Chances are you’re familiar with Brazil nuts. They’re usually the biggest ones in the bag of mixed nuts you get at the grocery store. They have a smooth, buttery texture, somewhat like Macadamia nuts.
They have a nutty flavor. You can eat the unshelled nuts as raw Brazil nuts, blanched, Brazil nut butter, or as Brazil nut oil. You can even drink them as Brazil nut milk.
Brazil nuts are tree nuts. But did you know that the Brazil nut is technically a fruit? It’s true! It is the fruit of the enormous tropical tree Bertholletia excelsa. The nuts come in a fruit pod or shell. This Brazil nut tree grows and is exported from the Amazon around the world.
Let’s talk about Brazil nuts and some of their benefits to health.
1) Rich in Nutrition
Brazil nuts are energy-dense. This means that they have a significant amount of calories per gram. People know Brazil nuts for their selenium content. Brazil nuts are the highest natural source of selenium in the food world.
Brazil nuts are also high in magnesium, copper, and zinc.
They have an excellent fatty acid profile as well. Brazil nuts are high in both monounsaturated and polyunsaturated fatty acids. These unsaturated fats are healthy fats.
Brazil nuts are also high in protein and other bioactive compounds.
Brazil nuts also contain the following vitamins and nutrients:
- Phosphorus: Brazil nuts contain 30% of the daily recommended intake of phosphorus.
- Manganese: Brazil nuts contain 17% of the recommended daily intake of manganese.
- Thiamine: Brazil nuts have 16% of the recommended daily intake of thiamine (vitamin B1).
- Vitamin E: Brazil nuts provide 11% of your recommended daily intake of vitamin E.
- Oleic acid
- Amino acids
- Ellagic acid
2) Rich in Selenium
Brazil nuts are the richest natural source of selenium in the world. Many studies have considered Brazil nuts as an alternative for selenium supplementation.
Studies have shown that supplementation with Brazil nuts is effective in increasing your selenium levels.
One study had participants consume one Brazil nut per day for six months. Researchers found that participants consuming Brazil nuts had higher selenium levels compared to the control group. The control group showed no change in their selenium levels at all.
More than a billion people worldwide may have a selenium deficiency. Using Brazil nuts as supplementation may be worth considering.
3) Thyroid Function
Thyroid gland function depends on the mineral selenium. There is no doubt about that. This is because selenium is at the active center of iodothyronine deiodinase. This is the enzyme that catalyzes the conversion of thyroxine (T4) to triiodothyronine (T3). This is important because T3 is the active form that the body uses.
One study looked at 40 patients. They received one nut per day for three months. Researchers observed the patients’ selenium plasma levels, serum T3, free T4, and thyroid-stimulating hormone (TSH). Before the experiment began, all patients were deficient in selenium. They all had low T3.
After one Brazil nut per day for three months, selenium levels skyrocketed. They went from 17.6 micrograms per Liter to 153.4 micrograms per Liter. T3 also rose, from 27.3 to 50.2 ng/dL. Free T4 went up from 0.87 ng/dL to 0.98 ng/dL. TSH levels went down, from 2.17 to 1.96 uUI/mL. Researchers concluded that Brazil nut supplementation is associated with improved thyroid hormone levels.
Although Brazil nuts contain selenium, they do not themselves contain iodine. This is why thyroid cancer patients on a low iodine diet can still safely consume Brazil nuts. Researchers have recommended post thyroidectomy patients to consume two to three Brazil nuts per day for up to ten days.
4) Reduce Inflammation
Brazil nuts help to improve the anti-inflammatory response. Researchers believe that they do this by activating nuclear factor E2 related factor 2 (called Nrf2 for short).
One population that Brazil nuts appear to be helpful for is hemodialysis patients. One study looked at 13 hemodialysis patients. They received one Brazil nut per day for three months. 12 hemodialysis patients received no supplementation. This was the control group.
Researchers evaluated the following inflammatory markers:
- Nuclear factor-kappa B
- Nrf2
- Nad(ph)h quinone oxidoreductase 1 (NQO1)
- Plasma malondialdehyde
- C reactive protein (CRP)
- Interleukin 6 (IL-6)
Results showed that inflammatory cytokines and malondialdehydes decreased significantly. There were no significant changes at all in the control group. Researchers concluded that Brazil nut supplementation is effective on Nrf2 activation in hemodialysis patients.
