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Bernasek study: long-term impact of feeding flour, and bread made from flour, to rats

flour organic fresh ground

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#1 MidwestGreg

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Posted 22 June 2020 - 07:06 PM

I ran across an interesting article that referenced a study by Bernasek that looked at the effects of feeding various combinations of flour/bread to rats.


The article can be found here: https://grandpappy.org/obread.htm




In 1970 a research study in Germany conducted by Bernasek evaluated the long-term impact of feeding flour, and bread made from flour, to some rats. The flour or the bread consisted of half of the daily diet of the rats. The rats were divided in five groups as follows:

  1. Group 1: The rats were fed fresh stone ground wheat flour.
  2. Group 2: The rats were fed bread made from fresh stone ground wheat flour.
  3. Group 3: The rats were fed stone ground wheat flour that had aged for 15 days.
  4. Group 4: The rats were fed bread made with the type of flour fed to Group 3.
  5. Group 5: The rats were fed white flour without the bran and germ.

After four generations the rats in Groups 1 and 2 were still fertile and they were capable of reproducing offspring. The rats in Groups 3, 4, and 5 were infertile and they could not reproduce offspring. For reference purposes four generations of rats is considered to be about 100 years for people.

There have been several other studies on rats that were fed white bread as a part of their diet and all of those studies reported that the health of the rats declined, the life expectancy of the rats decreased, and the number of rats born dead increased, when compared to rats in the same study that were fed whole grain bread.

It is not appropriate to extrapolate conclusions from a rat study to people. However, please allow me to make a few casual observations that may or may not have any relationship to the above study.

  1. In the 21st century in the USA approximately 20% of the adult men in all age groups have a significantly reduced sex drive. In the 21st century in the USA approximately 15% to 20% of men over the age of 20 have requested medical assistance for erectile dysfunction which is the same thing as impotence. An additional 9% of adult men are naturally sterile and they cannot father children. Many men under the age of 30 have no desire to marry or to father children.
  2. From the year 1998 to 2008 in the USA sales of the prescription drug viagra steadily increased until sales peaked in 2008 at $1,934,000,000. In the year 2019 generic viagra became available. Viagra is used to treat erectile dysfunction in men.
  3. In the 21st century in the USA approximately 10% of the women under the age of 44 cannot conceive, or they have trouble conceiving, or they cannot maintain a healthy pregnancy.
  4. In the 21st century in the USA approximately 10% of adult women cannot give birth to a live baby.
  5. In the 21st century in the USA "secondary infertility" is becoming more common where a woman can successfully give birth to one or two children but then the woman can no longer conceive. The official medical explanation is that this is the result of the normal aging process. However, could this problem be due to the foods that these women continue to eat?

Many people probably know someone on a personal basis who is in at least one of the above five groups of people.

In 1872 high-speed roller mills began producing bread for sale in Britain. The new bread was stripped of its bran and germ. In 1876 the birth rate in Britain was 36 per 1,000 people. Sixty-five years later in 1941 the birth rate had declined to 14 per 1,000 people which was a 61% decrease in births. During this same time period medical care in Britain was significantly improved, including improvements in prenatal care and improvements in the delivery process. Despite these improvements in medical care, and the improvements in the quality of life for many people, the birth rate declined by 61% in Britain.

Except for the above statistics, there is no data or scientific research to support the relationship between commercially processed bread and infertility in people. However, if this relationship were scientifically documented, and if a causal effect were discovered that was linked to infertility, then it would have a devastating impact on the food industry in the form of lawsuits and the loss of future sales. It would also interfere with the agenda of those people who wish to control the worldwide population explosion.

The milling of wheat grain into flour is done at a milling facility. The flour is then shipped to a baking facility. The baking facility then processes the flour into bread. The bread is then shipped to distributors who deliver the bread to grocery stores. I could not find any data on the internet for how much time elapses from when the grain was first ground into flour, and when the flour was baked into bread at a bakery. But I suspect that more than 14 days elapse from the time the grain is ground into flour and the flour is baked into bread. If this is true, then the above study on rats has some significant implications for the bread we purchase at a grocery store even if the bread is 100% whole wheat bread with 100% of its original bran and germ.



