Brazil nuts are a good source of protein, dietary fiber, heart-healthy mono- and polyunsaturated fats, vitamins and minerals.
They also contain a certain mineral – selenium – which can have negative health effects if consumed in large quantities.
Here, learn more about the benefits and side effects of Brazil nuts, as well as how much you can eat per day.
Selenium content of Brazil nuts
Brazil nuts contain a high content of the trace mineral selenium. Although your body needs selenium to survive, consuming too much can have negative health effects.
In small doses, selenium is an antioxidant that can support your immune system and help regulate your thyroid, among other bodily functions, explains the National Institutes of Health (NIH).
According to the United States Department of Agriculture (USDA), 1 ounce of Brazil nuts contains 544 micrograms (mcg) of selenium and one kernel contains 96 mcg.
How much selenium is safe?
The NIH lists the recommended dietary intake of selenium based on age group. These amounts are recommended to help maintain optimal health:
- Children, 7 months to 3 years 20mcg
- Children, 4 years to 8 years 30mcg
- Children, 9 years to 13 years 40mcg
- Adults, 14 years and older 55mcg
- Breastfeeding and pregnant people 60 to 70 mcg
How much selenium is toxic?
Eating just one Brazil nut exceeds the recommended daily intake of selenium. However, as it is a natural food source, this amount is very unlikely to cause a serious toxic reaction.
According to the NIH, there is a tolerable upper limit for selenium, or the highest possible amount you can consume with the least risk of side effects. Here are the limits based on age:
- Children, 1 to 3 years old 90mcg
- Children, 4 to 8 years old 150mcg
- Teenagers, 9 to 13 years old 280mcg
- Adults, 14 years and older 400mcg
According to the USDA list of Brazil nuts, eating just four a day could put you at risk for selenium toxicity.
Keep this in mind if you also eat other selenium-rich foods, such as shellfish, beef, turkey, chicken, fortified grains, beans, or whole-wheat products, or if you take selenium supplements, according to the Harvard TH Chan School of Public Health.
Symptoms of Selenium Toxicity
Selenium toxicity is also a condition known as selenosis. Research has shown that an early indicator of this condition is the smell of garlic on your breath. Other common symptoms include:
- Hair loss
- Discolored nails
- Gastrointestinal problems, such as nausea and diarrhea
- Shortness of breath
- Nervous system problems
In severe cases, symptoms may include difficulty breathing, dizziness, tremors, kidney or heart failure, and heart attacks, according to the NIH.
Allergic reaction vs. selenium toxicity
Selenosis and nut allergies have overlapping symptoms, but they are not the same.
Setonosis can occur from excessive consumption of Brazil nuts or other selenium-rich foods. A Brazil nut allergy occurs if you are already allergic to nuts.
According to the American College of Allergy, Asthma & Immunology (ACAAI), some common symptoms of a nut allergy include:
- Abdominal pain, cramps, nausea and vomiting
- Diarrhea
- Difficulty swallowing
- Itchy mouth, throat, eyes, skin, or other areas
- Nasal congestion or runny nose
- Nausea
- Shortness of breath
- Anaphylaxis, which is a life-threatening reaction that can put your body into shock
While nut allergies are usually lifelong (fewer than 10 percent of people get it, according to the ACAAI), starvation goes away after seeking appropriate treatment.
Brazil nuts contain barium
Studies have shown that Brazil nuts contain traces of a metal called barium, which is absorbed by plants through the soil. The amount of barium in Brazil nuts varies depending on where they are grown.
Although current research suggests that the amount of barium found in recommended servings of Brazil nuts is minimal and unlikely to cause harm, it is still important to know the side effects that can occur in the event of an accidental overdose, also known as barium poisoning.
According to the Centers for Disease Control and Prevention (CDC), signs and symptoms include nausea, salivation, vomiting, abdominal cramps, watery diarrhea, hypokalemia (a reduction in potassium levels in the blood that can lead to a rapid heart rate), muscle weakness, and paralysis.
Bottom line: A Brazil nut probably won’t increase your barium intake to the point where it poses a risk.
Nutritional Content of Brazil Nuts
Like most nuts, Brazil nuts are high in calories and fat. Six Brazil nuts contain 187 calories, 4.05 grams (g) of protein, 3.32 g of carbohydrates and 19 g of fat – including 4.56 g of saturated fat, 6.78 g of monounsaturated fat and 6.92 g of polyunsaturated fat, according to the USDA.
In general, according to PennState Extension, it is recommended that 20 to 35 percent of your daily calorie intake come from fat, and no more than 10 percent from saturated fat, according to the Dietary Guidelines for Americans.
Brazil nuts are also a good source of dietary fiber, with about 2.3 g of fiber per six grains, according to the USDA. Fiber can help improve your digestion, lower your cholesterol levels, and lower your risk of heart disease, says the Mayo Clinic.
Other Vitamins and Minerals in Brazil Nuts
Beyond healthy fats and fiber, Brazil nuts are also rich in certain vitamins and minerals. A serving of Brazil nuts (six grains) contains 6.24 mcg of folate, or vitamin B9, according to the USDA.
Folate may help lower blood pressure, support embryo development during pregnancy, and promote brain health, explains the Cleveland Clinic.
A serving of Brazil nuts also contains 1.6 mcg of vitamin E, an antioxidant important for fighting disease and supporting skin health, explains MedlinePlus.
Brazil nuts are also a rich source of magnesium, with 107 milligrams (mg) per serving, and phosphorus, with 206 mg per serving.
According to the NIH, magnesium may contribute to protein synthesis, blood sugar control, and muscle and nerve function. Phosphorus benefits bones, teeth and cell membranes, says Harvard TH Chan School of Public Health.
Drug and Drug Interactions
If you are taking certain prescription medications, talk to your doctor before adding Brazil nuts to your diet. Selenium content can cause a negative interaction with drugs like cisplatin, a powerful chemotherapy drug.
Also talk to a healthcare professional before mixing herbal supplements of any kind with Brazil nuts or other selenium-containing supplements to make sure it’s right for you.
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