Another study looked at 32 participants over the age of 50. The subjects ate six Brazil nuts per day. The results showed that the supplementation of Brazil nuts regulates biomarkers related to colorectal cancer. This was especially true of genes associated with inflammation.
5) Heart Health
Brazil nuts modulate the blood’s lipid profile. They do this by enhancing the antioxidant system and improving the anti-inflammatory response. The consumption of Brazil nuts has been linked with benefits to fat metabolism.
One study looked at 130 healthy participants at the University of Sao Paulo in Brazil. The study subjects ate one Brazil nut per day for eight weeks. Their total cholesterol concentration went down after the eight weeks were over.
Another study looked at less healthy patients. These were study subjects with high cholesterol levels. They ate Brazil nut flour containing 227.5 micrograms of selenium per day. The placebo group received dyed cassava flour instead. All patients had personalized dietary guidelines with nutritional recommendations. They followed these for 90 days.
The Brazil nut group saw great improvements in their lipid profile. Total cholesterol went down by 20.5 mg/dL. Non-HDL cholesterol went down by 19.5 mg/dL. Non-HDL cholesterol is what we commonly refer to as “bad cholesterol.” Researchers in this study concluded that supplementing with Brazil nuts reduces lipidemia in patients with high cholesterol.
A different study looked at 40 patients on hemodialysis. They ate one Brazil nut per day for three months. High-density lipoprotein cholesterol (HDL-C, or “good cholesterol”) increased significantly. Low-density lipoprotein cholesterol (LDL-C, or “bad cholesterol”) decreased significantly. Researchers in this study concluded that consuming just one Brazil nut per day effectively reduces atherogenic risk.
Another study observed 15 healthy subjects around 27 years of age. They were told to consume 45 grams of Brazil nuts per day for 15 days. The results showed that Brazil nuts altered cholesteryl ester transfer. This is helpful because it improves the non atherogenic reverse cholesterol transport pathway.
5) Antioxidant Effects
Studies show that Brazil nuts reduce oxidative stress. They do so by enhancing the antioxidant system in the body. Brazil nuts and their ingredients are able to scavenge free radicals and other reactive species. This decreases the risk of various non-communicable chronic diseases.
Selenoproteins are one of the compounds in selenium that play an important antioxidant role. One study found that Brazil nuts have a high total antioxidant capacity. This is why researchers recommended eating Brazil nuts to reduce the risk of chronic non-communicable diseases.
Just one Brazil nut per day for three months increases glutathione peroxidase levels. This also increases glutathione peroxidase activity. Glutathione peroxidase is a potent antioxidant.
One study looked at 91 patients with high blood pressure and cholesterol. Researchers gave these subjects granulated Brazil nut at 13 grams per day or a placebo for 12 weeks. This increased glutathione peroxidase activity from 112.66 to 128.32 nmol/min/mL.
It also lowered oxidized LDL levels from 66.31 to 60.68 U/L. Overall, Brazil nuts increased enzymatic antioxidant activity and reduced oxidation in LDL.
6) Lower Blood Sugar
Research has shown that Brazil nuts can help to lower blood sugar. One study looked at 130 healthy patients at the University of Sao Paulo in Brazil. The subjects ate one Brazil nut per day for eight weeks. After eight weeks of supplementation, fasting glucose levels went down.
7) Improve Brain Function
Brazil nuts improve brain function by enhancing the antioxidant system and improving the anti-inflammatory response.
Oxidative stress is closely related to cognitive impairment. This is why using antioxidants is a good way to preserve cognitive function in older adults.
Mild cognitive impairment and Alzheimer’s disease involve impaired biological activity of certain selenoproteins. Supplementing with Brazil nuts has shown potential in reducing cognitive decline in mild cognitive impairment patients. This could be a safe and effective nutritional approach early in the disease process to slow cognitive decline.
One study looked at 31 older adults with mild cognitive impairment. They ate one Brazil nut per day for six months. The researchers assessed the subjects’ cognitive functions with the CERAD neuropsychological tests. After six months, improvements in cognition markers were significantly higher on the Brazil nut group than controls.
Researchers concluded that Brazil nuts restore selenium efficiency. They added that Brazil nut supplementation could have positive effects on some cognitive functions of older adults with mild cognitive impairment.
Can you eat too many Brazil nuts?
It is possible to eat too many Brazil nuts. Too much of a good thing can indeed be a bad thing.
One study looked at selenium intake and levels of public preschool children. These students receive between 15 and 30 grams of Brazil nuts, three days per week. Researchers compared them to children from a nearby Brazilian city who do not receive Brazil nut enriched meals.
