Brazil Nuts: A Miracle Nut in your Diet

Brazil Nuts: A Miracle Nut in your Diet

The Brazil nut is a South American tree in the family Lecythidaceae, and also the name of the tree's commercially harvested edible seed. The Brazil nut family is in the order Ericales, as are other well-known plants such as blueberries, cranberries, sapote, gutta-percha, tea, gooseberries, phlox, and persimmons.

The Brazil nut tree is the only species in the monotypic genus Bertholletia. It is native to the Guianas, Venezuela, Brazil, eastern Colombia, eastern Peru, and eastern Bolivia. It occurs as scattered trees in large forests on the banks of the Amazon River, Rio Negro, Tapajs, and the Orinoco. The genus is named after the French chemist Claude Louis Berthollet.

The Brazil nut is a large tree, reaching 50 m (160 ft) tall and with a trunk 1 to 2 m (3.3 to 6.6 ft) in diameter, making it among the largest of trees in the Amazon rainforests. It may live for 500 years or more, and according to some authorities often reaches an age of 1,000 years. The stem is straight and commonly without branches for well over half the tree's height, with a large emergent crown of long branches above the surrounding canopy of other trees.

The bark is grayish and smooth. The leaves are dry-season deciduous, alternate, simple, entire or crenate, oblong, 2035 cm (7.914 in) long and 1015 cm (3.95.9 in) broad. The flowers are small, greenish-white, in panicles 510 cm (2.03.9 in) long; each flower has a two-parted, deciduous calyx, six unequal cream-colored petals, and numerous stamens united into a broad, hood-shaped mass.

In Brazil, it is illegal to cut down a Brazil nut tree. As a result, they can be found outside production areas, in the backyards of homes and near roads and streets. The fruit containing nuts is very heavy and rigid, and it poses a serious threat to vehicles and persons passing under the tree. At least one person has died after being hit on the head by a falling fruit.

Brazil nut trees produce fruit almost exclusively in pristine forests, as disturbed forests lack the large-body bees of the genera Bombus, Centris, Epicharis, Eulaema, and Xylocopa which are the only ones capable of pollinating the tree's flowers. Brazil nuts have been harvested from plantations, but production is low and is currently not economically viable.

The Brazil nut tree's yellow flowers contain very sweet nectar and can only be pollinated by an insect strong enough to lift the coiled hood on the flower and with a tongue long enough to negotiate the complex coiled flower. For this reason, the Brazil nut's reproduction depends on the presence of the orchid Coryanthes vasquezii, which does not grow on the Brazil nut tree itself.

Brazil Nuts: A Miracle Nut in your DietThe orchids produce a scent that attracts small male long-tongued orchid bees (Euglossa spp.), as the male bees need that scent to attract females. The large female long-tongued orchid bee pollinates the Brazil nut tree. Without the orchid, the bees do not mate, and therefore the lack of bees means the fruit does not get pollinated. The fruit takes 14 months to mature after pollination of the flowers. The fruit itself is a large capsule 1015 cm (3.95.9 in) in diameter, resembling a coconut endocarp in size and weighing up to 2 kg (4.4 lb). It has a hard, woody shell 812 mm (0.310.47 in) thick, which contains eight to 24 triangular seeds 45 cm (1.62.0 in) long (the "Brazil nuts") packed like the segments of an orange.

The capsule contains a small hole at one end, which enables large rodents like the agouti to gnaw it open. They then eat some of the nuts inside while burying others for later use; some of these are able to germinate into new Brazil nut trees. Most of the seeds are "planted" by the agoutis in shady places, and the young saplings may have to wait years, in a state of dormancy, for a tree to fall and sunlight to reach it, when it starts growing again. Capuchin monkeys have been reported to open Brazil nuts using a stone as an anvil.

Around 20,000 tons of Brazil nuts are harvested each year, of which Bolivia accounts for about 50%, Brazil 40%, and Peru 10% (2000 estimates). In 1980, annual production was around 40,000 tons per year from Brazil alone, and in 1970, Brazil harvested a reported 104,487 tons of nuts.

Brazil nuts are 18% protein, 13% carbohydrates, and 69% fat by weight, and 91% of their calories come from fat. The fat breakdown is roughly 25% saturated, 41% monounsaturated, and 34% polyunsaturated. Due to their high polyunsaturated fat content, primarily omega-6 fatty acids, shelled Brazil nuts soon become rancid.
Nutritionally, Brazil nuts are a good source of some vitamins and minerals. A cup (133 grams) of Brazil nuts contains the vitamins thiamin (0.8 mg55% DV) and vitamin E (7.6 mg38% DV); minerals calcium (213 mg21% DV), magnesium (500 mg125% DV), phosphorus (946 mg96% DV), copper (2.3 mg116% DV), and manganese (1.6 mg81%).

