do gmo foods cause cancer, harm dna, make animals sick

Expert response from Community Manager

Moderator for GMOAnswers.com

Thursday, 15/10/2015 16:09

Thank you for your questions. As you asked three separate questions, we will answer them in separate parts. The second portion of your question is answered in the second response below.

Do GMOs cause cancer? This is an extremely important question and is one of the top consumer questions about GMOs. GMO Answers’ post Do GMOs Cause Cancer?, provides relevant information and applicable studies.

Dr. Kevin Folta, University of Florida professor and horticultural sciences department chairman, also answered this question. An excerpt of his response is below. 

“The short answer is no, there is absolutely zero reputable evidence that GMO foods cause cancer.

“Cancer is a name applied to a spectrum of diseases where cells proliferate abnormally. There is no way that the subtle and well-understood alterations of a plant’s genes can cause cancer. There is nothing about the Bt protein (used in insect resistance, also in organic pest control), the EPSPS enzyme (which confers herbicide resistance simply by substituting for the native enzyme in the plant) or the process itself that would induce such cellular changes in human cells that would lead to cancer. It is just not plausible.”

In addition to Dr. Folta’s response, this study reviews seven cohort studies and 14 case studies and finds that there is “no consistent pattern of positive associations indicating a causal relationship between total cancer (in adults or children) or any site-specific cancer and exposure to glyphosate.”

Numerous questions similar to this and related topics have been submitted to GMO Answers about cancer. Following are multiple resources that explore this topic on GMO Answers.

• Will I get cancer?
  Answered by Dan Goldstein
• Have you reviewed the study showing that GMOs caused cancer in lab rats?
  Answered by Alan McHughen
• How can you say that [GMOs] are safe, when recent studies (not conducted by Monsanto) show a direct link to breast cancer from glyphosate?
  Answered by John Swarthout
• If Glycophosphate (ROUND UP) is so safe why are there more and more articles by Scientists saying it causes cancer, birth defects and so on? If it is so safe why is it banned in many countries? Do you deny that scientists are saying these things, or are only Monsanto scientists smart enough to know it is safe/unsafe?
  Answered by Donna Farmer, Ph.D.

Do GMO foods make animals sick? No. “There is no scientific evidence that animals in a production environment suffer health or reproductive issues because their feed is obtained from GMO crops,” states Yvonne Badke, Senior Biometrician, Breeding Research Group, Breeding and Trait Development Unit at Bayer. Yvonne answer a similar question about GMOs making animals sick. Here is an excerpt from Yvonne’s response:

“We are not exactly sure where the assumption in this question that animals are getting sick from GM feed is coming from. A few years ago, a rat-feeding study by Gilles-Eric Séralini, looking at the effects of GM corn, got a lot of attention because of its severe health impact on the subjects. However, the study received widespread criticism from the scientific community, and several government agencies in charge of food-safety issues have questioned its results. Several answers regarding the content and trustworthiness of Gilles-Eric Séralini’s results have been provided on GMO Answers; I refer you for more details to:

• http://gmoanswers.com/ask/have-you-reviewed-study-showing-gmos-caused-cancer-lab-rats
• http://gmoanswers.com/ask/if-critics-claim-seralinis-well-known-study-flawed-having-used-sprague-dawley-rat-doesnt-make

“There is no scientific evidence that animals in a production environment suffer health or reproductive issues because their feed is obtained from GMO crops. What is true is that the diet of animals grown for meat and dairy production has changed dramatically over the last century. Adding corn and soybean silage to the diet of cows (ruminants), swine and poultry has been extensively researched to obtain the optimal composition of feed for each species. We are aware that several articles claim that these animals suffered infertility or disease because their feed was GMO derived; however, when you look at the accompanying research, these effects were usually associated with a nutrient deficiency from the new composition of the feed. Once these effects were observed, steps were taken to identify the deficiency and introduce better-composed feed.” 

