6.3—Many foods contain phytoestrogens

Many foods contain endocrine disruptors. They include cereals fruits, berries, flaxseeds, alfalfa and various beans including soybeans and mung-bean.

Analysis of Peer-reviewed Research:

Genetic Roulette speculates about endocrine disruptors in food but fails to mention that normal diets contain a lot of chemicals made by plants that are endocrine disrupters. Foods that are rich sources of endocrine disrupter (usually marketed as phytochemicals or phytoestrogens) include flaxseed, mung-beans, soybeans, and cranberries). When hormonal effects from a diet are desired, for instance by woman managing the “change-of-life” or risks of breast cancer, or reducing colon cancer in both men and women, these compounds are desirable health promoting materials. When hormonal effects are undesired these compounds could well be regarded as dangerous or unhealthy. A potential undesirable effect of phytochemicals is disturbance of brain development in the unborn child.

In this section, Jeffrey Smith speculates about herbicides being potential endocrine disruptors, but doesn’t mention the large quantities of plant produced endocrine disruptors present in many foods (Mazur 1998, Tolman J (1996).). We regard Smith’s claims of endocrine disruption by herbicides as baseless, but that’s beside the point. His completely misleading discussion of feminising hormone-like activity in diets without any mention of the overall feminising influence of foods such as soybeans, alfalfa shoots, flaxseed, or mung-bean can only confuse people about making sensible food choices. We can only recommend that people, and especially mothers and pregnant women, become alert to reliable and professional sources of human health and nutritional advice, and avoid Genetic Roulette completely when it comes to anything to do with their health. Genetic Roulette is biased and highly inaccurate about health and nutrition. Interested readers should find out about plant compounds like the flavones apigenin and quercitin, the isoflavones genistein, biochanin A  and daidzein, and other phytochemicals  such as lignans, coumestrol, and ursolic acid. People should also investigate the wide variety of foods that are rich sources of phytochemicals, and consult health professionals and reputable books and magazines. Steer clear of Genetic Roulette and similar tracts written by people without scientific or medical training.

1. Endocrine disruptors are common in foods. Cereals, fruits and berries, soybeans and other legumes contain many components that are powerful endocrine disruptors. These have both benefits and pitfalls for human health. In some circumstances intake of these foods is considered healthy, for example in management of risks of breast cancer in women. In other circumstances – especially during pregnancy — excessive intake of endocrine disruptors is highly undesirable. Discussion of hormone activity in the food in terms of an oversimplified good versus bad compound argument is not helpful way of approaching a rather complicated but important health issue. Remember, chemicals in the diet can promote or reduce cancer risks and can affect brain development and normal organ development in unborn children, and there is no doubt that foods such as soybeans, flaxseed and mung-beans contain such chemicals. Many sheep and cows have been made sterile by grazing on clover pastures that are rich sources feminising chemicals such as genistein and coumestrol. Laboratory tests prove such plant chemicals in the diet can affect organ development in animals. (Cassidy 2003, Humfrey 1998, Tolman J (1996). Lindner 1976).

These effects have been known to science for 50-years but it is only relatively recently that the general public have started to hear about them. People should make up their minds about which foods they eat based on sound medical and nutritional advice. Their decisions to manage diet hormone-like chemicals should be based on their particular health circumstances, stage of life, whether they are pregnant or are breast-feeding.  Smith does not provide sound health information about food. He does not have biological science or medical credentials, his research efforts are woeful and his book is full of errors.


2. Androgens or male-like hormones get converted into estrogens or female-like hormones by an enzyme called aromatase. The enzyme catalyst that converts masculinising hormones into feminising hormones is discussed by Smith. Smith argues from experiments carried out on isolated human cells that herbicide preparations glyphosate and Roundup inhibit this catalyst. These are very artificial conditions with very high direct exposure of the enzyme to herbicide. The flaw in his reasoning is that such high exposures from diets containing at most traces of herbicide is virtually impossible. What is needed to establish whether or not the herbicide has endocrine disruption ability is tests on living animals that have been fed herbicide. Such experiments have been done without in any evidence of endocrine disruption (Williams and others 2000) but they are not mentioned by Smith. The article that he quotes (Richard and others 2005) describing effects on artificial cell systems only sees effects at much, much higher concentrations of herbicide than ever will be generated by food. It is highly unlikely that the herbicide components would enter the body at anything other than minuscule concentrations (Williams and others 2000) and this study actually demonstrates that glyphosate is unlikely to affect human reproduction.


3. Genetic Roulette does not mention the major studies demonstrating that glyphosate herbicides are safe. As is typical for Genetic Roulette, Smith avoids providing the reader with the crucial safety studies that argue against his line of reasoning. Particularly Smith avoids explaining how the herbicide components cannot get inside the body at concentrations that can do harm. The safety studies on glyphosate herbicide show that it does not bioaccumulate, it is mostly eliminated in faeces, and any material event is the body is rapidly eliminated in urine. Chemically, glyphosate is water loving and is unlikely to cross the surface layers of the body and enter cells. It is chemically dissimilar to the fat loving estrogen hormones which can bioaccumulate (Williams and others 2000).