In both cases, meals at school made up more than 90% of the children’s total food consumption. Researchers found that in both groups, these meals were inadequate in energy intake and macronutrient intake.
However, selenium intake was excessive in both groups. In the treatment group, children consumed 155.30 micrograms per day. In the control group, children were consuming 44.40 micrograms per day.
On days where Brazil nuts were added to meals, selenium intake was potentially toxic in the treatment group. But even though selenium exposure biomarkers were far higher than reference levels, none of the children had clinical symptoms of selenium overload.
Researchers concluded that the inclusion of Brazil nuts in school meals of children with already high dietary selenium intake could be dangerous. It increases selenium levels and may result in an increased risk for selenium toxicity.
This is associated with some chronic diseases. Therefore, researchers recommend continued monitoring of selenium intake in areas where there is high selenium content in the soil as well as the diet.
Selenium toxicity
Selenium can be toxic at elevated levels. Selenium overdose can lead to severe consequences.
There is a narrow range between the therapeutic dose and the toxic dose of selenium. This is why it’s tricky to use as a supplement.
Selenium’s effects depend on the form, dose, and method of treatment.
Selenium poisoning is called selenosis. It can happen in humans and animals. Selenosis can occur in animals when livestock feeds on plant species with accumulated selenium.
In foods, the bioavailability and toxicity of selenium depend on the chemical form. Usually, organic forms of selenium are more bioavailable. They also tend to be less toxic than the inorganic forms. Inorganic forms include selenites and selenates. Overall, the toxicity of most forms of selenium is low.
The most fatal form of selenium is selenious acid. Symptoms of selenious acid poisoning include stupor, low blood pressure (hypotension), and respiratory depression. This usually results in death. It is important to note that selenious acid is definitely not the form found in Brazil nuts!
In China, they have reported chronic selenium poisoning. This is from environmental exposure to excessive selenium. Symptoms include changes in the hair and nails. Excessive selenium exposure like this causes you to breathe out a compound called dimethyl selenide. It has a garlic-like odor.
The United States National Toxicology Program lists selenium sulfide as an animal carcinogen (cancer-causing). However, there is no evidence to show that other forms of selenium are carcinogenic.
Even though Brazil nuts are considered healthy, it is important to consume them in moderation.
Consuming a five-gram Brazil nut from an area high in selenium meets the daily recommended allowance for selenium. The recommended serving size of Brazil nuts is 30 grams. This might actually exceed the allowable daily intake of selenium at 400 micrograms.
In fact, it could even exceed selenium’s toxicity threshold of 1200 micrograms. Do not eat too many Brazil nuts, as you don’t need many to get your daily intake of selenium.
It is also important to note that Brazil nut allergy does exist, so don’t have Brazil nuts if you are allergic to other tree nuts, such as cashews or pistachios.
As you can see, Brazil nuts have a rich nutritional profile. Their selenium content is especially important. You may want to consider adding Brazil nuts to your diet if you have a thyroid condition like hypothyroidism or Hashimoto’s autoimmune thyroiditis. Brazil nuts can also be helpful if you have an inflammatory condition such as any of the following:
- Arthritis
- Inflammatory bowel disease (such as ulcerative colitis or Crohn’s disease)
- Sinusitis and seasonal allergies
- Heart disease (high blood pressure or high cholesterol, which increase your risk for heart attack and stroke)
- Cancer
- Autoimmune conditions such as lupus or rheumatoid arthritis where the immune system overreacts
Since Brazil nuts are beneficial to heart health, you may also want to include them in your diet if you have a family history or higher risk of heart disease. And since Brazil nuts are antioxidants, you may want to have them to help prevent non-communicable chronic diseases.
Due to Brazil nuts’ blood sugar lowering effects, they could be helpful if you have prediabetes, diabetes, or metabolic syndrome.
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Conclusion
Brazil nuts are worth having if you want to slow the process of cognitive decline. This is especially important if you have a higher risk of Alzheimer’s disease and other dementia forms. These risk factors include family history and previous head trauma.
Although we have outlined many great benefits of Brazil nuts, it is possible to have too many. You do not want selenium toxicity! Therefore, we recommend keeping your Brazil nut intake to a moderate level.
If you would like to add Brazil nuts to your diet, speak to your healthcare provider first. Brazil nuts may be a great choice for you since they act as a selenium supplement but are healthy food.
