Substances in Onion that Make You Shed Tears and Remedy Ailments
What's a drop of tear for all the remedies that onions offer?
If I could help it I would not peel onions. However, the tears elicited while peeling are worth remedies for cancer and other ailments.
When you peel an onion you activate an enzyme that releases the precursor of a tear jerker, chemically known as (+)-S-pro-l-enyl)-L-cysteine sulfoxide, for short, propenyl precursor. This substance produces pyruvic acid, ammonia, and propenylsulphenic acid that is unstable, volatile and irritating to the eyes (Paul, P.C. and H.H. Palmer. editors. Food Theory and Applications. 1972).
Propenyl precursor is also a building block for two more unpleasant substances: one, bitter substance; another, a substance for the biting and burning sensation on the tongue.
What is responsible for the aroma of onions? Dipropyl disulfide – onions have a high proportion of it. That sulfide means sulfur content. Whenever you see the prefix sulf, that means the compound contains sulfur.
Onions have an enzyme that can catalyze the breakdown of alkyl cysteine sulfoxides. If you chew or macerate onions, you convert cysteine sulfoxides to sulfinates that in turn breaks down to disulfides.
Why does cooked onions taste sweet? Onions contain a sweetener 50 to 70 times sweeter than sucrose, a sugar found in fruits and honey. This sweetener is called n-propanethiol.
The sulfur atom in substances where it is found does the trick. Sulfur is found in glutathione-sulfhydril, an enzyme that catches free radicals. Free radicals initiate the injury than results in cancer, or tumor, or emphysema, or arthritis, or glaucoma, or cataract, or retinoblastoma, or myoma, or endometriosis, or leukemia, or heart disease, or melanoma. The list seems endless. Glutathione-sulfhydril consists of glutamate, cystine, cysteine, and co-factors lipoic acid, selenium, zinc, and vitamin B1 (Pressman, A., H.D.C. Ph.D., C.C.N. and S. Buff. Glutathione: The Ultimate Antioxidant.1998). In themselves, selenium and zinc are antioxidants. Selenium protects against cancer; zinc protects against prostate cancer. Zinc is a component of insulin.
Cysteine is an amino acid that contains sulfur. Our body converts cysteine to cystine and back. These two can be considered as one amino acid in metabolism (Mindell, E. Earl Mindell’s Vitamin Bible. 1991:114). Cystine is the stable form of amino acid containing sulfur. When sulfur is metabolized it combines with other substances to detoxify the body.
Sulfur-containing amino acids guard against copper toxicity called Wilson’s disease. Cystine/cysteine protects against free radicals produced by smoke and alcohol. Drinkers and smokers may take L-cystine (cysteine supplement), and vitamin C three times as much as cysteine. Cysteine in therapeutic dose offers protection against nuclear radiation and X-ray (Mindell).
A caution though. A person suffering from diabetes should not take large doses of vitamins B1 and C, and cysteine and cystine.
Red onions contain quercetin that studies have shown to “suppress malignant cells before they can form tumors” (Mindell, E. Earl Mindell’s Vitamin Bible. 1991:13).
Indeed, the more tears it elicits the more potent is your onion.