If you have additional questions, please ask.

Expert response from Community Manager

Thursday, 15/10/2015 16:08

That is a great question and maybe the best way to start is to understand how DNA can be harmed. Traditionally, harm to DNA has been viewed as DNA damage or mutations. This occurs through agents that interact with DNA. Such agents can be synthetic chemicals, naturally occurring chemicals, such as reactive oxygen species found in the air, UV rays from the sun, or radiation. The key elements determining whether your DNA gets damaged is the ability of the substance to damage DNA and enough exposure to the substance in question to cause such damage. It is important to note that the body has DNA repair capabilities to deal with natural agents in our environment that can harm our DNA and thus, harm can only come from DNA damage if it is not adequately repaired by our own bodies. You may have heard about plant breeders that used radiation to induce mutations to increase genetic diversity to enable them to breed new traits into some of the vegetables that we commonly consume today. 

Potential impacts on DNA are considered and directly tested, as appropriate, in the safety assessments that are conducted on all pesticide products. In the case of GMOs, there is no plausible reason to presume that introduced DNA, RNA, or proteins could reach the cells to enable any interaction with, or impact to, DNA following ingestion. The DNA transferred into modified plants and the RNA and proteins made from such DNA are readily digested after ingestion and are no different than those naturally present in all whole foods. These biological molecules are broken down into their components that serve as building blocks in metabolism (e.g. nucleotides for DNA/RNA and amino acids for proteins). Thus the introduction of genes and expression of proteins and nutrients in GMOs does not result in any changes that could result in harm to DNA of people or animals that consume them.  

Internet rumors imply that GM products can cause DNA to be altered by a mechanism known as RNAi, or RNA interference. This natural process has existed as long as life as we know it has existed. Its discovery resulted in a Nobel Prize in 2006. RNA molecules found in our bodies are important messengers that control how our genes are expressed. Some of these RNAs may move from the cell in which they are made to other cells in the body as a means of signaling within the body. RNA interference results when a small RNA matches its intended target and reaches it, resulting ultimately in a gene’s expression being turned down, much like a dimmer switch does to a light. This process is very specific and requires a match between the code within the small RNA (“key”) and the intended messenger RNA target (“lock”) to be controlled. The functional result is to make less of the protein. This natural mechanism keeps our bodies functioning properly and is an important tool to help us respond to our environment.

A study in 2012 was the first of its kind and the only study to date that makes claims that small RNA molecules can be absorbed after eating plants in sufficient quantities to impact consumers (Zhang et al., 2012). This study used  mice that ate a human equivalent of 70 pounds  per day of a rice-only diet, and their findings were later determined to be due to nutritional imbalances and not due to small RNAs at all (Dickinson et al., 2013).  Independent investigators and Harvard (Snow et al., 2013) and Johns Hopkins Universities (Witwer et al., 2013) also showed a lack of any meaningful uptake of small RNAs from plant and/or animal based diets. This is consistent with a lack of success in developing oral RNA drugs that despite their high potential as very selective drugs, cannot overcome the biological barriers that humans have in place to protect us from our environment, including DNA, RNA, and proteins in our food. For this reason, we safely eat natural small RNAs that match human genes in our staple foods (Frizzi et al., 2014; Ivashuta et al., 2009) and do so every day without any apparent adverse effects.  

Plants are safe foods that are a healthy part of our daily diet and do not harm our DNA. GMOs are not completely novel life forms, they are nearly identical to their non-GMO counterparts, except that they have had a new sequence of DNA (gene) introduced into them in a well characterized manner. These GMO plants produce DNA, RNA, proteins and nutrients that are not new to nature or our diets but are made up of all the same fundamental natural building blocks as other foods that we eat. Thus, GMOs do not produce unique substances that can impact or harm our DNA. GMOs have no unique properties that make them any more likely to harm our DNA than their non GMO counterparts, e.g. non-modified varieties.  

