Are GM Foods Here To Stay – Podcast

Written By: Gloria Tsang, RD

Title: Founding Registered Dietitian

Alumni: University of British Columbia

Last Updated on:

Dr. Lisa Weasel helps us understand the GM food controversy.

Host: Gloria Tsang, RD
Guest: Lisa Weasel, PhD

There is quite a bit of coverage of genetically modified foods in the media, but a lot of it seems quite emotional. In the often passionate debate about GM foods, it is sometimes difficult to get the real scoop on what is fact vs. fiction. Molecular biologist Dr. Lisa Weasel, author of Food Fray, helps us understand the GM food controversy.



Gloria Tsang, RD: There is quite a bit of coverage of genetically modified foods in the media, but a lot of it seems quite emotional. In the often passionate debate about GM foods, it is sometimes difficult to get the real scoop on what is fact versus fiction. Welcome to the Nutrition Tidbits Podcast. This is Gloria Tsang, Editor-in-Chief for Joining me today is molecular biologist Dr. Lisa Weasel, author of the book Food Fray. She is here today to help us understand the GM food controversy. Welcome to the show Dr. Weasel.

Lisa Weasel, PhD: Thanks for having me.

Gloria Tsang, RD: Now with any controversial topics, there are always supporters and opponents. What exactly are the opposite camps debating about?

Lisa Weasel, PhD: I think that there is a lot of controversy around food systems today. We see a lot of food contamination incidents. I think people are having trouble trusting our food regulations. And when you get to a new technology, something that has never been tested out before, and it involves moving genes from one species to another species (that being our food), people can be concerned about playing god or if there is enough safety testing. On the other hand, genetically modified foods agricultural biotechnology may have the potential to help us address some of the pressing environmental issues that we have, like droughts, climate change, and increasing the security of our food supply globally as we see the cost going up. As more and more people are slipping into food insecurity and hunger around the world, we are looking for better ways to use technology to improve our food security. So I think those are the two opposing sides of the debate. To question whether this is a safe and responsible technology for our health and the environment versus whether it might have good humanitarian outcomes.

Gloria Tsang, RD: Currently, our foods are not labelled with GM (genetically modified) technologies so what are some of the GM foods that are widely consumed in North America?

Lisa Weasel, PhD: That’s an area where there is a lot of misunderstanding. I don’t think that people know which foods have genetically modified ingredients and it’s pretty simple. 92% of the soybeans grown in the United States last year were genetically modified. 80% of the corn, canola, cotton seed oil (any processed foods with cotton seed oil in it) and papayas are genetically modified. Starting next year (2010), sugar produced form sugar beets contained genetically modified ingredients. But that’s basically it in terms of what’s out there. So in general, soy, corn, canola and starting next year, sugar.

Gloria Tsang, RD: Are there any differences in nutritional value of foods that have been genetically modified?

Lisa Weasel, PhD: I think that some of the questions about nutritional value and how the genetically modified technologies affect the entire plant and overall biochemistry have yet to be answered. Technically, genetically modified foods, are engineered to have two traits. One is a gene that allows a plant to resist the application of herbicides so the plant will grow even when weed killer herbicides are applied to it. The second trait is a gene that includes a pesticide protein that kill pests when they bite into the food. So genetic modification is not intended to have nutritional alterations. That said, the overall biochemistry of the plant really has not been studied so there might be some unintended effects that do influence the biochemistry of the plant that will have an outcome on the nutritional side. So the answer to has not been thoroughly investigated at this point.

Gloria Tsang, RD: For many of us, we don’t really immediately associated GM foods with growth hormones but in your book, you have one chapter about that. So is the real deal with growth hormones in our milk supply?

Lisa Weasel, PhD: Yes, so that’s milk produced using recombinant bovine growth hormones (rBGH), so that’s a cow growth factor, a cow hormone, that has been engineered into bacteria using genetically modified techniques, so putting that cow gene into bacteria to produce that hormone, and then taking that hormone and injecting back into cows. This enables cows to produce more milk but it has a lot of side effects. One of those side effects causes the cow to produce higher levels of another growth factor called insulin-like growth factor. In high doses, this growth factor has been linked to cancer and all kinds of negative health outcomes. So I think the real concern. is the use of recombinant growth factor in cows to produce milk – altering the milk. There has been widespread national opposition to this in a lot of the major retailers. Places like Wal-Mart and Starbucks have decided not to source milk that has been produced using recombinant bovine growth hormones because of the potential safety reasons. So consumers are very aware of growth hormone in the milk.

Gloria Tsang, RD: So what are the potential safety issues and health implications for us as humans drinking milk that has been produced from cows that have been injected with this hormone?

Lisa Weasel, PhD: I think there are a few issues. It has been well documented and the company that produces the hormone actually include this on their warning label that cows that are injected with this growth hormone have an increased incidence of mastitis, which is an infection in the udder. They then have to be given a lot of antibiotics to treat those infections. These infections have a side effect of causing puss to be produced in the milk. So the milk from cows that are treated with these hormones can have some contaminants in it. Obviously our food safety systems try to screen these things out. We don’t want to sell milk that has puss contamination or that has antibiotic use, that’s not allowed. The increased use of antibiotics in dairy cattle obviously has significant health outcomes. And then the second thing is this issue of what it’s doing to the cow’s metabolism biochemistry causing the cow to produce this insulin-like growth factor in the milk. The levels vary. There has not been very good standardized tests done on this some debate about whether a small amount of that additional hormone in the milk could have human health effects. Again, a lot of this we have not had very good regulations of these issues. We have left regulations up to the companies that are producing these hormones. So we just really don’t know the answer.

Gloria Tsang, RD: So would organic milk be the answer then? For the general public, how do we know that the milk that we are drinking do not contain the growth hormones?

Lisa Weasel, PhD: There has been a very significant legal debate around labelling milk. In most states, labels are still allowed to say “produced not using recombinant growth hormone”. Although small, you can find those labels in most states on milk that’s not treated with hormones. The second thing is yes, as you say, organic. Organic milk does not allow the use of the hormone at all. So that will be another way to ensure that you are not getting hormone treated milk.

Gloria Tsang, RD: Great Dr. Weasel. You obviously have spent a lot of time researching this complicated issue. Do you think GM foods are here to stay?

Lisa Weasel, PhD: I think they are here to stay in terms of the current technologies. As I said, 92% of soybeans and 80% of the corn grown in this country last year were genetically modified varieties. In many cases, farmers can’t even source non-GM varieties. But I think that we are seeing a bit of the turning of the tide. Consumers are becoming more aware of their food across the board, how food is produced, what the safety issues are. We also have a new administration at the federal level with the USDA and I think we might see some stronger regulatory guidelines there. We are coming out of an era of deregulation on all fronts from banking to our food systems. I think with a lot of the food safety outbreaks we have seen recently, there is a growing awareness that we need to have a better regulatory system. I don’t think we are going to see GM foods disappear. I think we might see greater consumer awareness and a greater regulatory impact on some of these technologies.

Gloria Tsang, RD: Thank you for speaking with us Dr. Weasel.

Lisa Weasel, PhD: Sure, thanks for having me.

Gloria Tsang, RD: We have been talking to Dr. Lisa Weasel, author of the book, Food Fray. For more information about GM foods and healthy eating tidbits, go to


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