It has been a few years since these requests have been made, but the issue of Food Combining has come up several times recently and as such, I went to my old files and found the original article. This article was composed from several discussions on message boards and from emails on the topic during April 1997.
Except for cleaning it up a little, mostly in regard to spelling and grammar, I am leaving most all of it as written 17 years ago. Clearly, the references I listed have been update since, but the information in them will be fairly much the same in regard to the physiology and biochemistry of digestion and only further supporting my position.
Hopefully, one day I will update the references and the quotes.
In Health
Jeff
THE PHYSIOLOGY AND BIOCHEMISTRY OF DIGESTION: Is Food Combining Justified?© Jeff Novick, MS, RD, LD
April 1997
In recent years the American Natural Hygiene Society (ANHS), now known as the National Health Association, has liberalized its stand on food combining. Their present position states that it can be an effective means to prevent overeating. At the 1998 ANHS conference Dr Joel Fuhrman said that it was not important and wouldn’t add a year to your life. Harvey Diamond relaxed his stand and said that it may work for some people but not for everyone. Yet, amongst the natural hygienists and raw food communities, it is still adamantly promoted and followed. Well, does food combining work? Is it scientifically valid? And why or why not? Lets find out.
The basic principles of physiology and biochemistry of digestion that Shelton (and others) based their "rules" of food combining on were based on an incorrect and limited understanding of human physiology and biochemistry. I will just give a general overview of why that is so.
To begin with, lets look at the process of digestion and in doing so, lets look at it in relation to the four main areas that digestion takes place, the mouth, the stomach, the small intestine and the large intestine.
In the mouth the primary digestion that takes place is mechanical through the teeth, tongue and the chewing of our food. Besides the mechanical breakdown from chewing, the only real biochemical digestion is from salivary amylase, which is secreted by the salivary glands. It is a precursor and a preparatory step for the real starch digestion that happens later. And it works best in an alkaline environment. It is not where much starch digestion really takes place. The amylase works just to break down some larger starch molecules into smaller ones by breaking the bonds in the chains of the starch. Additionally, there is some lingual lipase that is released, mostly in infants (due to the high fat content of breast milk), but it does little to digest the fats we may eat.
The stomach is set up mainly to begin protein digestion by breaking the larger proteins into smaller ones and it does so in an acidic environment, though nowhere near as acidic as a carnivores. This is not the major site of protein digestion. The stomach however, is made up of a very strong musculature and also changes the mass of food that we swallowed from a bolus of food into something called chyme through the powerful churning and contractions and mixture with fluids. There is no other chemical breakdown that is either designed to happen or supposed to happen. Not for fats or for starches. No enzymes for the digestion of fat and/or carbohydrates are released. The system however, is designed to hold both fats and CHO’s in limbo while they get churned up and await their real digestion. And if we are eating normally and rationally, this will happen pretty quickly without the fermentation that the proponents of food combining say is supposed to be so rampant but no one seems to be able to document.
This chyme is then released (~ 5 ml at a time, about 1 tsp) into the first part of the small intestine where the acid is immediately neutralized and changed to a slightly alkaline environment again. Additionally, bile is released to act as an emulsifier for the fat molecules. This is also where the chemicals and enzymes for the major digestion of fats, starches and proteins happen, all together. It’s truly an amazing event. Many specific types of enzymes are released that act on specific substances and it all happens together in this alkaline environment. This is where the real complexity and wizardry of the process really happens. The other areas where just preparatory stages for this part. This is where most of the digestion really happens and it all happens together, fat, protein and starch and all in the same environment, which is slightly alkaline. Even for the protein!
Now, there are a few things that can really mess up or negatively influence this system that we know about for sure. One is a large amount of fats. It will slow the whole process down because the digestion of fat is very difficult, complicated and takes a long time. So there are actual chemicals released (CCK) that signal the system to slow down so it can have the time to work on the fat. It can take up to 4 hours or more.
Drinking with meals can also interfere somewhat depending on the fluid and its temperature, osmolality, etc.,
Stress and anxiety can and will shut the whole thing down. And cause a decrease of the secretions and blood flow that is necessary.
And another one and maybe THE big one... you guessed it, ****overeating*****!! Messes up everything including timing, chemicals, coordination, etc., etc., and it causes distention and problems in the whole process especially in the stomach .