Brazil nuts are perhaps the richest dietary source of selenium; 28 g (1 oz, 68 nuts) can contain as much as 544 g. This is 10 times the adult U.S. Recommended Dietary Allowances, more even than the Tolerable Upper Intake Level, although the amount of selenium within batches of nuts varies greatly. Recent research suggests that proper selenium intake is correlated with a reduced risk of both breast cancer and prostate cancer. This has led some health commentators and nutritionists to recommend the consumption of Brazil nuts as a protective measure. However, these findings are inconclusive. Other investigations into the effects of selenium on prostate cancer have also been inconclusive.

Brazil nuts have one of the highest concentrations of phytic acid at 2 to 6% of dry weight. Phytic acid can prevent absorption of some nutrients, mainly iron, but is also a subject of research and possibly confers health benefits. Despite the possible health benefits of the nut, the European Union has imposed strict regulations on the import from Brazil of Brazil nuts in their shells, as the shells have been found to contain high levels of aflatoxins, which can lead to liver cancer.

Brazil Nuts: A Miracle Nut in your DietBrazil nuts contain small amounts of radium. Although the amount of radium, a radioactive element, is very small, about 17 pCi/g (40260 Bq/kg), and most of it is not retained by the body, this is 1,000 times higher than in other foods. According to Oak Ridge Associated Universities, this is not because of elevated levels of radium in the soil, but due to "the very extensive root system of the tree."

As well as its food use, Brazil nut oil is also used as a lubricant in clocks, for making artists' paints, and in the cosmetics industry. Engravings in Brazil nut shells were supposedly used as decorative jewelery by the indigenous tribes in Bolivia, although no examples still exist. Because of its hardness, Brazil nut shell has often been pulverized and used as an abrasive to polish softer materials such as metals and even ceramics (in the same way as jeweler's rouge is used). A high luster could be acquired by a final application of carnauba wax, only produced in north-eastern Brazil.

The lumber from Brazil nut trees (not to be confused with Brazilwood) is of excellent quality, but logging the trees is prohibited by law in all three producing countries (Brazil, Bolivia and Peru). Illegal extraction of timber and land clearances present a continuing threat.

Brazil nuts are large seeds that grow in South American virgin rainforests. The crescent shaped seeds are enclosed in a dark brown, hard shell. The high fat, high calorie nuts are much loved because of their rich, creamy flavor. They have one of the highest contents of selenium amongst all nuts. They also contain iron, copper, phosphorous, potassium, zinc and magnesium. A 1 ounce serving of the nuts contains almost 200 calories. Below are some of the nutrients found in these nuts and their role in the body.

The remarkably high selenium content in the nuts gives them a potent antioxidant property. Brazil nuts are one of the richest sources of selenium. This mineral works with proteins to produce antioxidant enzymes. These help to prevent cellular damage by free radicals. Selenium enhances the efficacy of the immune system. It helps to reduce the risk of heart disease and prostrate cancer. It also slows down the aging process and enables the thyroid gland to function properly. However, too much selenium can upset the stomach, cause irritability, fatigue, and loss of hair and nails.

A 1 ounce serving of magnesium provides about 65 mg of magnesium. Brazil nuts have one of the highest amounts of magnesium amongst plant foods. This vital mineral enhances the release of energy from foods to support nerve and muscular functions. Magnesium supports the absorption of calcium in the body. It plays a vital role in the formation of healthy teeth and bones. The risk of osteoporosis can be reduced significantly by adequate intake of magnesium in the diet.

Magnesium supports a healthy heart. It helps to maintain healthy levels of blood pressure, normalizes the heart rhythm and assists blood to clot properly in the heart. This reduces the risk of stroke and heart disease. The mineral also enables steady recovery in the event of a stroke. It plays a vital role n the formation of new cells and helps to relax stiff and strained muscles.

Brazil Nuts: A Miracle Nut in your DietThe nuts contain the complete range of proteins. This supplies all the essential amino acids necessary for optimal growth and development. Brazil nuts can serve as an ideal source of protein in a vegetarian diet.


Most nuts have a good combination of healthy fats. Brazil nuts contain Omega-3 fatty acids. These fats help to lower bad cholesterol levels in the blood. However, the nuts have a higher content of saturated fats than other nuts. As such, it is important that you consume them in moderation. Excessive intake leads to high cholesterol levels. This increases the risk of heart-related health complications.

The nuts have a high content of fiber. Once consumed, they make you feel full. This helps to regulate food intake. When eaten in moderation and combined with other healthy foods, the nuts can enable proper weight control. Adequate fiber in the diet contributes to optimal intestinal functions. This allows one to pass stool regularly and with ease.



Dated 22 November 2013

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