by Dr. Lawrence Wilson

© September 2019, L.D. Wilson Consultants, Inc.


All information in this article is solely the opinion of the author and is for educational purposes only.  It is not for the diagnosis, treatment, prescription or cure of any disease or health condition.






A Major Liver Toxin



Fermentation In The Intestinal Tract

Fermentation In The Blood

Fermentation In The Tissues



Allergic Effects

Reduced Oxygenation

Vitamin B1 Deficiency

Other Possible Symptoms Of Aldehyde Overload








Definition. Aldehydes are toxic chemicals produced by fermentation of sugars.  They are produced by yeasts and fungi, which are called fermenting organisms.

Aldehyde poisoning is the second most common source of severe liver toxicity and ill health today.  Many people have a severe problem with aldehyde toxicity.




Some aldehydes are made inside the body.  Others come from eating fermented foods.




Digestive fermentation.  If a starchy or sweet food is not thoroughly digested and absorbed, some sugars remain in the intestines.  Fermenting organisms that live mainly in the large intestine ferment the sugars and produce aldehydes and alcohol.  Both are potent liver toxins, especially acetaldehyde.

The design of the large intestine prevents most of the toxins produced by fermenting organisms from being absorbed.  Therefore, this source of aldehydes is not as harmful as the ones described below.

One can tell if one has fermentation occurring in the large intestine because, among other chemicals, it produces methane gas.  This is a type of intestinal gas that is not too smelly.  In contrast, putrefaction of proteins, peptides and amino acide in the large intestine produces very foul-smelling gas.


Fermentation in the blood.  Once sugars are absorbed into the bloodstream, they circulate until they are absorbed in the liver.  Some people have fermenting organisms in the blood itself that convert sugars into aldehydes in the blood.

This is quite dangerous because the blood does not have any protection against the aldehydes and other toxic chemicals that fermentation produces.

As a result, fermentation of sugars in the blood is a very serious form of yeast infection that often kills the patient.

This problem is much worse in those with an elevated blood sugar.  One need not have full-blown diabetes.  Any elevation of the blood sugar worsens the problem of fermentation in the blood.

One can tell if this is occurring because the person will smell yeasty, which is a sour odor.  Women often know this odor because it occurs in the vagina when they have a yeast infection there.  This is an example of the next type of fermentation problem.


Fermentation in the tissues.  In many people, too much sugar goes to the tissues.  Eating sweets of any kind tends to produce this problem.  These sugars feed fermentative organisms such as yeasts and fungi, which then produce aldehydes and other toxic chemicals.

Common locations for these yeast infections are the sinuses, vagina, mouth, ears and occasionally other areas of the body.

This source of aldehydes is far more important and serious if one has high levels of AGES in the body.  These are advanced glycation end products and are sugar molecules bound to larger molecules, mostly proteins and fats or oils. 

Since AGES contain sugar, they feed fermentative organisms wherever they are located in the body.  Many, for example, accumulate in the liver and one can have fermentation inside the liver, which is also very dangerous.




The other source of aldehydes is from eating certain fermented foods.  Fermenting a food is a way of preserving it, in some cases, and cultures have used this method for millennia.  Today, however, some authorities suggest eating these foods to improve digestion and for other reasons.

Fermented foods have a number of problems.  They are raw foods, they are very yin, and some cause aldehyde toxicity.  

Foods that are very high in aldehydes include Rejuvelac, apple cider vinegar and kombucha tea.  Some home-made fermented foods are also high in aldehydes.  Our suggestions about eating fermented foods are:

1. Only small amounts.

2. The only acceptable fermented foods are those that are very low in aldehydes.  These are most cheese, yogurt, kefir, miso, sauerkraut and occasional use of tofu or tempeh.  These appear to be safe, when eaten in small amounts.  Please completely avoid the others.

3. Adults may only have a total of 4 ounces daily of cheese, yogurt and kefir combined.  In other words, if you eat four ounces of cheese in a day, then you may not have any more diary products at all.

For more about fermented food, please read Fermented Foods on this website.

While foods can be an important source of aldehydes, in most people the main source is fermentation due to too many sugars and carbohydrates in the diet.




According to a 2005 article in Crit Rev Toxicol. 2005 Aug;35(7):609-62.  Aldehyde sources, metabolism, molecular toxicity mechanisms, and possible effects on human health by O'Brien PJ, Siraki AG, Shangari N., Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada., the toxic effects of aldehydes are many.

They can include acting as haptens in allergenic hypersensitivity diseases, respiratory allergies, and idiosyncratic drug toxicity; the potential carcinogenic risks of the carbonyl body burden; and the toxic effects of aldehydes in liver disease, embryo toxicity/teratogenicity, diabetes/hypertension, sclerosing peritonitis, cerebral ischemia/neurodegenerative diseases, and other aging-associated diseases.

Red blood cell alteration.  Acetaldehyde alters red blood cell structure. It has been known since 1941 that acetaldehyde easily combines with red blood cell membrane proteins to convert the red blood cells into a "time-release capsuleÓ, releasing the acetaldehyde in the body far from the site where it attached to the red blood cell (3).

