Brazil nuts are a good source of healthy fats, fiber, and minerals, including selenium. These nuts may help boost heart health, protect brain function, regulate thyroid function, and provide other health benefits.

Brazil nuts can be part of a healthful eating plan in moderation, but eating too many could cause adverse side effects. These nuts are high in selenium, a mineral that is beneficial in small amounts but may be toxic in large quantities.

A doctor or registered dietitian can help people understand how to incorporate Brazil nuts into their diet.

Brazil nuts are among the richest dietary sources of selenium, an essential mineral with antioxidant properties. Selenium plays an important role in essential body processes like thyroid function and immune health.

A single Brazil nut can contain around 68 to 90 micrograms (mcg) of selenium, meaning that just one nut per day can provide the daily recommended allowance of 55 mcg for most adults.

In addition to selenium, Brazil nuts provide protein, essential minerals, and healthful fats.

According to the United States Department of Agriculture (USDA), a one-ounce serving amounting to about 28 grams (g) of Brazil nuts contains the following nutrients:

  • 185 calories
  • 4.01 g of protein
  • 18.8 g of fat
  • 3.29 g of carbohydrates
  • 2.1 g of fiber
  • 203 milligrams (mg) of phosphorus
  • 185 mg of potassium
  • 105 mg of magnesium
  • 44.8 mg of calcium
  • 1.14 mg of zinc
  • 0.68 mg of iron

Brazil nuts contain healthful fats called polyunsaturated and monounsaturated fatty acids. Consumption of unsaturated fats, particularly polyunsaturated fats, may help lower the risk of heart disease and cardiovascular events.

However, Brazil nuts are also higher in saturated fat than many other nuts. If a person is trying to reduce their saturated fat intake, Brazil nuts may not be the best choice.

Brazil nuts also provide dietary fiber. The American Heart Association (AHA) notes that eating fiber-rich foods can help improve blood cholesterol levels and lower the risk of stroke, heart disease, obesity, and type 2 diabetes.

The findings of a 2025 research review and analysis suggests that higher consumption of nuts decreases the risk of cardiovascular disease and all-cause mortality.

Selenium plays an essential role in hormone production. The thyroid gland uses selenium to convert thyroxine hormone (T4) into its active form, triiodothyronine hormone (T3).

Obtaining enough selenium from dietary sources may prevent or help regulate thyroid problems, such as hypothyroidism.

The selenium in Brazil nuts may boost the body’s antioxidant system and help prevent oxidative stress.

The liver uses selenium to form selenoproteins, many of which help remove excess free radicals. Free radicals cause oxidative stress, and studies have suggested links between them and many chronic health conditions, including cancer.

A 2015 placebo-controlled study examined the antioxidant effects of Brazil nut consumption. During the study, 91 people with hypertension and high blood lipid concentrations received either 13 g of granulated, partially defatted Brazil nuts or a placebo every day for 12 weeks.

The participants in the Brazil nut group had higher selenium levels and increased activity of an antioxidant enzyme called GPx3. They also had lower levels of oxidized low-density lipoprotein (LDL), which people sometimes refer to as “bad cholesterol.”

The antioxidant properties of Brazil nuts may also help reduce inflammation in the body. Inflammation has an association with many chronic health conditions, including obesity.

A small 2024 study looked at the potential anti-inflammatory effects of Brazil nuts in women with overweight or obesity who were consuming 500 calories per day.

Selenium blood concentrations were higher and levels of inflammatory markers, such as C-reactive protein, were lower in the group that consumed 8 g of Brazil nuts per day compared to the group that followed a nut-free diet.

Brazil nuts have powerful antioxidant effects due to their high selenium content, and people with selenium deficiency may have a higher risk of cognitive decline.

The Office of Dietary Supplements notes that research findings have been mixed. Some research has found that higher selenium consumption is associated with better cognitive scores in older adults, while other studies have not found links between selenium levels and cognitive ability.

Ultimately, more research is necessary to understand how selenium affects cognition and whether it could prevent or treat neurodegenerative diseases like Alzheimer’s disease.

When it comes to Brazil nuts, more is not always better. People may need to limit their intake of Brazil nuts to a few per day to avoid adverse side effects.

Like most nuts, Brazil nuts are calorie-dense. People who eat too many Brazil nuts may exceed their daily recommended calorie intake and could experience unintended weight gain.

As a member of the tree nut family, Brazil nuts may also cause allergic reactions in some people.

The American College of Allergy, Asthma, and Immunology states that an estimated 25% to 40% of people who have a peanut allergy react to at least one type of tree nut, though allergies to Brazil nuts are less common.

Selenium toxicity

Many of the health benefits of Brazil nuts come from their high selenium content. However, Brazil nuts could cause selenium toxicity if a person regularly eats them in large amounts.

Selenium toxicity may cause a variety of symptoms, such as:

  • dizziness
  • gastrointestinal problems
  • hair loss
  • brittle nails
  • skin rashes or lesions
  • nervous system issues
  • fatigue
  • irritability
  • muscle tenderness or soreness
  • joint pain

More rarely, it may also cause severe symptoms, which can include:

  • acute respiratory distress syndrome
  • heart attack
  • kidney failure
  • heart failure

In very rare cases, selenium toxicity can be fatal.

The selenium concentration in Brazil nuts varies depending on the amount present in the soil, so each nut may contain a different amount. The upper limit for adults is 400 mcg of selenium per day, so eating just 5 nuts may exceed that limit.

For most people, exceeding the upper limit on a single day isn’t usually dangerous. However, people should avoid exceeding the upper limit on a regular basis.

Moderating selenium intake

If a person still wants to add Brazil nuts to their diet but wants to make sure they’re not exceeding the upper limit of selenium intake, it may help to talk with a doctor or registered dietitian to determine a safe amount to eat.

Try Medical News Today’s search tool to find a local doctor or registered dietitian who can help.

Brazil nuts may provide some impressive health benefits, but it is best to eat them in moderation.

According to the findings of scientific studies, certain compounds in Brazil nuts may benefit health in a range of ways, such as lowering the risk of heart disease, regulating thyroid function, and boosting the body’s antioxidant system.

Brazil nuts are among the best food sources of selenium, an essential mineral known for its antioxidant properties. Although selenium can promote health, too much can result in selenium toxicity.