I searched, but could not find, the referenced study. I did find it footnoted in other articles - "Bernasek, 5th World Congress on Breads and cereals, Dresden, 1970. (cited in Aubert, 1989)"


Does anyone have access to the complete Bernasek study?

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#2 MidwestGreg

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Posted 22 June 2020 - 07:20 PM

Here is another interesting article that references the Bernaske study: http://eap.mcgill.ca...tions/EAP35.htm





There are several advantages to stone-ground wheat flour. The endosperm, bran, and germ remain in their natural, original proportions. Because the stones grind slowly, the wheat germ is not exposed to excessive temperatures. Heat causes the fat from the germ portion to oxidize and become rancid and much of the vitamins to be destroyed (Aubert, 1989). Since only a small amount of grain is ground at once, the fat from the germ is well distributed which also minimizes spoilage (Mount, 1975). Nutritive losses due to oxygen exposure are also limited by the fact that stone-ground flour is usually coarser (Thomas, 1976). As expressed in The Bread Book (Leonard, 1990), stone-ground flour is preferred by many bakers and natural food advocates because of its texture, its sweet and nutty flavour, and the beliefs that it is nutritionally superior and has a better baking quality than steel-roller-milled flour. Moritz and Jones (1950) and Schultz et al. (1942) showed that stone-milled flour was relatively high in thiamin, compared to roller-milled flour, especially when from hard wheat.



Because grains contain only about 12% water (or about 0.6 water activity), they are not predisposed to spoilage. However, grinding removes the protective layers and endangers the grain's biological stability. Deterioration of sensory and nutritional qualities depends on storage conditions, such as temperature, humidity, oxygen concentration, and light exposure. The lower the water activity, the lower is the loss of vitamins (Munzing, 1987). For example, a vitamin E loss of only about 23% occurred after a 13 months of storage at a 0.6 water activity (Rothe 1963, Plasch 1984, Pelschenke 1961). In order to reduce oxidation of Essential compounds and the development of rancidity, many authors recommend storing ground flour for no more than two weeks (Solder 1984, Bruker 1984, Schnitzer 1986, Schnitzer (no year), Thomas 1982, Thomas 1986, Koerber 1986).


Antioxidants present naturally in grains (vitamin E and lecithin) help prevent oxidation of the fatty acids and the associated rancidity only for a limited time, and under 'favourable' conditions.


Glutamic acid decarboxylase, the most sensitive enzyme in the grain, is used to indicate the health of the grain. When heated or exposed to increased humidity, even under 'favourable' conditions, it losses activity very quickly in wheat. It was found to be even more sensitive in rye (Muzing, 1987).


The B vitamins are liable to be destroyed by light and air, and it also seems that other substances, still unknown, are quickly destroyed (Aubert, 1989). Other deteriorations include denaturation of lipoproteins, phospholipid hydrolysis, auto-oxidation of unsaturated fatty acids of phospholipids, polymerization within lipoproteins, browning, Maillard reaction of amino groups from phospholipids and aldehyde groups from sugars, and carotene and aroma losses (Lea, 1957; Thomas, 1976).


Lipids in milled wheat are much more susceptible to enzymatic degradation, because enzymes are incorporated into the flour with fragments of bran and germ and with microorganisms from the surface of the grain. Associated with lipid deterioration are losses of carotenoids and vitamin E (Galliard, 1983).


The nutritional importance of using fresh stone-ground grains for bread-making was revealed in the results of feeding studies in Germany (Bernasek, 1970). Rats were fed diets consisting of 50% flour or bread. Group 1 consumed fresh stone-ground flour. Group 2 was fed bread made with this flour. Group 3 consumed the same flour as group 1 but after 15 days of storage. Group 4 was fed bread made with the flour fed to group 3.


A fifth group consumed white flour. After four generations, only the rats fed fresh stone-ground flour and those fed the bread made with it maintained their fertility. The rats in groups 3 to 5 had become infertile. Four generations for rats is believed to be equivalent to one hundred years in humans.


Different ecological standards for flour storage set limits of 15 to 60 days (Picker & Pedersen, 1990), although rancidity has been detected as early as 2 to 14 days after milling (Larsen, 1988). Nutrient analysis studies are required to determine the exact nutrient losses accompanying the development of rancidity and thereafter.