As this happens, however, the membrane covering the red blood cell becomes stiffer.  Yet in order to travel through the capillaries, which are the smallest blood vessels and which feed the trillions of individual cells, the red blood cell must be able to fold or deform. The average red blood cell diameter is 7 microns; yet a typical capillary is only 2 microns in diameter.

Red blood cells stiffened through chronic acetaldehyde exposure will have difficulty deforming sufficiently to pass through capillaries.  Consequently, red blood cell-carried oxygen to many cells is reduced. (3) (Our brains require 20% of all the oxygen we breathe!)

Other reasons for reduced oxygenation.  The work of K.K. Tsuboi and colleagues has shown that acetaldehyde forms stable combinations with hemoglobin in red blood cells. This reduces the ability of red blood cells to accept, hold, and transport oxygen through the bloodstream, which is their primary function. (5)

Effects on the brain.  Acetaldehyde decreases the ability of the protein tubulin to assemble into microtubules. (6) Microtubules are long, thin, tube-like structures that serve several functions in the brain cell. They help provide structural support to the nerve cell, somewhat like girders in a bridge or a building, keeping the nerve cell and the dendrites semi-rigid.

Dendrites are the feathery-looking extensions from the main body of the nerve cell that connects nerve cells to each other. Some neurons connect through dendrites to as many as 100,000 other neurons.

Microtubules also serve to transport nutrients and biochemical raw materials manufactured in the cell body to the dendrites. When this raw material transport is compromised, the dendrites will gradually atrophy and die off.

Two classic examples of brain pathology involving degeneration of the dendrites in humans are chronic alcoholic brain damage and Alzheimer's disease.

Vitamin B1 deficiency.  Acetaldehyde can cause a deficiency of vitamin B1 or thiamin.  Vitamin B1 is so critical to brain and nerve function it is often called the "nerve vitamin." The work of Dr. Herbert Sprince, MD(7) showed that acetaldehyde has a very strong tendency to combine with vitamin B.  Unfortunately, in detoxifying acetaldehyde, vitamin B1 is destroyed.

Wernicke-Korsakoff syndrome.  Moderately severe B1 deficiency in humans leads to a group of symptoms called Wernicke-Korsakoff syndrome.  This syndrome is characterized by mental confusion, poor memory, poor neuromuscular coordination, and visual disturbances.

Its primary accepted cause is chronic alcoholism.  Vitamin B1 is also necessary for the production of ATP in all body cells including the brain.  The brain uses between 20% and 50% of the body's total energy, even while asleep.

Vitamin B1 is also essential for the production of acetylcholine.  Acetylcholine is one of the brain's major neurotransmitters, facilitating optimal memory, mental focus and concentration, and learning. 

Alzheimer's disease represents a rather extreme case of memory loss and impaired concentration.  This can be due to destruction of acetylcholine-using brain cells.

In a classic experiment reported in 1942, R.R. Williams and colleagues found that even mild B1 deficiency in humans continued over a long period of time (the experiment ran six months) produces symptoms including apathy, confusion, emotional instability, irritability, depression, feelings of impending doom, fatigue, insomnia, and headaches, all symptoms of less-than-optimal brain function.




Common symptoms associated with aldehyde toxicity are:

Yeast or fungal infections

Sugar craving

Skin problems

Sinus problems (fungal overgrowth)

Low thyroid

Gas and bloating

Epstein-Barr virus syndrome

Copper symptoms: headache, easy bruising, mind racing, brain fog


Many poor or very poor eliminator patterns on the hair test

Sympathetic dominant

Sugar and/or carbohydrate addiction




Lowering the level of aldehydes in the body mainly requires reducing starches and all sugars in the diet.  This includes reducing or eliminating fruit, candy, ice cream, pastries, cookies, candy and sweet drinks such as soda pop and juices.

This is usually sufficient to enable the body to slowly get rid of stored aldehydes.




1. Cleary, J.P. The NAD Deficiency Diseases. J Orthomolecular Med, 1986, 1:164-74.

2. Galland, L.D. Nutrition and Candida Albicans, 1986 A Year in Nutritional Medicine, ed J. Bland. New Canaan :Keats Pub., 1986, 203-238.

3. Truss, C.O. Metabolic Abnormalities in Patients with Chronic Candidiasis: The Acetaldehyde Hypothesis. J Orthomolecular Psychiatry, 1984, 13:66-93.

4. Levine, S. and Kidd, P. Antioxidant Adaptation, pp. 70-71. San Francisco : Biocurrents Pub., 1986.

5. Tsuboi, K.K. et al. Acetaldehyde-Dependent Changes in Hemoglobin and Oxygen Affinity of Human Erythrocytes. Hemoglobin, 1981, 5:241-50.

6. Tuma, D.J. et al. The Interaction of Acetaldehyde with Tubulin, in: Ann NY Acad Sci, ed. E. Rubin , Vol. 492, 1987.

7. Sprince, H., et al. Protective Action of Ascorbic Acid and Sulfur Compounds against Acetaldehyde Toxicity: Implications in Alcoholism and Smoking. Agents and Actions, 1975, 5:164-73.

8. Williams, R.R., et al. Induced Thiamin (Vitamin B1) Deficiency in Man. Arch Int Med, 1942, 69:721-38.



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