Autor: Julio Cesar Tafforelli | Publicado: 2011-08-18T14:49:00-07:00

The food enzyme theory in a nutshell

Howell's theory of "food enzymes" as discussed in the above two books basically proposes the following:

That the enzymes present in raw foods are of significant help in digesting the foods themselves once they are put into the human digestive system.  
That cooking destroys these "food enzymes," forcing the body to produce more of its own digestive enzymes than would otherwise be necessary to digest the food.  
That the body has a finite lifetime "enzyme potential" for manufacturing digestive enzymes,  which is important for preserving health and longevity; and a portion  of which is unrecoverably "used up" in producing otherwise unnecessary  digestive enzymes each time cooked foods are eaten.  
That enzymes in raw food also carry the "life force,"  which can be transferred to the body, enhancing vitality and longevity;  and that the body must use up some of its own "life force"/"enzyme potential" to compensate whenever cooked foods (that have no life force/live enzymes) are eaten.  
In a nutshell, those are the primary elements of Howell's "food enzyme"  theory. It is basically a hybrid two-part theory, part hypothetical  science, part mystical theory. The first three bullet points above put  forward the physiological elements of the theory; the fourth bullet  proposes a mystical element that is, ultimately, unverifiable by  experimental method, thus unscientific. In one sense, if the principle  of Occam's Razor were to be employed, the fourth bullet could be pared  away from the theory as entirely unnecessary, since it is essentially a  redundant duplication (one restated in mystical terminology) of the  physiology proposed in bullet point number three.

Reference sources for theory are outdated. Although both Howell books proposing the food-enzyme theory are dated, they are still among the most often-cited references in raw-food  circles. In the 1946 book, for example, most scientific references  cited are from the 1920s and 1930s. (By the way, isn't it startling that  three major raw-foodist references are more than 50 years old--leukocytosis,  Pottenger's cats, and Howell's 1946 book?) As we proceed, we'll see  several examples where Howell's claims are based on such outdated  science (which is still harked back to by his proponents today) as to  completely invalidate a claim by that very fact, let alone the logical  problems which also riddle much of Howell's theory.


 Example of diversionary tactics that may be engaged in by present-day promoters of Howell's theories

Just as relevant to our discussion of Howell's "food enzymes" theory  besides Howell's own writings, though, are the flavor of the arguments  made by raw-foodists who promote Howell's theories today. To begin  our discussion, let's take as one example a debate over Howell's enzyme  theories that occurred on the Veg-Raw email list (currently defunct) in  May and June of 1998, to give an up-to-date illustration.

Two commonly encountered logical fallacies.

In this debate, the supporters of Howell's theories engaged in two  major logical fallacies that typify the kind of reasoning commonly  offered in defense of his theories. First, when asked for credible  evidence for the claims of Howell, his proponents asserted that such  proof was in fact provided in the unabridged (rare, perhaps privately  published) 700+ page version of Enzyme Nutrition, quotes and/or  evidence from which no one was able to produce because no one had  actually seen a copy. One might as well claim that the unabridged  version has credible proof that the earth is flat, i.e., such claims are  pure speculation. Claims that aspire to be scientific (including the  enzyme theories of Howell) require credible scientific evidence, not  "vaporware" proofs based on evidence that advocates themselves admit  they have not yet seen, or can produce, even at the very same time they  claim it exists.

Second, the supporters of Howell's theories made the common rawist error  of adopting an unproven theory, and then aggressively demanding that  others disprove it. By all logical standards of evidence, the burden of  proof rests on those who propose a theory to provide evidence for it; a  burden the rawists here would apparently have preferred to be able to  reverse or escape. Thus, those who advocate speculative claims, such as  the ones Howell put forward, are logically required to provide  reasonable proof, and as we shall see below, the proof provided is not  adequate.





  With that as preface, let's now look at the main arguments by Howell  "proving" that food enzymes are important for human health, and the  weaknesses of these arguments. It will appear that, in fact, "food  enzymes" (meaning enzymes present in foods before they are eaten, as  opposed to digestive enzymes produced by the body) play a very minor  role in our health, if any.  
 CLAIM: Enzymes are not merely catalysts. They contain the "life force," which is subtle and unmeasurable. Once the body's enzyme potential has been used up, we die. Therefore, preserving our enzyme potential will ensure longevity.

COMMENT: First  let's note that, in the form it's asserted, the above claim constitutes  assuming to be true what insteads needs to be demonstrated/proven  via evidence (and not simply assumed).

That there is an "enzyme  potential" needs to be shown by evidence, yet here it is instead assumed  at the beginning without proof. This is unfortunately a common logical  fallacy in much of rawist thinking.

That enzymes are held to be the "life force" is mystical, not scientific.  If the author starts with these particular assumptions, one must  question the scientific value of their reasonings. One of the most  fundamental axioms in science is that the components of a theory must be  at least in principle "falsifiable" to qualify as science in the first  place. (That is, the components have to be capable of being observed and  in principle testable for truth or falsity by physical observation or  measurement.)

If one cannot physically observe or measure something, then it is not  amenable to scientific testing, and advocates can basically affirm  anything they want with regard to it, no matter what experimental  results are gotten, since there is no scientific way to confirm or  disconfirm something allegedly immaterial. Therefore, if one claims that  enzymes contain a "life force" that transcends their measurable  physical characteristics, then it is by definition a mystical assertion  and not a scientific hypothesis.

