April 6, 2016
Modern Industrial Foods and Their Effects on the Human Body
The health effects of pesticides, antibiotics, hormones, genetic engineering, and food additives
The majority of American farmland today is dominated by industrial agriculture featuring chemically intensive food production in large single-crop farms and animal production facilities. Modern food processing has grown into a large industry with revenue of hundreds of billions of dollars. The effects of industrial agriculture and the food processing industry on the environment and public health have raised concerns over the decades. This Healthcare Perspectives article reviews recent publications on modern interventions commonly used in the food industry, including genetic engineering, pesticides, antibiotics, hormones, and food additives, as well as their possible detrimental effects on the human body.
The majority of American farmland today is dominated by industrial agriculture featuring chemically intensive food production in large single-crop farms and animal production facilities. Modern food processing has grown into a large industry with revenue of hundreds of billions of dollars. The effects of industrial agriculture and the food processing industry on the environment and public health have raised concerns over the decades. This Healthcare Perspectives article reviews recent publications on modern interventions commonly used in the food industry, including genetic engineering, pesticides, antibiotics, hormones, and food additives, as well as their possible detrimental effects on the human body. It also discusses the benefits of avoiding industrial foods and choosing organic products—strategies that may prevent disease and provide valuable nutrients.
Before industrial agriculture and food processing, people ate food that consisted of whole grains and fruits and vegetables eaten in season or naturally preserved in the summer for winter months. Their food came from animals that grazed freely and lived according to their natural instincts. Now, industrial agriculture has taken over our food supply. Food has become “products” for the profit-driven food industry.1 In an attempt to feed more people in an easier and more productive way, the food industry has changed the way food has been naturally produced for thousands of years. Chemical-laden food products contribute to diseases that affect people’s quality and length of life. The incidence of obesity, cancer, heart disease, high blood pressure, and diabetes is at an all-time high, and most of these diseases can be controlled by the food we consume.2-3
Genetic engineering (GE) is the process of transferring specific traits, or genes, from one organism to another. The resulting organism is called a transgenic organism or genetically modified organism (GMO), also known as genetically modified (GM) food. A large percentage of processed foods in American supermarkets now contain GM ingredients.4 The principal transgenic crops grown commercially are herbicide-resistant or glyphosate-tolerant strains and include soybeans, corn, sugar beet, cotton, and canola. In the United States, 93% to 94% of soybeans, 86% of corn, and 95% of sugar beets are glyphosate-resistant GM products.4-5
Extensive use of herbicides during crop growth results in glyphosate residues on GM products. One study found that glyphosate residues were clearly detectable in GM soybeans (3.3-5.7 mg/kg) and not in non-GM controls; additionally, non-GM soybeans had a richer nutritional profile than GM soybeans.5 Moreover, according to Cornell University, glyphosate is highly adsorbed by most soils, particularly those with high organic content. Microbes are primarily responsible for the breakdown of glyphosate. It may take as many as 174 days for half of the herbicide to break down to its still-toxic degradation byproduct aminomethylphosphonic acid (AMPA).6 In addition, a study by the US Geological Survey revealed that glyphosate and AMPA were found in more than 75% of air and rain samples tested in Mississippi in 2007.7 Research also found that glyphosate was detected in animal and human urine. Cows kept in GM-free areas had significantly lower glyphosate concentrations in their urine than did conventional farm cows. Glyphosate was detected in the intestine, liver, muscles, spleen, and kidney of slaughtered cows. Moreover, levels of glyphosate were significantly higher in the urine of humans who consumed a conventional diet vs those who followed an organic diet.8
Why should we be concerned about glyphosate? As a broad-spectrum herbicide, glyphosate kills most plants. It prevents the plants from synthesizing certain amino acids that are needed for plant growth. Glyphosate stops a specific enzyme pathway, the shikimic acid pathway, which is necessary for plants and some microorganisms to live.9 As a matter of fact, its ability to alter the microbiome of humans and plants is likely to negatively impact our health.10-12 Disturbance of our intestinal flora results in dysbiosis, a microbial imbalance. Altering susceptibility of the body to infection and allergy and affecting autoimmunity, dysbiosis is a possible root cause of many modern diseases such as systemic inflammation, allergy and sensitivity, autoimmune diseases, and cancer.13 Research has also found that the urine of chronically ill humans contains significantly higher glyphosate residues than that of a healthy population. The presence of glyphosate residues in both humans and animals could be leading humans toward numerous health hazards.8
Moreover, glyphosate is now linked to liver and kidney damage;14-15 bone marrow damage;16 infertility;17 gluten intolerance; celiac disease;10 and neurological diseases such as depression, attention deficit hyperactivity disorder, autism, Alzheimer’s disease, Parkinson’s disease, amyotrophic lateral sclerosis, and multiple sclerosis.11 Glyphosate is pervasive in our food supply, air, and water. Although the amount of glyphosate in individual products may not be large, the cumulative effect, particularly considering how much processed food Americans eat, could be devastating. Glyposate may in fact be the most biologically disruptive chemical in our environment.