Dickinson, B., Y. Zhang, J.S. Petrick, G. Heck, S. Ivashuta and W.S. Marshall. 2013. Lack of detectable oral bioavailability of plant microRNAs after feeding in mice. Nature Biotechnology 31:965-967.

Frizzi, A., Y. Zhang, J. Kao, C. Hagen and S. Huang. 2014. Small RNA profiles from virus-infected fresh market vegetables. Journal of Agricultural and Food Chemistry62:12067-12074.

Ivashuta, S.I., J.S. Petrick, S.E. Heisel, Y. Zhang, L. Guo, T.L. Reynolds, J.F. Rice, E. Allen and J.K. Roberts. 2009. Endogenous small RNAs in grain: Semi-quantification and sequence homology to human and animal genes. Food and Chemical Toxicology 47:353-360.

Snow, J.W., A. Hale, S.K. Isaacs, A.L. Baggish and S.Y. Chan. 2013. Ineffective delivery of diet-derived microRNAs to recipient animal organisms. RNA Biology 10:1107-1116.

Witwer, K.W., M.A. McAlexander, S.E. Queen and R.J. Adams. 2013. Real-time quantitative PCR and droplet digital PCR for plant miRNAs in mammalian blood provide little evidence for general uptake of dietary miRNAs: Limited evidence for general uptake of dietary plant xenomiRs. RNA Biology 10:1080-1086.

Zhang, L., D. Hou, X. Chen, D. Li, L. Zhu, Y. Zhang, J. Li, Z. Bian, X. Liang, X. Cai, Y. Yin, C. Wang, T. Zhang, D. Zhu, D. Zhang, J. Xu, Q. Chen, Y. Ba, J. Liu, Q. Wang, J. Chen, J. Wang, M. Wang, Q. Zhang, J. Zhang, K. Zen and C.-Y. Zhang. 2012. Exogenous plant MIR168a specifically targets mammalian LDLRAP1: Evidence of cross-kingdom regulation by microRNA. Cell Research 22:107-126.

Expert response from Community Manager

Moderator for GMOAnswers.com

Thursday, 15/10/2015 16:09

Thank you for your questions. As you asked three separate questions, we will answer them in separate parts. The second portion of your question is answered in the second response below.

Do GMOs cause cancer? This is an extremely important question and is one of the top consumer questions about GMOs. GMO Answers’ post Do GMOs Cause Cancer?, provides relevant information and applicable studies.

Dr. Kevin Folta, University of Florida professor and horticultural sciences department chairman, also answered this question. An excerpt of his response is below. 

“The short answer is no, there is absolutely zero reputable evidence that GMO foods cause cancer.

“Cancer is a name applied to a spectrum of diseases where cells proliferate abnormally. There is no way that the subtle and well-understood alterations of a plant’s genes can cause cancer. There is nothing about the Bt protein (used in insect resistance, also in organic pest control), the EPSPS enzyme (which confers herbicide resistance simply by substituting for the native enzyme in the plant) or the process itself that would induce such cellular changes in human cells that would lead to cancer. It is just not plausible.”

In addition to Dr. Folta’s response, this study reviews seven cohort studies and 14 case studies and finds that there is “no consistent pattern of positive associations indicating a causal relationship between total cancer (in adults or children) or any site-specific cancer and exposure to glyphosate.”

Numerous questions similar to this and related topics have been submitted to GMO Answers about cancer. Following are multiple resources that explore this topic on GMO Answers.

• Will I get cancer?
  Answered by Dan Goldstein
• Have you reviewed the study showing that GMOs caused cancer in lab rats?
  Answered by Alan McHughen
• How can you say that [GMOs] are safe, when recent studies (not conducted by Monsanto) show a direct link to breast cancer from glyphosate?
  Answered by John Swarthout
• If Glycophosphate (ROUND UP) is so safe why are there more and more articles by Scientists saying it causes cancer, birth defects and so on? If it is so safe why is it banned in many countries? Do you deny that scientists are saying these things, or are only Monsanto scientists smart enough to know it is safe/unsafe?
  Answered by Donna Farmer, Ph.D.