In the 1940s, a flour enrichment program was instituted to compensate for wartime shortages of other foods. However, in the 'enriched' flour only the B vitamins - thiamin, riboflavin, and niacin - and the mineral, iron, were added, in amounts approximately equivalent to those removed from whole wheat (Jenkins, 1975).


Flour 'Enrichment' implies a loss of nutrients and should not be equated with wholesomeness. For approximately 20 nutrients, there is an average loss of 70-80% to in refined and enriched flour (Davis, 1981). Its consumption clearly places the body at a disadvantage, casting a burden on the rest of the diet. The addition of more nutrients to refined flour has been considered, but it is limited by, for example, the effect of some nutrients on sensitive individuals (Pomeranz, 1988).


Since research is incomplete concerning nutrient requirements, interactions, optimal ratios, and toxicities (Allison et al., 1980), many believe that the safest option is to consume flour containing the nutrients in their natural proportions.

Edited by MidwestGreg, 22 June 2020 - 07:35 PM.

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#3 MidwestGreg

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Posted 22 June 2020 - 07:22 PM




As with most raw commodities, grains included, processing is the primary means used to maintain and increase market share. Typically, relatively little time and money is invested to examine possible health implications of such processing. Concerning grains, the separation of the milling and baking industries has led to the adulteration of flour with various chemicals, as flour manufacturers have sought to maximize profits and meet customer demands. For example, removing the germ not only prevents flour spoilage, it generates profits when sold to millfeed producers and pharmaceutical companies.


For centuries, bakers have known that 'good quality' baked goods could not be made with freshly milled flour, because the dough would lack strength and resilience to trap gas. Until the 20th century it was common practice of storing flour for months to allow oxygen to condition it.


However, as well as storage costs, spoilage and insects caused losses. Chemical oxidizing agents or bleaches were developed to produce the same aging effects in 24-48 hours (Baker's Digest, 1962). They cause one of two effects: oxidation of the gluten (so less sulfhydryl groups are left to disturb disulfide bonds that need to form during dough fermentation for the bread to rise), and bleaching of the yellowish carotene pigments which could have been sources of vitamin A (Thomas, 1986; Jenkins 1975; Freeland-Graves & Peckham, 1987).


Bleaching agents did not come into use without opposition. A 1954 issue of the National Police Gazette, reports that, Harvey W. Wiley, Chief of the Food and Drug Administration early this century, won a Supreme Court decision outlawing bleaches, but he Was forced out of the FDA, and the Supreme Court order was bypassed through administrative actions. The approval of chlorine dioxide as a bleaching agent was not without protests by U.S. Army nutrition experts (Rorty, 1954).


Today, the Canadian Food and Drug Act and Regulations Division 13, B.13.001 permits the addition of numerous chemicals to white, whole wheat, and rye flours (Daniels, 1978). These include chlorine, chlorine dioxide, benzoyl peroxide, potassium bromate, ammonium persulfate, ammonium chloride, acetone peroxide, azodicarbonamide, ascorbic acid, l-cysteine, mono-calcium phosphate. Regulations also specify the acceptable levels.


The addition of a variety of chemicals to bread is also permitted in the USA, but in many European countries the use of additives is almost completely prohibited (Jenkins, 1975). In Germany, for instance, chemical oxidizing agents were banned in 1958 (Marine & Van Allen, 1972).

Nitrogen bichloride, also known as agene, was one of the earliest bleaching agents. After 40 years of use, it was finally found to cause canine hysteria, and was outlawed (Rorty, 1954). The currently most common bleaching agent is benzoyl peroxide. It must be neutralized by adding such substances as: calcium carbonate (chalk!), calcium sulphate, dicalcium phosphate, magnesium carbonate, potassium aluminum sulphate, sodium aluminum sulphate, starch, and tricalcium phosphate.


The most common maturing agent in use is potasssium bromate, and it is added with carriers such as calcium carbonate, dicalcium phosphate, or magnesium carbonate. An alternative method to oxidize the flour to cause the same improvements in bread quality, is overmixing the dough three to four times normal to bring it in contact with oxygen. The lipoxidase enzyme in wheat germ or in soya flour, if it is added, uses the oxygen to oxidize the flour (Horder et al., 1954).