Antibiotics play a critical role in fighting infections and are credited with saving millions of human lives. Unfortunately, inappropriate use of antibiotics is threatening their efficacy. Today, antibiotics are routinely fed to livestock, poultry, and fish on industrial farms to promote faster growth and to compensate for the unsanitary conditions in which they are raised. According to a new report by the US Food and Drug Administration (FDA), approximately 80% of all antibiotics used in the United States are fed to farm animals.18 It is estimated that approximately 75% of all antibiotics given to animals are not fully digested and eventually pass through the body and enter the environment.19 The use of antibiotics in the food industry is responsible for drug-resistant bacteria emerging on farms and then reaching the general population through the environment, human or animal carriers, and the food consumers eat.
When bacteria are continually exposed to even small amounts of antibiotics, they can develop immunity to the drug, becoming “antibiotic-resistant bacteria” as they have adapted to the point at which antibiotics no longer kill them. As a result, some antibiotics have lost their effectiveness against specific infectious diseases. The US Centers for Disease Control and Prevention (CDC) estimates that each year in the United States, almost 2 million people acquire bacterial infections in hospitals, 70% of which are resistant to at least one commonly used antibiotic.20
Antibiotics are also known to disrupt microbial diversity of the gut flora and increase risk for chronic diseases such as asthma, allergy, heart disease, diabetes, cancer, and obesity.21-22 Although antibiotic residues do not appear in food in large quantities, they may still affect microbial diversity by inhibiting healthy bacteria. One study found that legal amounts of antibiotic residues applied by sausage manufacturers to cured meats could still be high enough to kill bacteria. Sausage is fermented with lactic acid–producing microbes to kill dangerous bacteria like salmonella and E coli. The researchers found that while legal levels of antibiotic residues in meat didn’t kill the pathogenic bacteria, they did kill the helpful microbes intended to keep the “bad” bugs at bay.23 Yet a 2015 report from the FDA revealed that 1% of testing samples of milk produced by US dairy farmers contained drugs, most of which were antibiotics.24 The cumulative amount of antibiotic residues in food is likely causing imbalance of gut flora and affecting our immunity and long-term health. In 2012, the FDA asked livestock and poultry producers to phase out use of antibiotics for growth purposes.
Since the 1950s, the FDA has approved a number of steroid hormone drugs for use in beef cattle and sheep, including natural estrogen, progesterone, and testosterone and their synthetic counterparts. The hormones increase the animals’ growth rate and the efficiency with which they convert their feed into meat.25 Six hormones are now commonly used in almost all conventional beef cattle farms in Canada and the United States: 3 natural steroids (ie, estradiol, testosterone, progesterone) and the 3 synthetic hormones [ie, zeranol (an estrogen), trenbolone acetate (a steroid with androgen and glucocorticoid action), melengestrol acetate (a potent progestin)].26 Measurable levels of all of these growth-promoting hormones are found at slaughter in the animals' muscle, fat, liver, kidneys, and other organ meats. Based on traditional toxicity testing methods, the FDA has set “acceptable daily intakes” (ADIs) for these hormones.