So, why does food combining seem to work so well for those who espouse it? Probably because when practicing food combining they also usually stop overeating (relatively speaking), cut down on the fats, stop drinking with meals, and eat simpler meals all of which have been shown to be helpful. It is also much easier to overeat on cooked, processed, refined, foods then on whole natural raw foods.
So, a lot of what Shelton (and others) said may be accurate somewhat in theory, but it may not actually hold water for the reasons he gave. Starch and protein where never meant to be digested together in the stomach and the system is set up to take care of that as there are some natural foods that do contain both and sometimes in significant concentrated amounts. Or were they a flaw in nature?
Food combining, (from my understanding of it, and my conversations with many of the Natural Hygiene professionals who have come before us) was originally designed and set up NOT for the true practicing Natural Hygienist (who wouldn’t really need it anymore due to the simplicity of their diet), but for the person in transition who was still eating all the "other" stuff, to help ease and simplify their dietary practices and meals and too reduce their dietary atrocities. That’s why except for his little book on it, which if you check out the recipes, aren’t very hygienic to begin with, he never really promoted it. It’s everyone else who has. What role does food combining really play when we are already eating mostly simple healthy meals anyway!
The info someone also just posted about achloridosis in humans has been coming to light more and more lately. Especially in the elderly though many middle age adults are also showing it. Seems we have stomachs that aren't doing what they are supposed to be doing in the area of digestion. My guess (and this is a guess) is because of the years and years of overstressing the system with highly concentrated proteins, which overworks and overstresses the acid mechanisms and components. Overuse becomes wear and tear that leads to breakdown and deficiency.
Also remember, (still my theory here)
, another problem is that we go from a conventional diet to a raw food or healthy diet and we haven’t give our system a chance to adjust. It takes a while for certain enzymes to build up their levels (if they still can) to the change. You are talking going from about 11 grams of fiber a day to about 40-60!! Holy Gas and cramping, Batman!!
So, to really improve your digestion without worrying about food combining, just make sure it is whole, natural and unprocessed food, keeping variety simple, chew your food really well, eat slowly, enjoy your food, and most of all RELAX, RELAX, RELAX!!
To me it seems like most of us just use food combining to complicate our lives and to see how far we can go and with what we can get away with in the area of dietary entertainment and complexity.
Keep it simple, relax, and enjoy your food.
In Health
Jeff
Question: You mentioned that for SOME of Herbert Shelton's food combining rules that he knew of no physiological backing. I am interested to know which of the rules this might be.
In Herbert Shelton’s "classic" book on nutrition, "The Science and Fine Art Of Food and Nutrition" (The Hygienic System: Vol II, 1935) in the chapter on Correct Food Combining,
P.317 STARCH- STARCH Combination
"It may be true that the starch splitting enzymes manifest a preference for one starchy food, although I have been unable to find any physiological ground for the statement...”
P. 318 TAKE MELONS ALONE
"I know of no physiological reason for this rule."
Question: ; You said, "the basic principles of physiology and biochemistry of digestion that Shelton (and others) based their "rules" of food combining on were based on an incorrect and limited understanding of human physiology and biochemistry." I would be quite interested in the studies/sources/references. Can you provide me enough info that I could explore the issue independently?
In response to your request on references/citations on food combining and digestion, I will give you just a few of my references and some quotes to get you going.
To begin with, any good advanced level (or medical) textbook on nutrition, biochemistry, physiology and/or anatomy will serve your purpose quite well. And point you in the right direction.
Some of them that I like include:
Grof JL, Gropper SS, and Hunt SM.. Advanced nutrition and human metabolism. (2nd ed). Minneapolis: West Publishing Company. 1995.
Guyton AC. Textbook of medical physiology. (8th or 9th ed). Philadelphia: Saunders. 1991.
Guyton AC. Anatomy and physiology. Philadelphia: Saunders, 1985
Ganong WF. Review of medical physiology. (16th ed). Norwlak: Appleton and Lange. 1993.
More specifically on just digestion:
Johnsohn LR, et al., eds. Physiology of the gastrointestinal tract. 2nd ed. Vols I & II. New York: Raven Press. 1987.
Walsh JH. Gastri Secretion. in: Green M. The role of the gastrointestinal tract in nutrient delivery. New York: Academic Press, 1984,3: 107-118.