In addition to the chemicals permitted to be added to flour, many more are permitted to be added to bread before baking to facilitate the manufacturing process, to produce a light texture, and to improve conservation quality. These chemicals include emulsifiers, conditioners, and preservatives (Hall, 1974). At the present time, the Health Protection Branch in Canada allows the addition of almost 30 different chemicals, in limited quantities, to flour and bread. Yeast may also contain the Yeast foods additives: calcium sulfate and ammonium chloride (Aubuchon, 1990).


Chemicals likely to be found in conventional breads include: lecithin, mono- and di- glycerides, carragheenan, calcium sulfate, calcium carbonate, dicalcium sulfate, ammonium chloride, potassium bromate, calcium bromate, potassium iodate, calcium peroxide, azodicarbonamide, tricalcium phosphate, monocalcium phosphate, calcium propionate, sodium propionate, sodium diacetate, lactic acid, calcium stearoyl-2-lactylate, lactylic stearate, sodium stearyl fumarate, succinylated monoglycerides, ethoxylated mono- and all-glycerides (Marine & Van Allen, 1972)


In Germany, propionic acid, sodium propionate, calcium propionate, and potassium propionate have been banned as preservatives since March 1988. This was in response to earlier experiments which found that rats fed these substances developed tumors. These results have been questioned, however, because the tumors were reversable. Nevertheless, the German government decided that as few additives as possible should be found in food, and therefore saw no need to reverse their decision ("Nach..." 1987, "Jetzt..." 1988).


A topic receiving more attention, as people become more concerned about the foods they eat, is food irradiation. Approval for irradiation of wheat and wheat flour for disinfection was granted in 1969 in Canada (Conference on Irradiation, Laval, Que. 1984). Wheat irradiation prevents insect eggs, larvae and pupae from developing (Vanderstoep, 1986), but may also cause nutritional damage. Vitamins damaged by irradiation include vitamin A, B1, B2, B3, B6, B12, folic acid, vitamin C, E, and K. Essential polyunsaturated fatty acids are also affected (Webb et al.,1987). Although wheat, white flour, and whole wheat flour are treated with lower-energy ionizing radiations from Cobalt-60, there is still a possibility that some compounds within the food become radioactive, although the radioactivity rapidly decays (Josephson & Peterson, 1983). Toxic chemicals called radiolytes may also form, which may cause health problems over the long term. Some adverse effects have been found related to these, but there is still much scientific uncertainty (Josephson & Peterson, 1983). Irradiation technology is a serious health hazard and environmental hazard, especially if accidents occur where it is used.

Edited by MidwestGreg, 22 June 2020 - 07:31 PM.

#4 MidwestGreg

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Posted 22 June 2020 - 07:26 PM





Since bread and wheat products are such an important part of daily food consumption, it follows that such food items be healthy and wholesome. Today's milling, refining, bleaching, enriching, and addition of various chemicals to flour and baked breads cause many scientists and medical workers to question their nutritional quality as well as their safety. There is little information on what bleaching and maturing agents do to the flour other than meet bakers' criteria, and toxicology tests may not realistically assess the dangers, since chemicals are tested separately. The general public, has become conditioned to commercial bread products, and is uninformed about the effects of the processing that flour undergoes. Many recorded cases demonstrate the effects of the quality of flour on the health of people or animals, and illustrate the importance of the nutritional value of bread to physical health.


Refined flour has been found less effective in promoting the growth of weanling rats than wholemeal, if the flour was the main source of protein (Chick, 1958).


Steel roller mills were introduced in Britain in 1872. By 1876, the birth rate began to decline from 36/1000 to less than 14/1000 in 1941, at which time the National Loaf became compulsory (85% extraction, including the germ). In the next two years, the birth rate rose to 16/1000. Vitamin E deficiency was the suspected cause, since it was believed to have something to do with human and animal reproduction, and is destroyed in the refining of flour. Friend Sykes was said to get his horses and cows to breed by feeding them wheat germ for two months, and Dr. L. J. Picton did the same with his stallions (Day, 1966).