Questions and controversy about the effects of these added hormones on human development and health have lingered for decades. Due to the possible health risks for humans, the use of feeding hormones in livestock production was banned in Europe in the 1980s. Scientists raised concerns that the ADIs, a toxicity indicator, may not reflect the capacity of these hormones, which are potent endocrine disruptors, to alter normal human physiology and health in the long term. Moreover, the possible effects on human populations exposed to residues of anabolic sex hormones through meat consumption have never been well studied. This gap in research is remarkable given that beef-eating Americans have been exposed to these hormones on a regular basis for more than 50 years.27
To explore the effects of these hormones, scientists carried out a study assessing the consequences of beef consumption by pregnant women to their adult sons.27 The study assessed sperm quantity and quality among 773 men. Data on beef consumption during pregnancy were available from the mothers of 387 men. Based on their beef consumption, these mothers were divided into a high beef consumption group (more than 7 meals per week) and a low beef consumption group (fewer than 7 meals per week). The scientists compared sperm concentrations and quality among the men born to women in the high and low beef consumption groups. They found that sperm concentration was 24.3% higher in the sons of mothers in the low beef consumption group. Further, nearly 18% of the sons born to women in the high beef consumption group had sperm concentrations below the World Health Organization (WHO) threshold for subfertility. The authors concluded that maternal beef consumption is associated with lower sperm concentration and possible subfertility, and the associations may be related to the presence of anabolic steroids and other xenobiotics in beef. This study suggests that the FDA should reconsider the allowance of the use of hormones to promote growth in the beef industry. In the meantime, people wanting to avoid the risk of long-term health issues can do so by choosing organic and natural beef.
Recombinant bovine growth hormone (rBGH), also known as recombinant bovine somatotropin (rBST), is another hormonal drug commonly used in the US farm industry. Human and bovine growth hormone, also called somatotropin, is made by the pituitary gland and promotes growth and cell replication. Monsanto (St Louis, Missouri) developed a recombinant version, rBGH, by using genetically engineered E coli bacteria. Sold under the brand name “Posilac,” rBGH increases milk production by 10% to 15%. One government study from 2007 estimated that approximately 17% of all dairy cows in the United States were given this GM growth hormone.29
The use of rBGH has been under increasing scrutiny. Japan, Australia, New Zealand, Canada, and the 28 states of the European Union currently do not allow the use of rBGH due to animal and human health concerns. Reports revealed that in addition to many other health issues, cows treated with rBGH face a significant increase in the risk of clinical mastitis, a bacterial infection of the udder, which could lead to increased use of antibiotics, an increased risk of antimicrobial residues in milk, and an increase in antibiotic-resistant bacteria.30-31 Moreover, milk from rBGH-treated cows contains higher levels of insulin growth factor-1 (IGF-1), a potent hormone that promotes tissue growth.31 While humans naturally have IGF-1, elevated levels have been linked to various types of cancer.32-33 Although no direct connection has been made between elevated IGF-1 levels in milk and elevated IGF-1 levels or cancer in humans, some scientists have expressed concerns over the possibility of this relationship.31 The American Cancer Society has called for more research to better address these concerns.34
The preservatives sodium or potassium nitrate and nitrite fight harmful bacteria in bacon, ham, salami, and other processed and cured meats and also gives the meats pink coloration. However, under certain conditions, nitrite can damage cells and cause cancer. In an effort to minimize cell damage while still preventing foodborne illnesses such as botulism, the US Department of Agriculture (USDA) enforces a limit of 200 parts of nitrate/nitrite preservatives per million parts of meat, by weight.
How do nitrates and nitrites damage the body? This involves a little bit of chemistry. Nitrates (NO3) differ from nitrites (NO2) by only one oxygen atom. Nitrates are turned into nitrites by bacteria in the mouth or enzymes in the body. Then, nitrites can either turn into nitric oxide (NO; good) or nitrosamines (bad).35 If nitrite loses an oxygen atom, it turns into NO, which reacts with the oxygen-binding proteins in the meat, changing its color. However, when nitrites are exposed to high heat in the presence of amino acids, they can turn into compounds called nitrosamines.35 There are many different types of nitrosamines, most of which are well-known potent carcinogens.36 Nitrosamines are among the main carcinogens in tobacco smoke. Because most bacon, hot dogs, and other processed meats tend to be high in sodium nitrite and amino acids, exposing them to high heat during cooking creates the perfect conditions for nitrosamine formation.37 It is important to keep in mind that nitrosamines mostly form during high heat. Even though vegetables also contain nitrates and nitrites, they are rarely exposed to such high heat when cooking.
Carcinogenic nitrosamines are a well-known problem in processed meats, and manufacturers are required to limit the amount of nitrites they use. To minimize daily exposure to nitrosamines, choosing “nitrate-free” meats is recommended.
Artificial food coloring makes many foods more appealing and desirable. Every year, food manufacturers pour 15 million pounds of artificial food dyes into US foods. The safety of these dyes has been called into question, and the FDA requires that the artificial food coloring currently permitted for use meet strict safety requirements. However, recent scientific studies have linked food coloring to a number of potential health problems, most notably certain types of cancer in animals and attention deficit disorder and hyperactivity in children.
