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Efficient Digestion



Aug 11, 2010
By Dr. Herbert M. Shelton
Reprinted from Dr. Shelton's Hygienic Review
A view frequently expressed by medical authors and apparently held by the whole profession, is that if two foods may be digested separately, they may be digested together. They extend this principle to cover the whole menu: if each article of food in a bill-of-fare is separately digestible, then they are digestible if eaten. in a twenty-one course dinner, with the diner partaking of everything from soup to nuts.

Conventional diet causes digestive problems
In a limited way, this view is true, else would conventional eaters die from lack of food. Instead of dying, they thrive after a fashion, many of them even growing fat on the conventional diet with its haphazard mixtures. That digestion is not very efficient, is shown, however, by gas, sour eructations, discomforts, foul stools and the presence of large quantities of undigested food in the stools. At least half of the food eaten by most people is passed out undigested.

It is commonly held that foods may be taken into the digestive tract in the most indiscriminate and haphazard manner, in any possible combination, and in whatever amount the eater may desire will be well and efficiently digested. This view is not based upon physiology, but upon the determination of the profession that the customary practices of the people shall not be distrubed. Every student of physiology is well aware that the digestive enzymes have certain well-defined limitations and that different digestive juices are secreted for use in digesting different kinds of food substances. These limitations should be respected in our eating habits.

Proper food combining does not cause digestive problems
The inhibiting effect upon protein digestion of acids, sweets and fats makes it important to avoid combining these three types of foods. Good digestion depends upon a number of factors, but simplicity of meals with combin ations of foods that do not overstep the known enzymic limitations is one of the most important of these factors.

Vinegar retards digestion
Experiments have shown that as small a portion of vinegar as one in 5,000 sppreciab1y diminishes the digestion of starch by its inhibiting or destructive effect upon the salivary amylase. One part in 1,000 renders starch digestion very slow and twice this quantity arrests it altogether. From these facts it becomes evident that vinegar, pickles (saturated with vinegar),salads on which vinegar has been sprinkled and salad dressings containing vinegir, are unwholesome substances to take into the human digestive tract, especially when taken with starchy foods such as cereals, bread, legumes, potatoes and the like.

Vinegar is not an evil merely because its highly toxic acetic acid content destroys ptylain (salivary amylase),but it also contains alcohol, which precipitates the pepsin of the gastric juice and retards or prevents gastric digestion of proteins. What wonder then that pickles and vinegar have been found useful in reducing weight. They cripple the first two stages of digestion. My readers should know that apple cider vinegar, which is so much lauded today as a "wonder drug" in folk medicine con tains both acetic acid and alcohol and is unfit for use, not alone because it impairs digestion, but also because it contains these two virulent poisons.

Acids destroy digestive enzymes
All acids destroy salivary amylase, the starch-splitting enzyme in the saliva, and thus arrest starch digestion in the mouth and stomach. Even those acids that are valuable as food, such as the acids of pineapples, grapefruit, oranges, tangerines, lemons, limes, tomatoes, apples, grapes, peaches, cherries, etc., destroy the amylase of the saliva and arrest the digestion of starch. For this reason, such foods should not be eaten at the same meal with starches-potatoes, bread, cereals, le gumes (beans and peas),Jerusalem artichokes, carrots, cauliflower, parsnips and similar foods.

Acids inhibit the secretion of gastric juice, hence they suspend or retard protein digestion in the stomach. These fruits should not be eaten with protein foods-such as eggs, flesh, cheese, nuts, etc. They make a better combination with nuts and cheese than with flesh and eggs for the reason that the cream in cheese and the oil in nuts also inhibit gastric secretion, and the taking of acid foods with these foods does not inhibit the secretion of gastric juice more than does the fat. Nuts and cheese still combine better with green vegetables.

Alcohol and cooking ingredients interfere with digestion
I have mentioned above that by precipitating the pepsin of the gastric juice, the enzyme that initiates protein digestion, alcohol impairs protein digestion. There are many other substances that destroy pepsin. Extensive tests have shown that the residues left in bread by baking powders retard the digestion of protein. Although most of these tests were made with cream of tartar powders, no powder seems to be exempt from this effect. Baking soda also destroys pepsin and retards gastric digestion. Many drugs both acids and alkalies, have been used with which to reduce weight because they retard digestion.