Do GMO foods make animals sick? No. “There is no scientific evidence that animals in a production environment suffer health or reproductive issues because their feed is obtained from GMO crops,” states Yvonne Badke, Senior Biometrician, Breeding Research Group, Breeding and Trait Development Unit at Bayer. Yvonne answer a similar question about GMOs making animals sick. Here is an excerpt from Yvonne’s response:

“We are not exactly sure where the assumption in this question that animals are getting sick from GM feed is coming from. A few years ago, a rat-feeding study by Gilles-Eric Séralini, looking at the effects of GM corn, got a lot of attention because of its severe health impact on the subjects. However, the study received widespread criticism from the scientific community, and several government agencies in charge of food-safety issues have questioned its results. Several answers regarding the content and trustworthiness of Gilles-Eric Séralini’s results have been provided on GMO Answers; I refer you for more details to:

• http://gmoanswers.com/ask/have-you-reviewed-study-showing-gmos-caused-cancer-lab-rats
• http://gmoanswers.com/ask/if-critics-claim-seralinis-well-known-study-flawed-having-used-sprague-dawley-rat-doesnt-make

“There is no scientific evidence that animals in a production environment suffer health or reproductive issues because their feed is obtained from GMO crops. What is true is that the diet of animals grown for meat and dairy production has changed dramatically over the last century. Adding corn and soybean silage to the diet of cows (ruminants), swine and poultry has been extensively researched to obtain the optimal composition of feed for each species. We are aware that several articles claim that these animals suffered infertility or disease because their feed was GMO derived; however, when you look at the accompanying research, these effects were usually associated with a nutrient deficiency from the new composition of the feed. Once these effects were observed, steps were taken to identify the deficiency and introduce better-composed feed.” 

If you have additional questions, please ask.

Expert response from Community Manager

Thursday, 15/10/2015 16:08

That is a great question and maybe the best way to start is to understand how DNA can be harmed. Traditionally, harm to DNA has been viewed as DNA damage or mutations. This occurs through agents that interact with DNA. Such agents can be synthetic chemicals, naturally occurring chemicals, such as reactive oxygen species found in the air, UV rays from the sun, or radiation. The key elements determining whether your DNA gets damaged is the ability of the substance to damage DNA and enough exposure to the substance in question to cause such damage. It is important to note that the body has DNA repair capabilities to deal with natural agents in our environment that can harm our DNA and thus, harm can only come from DNA damage if it is not adequately repaired by our own bodies. You may have heard about plant breeders that used radiation to induce mutations to increase genetic diversity to enable them to breed new traits into some of the vegetables that we commonly consume today. 

Potential impacts on DNA are considered and directly tested, as appropriate, in the safety assessments that are conducted on all pesticide products. In the case of GMOs, there is no plausible reason to presume that introduced DNA, RNA, or proteins could reach the cells to enable any interaction with, or impact to, DNA following ingestion. The DNA transferred into modified plants and the RNA and proteins made from such DNA are readily digested after ingestion and are no different than those naturally present in all whole foods. These biological molecules are broken down into their components that serve as building blocks in metabolism (e.g. nucleotides for DNA/RNA and amino acids for proteins). Thus the introduction of genes and expression of proteins and nutrients in GMOs does not result in any changes that could result in harm to DNA of people or animals that consume them.  

Internet rumors imply that GM products can cause DNA to be altered by a mechanism known as RNAi, or RNA interference. This natural process has existed as long as life as we know it has existed. Its discovery resulted in a Nobel Prize in 2006. RNA molecules found in our bodies are important messengers that control how our genes are expressed. Some of these RNAs may move from the cell in which they are made to other cells in the body as a means of signaling within the body. RNA interference results when a small RNA matches its intended target and reaches it, resulting ultimately in a gene’s expression being turned down, much like a dimmer switch does to a light. This process is very specific and requires a match between the code within the small RNA (“key”) and the intended messenger RNA target (“lock”) to be controlled. The functional result is to make less of the protein. This natural mechanism keeps our bodies functioning properly and is an important tool to help us respond to our environment.

