Selenium in Brazil Nuts – How Many Should You Eat Per Day?

There is more selenium in Brazil nuts (Bertholletia excelsa) than in any other known food source.

Consuming one of these nuts per day is adequate to meeting the suggested dietary intake of this mineral. Brazil nuts are also a rich source of several other beneficial nutrients, minerals and vitamins.

Selenium is a rare trace element (Se) that is essential for human health. We cannot make this mineral internally and must derive it from our diet to meet our needs.

As a micronutrient, it only takes a small amount of selenium to satisfy the body’s requirements. The US RDA (Recommended Dietary Allowance) for selenium is 55 micrograms (mcg) in healthy adults.

Selenium deficiencies are rare in healthy people. However, there may be instances in which increase your dietary intake of this mineral by eating more brazil nuts could support specific health benefits.

If you get too much selenium in your diet, selenosis (selenium toxicity) can develop. The UL (upper tolerable level) is 400 mcg/day for those over 14 years of age. Avoid consuming too many Brazil nuts or too much of other selenium-rich foods.

Selenium

Essential Mineral

Anti-Oxidant

Immunity

Thyroid Function

How It Works:

• Cofactor for antioxidant enzymes
• Supports thyroid function & metabolism
• Promotes immune function & fertility

Dosage:

Up to 400 mcg per day

Safety:

Rated Likely Safe at Appropriate Dosages

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How Many Brazil Nuts for Daily Selenium?

One brazil nut per day provides the entire Food and Drug Administration’s RDA for selenium consumption.

Brazil nuts are purported to exhibit anti-inflammatory, anticancer, mood-enhancing, heart-healthy and pro-thyroid properties. Many people add Brazil nuts to their diets to meet their selenium needs and to support cardiovascular health and antioxidant status.

In nature, selenium is found primarily in soil and in small amounts in water sources. Some plants accumulate selenium from the soil as they grow and mature.

The amount of selenium yielded from a plant depends on the mineral content of the soil that it grows in. This is also the case for Brazil nut trees.

Trees that grow in selenium-rich soil will yield nuts with higher amounts of this mineral. The content in a single nut can vary between 68–91 mcg per nut.

Other factors that can affect how much selenium a Brazil nut contains include the size of the nut, amount of organic material in soil, soil pH and the form(s) of selenium in the soil.

According to the National Institutes of Health (NIH), as a standard, one ounce of Brazil nut contains 544 micrograms of selenium. That is more than 9 times the RDA. One ounce equates to between 4 and 6 individual nuts. [1]

While these nuts can be used to maintain adequate levels of this mineral in the diet, eating too many could increase the risk of certain health problems.

NIH states that, “Brazil nuts contain very high amounts of selenium (68–91 mcg per nut) and could cause selenium toxicity if consumed regularly.”

Selenium Health Benefits

Selenium is important for human health and plays several important roles in the body. It is involved in protection from oxidative stress, detoxification of the body, energy metabolism, fertility and more.

Selenium is the base constituent of dozens of selenoproteins, selenoenzymes and other selenocompounds that occur naturally in the human body. The effects of these endogenous chemicals are being explored with regards to:

• Immune system dysfunction;
• Thyroid dysfunction/disease;
• Various types of cancer;
• Cardiovascular health;
• Metabolic disorders;
• Diabetes mellitus;
• Cognitive decline;

According to a 2016 research study from Germany, “Selenium may modulate a broad spectrum of key biological processes, including the cellular response to oxidative stress, redox signalling, cellular differentiation, the immune response, and protein folding.” [2]

Best Food Sources

While Brazil nuts contain the highest concentrations of selenium, many other foods also contain appreciable amounts of this important trace mineral.

The following are some other foods which are good selenium sources, along with the amounts provided per serving:

• 3 ounces dry heat-cooked yellowfin tuna: 92 mcg;
• 3 ounces dry heat-cooked halibut: 47 mcg;
• 3 ounces roasted ham: 42 mcg;
• 3 ounces roasted bottom round beef: 33 mcg;
• 3 ounces roasted turkey breast: 31 mcg;
• 3 ounces roasted chicken breast: 22 mcg;
• 1 cup cottage cheese: 20 mcg;
• 1 cup cooked long-grain brown rice: 18 mcg;
• 1 large hard-boiled chicken egg: 15 mcg;
• 1 slice whole wheat bread: 13 mcg;
• 1 cup of boiled spinach: 11 mcg;
• 1 ounce roasted cashew nuts: 1 mcg;

If you would like to know the amount of selenium in other foods than those above, the USDA National Nutrient Database provides a comprehensive list online.

Brazil Nuts and Selenium Toxicity

Although rare, selenium toxicity (selenosis) is more common than being deficient in this mineral. Toxicity can occur when too much of this compound accumulates in the body, whether from food sources or from consumption of dietary supplements.

If you want to make sure you are getting the RDA for selenium each day (55 mcg), then one Brazil nut should be more than sufficient.

If you want to stay under the UL of 400 mcg/day, then do not exceed more than 4 nuts per day.

Be mindful for the following early signs of selenium toxicity:

• Garlic breath and/or metallic taste in mouth;
• Hair and/or nail loss and/or brittleness;
• Nervous system abnormalities;
• Mottled (spotted) teeth;
• Skin lesions/rashes;
• Irritability;
• Vomiting;
• Diarrhea;
• Fatigue;
• Nausea;

More serious symptoms can be brought on by chronic selenium toxicity. Some of these include hair loss, tenderness in muscles, light-headedness, facial flushing and tremors. Selenosis may also cause severe neurological and/or gastrointestinal problems.

In the most severe cases, overdose can cause myocardial infarction, respiratory distress syndrome, cardiac failure, kidney failure, and (very rarely) death. [3]

Cases of severe toxicity are not likely when consuming selenium from brazil nuts or other healthy food sources. The risk of excess consumption is more likely when using high-dose dietary supplements.

Selenium Drug Interactions and Health Risks

Increasing your intake of this mineral may not be appropriate for everyone. While selenium is rated Likely Safe when used orally and appropriately at recommended dosages, its use is contraindicated for some people.

Selenium and selenoproteins have numerous biological and neurological effects. Supplementation may cause interactions with certain health conditions, prescription drugs and herbal supplements.

Seek medical advice about eating more Brazil nuts, or taking a selenium supplement, especially if you have been diagnosed previously with an autoimmune disease, low thyroid (hypothyroidism), infertility, skin cancer or if you are receiving hemodialysis.

Discontinue selenium supplementation if you are scheduled for surgery within the next three weeks.

Drugs that may interact with this supplement include warfarin, barbiturates, contraceptives, antiplatelets, anticoagulants, gold salts and immunosuppressants.

Some herbal supplements that can interact with selenium include dashen, garlic, gingko, ginseng, ginger and angelica.

Talk to your doctor before using Brazil nuts to increase your intake of selenium. Ask your doctor whether it is appropriate for you to get more of this mineral in your diet depending on your specific health status.

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