Whole Grains versus Refined Grains
It seems like “whole grain” is the buzz-phrase these days, with everything from cookies to pasta making healthful claims based on their inclusion of whole grains. What makes a grain “whole?” And is it really that different from refined grain? The answer to the latter question is most definitely yes.
The Structure of the Grain Kernel
First, let’s take a look at the nature of a grain kernel. It is composed of four layers: the hull, bran, germ, and endosperm.
The hull is the outer layer, and is generally considered inedible. It encloses the grain in its own sealed package, which accounts for whole grains’ excellent keeping quality.
The bran layers are where the fiber and B vitamins reside. Fiber is vital to intestinal health – its bulk prevents and treats constipation, and decreases the chances of developing disorders such as hemorrhoids and even cancer. Foods high in fiber make you feel more full, and regulate blood sugar by slowing absorption of the food. Fiber consumption is important to cardiovascular health, too. Studies have shown that consuming bran lowers blood cholesterol.
The germ of the grain houses the oils, vitamins, minerals, and protein. This is where the important antioxidant vitamin E is found. This vitamin aids circulation, promotes reproductive health, and is good for the skin. It is worth noting that freezing grains, whole or ground, destroys vitamin E.
A grain’s endosperm is the very inner part of the kernel, and is the grain’s starchy source of complex carbohydrates. This is where the grain’s sugar is found – it is the endosperm that is broken down in the body and converted to glucose, the body’s essential energy source.
Now that we have dissected the grain kernel, it is evident that the whole kernel is a powerful nutritional package. When a grain is refined, much of that nutrition is lost.
How Grain Is Refined
When a grain is put through the refining process, the bran and germ layers are stripped off, and what remains (the endosperm) is ground and pulverized into what we know as white flour. Often, the flour is chemically bleached to give it a more uniform color. Then, the flour is often “enriched” by having some of the vitamins that were removed in the refining process put back in.
Remember that the endosperm is the kernel’s source of sugar. Eating white flour is much like eating white sugar – it is absorbed quickly by the body without any fiber and protein to slow it down, and its lack of substance and nutrients means it does not promote intestinal or cardiovascular health. Consumption of refined grains has been implicated in health problems such as heart disease, diabetes, and obesity (to name a few).
There is no question that whole grain is nutritionally superior to refined grain.
photo credit: thebittenword.com
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