4. Where endocrine disruption is important in understanding effects of soybeans fed to rats, Jeffrey Smith conveniently forgets about endocrine disruption. In Genetic Roulette sections 1.10 through 1.12, the growth behaviour of mice fed different types of soybean is discussed at length. In these experiments, carried out by Manuela Malatesta and her colleagues,  a variety of soybean that  has been genetically manipulated it is compared with a so-called wild-type soy variety. In these experiments, it is crucial to check the phytoestrogen composition of the different soy varieties, because endocrine disruption by plant produced chemicals is known to happen when rodents are fed soybeans (Brown, Setchell 2001, Thigpen and others 2004). Jeffrey Smith avoids any discussion of this and instead tries to blame genetic engineering for differences in organ responses to diets used in these mouse experiments. There is no analysis of phytoestrogens levels in the different types of soybean used in Manuela Malatesta’s studies and this lack of chemical analysis of animal feed for estrogens means that Malatesta’s conclusions are wrong.

See discussion of Sections 1.10-1.12

1.10 Mice fed Roundup Ready soy had normal liver cells

1.11 Mice fed Roundup Ready soy had no changes in pancreatic cells or enzymes

1.12 Mice fed Roundup Ready soy had no changes in testicular cells

5. Where endocrine disruptor production by microbes is important in explain pig and cow infertility, Smith also doesn’t mention it. Certain molds can produce endocrine disruptors during growth on cereal grains. When farm animals eat these moldy grains they can become sterile. In section 1.8 of Genetic Roulette discusses an example where farm animals became sterile after eating grain, but doesn’t mention the most probable cause of this problem which was growth of fungus on the grain causing fungal endocrine disruptors to be formed (notably the mold-produced chemical known as zearalenone).

See also

1.8 Pigs and cows don’t become sterile from eating GM corn


Brown NM and Setchell KDR (2001). Animal models impacted by phytoestrogens in commercial chow:  implications for pathways influenced by hormones.  Laboratory Investigation 81:735–747.

Cassidy A. (2003) Potential risks and benefits of phytoestrogen-rich diets. Int J Vitam Nutr Res. 73(2):120-6.

CAST ( 2004).  Mycotoxins:  Risks in Plant, Animal, and Human Systems. Council for Agricultural Science and Technology, Ames, Iowa, USA

Humfrey CD (1998) Phytoestrogens and human health effects: weighing up the current evidence. Nat Toxins. 6(2):51-9.

“Evidence from studies of various animal species has demonstrated that ingestion of high levels of phytoestrogens can produce adverse effects on reproductive endpoints including fertility. Studies in laboratory animals have also shown that exposure to high doses of phytoestrogens during development can adversely affect brain differentiation and reproductive development in rodents, but may also have possible beneficial effects. In humans, there is a lack of information concerning the possible effects of high doses of phytoestrogens in infants and this should be addressed as a matter of priority so that any risks (or benefits) can be established. In adults, no current data exist to suggest that consumption of phytoestrogens at the levels normally encountered in the diet is likely to be harmful. Epidemiological studies suggest that foodstuffs containing phytoestrogens may have a beneficial role in protecting against a number of chronic diseases and conditions.”

Lindner HR (1976). Occurrence of anabolic agents in plants and their importance. Environ Qual Saf Suppl. (5):151-8.

Mazur W (1998). Phytoestrogen content in foods. Baillieres Clin Endocrinol Metab. 12(4):729-42.

Richard S and others (2005). Differential effects of glyphosate and Roundup on human placental cells and aromatase. Environmental Health Perspectives 113:716-720

Thigpen JE, Setchell KDR, Saunders HE, Haseman JK (2004). Selecting the appropriate rodent diet for endocrine disruptor research and testing studies. ILAR Journal. 45:401-416. Rodent diets differ significantly in estrogen activity primarily due to large variations in phytoestrogen content.These estrogens can profoundly influence rodent physiology.

Tolman J (1996). Nature’s hormone factory: Endocrine disruptors in the natural environment. Competitive Enterprise Institute.” For millions of years plants have been quietly producing chemicals. Through countless generations they have been perfecting a potpourri of chemicals, some benign some deadly. As the ability to detect, isolate, measure and test chemicals found in nature has progressed a starling fact has emerged: hundreds of plants appear to produce endocrine disrupters.”

Williams GM, Kroes R, Munro IC. (2000). Safety evaluation and risk assessment of the herbicide Roundup and its active ingredient, glyphosate, for human. Regul Toxicol Pharmacol 31:117–165.

“The oral absorption of glyphosate and AMPA is low, and both materials are eliminated essentially unmetabolized. Dermal penetration studies with Roundup showed very low absorption. Experimental evidence has shown that neither glyphosate nor AMPA bioaccumulates in any animal tissue. No significant toxicity occurred in acute, subchronic, and chronic studies.”

Genetic Roulette Falsely Claims:

Tiny amounts of herbicide may act as endocrine disruptors.

1. Certain chemicals may disrupt endocrine function at extremely low concentrations.

2. Research on Roundup suggests it may be such and chemical, disrupting endocrine activity related to human sex hormone production, but more research on this and other herbicides is needed.

3. The increased use of Liberty and Roundup, due to GM crops, may expose the population through food and water to these low-dose effects.

Genetic Roulette claims that herbicides have hormone-like activity and this may interfere with human health by disrupting endocrine hormone circuits.