According to the Center for Science in the Public Interest (CSPI), 9 of the food dyes currently approved for use in the United States are linked to health issues ranging from cancer and hyperactivity to allergy-like reactions. For instance, Red #40, which is the most widely used dye, may accelerate the appearance of immune system tumors in mice and also triggers hyperactivity in children. Blue #2, used in candies, beverages, pet foods, and more, was linked to brain tumors. And Yellow #5, used in baked goods, candies, cereal, and more, may not only be contaminated with several cancer-causing chemicals but is also linked to hyperactivity, hypersensitivity, and other behavioral disorders in children. Another dye, Red #3, has been acknowledged for years by the FDA to be a carcinogen, yet it is still in the food supply.38
The effects of artificial food colors on children’s behavior has been studied for more than 35 years. In a double-blind, placebo-controlled study of the ingestion of synthetic food colorings and behavioral change in approximately 800 children, 1 of 6 dose levels (1, 2, 5, 10, 20, and 50 mg) of tartrazine (Yellow #5) was administered randomly each morning, and parents recorded behavioral ratings at the end of each 24-hour period. Significant reactions were observed at all 6 dose levels. With a dose increase of >10 mg, the duration of effect increased. The study concluded that increases in irritability, restlessness, and sleep disturbance were associated with the ingestion of tartrazine in some children. A dose-response effect was also observed.39
A 2012 publication examined the controversial topic of artificial food coloring and hyperactivity in children, and the authors gave testimony to the 2011 FDA Food Advisory Committee. The authors noted that while artificial food colors were not a major cause of ADHD, they did seem to affect children both with and without ADHD.40 A 2009 publication reviewed clinical studies and a meta-analysis of 15 double-blind clinical trials and found that artificial food coloring increased hyperactive behavior in already hyperactive children. The paper concluded that it was best for children to avoid artificial food coloring.41
An emulsion in food is a mixture of oil and water, such as in ice cream, milk, and salad dressing. Approximately 15 different emulsifiers are commonly used in processed Western foods for purposes such as smoothing the texture of ice cream and preventing mayonnaise from separating. The FDA rules that emulsifiers are “generally regarded as safe” because there is no evidence that they increase the risk of cancer or have toxic effects in mammals. However, a study published in Nature in 2015 suggested otherwise. Scientists fed common emulsifiers, carboxymethylcellulose and polysorbate-80, in water to healthy mice with their diet otherwise unchanged. They found that the mice became obese and developed metabolic problems such as glucose intolerance. In mice genetically engineered to be prone to inflammatory gut diseases, emulsifiers also showed an increase in the frequency with which the animals developed inflammatory bowel disease and in its severity. The most severe health effects were seen in mice that consumed the chemicals at a level similar to that of a person whose diet consists of only ice cream. But the researchers saw effects even at one-tenth the concentration of emulsifiers that the FDA allows in a food product.42
Wheat is one of the most common foods in the American diet. For many Americans, every meal and snack contains foods made with wheat flour. However, recent reports have indicated that people increasingly cannot eat wheat due to celiac disease, an autoimmune reaction to wheat protein gluten that causes damage to the small intestine, or due to non-celiac gluten sensitivity (NCGS). It is estimated that 1 in 133 Americans suffer from celiac disease, and many more cases are undiagnosed and/or unaccounted for.43 But wheat has been used for thousands of years. Why didn’t it cause problems until recently? It is clear that there could be more to this than gluten. The problem may lie in the differences between ancient and modern wheat.
