent you from overdosing with selenium.

How Essential Is Selenium to Your Health?

Selenium is an essential mineral. Having an adequate level of selenium may prevent you from suffering an early death or ending up in the hospital!

I hope by now you understand how important selenium is to your health. So now let’s get practical and dive into making a selenium-rich dish to eat for your good health!


Recipe Name: Steamed Broccoli with Pesto


  • 1 1/2 cups chopped fresh basil
  • 1/4 cup Brazil nuts
  • 3 cloves garlic
  • ½ tsp finely grated lemon zest
  • 1/4 cup olive oil
  • 1 pinch ground nutmeg
  • ½ tsp salt and pepper to taste
  • 2 lbs broccoli florets


  1. 1
    In a large steamer, add water and bring to a boil.
  2. 2
    Place broccoli into a steamer and steam for 2-4 minutes. Remove from the heat and spread on a large platter.
  3. 3
    In a food processor, add basil, brazil nuts, garlic, lemon zest, olive oil, nutmeg, salt and pepper and process until a smooth sauce is formed. Add 1 tsp of liquid at a time if the sauce is too lumpy and thick
  4. 4
    Drizzle the pesto on top of the broccoli and serve. (Makes 4 servings)

If you enjoy eating Brazil nuts, other than making pesto, you may also want to add a couple of pieces when you make almond cookies, almond milk or hummus. If you enjoy my vegan cream of parsley soup recipe, instead of making it into a cream soup, you can reduce the water in the recipe and make it a creamy sauce by blending a few pieces in, together with cashews. This sauce would be an ideal dipping sauce for roasted vegetables such as yam, asparagus, zucchini, sweet potatoes and tomatoes. If you are like me, and you enjoy eating freshly made nut butter, you may want to mix your favourite nuts with 1-2 brazil nuts to make your favourite nut butter for a snack.

Can you overdose Selenium by eating Selenium-rich food?

While an adequate level of selenium brings a range of health benefits and may help prevent many types of metabolic and autoimmune diseases from developing, having too much of this micro-nutrient can also be toxic for our body!

If you are taking a daily multivitamin that contains selenium, it is important to know how much selenium is in a daily dose. Selenium repletion can create unexpected adverse health effects. For example, according to a number of medical studies, people with a specific selenoprotein gene defect can react to a selenium overload by triggering diabetes mellitus. Also, while an adequate serum level of selenium is important to correct autoimmune thyroiditis due to selenium deficiency, for some people, overdosing with selenium may also cause thyroid malfunction.

So while selenium is important to your health, don’t overdo it.

What are some of the acute Selenium toxicity symptoms?

The first signs of acute selenium toxicity may include shortness of breath, flushing of the face, tremors of the body, and body pain. Chronic selenium toxicity can cause garlic breath, loss of taste, nausea, diarrhea and brittle nails, etc. Acute selenium toxicity can lead to more severe conditions, including severe gastrointestinal and neurological symptoms, acute respiratory distress syndrome, myocardial infarction, kidney failure, cardiac failure, and, in very occasional cases, death.

To prevent selenium toxicity, your routine for taking brazil nuts should be to consume these nuts just 2-4 times per week in small amounts (1-3 pieces at a time), unless your blood test shows a very low serum selenium level, which requires rapid replenishment. These conditions would however, result only from consuming very large amounts of selenium.

Do You Like This Article?

If you like the content of this article, please share it with those you think may benefit from it!


  1. 1
    The missing link? The potential role of selenium in the development of liver cancer and significance for the general population
  2. 2
    Supplemental Selenium May Decrease Ovarian Cancer Risk in African-American Women
  3. 3
    Selenium nanoparticles: potential in cancer gene and drug delivery.
  4. 4
    The Association Between Serum Levels of Selenium, Copper, and Magnesium with Thyroid Cancer: a Meta-analysis.
  5. 5
    Selenium-enriched polysaccharides from Pyracantha fortuneana (Se-PFPs) inhibit the growth and invasive potential of ovarian cancer cells through inhibiting β-catenin signaling.
  6. 6
    Selenoprotein P in colitis-associated carcinoma.
  7. 7
    FOXE1 Polymorphism Interacts with Dietary Iodine Intake in Differentiated Thyroid Cancer Risk in the Cuban Population.
  8. 8
    Immune Modulation by Vitamin D: Special Emphasis on Its Role in Prevention and Treatment of Cancer.
  9. 9
    Association between Serum Selenium Concentrations and Levels of Proinflammatory and Profibrotic Cytokines-Interleukin-6 and Growth Differentiation Factor-15, in Patients with Alcoholic Liver Cirrhosis.
  10. 10
    High dietary selenium intake is associated with less insulin resistance in the Newfoundland population.
  11. 11
    Prenatal exposure to selenium may protect against wheezing in children by the age of 3.
  12. 12
    Dietary intake is associated with respiratory health outcomes and DNA methylation in children with asthma.
  13. 13
    Treatment with Myo-Inositol and Selenium Ensures Euthyroidism in Patients with Autoimmune Thyroiditis.
  14. 14
    Survivin and NAIP in Human Benign Prostatic Hyperplasia: Protective Role of the Association of Serenoa repens, Lycopene and Selenium from the Randomized Clinical Study.
  15. 15
    Significant changes in circulating microRNA by dietary supplementation of selenium and coenzyme Q10 in healthy elderly males. A subgroup analysis of a prospective randomized double-blind placebo-controlled trial among elderly Swedish citizens.
  16. 16
    Antioxidative capacity of a dietary supplement on retinal hemodynamic function in a human lipopolysaccharide (LPS) model.
  17. 17
    Dietary patterns, foods and nutrients in male fertility parameters and fecundability: a systematic review of observational studies.
  18. 18
    Effect of selenium supplementation for protection of salivary glands from iodine-131 radiation damage in patients with differentiated thyroid cancer.

Bernadette Yu

Bernadette Yu is an Ontario Registered Acupuncturist & Traditional Chinese Medicine Practitioner. She provides Acupuncture Treatment, Chinese Herbal Medicine Consultation and prescriptions, Nutritional Counselling and Bioenergetic testing services in a medical clinic in Mississauga, Ontario.

{"email":"Email address invalid","url":"Website address invalid","required":"Required field missing"}