Bertholletia excelsa - The Brazil Nut


B. excelsa is very similar to most plants when it comes to acquisition of food.  The main source of “food” acquisition comes from the photosynthesis that takes place on the cellular level throughout the plant.  With the crown of the tree being so high over the canopy in the Amazon, light is usually very plentiful for the leaves of B. excelsa, which allows for plenty of photosynthesis to take place.  In addition to food production, the leaves also serve as sites for gas exchange with the environment through the use of stomata (right).  The xylem in the trunk of the plant work to transport water from the roots of the tree to the top and throughout the trunk, and the phloem transports nutrients (such as the food created from photosynthesis) from the top of the tree and the branches to the lower parts of the tree.  Excess food in the tree is stored as starch.

This photo is a cross-sectional view of a plant.  The xylem and phloem are on the inside of the plant and lie near to the center.  The xylem (#5) lies deeper in the stem than the phloem and is responsible for the transportation of water in the plant (from the roots to the upper regions).  The phloem (#6) lies next to the xylem and is responsible for the transportation of sugars and nutrients throughout the plant (from the source of food production to the structures using the food).  In this particular photo, the xylem and phloem are positioned outside of the pith (#4) and medial to the endodermis (#3).  Beyond the endodermis are the cortex (#2) and the epidermis (#1)


A Brazil nut is one of the more exotic nuts that can be commonly found throughout the United States.  These delicious nuts can be found in a majority of grocery stores, and are often used in premium nut mixes.  The Brazil nuts are not considered to be premium simply because they must be imported, but because they are loaded with nutritional value that rivals most other common nuts such as cashews or peanuts, specifically in selenium concentration.  The amount of selenium in just one ounce of Brazil nuts is approximately 780% of one's daily intake.  These high levels of selenium help to produce antioxidant enzymes, which help protect the body against damage and diseases such as cancer and heart disease (see more at Brazil Nuts, Health, & Digestion!).  Simply eating Brazil nuts instead of a fatty snack on a regular basis can dramatically reduce intake of saturated fat and improve lipid profile as well as microvascular function.  This regular intake of Brazil nuts, over time, can actually lead to an overall healthier diet and help combat obesity.


The photo above is used to compare the different body sizes found throughout individuals.  In the United States, none of the three images are out of the ordinary, which is a big concern.  The image to the left depicts an average body size, the middle image depicts an overweight individual, and the right image depicts an obese individual.  Brazil nuts are a viable alternative to fatty snack foods, and could potentially be a step towards a healthier life for anyone.


To learn more, continue to the Reproduction page!

Peter Zepke of University of Wisconsin - La Crosse.  BIO 203 - Spring 2012.