According to William Davis, MD, author of the book Wheat Belly, modern wheat is not the same grain our ancestors used. In fact, everything has changed dramatically in the past 50 years under the influence of industrial agriculture. Wheat gluten proteins undergo considerable structural change with hybridization. In hybridizing wheat for food production reasons, we have engineered a new kind of wheat with significant genetic differences from the original grain. Those differences could potentially have impacts on human health.44
Industrial farming has also changed the way we grow, harvest, and process wheat. In addition to the use of pesticides and herbicides during wheat growth, ther herbicide Roundup (Monsanto, St Louis, Missouri) is also applied before harvest.10,45 The pre-harvest weed control application is a management strategy to not only control perennial weeds but also to facilitate harvest management and get a headstart on next year’s crop. The procedure of pre-harvest application of glyphosate was clearly described in the manual prepared by Monsanto, the company that makes the herbicide.46 Residual glyphosate in wheat products has been suggested as the cause for gluten intolerance and celiac disease.10
A whole grain of wheat consists of 3 layers: the bran, germ, and endosperm. The bran, the hard outer shell of the kernel, is the layer that contains most of the fiber. The germ is the nutrient-rich embryo that will sprout into a new wheat plant. The endosperm accounts for 83% of the grain and is mostly starch. Today’s milling industry is designed for mass production, using high-temperature, high-speed steel rollers. The resulting white flour, made from only the endosperm, is nearly all starch and has little nutritional value.47
Modern wheat starch contains high levels of a super starch called amylopectin A, a long chain of glucose with a very high glycemic index, meaning it converts to glucose very quickly. Thus, above average intake of wheat product is suggested to be a major contributor to obesity, diabetes, heart disease, cancer, dementia, depression, and many other conditions.44,48
Flour used to be aged with time, improving the gluten and the baking quality. Now it is treated with chlorine to instantly produce similar qualities in the flour. The use of chlorine in bleaching flour is considered an industry standard. The chlorine gas undergoes an oxidizing chemical reaction with some of the proteins in the flour, producing alloxan as an unintended byproduct.47 According to Professor Joe Schwarcz, Director of the McGill University Office of Science and Society, alloxan is the byproduct of xantophyll oxidation. Xantophylls are yellow compounds in wheat that react with oxygen, causing flour to turn white.49 Alloxan is a poison that is used to produce diabetes in healthy laboratory animals (mice and rats) so that scientists can then study diabetes “treatments” in the lab. Alloxan causes diabetes because it produces enormous amounts of free radicals in pancreatic beta cells, thus destroying them.50
Organic farming is a form of agriculture that relies on techniques such as crop rotation, green manure, compost, and biological pest control. Organic farms do not use GM seed, synthetic pesticides, or fertilizers. Certified organic refers to agricultural products that have been grown and processed according to uniform standards that have been verified by the US Department of Agriculture.
Eating organically grown foods is the only way to avoid the cocktail of chemical poisons present in industrially grown food. It also helps us to avoid GM food as well as hormones, antibiotics, and drugs in animal products. A 2014 article reviewed a large number of studies comparing organically grown foods with conventionally grown foods and found that higher amounts of pesticide residues (and in many cases of heavy metals) were seen in the conventionally produced crops vs organic crops. The research also concluded that animal studies as well as in vitro studies showed a clear indication of beneficial effects of organic foods and extracts as compared to conventional ones.51
Organically grown foods contain more nutrients, vitamins, minerals, enzymes, and micronutrients than commercially grown foods because organic farming incorporates the use of purely natural products and techniques without the use of chemicals. A 2001 article reviewed 41 published studies comparing the nutritional value of organically grown and conventionally grown fruits, vegetables, and grains and concluded that there were significantly more nutrients in organic food crops.52
During the past 2 decades, the market for organic food and other products has grown rapidly. Despite its increasing popularity, organic agriculture still accounts for only 1% of global cropland. A paper published in the Proceedings of National Academic Science USA in 2015 analyzed the financial performance of organic and conventional agriculture from 40 years worth of studies covering 55 crops grown on 5 continents. The authors found that, in spite of lower yields, organic agriculture was significantly more profitable than conventional agriculture and had room to expand globally.53 Moreover, with their benefits to health and the environment, organic farming and the natural food movement are likely to contribute significantly to maintaining public health and sustainably feeding the world.
Traditionally grown foods and industrial foods are different in many ways. Studies suggest that modern interventions such as GE, pesticides, antibiotics, hormones, and food additives in industrial agriculture and the food-processing industry may have a negative influence on our health. Avoiding industrial foods and choosing organic products may help to prevent modern diseases and provide more valuable nutrients as well.
- Stuckler D, Nestle M. Big food, food systems, and global health. PLoS Med. 2012;9(6):e1001242.
- Brownell KD, Warner KE. The perils of ignoring history: Big Tobacco played dirty and millions died. How similar is Big Food? Milbank Q. 2009;87(1):259-294.
- Igumbor EU, Sanders D, Puoane TR, et al. “Big food,” the consumer food environment, health, and the policy response in South Africa. PLoS Med. 2012;9(7):e1001253.
- Bawa AS, Anilakumar KR. Genetically modified foods: safety, risks and public concerns-a review. J Food Sci Technol. 2013;50(6):1035-1046.