Some quotes from the above references…
"Moreover, certain foods and/or food related substances appear to increase the relaxation of the lower esophageal sphincter.... manifested as heartburn... including smoking, chocolate, high-fat foods, alcohol, and carminatives like peppermint"
"another enzyme present in the gastric juice is alpha-amylase that originated from the salivary glands in the mouth. This activity retains some activity in the stomach until it is inactivated by the low pH of gastric juice."
"very little chemical digestion of nutrients occurs in the stomach for the initiation of protein hydrolysis by the protease pepsin" [JN - this only breaks down large protein molecule into slightly smaller peptides]
"most protein digestion takes place in the duodenum, however, and the contribution of the stomach to the total process is small." [JN-very small]
"normally 92-97% of the mixed American diet is digested and absorbed." [JN- and that is on a typical cooked food, poorly combined, high in fat, sugar, salt, irritants, high in animal foods, refined and processed]
"when eaten alone [food] leave the stomach [quicker]. In a mixed diet, emptying of the stomach is prolonged. Liquids empty more quickly then solids, large particles more slowly then small, & hypertonic foods or liquids more slowly then isotonic" [JN - so simple meals, chewed well]
"When protein foods are in the stomach, the pH of the gastric contents actually rises (JN - becoming less acidic) because proteins act as buffers to tie up H+. .... As protein is digested, the gastric contents gradually become more acidic... "
"CHO digestion continues in the stomach until the gastric contents become more acidic." [JN - in spite of the supposed "bad' combo]
"If the digestible CHO remained in the stomach long enough, the acid hydrolysis could reduce most of it to the monosaccharide stage. However the stomach usually empties itself before significant digestion takes place and CHO digestion takes place almost entirely in the small intestine, with the greatest activity in the duodenum." [JN - so the protein enzymes would actually help to digest the CHO, not interfere with its digestion]
"The major portion of fat digestion takes place in the small intestine." [JN - over 95%]
"Normally there is very little bacterial action in the stomach because the hydrochloric acid acts as a germicidal agent... Bacterial action is most predominant in the large intestine. Colonic bacteria contribute to the formation of gases, acids and various toxic substances, many of which contribute to the odor of the feces. The ingestion of CHO in general leads to increased fermentation in the large intestine; protein yields increased putrification. If faulty absorption in the small intestine allows large amounts of protein or CHO to reach the large intestine, bacterial action may lead to the formation of excessive gas and also of toxic substances."
"Emotional upsets, fear, anxiety, or other states that trigger the flight-or fight response, inhibit gastric [and pancreatic] secretions." [JN – Stress is an important factor]
"the only stomach function essential to life is secretion of intrinsic factor. If B12 is administered by injected, individuals can survive ... even after total gastrectomy."
"Pancreatic juice contains sodium bicarbonate which is basic or alkaline in contrast to the stomachs acid. The pancreatic juice neutralizes the acidic chyme as it leaves the stomach to enter the small intestine. From this point on, the chyme remains at the neutral or slightly alkaline pH at which ALL the enzymes of both the pancreas and intestine work best." [JN - this is where the majority of all digestion takes place, all in the same slightly alkaline environment, and all at once.]
"Receptors of the duodenum bulb are sensitive to osmolarity of the chyme, volume of the chyme present in the duodenum, and presence of acid and/or irritants in the small intestine. Gastric emptying is also partially effected by the macronutrient composition of the food. CHO and PRO appears to empty at approximately the same rate from the stomach, fat, however slows gastric emptying into the duodenum, as do many free amino acids. Complex CHO, especially insoluble fiber, decrease the rate of gastric emptying."
"The individuals particular emotional make-up and his manner of dealing with life’s day to day problems and challenges will often be reflected in the functions of his digestive tract.... It is not what he eats; it’s what is eating him that is important. Surrounding every stomach there is a person."
"The best advice is eat less at a sitting, eat slowly, chew food more thoroughly, and relax while eating." As I said in my original post....
The basic principles of physiology and biochemistry of digestion that Shelton (and others) based their "rules" of food combining on were based on an incorrect and limited understanding of human physiology and biochemistry.
So, to really improve your digestion without worrying about food combining, just make sure your diet is based on minimally processed plants, keep variety simple, chew your food really well, eat slowly, enjoy your food, and most of all RELAX, RELAX, RELAX!!
Much simpler this way!
In Health
Jeff