Brazil Nuts: Benefits of Selenium in Small Quantities
Medically reviewed by Karina Tolentino, RD
Brazil nuts are the large seeds of giant trees grown in the Amazon jungle. These tree nuts provide a low-fat source of micronutrients. They are unique because they contain the highest amounts of selenium found in foods consumed by humans.
Selenium is a trace mineral that your body needs in very small amounts. It plays a key role in many aspects of your health. It supports your thyroid hormone, metabolism, and reproduction. It also guards cells from damage and infection.
Eating more than a few Brazil nuts can lead to toxic levels of selenium. When these levels remain high for a long time, they can have severe results like kidney disease or a heart attack.
This article describes how to eat Brazil nuts to safely enjoy them. It details the symptoms of having too many Brazil nuts, what you can gain from eating them safely, and how to purchase quality products.
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What's a Safe Serving of Brazil Nuts?
The amount included in a safe serving of Brazil nuts varies depending on your age and sex. Other factors and conditions such as medical ailments, pregnancy, or breastfeeding, can also affect the amount of Brazil nuts per day that is safe for you to consume.
For most nuts, the general guideline is that it is safe to eat one ounce of nuts daily. Eating nuts on a regular basis has been linked with many health benefits in adults. However, Brazil nuts are the exception to this rule because they contain highly concentrated amounts of selenium.
A single Brazil nut can have 68–91 micrograms (mcg) per nut. With such a high level of selenium in each nut kernel, research suggests that a healthy adult may be able to achieve the benefits of eating Brazil nuts by consuming a serving of just four kernels.
Risks of Selenium Overdose
The risks of selenium overdose are minimal for most people. The average American diet provides about 100 mcg per day of selenium.
The amount of selenium in a daily diet is well above the current recommended dietary allowance (RDA) of 55 mcg per day for adolescents and adult men and women age 19 and older. The RDA is 60 mcg for pregnant women and 70 mcg for women who are breastfeeding (lactating).
The RDA is the average daily level of intake sufficient to meet the nutritional requirements of almost all healthy people.
Your risk of selenium overdose is higher if you take selenium supplements or consume too many Brazil nuts. The exact amount of selenium in a Brazilian nut depends on how much selenium was in the soil where the Brazil nut was grown, so it is important to read product labels to know what you are consuming.
If you eat more than four Brazilian nuts, it is possible to exceed the upper limit (UL), which is the maximum daily intake of a nutrient unlikely to cause adverse health effects. For adolescents and all adult men and women age 19 and older, the UL for selenium is 400 mcg daily.
Symptoms to Look for
The early symptoms of selenium overdose can be confused with many other conditions. If you have consumed Brazil nuts or another source of selenium, contact your healthcare provider if you develop any include the following conditions:
Nausea
Hair loss
Nail discoloration and/or brittleness
Skin rash or lesions
Skin flushing
Muscle tenderness
Discolored teeth
If the high levels of selenium remain chronically elevated, you can experience the following health problems:
Uses for Brazil Nuts
Brazil nuts can be eaten raw, cooked, or roasted. They can be used as snacks or in salads. Brazil nuts can also be added to ice creams, chocolate, and other candies.
When finely chopped or ground, Brazil nuts can be mixed into brownies, cakes, cheesecakes, or other sweets. They can also be used in recipes for homemade pesto sauce. mayonnaise, and alternatives to cheese and milk.
Benefits of Eating Brazil Nuts
The benefits of eating Brazil nuts are similar to those you can achieve with other tree nuts. They also include advantages that are unique to their nutritional profile.
Promotes Heart Health
The selenium in Brazil nuts is linked with a lower risk of coronary heart disease. In a study of healthy adults, the results suggested that eating an average of four Brazil nuts may be sufficient to improve lipid profiles by reducing low-density lipoprotein (LDL) (“bad”) cholesterol and increasing high-density lipoprotein (HDL) (“good”) for up to 24 hours. Researchers reported that the benefit may last as long as 30 days without causing toxicity in your liver toxicity or kidneys in healthy adults.
Supports Thyroid Function
The selenium in Brazil nuts can help keep your thyroid healthy. Selenium concentration is higher in your thyroid gland than in any other organ in your body. Maintaining the necessary concentration of selenium can help you prevent thyroid disease and maintain your overall health.
However, there is a small margin of error in maintaining proper selenium levels for thyroid health. Your healthcare provider can provide direction about the best way to achieve healthy levels. If you have either a deficiency or excess of selenium, you increase your risk of adverse health problems.