A study in 2012 was the first of its kind and the only study to date that makes claims that small RNA molecules can be absorbed after eating plants in sufficient quantities to impact consumers (Zhang et al., 2012). This study used  mice that ate a human equivalent of 70 pounds  per day of a rice-only diet, and their findings were later determined to be due to nutritional imbalances and not due to small RNAs at all (Dickinson et al., 2013).  Independent investigators and Harvard (Snow et al., 2013) and Johns Hopkins Universities (Witwer et al., 2013) also showed a lack of any meaningful uptake of small RNAs from plant and/or animal based diets. This is consistent with a lack of success in developing oral RNA drugs that despite their high potential as very selective drugs, cannot overcome the biological barriers that humans have in place to protect us from our environment, including DNA, RNA, and proteins in our food. For this reason, we safely eat natural small RNAs that match human genes in our staple foods (Frizzi et al., 2014; Ivashuta et al., 2009) and do so every day without any apparent adverse effects.  

Plants are safe foods that are a healthy part of our daily diet and do not harm our DNA. GMOs are not completely novel life forms, they are nearly identical to their non-GMO counterparts, except that they have had a new sequence of DNA (gene) introduced into them in a well characterized manner. These GMO plants produce DNA, RNA, proteins and nutrients that are not new to nature or our diets but are made up of all the same fundamental natural building blocks as other foods that we eat. Thus, GMOs do not produce unique substances that can impact or harm our DNA. GMOs have no unique properties that make them any more likely to harm our DNA than their non GMO counterparts, e.g. non-modified varieties.  

Dickinson, B., Y. Zhang, J.S. Petrick, G. Heck, S. Ivashuta and W.S. Marshall. 2013. Lack of detectable oral bioavailability of plant microRNAs after feeding in mice. Nature Biotechnology 31:965-967.

Frizzi, A., Y. Zhang, J. Kao, C. Hagen and S. Huang. 2014. Small RNA profiles from virus-infected fresh market vegetables. Journal of Agricultural and Food Chemistry62:12067-12074.

Ivashuta, S.I., J.S. Petrick, S.E. Heisel, Y. Zhang, L. Guo, T.L. Reynolds, J.F. Rice, E. Allen and J.K. Roberts. 2009. Endogenous small RNAs in grain: Semi-quantification and sequence homology to human and animal genes. Food and Chemical Toxicology 47:353-360.

Snow, J.W., A. Hale, S.K. Isaacs, A.L. Baggish and S.Y. Chan. 2013. Ineffective delivery of diet-derived microRNAs to recipient animal organisms. RNA Biology 10:1107-1116.

Witwer, K.W., M.A. McAlexander, S.E. Queen and R.J. Adams. 2013. Real-time quantitative PCR and droplet digital PCR for plant miRNAs in mammalian blood provide little evidence for general uptake of dietary miRNAs: Limited evidence for general uptake of dietary plant xenomiRs. RNA Biology 10:1080-1086.

Zhang, L., D. Hou, X. Chen, D. Li, L. Zhu, Y. Zhang, J. Li, Z. Bian, X. Liang, X. Cai, Y. Yin, C. Wang, T. Zhang, D. Zhu, D. Zhang, J. Xu, Q. Chen, Y. Ba, J. Liu, Q. Wang, J. Chen, J. Wang, M. Wang, Q. Zhang, J. Zhang, K. Zen and C.-Y. Zhang. 2012. Exogenous plant MIR168a specifically targets mammalian LDLRAP1: Evidence of cross-kingdom regulation by microRNA. Cell Research 22:107-126.