Anything that either inhibits the secretion of the digestive juices or that alters their chemistry, or that destroys their enzymes, will retard or suspend the process of digestion. It is important, therefore, that we take nothing with our foods that either alters the acid-alkaline reactions of the digestive fluids, inhibits their secretion or destroys their enzymes. It is also important that we refrain from taking foods at the same meal that either directly or indirectly interfere with the digestion of each other.

Tea, coffee and condiments cause indigestion
Tea and coffee, not alone because of the toxic substances which they contain, but also because of the sugar that is commonly taken with them, inhibit the digestion of foods in-the stomach. They are common causes of indigestion. Condiments of all kinds also, because of the irritation of the stomach which they occasion, inhibit stomach digestion. As they are indigestible and occasion irritation throughout the whole length of the digestive tract, it is likely that they also inhibit intestinal digestion. Salt inhibits stomach digestion, also. There are a number of products widely so1d in health food stores, that consist of powdered vegetables, some of them containing highly salty sea weeds, others with salt added. They are used with which to make broths and they are sprinkled on salads and other foods as seasonings and supplements. They inhibit stomach digestion, sometimes for hours.

Onion family causes digestive problems
There is no reason to doubt that all the members of the onion family-onions, garlic, leeks, shallots, chives, etc. -as well as radishes and all other foods containing appreciable amounts of mustard oil, because they occassion irritation of the stomach and intestines as they occasion irritation of the mouth and throat, inhibit digestion. Horseradish and mustard are especially strong in occasioning irritation, but ordinary white and red radishes occasion considerable irritation. There seems to be no good reason why we should eat such items.

It seems that it is the part of wisdom to refrain from eating practices that retard, inhibit and impair digestion, rather than to eat in the indiscriminate and haphazard manner that is common and then resort to drugs to pal liate the resulting discomfort. To avoid discomfort by avoiding its cause is certainly preferable to deliberately inviting trouble and then seeking to palliate it with drugs that are worse in their damaging effects than the foods, food additives and combinations that are responsible for the initial trouble.

Nature does not mix foods
The eating of complex mixtures of foods is not seen in nature. Animals not only stay strictly with the foods to which they are constitutionally adapted (those to which their digestive secretions and processes are specially adapted) but they refrain from mixing these indiscrimin ately.

Man mixes foods from all sources. He will combine in one meal the diet of the tiger (carnivore),that of the pig (omnivore),that of the sheep (herbivore),that of the bird (graminivore) and that of the primate (frugivore),and expect such a combination of foods to be as speedily and as efficiently digested in his stomach as the tiger's diet is digested in the tiger's stomach and the sheep's diet is digested in the stomach of the sheep. On the face of it, it would seem that however great is the adaptive capacity of the human digestive tube, it would not be capable of adjusting its digestive secretions to so many different types of diet at one and the same time.

Why should we expect the human digestive tract to be able to efficiently digest such meals? It is often asserted that "normal (human) digestive tracts have been coping with such combinations for centuries without a whim per," but such a statement is based, not on fact, but on ignorance of the history of mankind's eating practices as well as upon an ignoring of the facts of contemporary human suffering. Present-day eating practices are not centuries old. The meals of man, until very recent times, have been very simple and have consisted of but two or three articles of food. With several notable exceptions, even the meals of the wealthy classes have been very simple when compared to the eating practices of today.

Mono meals ideal
That the human digestive tract copes with such combin ations today without a whimper is simply not true. Indeed, the whimpering assumes the proportion of a loud national groan. Viewing the eating practices of the lower animals, we observe the utmost simplicity. "Every animal keeps to one dish-herbs are the food of this species-fish of that- and flesh of a third," wrote an early Hygienist, who advised: "Be content with one dish at a meal, in the choice of that consult your palate."

Certainly the human digestive tract, like that of the lower animals, can make a far more complete and efficient adjustment of its secretions to the character of the food eaten if but one food is eaten at the meal. It may turn out in the long run that all of our efforts to work out compatible food mixtures is an effort to stray away from the simple path of nature without suffering.


VIP Member
Dec 23, 2010
interesting read but I can't verify its accuracy with no footnotes.


Jun 7, 2012
Love raddishes with roast beef. Interesting about acids & carbs.


Mar 30, 2014
very interesting read indeed. Def would like footnotes though