If thyroid disorders occur, selenium may also help improve symptoms of the following thyroid diseases:
Hashimoto's thyroiditis: An autoimmune disease in which thyroid tissue is gradually destroyed and hypothyroidism (low levels of thyroid hormone)
Graves' disease: A thyroid disorder that results in hyperthyroidism (excess levels of thyroid hormone)
Reduces Inflammation
Brazil nuts are rich in antioxidants, substances that protect your body from the effects of unstable molecules called free radicals. Antioxidants include nutrients like vitamin E, selenium, and polyphenols like ellagic acid and gallic acid.
Supports Brain Health
Selenium supports important brain functions of your central nervous system like memory, coordination, motor performance, and cognition. Research indicates that the benefit of selenium for brain health is due to its antioxidant properties and its impact on inflammation. Selenium may also support important pathways of brain signaling during neurotransmission.
Maintains Strong Bones
Brazil nuts are a good source of magnesium, an essential nutrient for maintaining bone density. Magnesium contributes to bone formation and supports bone-regulating cells. Research indicates that higher magnesium levels lead to greater bone mineral densities.
Supports Immunity
Brazil nuts provide about 10% of the recommended daily allowance of zinc. Normal zinc levels are necessary to activate T-lymphocytes, a type of white blood cell that helps protect your body from infections that include the common cold and pneumonia.
Selenium and Testosterone
Studies reveal a strong connection between selenium and testosterone, though there is conflicting research. While some research shows that selenium has potential as a testosterone booster, the effect of selenium in other research had a positive impact on male semen production though not necessarily testosterone.
Before using selenium, consult your healthcare provider for guidance on the best way to boost testosterone levels.
Nutrition Breakdown
The nutrition breakdown for unsalted and unroasted Brazil nuts reflects food that is low calorie and nutrient dense. It is an excellent source of healthy fats and other micronutrients, including magnesium, copper, zinc, phosphorous, thiamine, and vitamin E.
The U.S. Department of Agriculture (USDA) reports the following Brazil nut nutrition facts for a 1-ounce serving, equivalent to 28.35 grams (g), consisting of about six kernels:
Calories: 187
Protein: 4.1 g
Sugars: 0.7 g
Fat: 19 g (24% Daily Value, or DV)
Carbohydrates: 3.3 g (1% DV)
Fiber: 2.1 grams (7% DV)
Selenium: 544 mcg (990% DV)
Copper: 0.5 milligrams (mg) (20% DV)
Magnesium: 107 mg (25% DV)
Phosphorous: 206 mg (15% DV)
Manganese: 0.35 mg (15% DV)
Zinc: 1.15 mg (10% DV)
Thiamine: 0.18 mg (15% DV)
Vitamin E: 1.6 mg (10% DV)
Sodium: 1 mg (0% DV)
Percent daily value (DV) tells you how much a nutrient in a serving of this food contributes to a daily diet of 2,000 calories.
Brazil Nuts and Tree Nut Allergies
An allergy to tree nuts is one of the eight most common food allergies. While an allergy to one tree nut doesn't always mean that you are allergic to all types of tree nuts, you can be allergic to more than one type of tree nut. Since reactions to tree nuts can include life-threatening anaphylaxis, you should know if it is safe for you to eat Brazil nuts.
How to Find Quality Brazil Nuts
You can find quality Brazil nuts in most grocery stores or online. Brazil nuts are packaged as dry-roasted, sliced, raw (in the shell or shelled), blanched, or roasted, with or without added salt. They are sold alone or as part of mixed nuts. The type of Brazil nut you purchase will depend on the way you plan to use it.
Quality Brazil nuts should be a creamy color, whole, and healthy-looking. Brazil nuts that are not fresh tend to be darker with an off-taste or smell. Quality Brazil nuts in shells have shells with a uniform size. The shells are free from cracks or other damage.
If you're eating Brazil nuts to increase your selenium levels, read the package's nutrition labels to understand how much selenium you are consuming. There are natural variations of selenium concentration in Brazil nuts and soils. These differences likely result from variations in the soil across several regions of the Amazon and South America.
Learn More: Eating Nuts to Help Lower Your Risk for Heart Disease
Summary
Brazil nuts have many health benefits. They are a good source of protein, fiber, healthy fats, and antioxidants.
The nutrients in Brazil nuts support brain health, thyroid function, and healthy cholesterol levels. Brazil nuts also have strong anti-inflammatory effects that aid your body in fighting disease.
Brazil nuts contain the highest concentration of selenium of any food consumed by humans. Since high selenium levels can pose health risks, Brazil nuts should be eaten with care. Research shows that you can enjoy the health benefits of Brazil nuts by eating just four kernels at one time.
Read the original article on Verywell Health.
