Brazil nuts are the seeds of the towering rainforest tree, Bertholettia excelsa. The Brazil nuts grow in a large football sized fruit, each containing 5-12 seeds. When these come thundering down from the tree canopy 60m up, you would not want to be standing underneath!
As with most nuts, Brazil nuts are super nutritious and energy dense. They have a generous amount of quality fats, plenty of protein and fibre as well as a range of minerals and vitamins. Brazil nuts are also a rich source of phytochemicals, especially antioxidants. Their massive unique selling point however is the amount of Selenium they contain - 1 nut gives you between 50-200% of the RDA of Selenium (depending on the nut and the relative richness of selenium in the soil where its parent tree grows)!
Selenium
Selenium is an essential trace mineral that we have to ingest from the outside. It is critical in healthy thyroid function, as well as being involved in immune system function and cell growth. High levels of selenium have been linked to enhanced immune function and better outcomes for cancer, infections, infertility, pregnancy, heart disease and mood disorders.
Selenium + Thyroid
The thyroid gland has the highest concentration of selenium in your body. It is required for the production of the thyroid hormone T3. Many people with Thyroid issues eat Brazil nuts every day as a natural food-based selenium supplement.
Selenium + Testosterone
Brazil nuts have been shown to help increase men's testosterone levels and improve the quality of semen. This is due once again to the selenium content of Brazil nuts, as testicles contain high levels of selenium.
Selenium + Emotional Health
Brazil nuts have been found to help lift a person's mood. Low levels of selenium were directly related to feelings of tiredness, depression and anxiety. Eating just one Brazil nut a day increased selenium levels enough to improve all of these indicators (1).
Anti-inflammatory
Chronic inflammation is connected with almost every common chronic disease - including cancer, heart disease, depression and diabetes. The antioxidants in Brazil nuts help maintain healthy cells, preventing damage from free radicals. Selenium (again!) is a key anti-inflammatory antioxidant, as are vitamin E and phenols such as gallic acid and ellagic acid.
Cardiovascular health
Several studies have confirmed that eating a small serving of Brazil nuts daily improves cardiovascular health in general. One study found that daily Brazil nut consumption improved red blood cell health, increased selenium levels, decreased cholesterol levels and improved microvascular function (2). Another study found that regular consumption of Brazil nuts reduced the risk of developing atherosclerosis (3).
Lower Cholesterol
A fantastic and emphatic study found that eating just 4 Brazil nuts a day can significantly improve cholesterol balance (4). The effect kicks in within 6 hours of eating the nuts, and lasts for at least 30 days. The individuals in the study showed a reduction of the 'bad' LDL-cholesterol and an increase of the 'good' HDL cholesterol that was still apparent after 30 days. This would reduce the risk of a heart attack or stroke by 20% or more.
As is clear, Brazil nuts are a pretty amazing nut. Add to this list of health benefits the ones that come with most nuts - quality fats, high protein, helping weight loss and general good health - and why on earth wouldn't you eat a few a day?!
Other sources: Nutritional Medicine ; healthyandnaturalworld ; healthline