Phenolics in foods and beverages
Phenolic compounds are ubiquitous in foods, spices, and drugs(especially some nasal sprays).
They give plant foods many of their natural colors (e.g., flavonoids) and characteristic flavors (e.g., benzoic acid).
In the plant these are antimicrobial antifungal .
Two common phenolics include vanillin , from both natural and artificial vanilla, and catechol, from coffee tea, and vegetables such as apples and potatoes that brown on cut surfaces.
Except for coumarin and safrole ( which is carcinogenic), phenolics were originally thought to be nontoxic, but recent data have raised questions about these natural constituents.
Phenols have been reported in some studies to be cancer promoters. They appear to speed the formation of the carcinogen nitrosamine by accelerating the reaction of amines with a common air pollutant, nitrogen dioxide.
Nitrogen dioxide in the environment comes from cooking with gas, cigarette smoke, generation of power , and automobile exhaust .
In surprising contrast, some studies have shown that other phenolics such as chlorogenic and gallic acid inhibited nitrosation reactions.
Likewise, certain phenolics such as gallic, caffeic, and chlorogenic acid reduce mutagen formation under specified situations.
They were at least as effective as vitamin C in this regard .
For example , coffee and tea , which contain both caffeic and chlorogenic acid, reduced mutagens caused by salt-cured fish.
Some Common phenolics in Food and Beverages
Common sources Amount Compound
Cinnamic acid Plums, cherries, apples, pears, grapes 90-182
Caffeic acid Brussels sprouts, radishes, cabbage, eggplant 1-30
Chlorogenic acid Apples 89
Gallic acid Cup of black tea 5-10
Coumarin Cabbage, radish, spinach 2-15
The phenolic coumarin is found in herb teas made from tonka beans, meliot, and woodruff, in the flavoring oil of bergamot and in the spice cassia ( sometimes sold as cinnamon).
Coumarin impairs blood clotting , causes menstrual irregularities, damages, the liver and other organs, and causes adverse symptoms in children identified as hyperkinetic.
Coumarin fed to experimental animals induced bile duct carcinomas, primarily because the DNA repair process was inhibited.
Safrole is a phenolic that makes up 80% of the essential oil extracted from sassafras tree root and bark.
Prized since its discovery in the new world , sassafras was used in teas, tonic, and cure-alls.
The bark of the sassafras tree is made into file powder, a gumbo ingredient in the New Orleans area.
Safrole is also a minor component of the spices nutmeg, star anise, mace, and cinnamon.
It was established as being carcinogenic to rats and was banned as a food additive in 1960.
Until that time, natural and synthetic safrole were used to flavor root beers and other foods.
Besides being carcinogenic, it has been subsequently shown to injure the liver.
Despite the banning of safrole, sassafras is still a popular ingredient in herb teas and preparations.
Estragole
The aromatic oil from tarragon, basil, and fennel, has a structure similar to that of safrole and is a weak carcinogen.
Tarragon frequently flavors salad dressings, vinegars, and other dishes.
Basil also flavors vinegars and is used widely in many cuisines.
Methyl eugenol, also similar to estragole in structure, is found in bay leaves, cloves, and lemon grass. It has weak to moderate carcinogenic activity in rodents.
Al these compounds, although carcinogenic, are found in human diets at very low levels.
The potential carcinogenically of these low doses to humans is unknown .
Black pepper , a seasoning widely used in nearly every cuisine in the world, also has some compounds that are suspect.
The average intake of pepper is approximately 280 milligrams per person per day.
Pepper contains low levels of safrole and tannins as well as a large amount of a related compound, piperidine, which can become a strong carcinogen.
In addition, black pepper contains at least seven other substances that have been implicated as either inducing or promoting cancer.
Experiments with pepper fed in large amounts show it to be a tumor promoter for mice.
However when fed at five to 20 times the normal human intake , it had no effect on the growth, feed efficiency , organ weight , or blood constituents of laboratory animals .
Epidemiological data from countries such as Curacao, where consumption of red and black pepper is high, do not necessarily show the same effects of of peppers as animals studies.
In fact, components other than peppers accounted for cancer incidence.
In addition to factors in black pepper that have been implicated as cancer-promoting, both red and black peppers significantly increase stomach acid, pepsin secretion, and potassium loss.
Peppers can also cause tiny amounts of bleeding in the lining of the stomach, and in some individual the bleeding can be significant.
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