Documented in 1936, was the diversity in physique of the different tribes of India, showing the effects of foods on health (McCarrison, 1936). The northern races were much stronger, due to wheat being the staple of their diet. They consumed chapattis cakes made from fresh coarse whole wheat flour. Experiments with albino rats determined the value of some of the Indian diets, and these results conformed with their effects observed on men. About 1 000 rats were fed a diet equivalent to the northern Indians' for a period equivalent to 50 human years. None were ill or died, or even delivered dead offspring. Deficiently-fed rats under the same conditions developed many ailments. Overall, 30% of the rats fed white flour died while only 4% of those fed whole wheat died. It was concluded that adequate nourishment could be found in a diet of whole cereal grains, milk products, legumes, fruits and vegetables, and eggs and meat occasionally.


Rats on the healthy northern diet were also compared to rats fed a diet equivalent to that of the poorer classes of England (McCarrison, 1936). This diet, deficient in vitamins and minerals, consisted of white bread, margarine, very sweet tea with a little milk, boiled cabbage and potato, cheap tinned meat, and jam. These rats had stunted growth, were badly proportioned, had dull coats, were nervous, bit attendants, and by the 60th day, began killing and eating the weaker ones. Post-mortem examinations revealed a high incidence of lung and gastrointestinal diseases. McCarrison believed that vitamin deficiency was responsible for the many health problems.


Dr. Estelle Hawley, of Rochester University, fed a group of rats McCay-Cornell bread made with unbleached flour, wheat germ, and soybean flour and a lot of milk solids. She fed another group commercial enriched white bread. Both groups also received an amount of margarine equivalent to 10% of the weight of the bread (Rorty, 1954). The first group lived healthy, but the second group became ill, produced stunted offspring and were extinct by the fourth generation.


A journal article, written in 1942, discusses the deterioration of the physique of the British, between the 18th century and the Boer War around 1900 (Alvarez, 1942). The most probable explanation was that they had come to depend too much on white flour and sugar, whereas their ancestors had eaten plenty of 'whole wheat flour.


In Denmark, during World War II, due to a food crisis, many domestic animals were slaughtered and their grain rations fed to humans. Consumption of white bread was stopped, and replaced by a bread made from a wholemeal of 67% rye, 21% oats, and 12% bran, called Kleiebrot. Consequently, the death rate fell to the lowest level ever registered in Europe. There were significant declines in the incidence of high blood pressure, heart disease, kidney problems, diabetes, and cancer, and there were no cases of digestive troubles (Marine & Van Allen, 1972; Day, 1966).


In 1970, Dr. Roger Williams, of the University of Texas's Clayton Research Foundation, recorded the effects, on 64 weanling rats, of being fed bread made from enriched flour (Passwater, 1975). Forty were dead within ninety days, and the rest had stunted growth, whereas similar rats fed whole-grain bread were normal; only three were not well.


A fear exists, among medical professionals, that emulsifiers, some of which are added to bread, may promote the absorption of otherwise non-absorbed substances, some of which may be carcinogenic. Emulsifiers include monoglycerides, diglycerides, and poly compounds which usually go by variations of the words 'stearate' and 'sorb' (ea. stearyl, polysorbate). Although glycerides are naturally produced by the body, this does not prove that their artificial use is safe. Some emulsifiers have been found to increase vitamin A absorption tremendously. This may be dangerous if the rest of an individual's diet supplies a large amount of vitamin A. Dr. Anton Carlson expresses the view that many have by stating, n...Small amounts of injury in certain percentages of the people may go undiscovered for generations. This is a serious problem involved in the changes of such a fundamental thing as the type of food for mans (Marine & Van Allen, 1972).


Enriched flour may have a lower vitamin bioavailability, since synthetic vitamins have been found to act different',y. For instance, they react differently to light, and synthetic vitamin C does not cure scurvy in mice as quickly as natural vitamin C (Day, 1966). Enriched flour products have also been found to lose more vitamins due to heat than do non-enriched products, because added vitamins are less heat-resistant. This is believed to be due to the absence of naturally occurring stabilizers (Mender, 1983; Thomas, 1990).


Many people claim to control allergic symptoms by eliminating bleached wheat products from their diets (Marine & Van Allen, 1972).

Edited by MidwestGreg, 22 June 2020 - 07:29 PM.

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