Enzymes ARE catalysts, in the broad  sense (i.e., they speed up a chemical reaction, or allow a barrier of  potential to be crossed, and are left unchanged after the reaction has  occurred). The mode of action of various enzymes has been described by  scientists--there is nothing mysterious. Anyone not convinced by  the last statement is invited to check out a textbook about enzymes in  any university library.

Enzymes are not the "life force," and the idea that we have a certain  "quantity of life force" at birth, and that by eating "living foods" we  can increase our life potential (or at least preserve it) is naive and  unproven. No one has ever measured any enzyme potential (in the sense  that Howell understands it); and, according to modern theories of aging,  such processes as cumulative oxidative damage to tissue, the decreasing  length of telomeres with each cell division, and other known processes  currently under investigation, rather than enzymes, are the most likely  reasons for the process of aging.

Howell postpones his proof of an "enzyme potential."

It should be added that the logical organization of Howell's books  suffers greatly from the fact that he postpones the "proof" that the  body has a limited enzyme potential, and some arguments in the first  chapters rely on that assumption. Since, as we shall see, his proof of  the existence of an enzyme potential is seriously flawed, these  arguments become invalidated.

Side note in regard to Kirlian photos.

Raw advocates often cite Kirlian photos that compare cooked and raw  foods as evidence of the "life force" in raw foods. Kirlian photos do  show something, but there is no evidence that they are somehow photos of  a (subtle and/or mystical) "life force."

The logical, plausible explanation for Kirlian photos is that they show  the effects of a type of corona discharge (the same phenomenon that  produces lightning). The power of such a discharge will depend on  moisture content (which in humans may vary with stress, e.g., sweating)  and other relevant physical factors.

A corona discharge effect depends on ionized gases that result when a  small electric current is applied to the object being photographed.  Cooked foods have been heated, and heating can cause a loss of ions via  steam and compounds dissolving into the water used in cooking (and the  cooking water is usually discarded). Hence one would expect Kirlian  photos of raw foods to have a stronger corona discharge than similar  cooked foods.

Even more telling, if Kirlian photos were actually the "life force"  instead of a corona discharge effect, one would expect there to be no  difference between Kirlian photos taken in a vacuum (where there are no  ionized gases to create the corona discharge effect), and photos taken  in normal atmospheric conditions. However, Kirlian photos taken of an  object in a vacuum show no "aura." Thus we conclude that Kirlian photos  do not show the "life force" or "aura," and are not credible evidence in  comparing raw and cooked foods.




   Food enzymes act in the mouth and in the upper stomach, before our own enzymes have begun to digest the food.  A few enzymes are left undestroyed by the stomach acids and are  absorbed by the intestine. Thus, eating raw food will preserve the  enzyme potential.
&nbsp;The impact of pre-digestion by salivary enzymes is small.

Tortora and Anagostakos [1981, p. 628] note:

 Even though the action of salivary amylase may continue in the stomach,  few polysaccharides [carbohydrates] are reduced to disaccharides by the  time chyle [the mass of food and digestive fluids in the stomach] leaves  the stomach. Also, Tortora and Anagostakos [1981, p. 629] report that  90% of all nutrients are absorbed in the small intestine. Further,  digestion in the small intestine relies on bile and pancreatic enzymes,  as a large part (but not 100%) of the food enzymes are destroyed in the  stomach prior to the food reaching the small intestine. The above quote,  coupled with the 90% absorption figure, suggests by extension that  enzymes in raw food are of very limited nutritional significance.

Certainly cooking destroys enzymes in food, but may improve digestibility for other reasons.

Indeed, as we saw earlier, cooking sometimes alters the cell structure  so that the nutrients become more accessible to our own body's digestive  enzymes (such as by gelatinizing starch), or destroys anti-amylases or anti-proteases. Thus, in many cases, cooked food actually requires less enzymes for digestion than raw food.

Digestive enzymes, like any catalyst, are reused/recycled multiple times.

Thus, any supposed "savings" (of energy, or of a proposed "life force")  in the production of digestive enzymes to make up for food enzymes lost  to cooking (assuming the latter are of much use to digestion in the  first place) would be very small and mostly illusory given that enzymes  are reused during digestion anyway. (Note: Tortora and Anagostakos  [1981, pp. 46-47] discusses reuse of enzymes.)

Instances of decreased digestibility from cooking are primarily due to reasons besides enzymes.

It should be added that, when cooking does decrease digestibility, it's  often not because food enzymes have been destroyed. There are many  examples (see above) of foods whose protein digestibility decreases only  at temperatures much higher than 100°C (212°F). But obviously, enzymes  are already destroyed at 100°C. Also, protein availability may decrease  (slightly) because of the Maillard reaction, which has nothing to do  with enzyme denaturation. So it is not true that cooking necessarily  demands more enzyme production by the body, and it's also not true that,  in the cases where cooked food is less digestible, the effect can be  attributed to enzyme destruction.

Finally and more importantly, the idea that the body has a limited  enzyme potential is, to say the least, dubious. Digestive enzymes in  food are just what they are: a possible help in digestion. Obviously  enzymes do indeed help--inside or outside the body: ripening of  fruits, sprouting of seeds, legumes and grains, and aging of meat are  examples of important actions of enzymes that occur prior to  consumption. But some types of food processing can also improve  digestion, including cooking in some cases.