The onion is one of the oldest vegetables known to man, having been cultivated from the most remote period, as references in Sanskrit and Hebrew literature indicate. It is represented on Egyptian monuments. An inscription on the Great Pyramid states that sixteen hundred talents had been paid for onions for the workmen who built the Pyramids. There were certain religious sects who maintained that onions were impure and forbade their disciples and priests to eat them.
5.1 The Plants
Onions were raised in America as early as 1750. The leading onion-growing states include California, Idaho, Michigan, New York, Oregon and Texas. But onions are grown in many other states and Canadian provinces. Mexico, Italy, and Spain are also noted for their onions.
The onion plant is a biennial (a plant that lives for two years). The upper part of the plant is a set of leaves growing inside each other. The lower part of the leaves become very thick. The flowers are small and white, and grow in round clusters. The bulbs are enclosed in a thin papery covering made up of dried outer leaves. The onion plant has a few shallow roots.
The different kinds of onions have many sizes, colors, and shapes. People who trade in onions classify them as American (strong onions) and foreign (mild onions). The strong type includes the Yellow Globe types and the flatter Ebenezer type.
The onion is not particularly high in vitamins or in energy value.
5.2 A Toxic Substance
The substance in onions which gives them their characteristic odor and flavor is mustard oil, a volatile oil which is highly toxic. Its vapors are so irritating that they cause profuse watering of the eyes just by being in contact with the vapors for a few seconds. This oil, if applied directly to the skin, would cause extreme redness and blistering.
Anyone can testify to the fact that after they have eaten onions, even if it was only a small amount, the onion smell stays in their breath for a long time afterwards. The body eliminates much of this toxic oil through the breath as it attempts to get rid of this poison from the system.
5.3 Contributes to Goiter
As mentioned earlier, the mustard oil is metabolized in the body to thiocyanate. Ordinarily small amounts of thiocyanate are eliminated. But in large amounts this substance is highly toxic and results in disease. Thiocyanates are goitogenic. They contribute to the formation of a goiter by decreasing thyroxine synthesis in the thyroid gland. Thyroxine performs many important functions in the body.
One important function that thyroxine has in the body is to increase the rate at which cells burn their fuel, glucose. It also works in partnership with cortisol (a hormone of the adrenal glands) in defending the body against stress resulting from extreme cold. Thyroxine is also involved in other antistress responses. Emotional stress and severe hunger also provide an elevated thyroxine output. In general, thyroxine comes into play when there is an extra demand for energy. Thyroxine also increases the heart rate. When it is synthesized within the cells of the thyroid, this hormone becomes a part of a protein (thyro-globulin) until needed. When needed, a complex reaction involving the proteolysis (hydrolysis) of thyroglobulin and the synthesis of thyroxine takes place.
This is the point where the thiocyanate interferes with the synthesis of thyroxine. Apparently, the interference occurs with this protein but further research still has to be done in this area. At any rate, much harm can result.
5.4 Onions and Anemia
In The Complete Book of Food and Nutrition, J.I. Rodale relates a series of experiments concerning the adverse effects of eating onions. According to Rodale, Dr. M. Kaiser, of the University of Illinois College of Medicine, gorged (experimentally) on enough onions to bring himself down with an all-out case of anemia in a single week.
Experimenting with dogs, the same Illinois scientist first tried them out on the ordinary onion oil extract that is widely used in restaurants and homes for food-flavoring, and discovered that a daily dose of a mere quarter teaspoonful of this substance produced the disease in marked degree. Found to be too potent to try in a proportionate scale on humans, this extract should, they agreed, not even be used in extreme moderation in seasoning.
The next stage in the course of their study consisted simply of enlisting volunteer medical students to overeat the plain food, and in this stage Dr. Kaiser himself participated. Besides their regular diet, the group consumed over two pounds of cooked onions daily for 5 days. At the end of this time all showed typical anemia symptoms, dragging themselves around in an exhausted state and turning pale to their fingertips. On laboratory examination, the red cell count in their blood exhibited a drop of about a million, and the hemoglobin content was also starkly reduced. But this was only a slight anemia when compared with that of the dogs, which for 15 days had been fed comparable amounts of the pungent bulbs. In the animals both red cell count and hemoglobin had sunk to 50 percent below normal.
This destruction of the red blood cells and subsequent liberation and loss of hemoglobin has very grave consequences to the body’s overall integrity. The red blood cells, along with the other constituents of the blood, perform many very important functions. Below is a list of just some of these duties:
- It is the medium by which oxygen is transported from the lungs to the tissues.
- Carbon Dioxide, a product of the metabolism of cells is transported from the tissues to the lungs.
- Nutrient materials are absorbed from the intestine and carried to the tissues.
- Many organic substances that represent breakdown products of metabolism are carried by the blood to the kidneys for excretion.
- Hormones, the secretions of ductless or endocrine glands, are distributed throughout the body by the bloodstream.
- The blood flows from the deeper and warmer parts of the body to the extremities and tends to distribute heat more evenly to all parts of the body.
- The blood plays an important part in maintaining acid-base balance of the tissues.
- There is a constant relationship between blood volume and the fluid content of the tissues.
- The ability of the blood to form a clot and so reduce bleeding has been of survival value to animals and man.
- The blood performs an important part in cleaning up
foreign matter and dead cells from the body.
We can thus see that by disturbing one thing in the body we disturb many functions. But these problems can be avoided simply by staying on a correct diet and avoiding such toxic foods as garlic and onions.