ANCESTRAL EATING: The Case for Raw Food (and Failing That, Gelatin)

Francis Pottenger on "hydrophilic colloids"

We’ve already encountered Francis Pottenger in our earlier instalment on his raw-food experiments with cats. If you want to get up to speed on who Pottenger was and what he did—the TL;DR is that he was a highly respected doctor with significant clinical experience—read the introduction of that earlier piece.

Here I’m reproducing a speech Pottenger gave in the later 1930s on the subject of “hydrophilic colloids”, which he maintained are an essential structure of foods in their raw state. Hydrophilic colloids are much easier for us to digest, and therefore foods in their natural state are perfectly suited, more or less, to digestion. The problem comes when we cook foods and disturb their colloidal structure. Suddenly they become more difficult to digest and less nutritious.

Now, this runs totally contrary to what we’re generally led to believe about the digestibility and the nutritional content of raw vs. cooked foods. We’re told, for example, that the “invention” of fire and therefore cooking was a trigger for a great evolutionary burst among our ancestors because it allowed them to absorb more nutrition from their foods and therefore grow bigger brains. But there’s actually good reason to believe that what cooking really did and does is make food—especially meat—quicker to eat, rather than making it more nutritious. And there’s also good reason to believe that the “trigger” event for the massive growth of the human brain wasn’t cooking, but probably something else, much earlier. Read this piece about fermentation’s potential role in human evolution if you want to understand some of the problems with the “cooking” theory.

What’s particularly interesting about this speech by Pottenger is his recommendation that gelatin should be added to a modern cooked diet in order to restore the balance of hydrophilic colloids. This is pretty close to the advice given by Ray Peat, which we’ve also looked at in a piece about gelatin.

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Hydrophilic colloids form the substratum of all living protoplasm. They possess the property of readily taking up and giving off the substances essential to cell life. Precipitation of the hydrophilic colloids of protoplasm causes cell death.

PHYSIOCHEMICAL CONSIDERATIONS

Man's food in the raw state consists largely of hydrophilic colloids. The heat of cooking on the other hand—to mention only the physiochemical change— precipitates the colloids of our diet. This change in colloidal state alters the hydration capacity of our foods so as to interfere with their ability to absorb digestive juices. The amount of interference depends upon both the degree of thermo-concentration and the specific character of the colloidal medium itself. Certain colloids will withstand more heat than others; for instance, cellulose of vegetable origin and certain pectins will stand a greater temperature without being precipitated than the proteins of animal origin.

Any hydrophilic colloid, be it living protoplasm or a mineral jell, has a certain hydration capacity under given conditions. By varying the physiochemical conditions surrounding such a colloid, it may be made to expand or contract. In the laboratory the expansion and contraction of colloids can be controlled within set limits at will.

Familiar laboratory experiments dealing with the absorption of chemicals and fluid by hydrophilic colloids are the experiments described by M. H. Fischer. If two gelatin squares of similar weight are immersed in finger bowls, one containing distilled water, the other a solution of hydrochloric acid of 1/100 normal concentration, we find two interesting phenomena. First, the gelatin square in the acid expands at a much greater rate than the square in the water. Second, the solution about the square in the acid medium becomes almost of the same hydrogen ion concentration as distilled water. Now, if tile acid solution is made stronger, the gelatin is digested, making a colloidal suspension, and unless too great a concentration of acid is present the acidity of the solution approaches neutrality. On the other hand, gelatin precipitated by heat fails to take up water or acid.

PHYSIOLOGIC APPLICATION

If man did not cook his food, there would be no need for the addition of any hydrophilic colloid to his dietary. Uncooked foods contain sufficient hydrophilic colloid to keep his gastric mucosa in excellent condition. On the other hand, man living largely on cooked foods presents a different problem. Recall the description of the stomach contents so vividly described in medical school days, as consisting of several layers, each layer assuming its position by virtue of its specific gravity; meat first, then vegetables and fruits followed and interspersed by the mashed potatoes, and last the water layer with its scum of fat; and how this was churned around and had poured into it sufficient gastric juices to digest the meal in one and one-half to four hours if all was well. If such gastric contents are removed and examined, the aqueous layer is found to be strongly acid, the degree differing with the individual. The digestive action takes place between the food particles and the gastric mucosa, which to be sure does not digest itself.

If we give a similar meal to another man, adding to it a hydrophilic colloid of excellent hydration capacity, let us say 1/2 to 1 ounce of gelatin, a definite change takes place in the contents, and if they are withdrawn for analysis, a gluey mass is recovered. It is not sour as would have been the contents of the stomach which did not contain gelatin; and on the contrary it does not show any acidity till 'the colloid is broken down. Under these conditions, digestion is quite generally distributed throughout the mass.

The gelatinous mass that results from the ingestion of a prepared hydrophilic colloid such as gelatin is formed more quickly than is the case when such raw foods as fruits and vegetables are used, which must first take up the digestive juices and then be partially digested before the mass develops. Raw meats apparently become gelatinous in less time than vegetables. But, as digestion proceeds, all raw foods become more or less gelatinous before liquification takes place. In case of cooked foods, gastric digestion is also directed toward the liquification of the stomach contents, but it is interfered with by the fact that the heat of cooking has precipitated the colloids.