- Bohn T, Cuhra M, Traavik T, Sanden M, Fagan J, Primicerio R. Compositional differences in soybeans on the market: glyphosate accumulates in Roundup Ready GM soybeans. Food Chem. 2014;153:207-215.
- Pesticide Management Education Program. Pesticide Information Profile: Glyphosate. Accessed March 24, 2016.
- Majewski MS, Coupe RH, Foreman WT, Capel PD. Pesticides in Mississippi air and rain: a comparison between 1995 and 2007. Environ Toxicol Chem. 2014;33(6):1283-1293.
- Krüger M, Schledorn P, Schrödl W, Hoppe H-W, Lutz W, Shehata AA. Detection of glyphosate residues in animals and humans. J Environ Anal Toxicol. 2014;4(2):210.
- National Pesticide Information Center. Glyphosate general fact sheet. Accessed March 24, 2016.
- Samsel A, Seneff S. Glyphosate, pathways to modern diseases II: celiac sprue and gluten intolerance. Interdiscip Toxicol. 2013;6(4):159-184.
- Samsel A, Seneff S. Glyphosate, pathways to modern diseases III: manganese, neurological diseases, and associated pathologies. Surg Neurol Int. 2015;6:45.
- Shehata AA, Schrodl W, Aldin AA, Hafez HM, Kruger M. The effect of glyphosate on potential pathogens and beneficial members of poultry microbiota in vitro. Curr Microbiol. 2013;66(4):350-358.
- Myles IA. Fast food fever: reviewing the impacts of the Western diet on immunity. Nutr J. 2014;13:61.
- Mesnage R, Arno M, Costanzo M, Malatesta M, Seralini GE, Antoniou MN. Transcriptome profile analysis reflects rat liver and kidney damage following chronic ultra-low dose Roundup exposure. Environ Health. 2015;14:70.
- Jayasumana C, Paranagama P, Agampodi S, Wijewardane C, Gunatilake S, Siribaddana S. Drinking well water and occupational exposure to Herbicides is associated with chronic kidney disease, in Padavi-Sripura, Sri Lanka. Environ Health. 2015;14:6.
- Prasad S, Srivastava S, Singh M, Shukla Y. Clastogenic effects of glyphosate in bone marrow cells of swiss albino mice. J Toxicol. 2009;2009:308985.
- Walsh LP, McCormick C, Martin C, Stocco DM. Roundup inhibits steroidogenesis by disrupting steroidogenic acute regulatory (StAR) protein expression. Environ Health Perspect. 2000;108(8):769-776.
- US Food and Drug Administration. Center for Veterinary Medicine. Summary report on antimicrobials sold or distributed for use in food-producing animals. Accessed March 24, 2016.
- Chee-Sanford JC, Mackie RI, Koike S, et al. Fate and transport of antibiotic residues and antibiotic resistance genes following land application of manure waste. J Environ Qual. 2009;38(3):1086-1108.
- Bren L. Battle of the bugs: fighting antibiotic resistance. FDA Consum. 2002;36(4):28-34.
- Fouhy F, Guinane CM, Hussey S, et al. High-throughput sequencing reveals the incomplete, short-term recovery of infant gut microbiota following parenteral antibiotic treatment with ampicillin and gentamicin. Antimicrob Agents Chemother. 2012;56(11):5811-5820.
- Le Chatelier E, Nielsen T, Qin J, et al. Richness of human gut microbiome correlates with metabolic markers. Nature. 2013;500(7464):541-546.
- Kjeldgaard J, Cohn MT, Casey PG, Hill C, Ingmer H. Residual antibiotics disrupt meat fermentation and increase risk of infection. mBio. 2012;3(5):e00190-00112.
- US Food and Drug Administration. Center for Veterinary Medicine. Milk drug residue sampling survey. Accessed March 24, 2016.
- US Food and Drug Administration. Steroid hormone implants used for growth in food-producing animals. http://www.fda.gov/AnimalVeterinary/SafetyHealth/ProductSafetyInformation/ucm055436.htm. Accessed March 24, 2016.
- Meyer HH. Biochemistry and physiology of anabolic hormones used for improvement of meat production. APMIS. 2001;109(1):1-8.
- Swan SH, Liu F, Overstreet JW, Brazil C, Skakkebaek NE. Semen quality of fertile US males in relation to their mothers' beef consumption during pregnancy. Hum Reprod. 2007;22(6):1497-1502.
- Butler LJ. The profitability of rBST on US dairy farms. AgBioForum. 1999;2(2):111-117.
- United States Department of Agriculture. Animal and Plant Health Inspection Service Highlights of dairy 2007 part IV: reference of dairy cattle health and management practices in the United States, 2007. Accessed March 24, 2016.
- Burton JL, McBride BW, Block E, Glimm DR, Kennelly JJ. A review of bovine growth hormone. Canadian J Animal Sci. 1994;72(4):167-201.
- European Commission Scientific Committee on Veterinary Measures Relating to Public Health. Assessment of potential risks to human health from the hormone residues in bovine meat and meat products. http://ec.europa.eu/food/safety/docs/cs_meat_hormone-out21_en.pdf. Published April 30, 1999. Accessed April 5, 2016.
- Sarkissyan M, Mishra DK, Wu Y, Shang X, Sarkissyan S, Vadgama JV. IGF gene polymorphisms and breast cancer in African-American and Hispanic women. Int J Oncol. 2011;38(6):1663-1673.
- Wang Q, Liu L, Li H, et al. Genetic and dietary determinants of insulin-like growth factor (IGF)-1 and IGF binding protein (BP)-3 levels among Chinese women. PLoS One. 2014;9(10):e108934.
- American Cancer Society. Recombinant bovine growth hormone. Accessed March 24, 2016.
- Honikel KO. The use and control of nitrate and nitrite for the processing of meat products. Meat Sci. 2008;78(1-2):68-76.
- Brown JL: N-Nitrosamines. Occup Med. 1999;14(4):839-848.
- Scanlan RA. Formation and occurrence of nitrosamines in food. Cancer Res. 1983;43(5 Suppl):2435s-2440s.
- Kobylewski S, Jacobson MF. Food dyes, a rainbow of risks. Accessed March 24, 2016.
- Rowe KS, Rowe KJ. Synthetic food coloring and behavior: a dose response effect in a double-blind, placebo-controlled, repeated-measures study. J Pediatr. 1994;125(5 Pt 1):691-698.
- Arnold LE, Lofthouse N, Hurt E. Artificial food colors and attention-deficit/hyperactivity symptoms: conclusions to dye for. Neurotherapeutics. 2012;9(3):599-609.
- Artificial food colouring and hyperactivity symptoms in children. Prescrire Int. 2009;18(103):215.
- Chassaing B, Koren O, Goodrich JK, et al. Dietary emulsifiers impact the mouse gut microbiota promoting colitis and metabolic syndrome. Nature. 2015;519(7541):92-96.
- Fasano A, Berti I, Gerarduzzi T, et al. Prevalence of celiac disease in at-risk and not-at-risk groups in the United States: a large multicenter study. Arch Intern Med. 2003;163(3):286-292.
- Davis W. Wheat Belly: Lose the Wheat, Lose the Weight, and Find Your Path Back to Health. Emmaus, PA: Rodale; 2011.
- Agriculture and Horticulture Development Board. Pre-harvest glyphosate application to wheat and barley. Accessed March 24, 2016.
- Monsanto: Preharvest Staging Guide. http://roundup.ca/_uploads/documents/MON-Preharvest%20Staging%20Guide.pdf. Accessed April 5, 2016.
- Mercola JM. The little-known secrets about bleached flour. Accessed March 24, 2016.
- Perlmutter D, Loberg K. Grain Brain: The Surprising Truth About Wheat, Carbs, and Sugar—Your Brain’s Silent Killers. First ed. New York, NY: Little, Brown and Company; 2013.
- Schwarcz J. Office for Science and Society. Alloxan. Accessed March 24, 2016.
- Drews G, Kramer C, Dufer M, Krippeit-Drews P. Contrasting effects of alloxan on islets and single mouse pancreatic beta-cells. Biochem J. 2000;352 Pt 2:389-397.
- Johansson E, Hussain A, Kuktaite R, Andersson SC, Olsson ME. Contribution of organically grown crops to human health. Int J Environ Res Public Health. 2014;11(4):3870-3893.
- Worthington V. Nutritional quality of organic versus conventional fruits, vegetables, and grains. J Altern Complement Med. 2001;7(2):161-173.
- Crowder DW, Reganold JP. Financial competitiveness of organic agriculture on a global scale. Proc Natl Acad Sci USA. 2015;112(24):7611-7616.