A new study came out last month out of France. In it, researchers found that rats on diets consisting of 11%, 22%, and 33% Roundup-resistant genetically modified corn developed far more mammary tumors than control rats on non-GMO corn diets. GMO diet rats died earlier and in greater numbers. Why is this study notable amidst all the other studies that seem to show the safety of GMOs? Well, it’s one of the few long term GMO feeding studies, lasting a full two years, which, to a rat, is the equivalent of 60 of our human years. The other safety studies which found no evidence of toxicity in GM foods tend to last just 90 days, or 15 rat years. In other words, the French study studied rats over the course of an entire lifespan, whereas other studies have looked at rats for a relatively brief snippet of their lives. Cancer generally develops over a lifetime, as you probably know, so this would appear to be more relevant to human health than the shorter trials.
Of course, there has been a huge outcry against the study and its author. Critics have said the sample sizes (ten rats per group of each sex) were too small, but judging from the official guidelines of the Organization for Economic Co-Operation and Development (OECD), which states that oral toxicity experiments using rats must use at least 20 animals per group (10 males and 10 females), the French study was just doing what other GMO studies have done. Even if the sample sizes are inadequate, couldn’t that be rectified by running a longer, larger, later study to attempt to replicate its findings?
Obviously, genetically modified organisms (GMOs) are a testy subject, and people from both sides of the argument make articulate, seemingly logical points about why the other side is completely and utterly wrong. I don’t claim to have the answer either way, but hopefully this post will help you make a decision that works for you.
To date, it’s true that there exists no conclusive hard evidence that GM foods are dangerous to people. There are no human feeding trials, and, because GM foods aren’t labeled (at least in the United States) and people don’t know what they’re eating enough to give an accurate account of their food intake, epidemiological studies on the effects are impossible to conduct. You can’t ask people how often they’ve eaten GM foods over the past ten years if the average person doesn’t even know what GMOs are. There are some animal studies, like the one mentioned above, but there have been mixed results, with some independent studies showing potentially problematic differences in health outcomes between GMOs and non-GMOs, and industry studies showing no significant differences.
Personally, I’m not so worried about a fish gene being put into a tomato, or insect genes in strawberries on their own merits. I’m worried about whether that particular gene codes for the production of a lectin that might harm the person that eats the crop. I’m worried about the amount of Roundup that farmers will therefore spray on the crops, having been given carte blanche to use gallons of the stuff. I’m worried about the Roundup-resistant weeds and Bt-resistant bugs that are popping up in response to all the Roundup being applied and Bt-crops being used. I’m worried about the more toxic herbicides and pesticides being used to take care of these new superweeds and superbugs. Didn’t a wise man once say that “Life finds a way“? Though he was a fictional character talking about the unintended consequences of using frog DNA to “plug” the holes in dinosaur DNA, I think he was right.
A lot of people are worried about the potential of unintended effects to arise. I think John Hagelin said it well in his statement to the EPA:
Numerous eminent molecular biologists recognize that DNA is a complex nonlinear system and that splicing foreign genes into the DNA of a food-yielding organism can cause unpredictable side effects that could harm the health of the human consumer. Yet, the genetic engineering of our food – and the widespread presence of genetically altered foods in American supermarkets – is based on the premise that the effects of gene-splicing are so predictable that all bioengineered foods can be presumed safe unless proven otherwise.
Take a recent example of transgenic modification applied to cassava, a staple starchy tuber for millions (if not billions) of people across the globe. This is the stuff that’s high in cyanide, requires extensive processing to remove said cyanide, and has an extremely paltry protein content (the lowest of all staples foods, in fact). Transgenic insertion of a gene into the plant increased the protein content four-fold and reduced the cyanide content by up to 55%, turning a decent staple into a fantastic, protein-rich one – at least on paper. The increased protein came from a novel chimeric storage protein called zeolin, which was cobbled together using zein (from corn) and phaseolin (from beans, used in “carb blocker” products). For someone who relies on cassava for, well, everything, the increased protein is welcome and perhaps even necessary. But zein (also known as corn gluten) is a prolamine, a type of plant protein that many people have trouble digesting, as well as an herbicide in its own right (PDF). Wheat gluten is another (in)famous prolamine. Phaseolin is a “carb blocker”; it literally reduces your absorption and digestion of glucose. The zeolin may not have the same properties as zein or phaseolin, and even if it did, those properties may be worth it if it’s the best source of protein in the area, but I think this example shows that genetic engineering has the potential to have unintended effects.
Plus there’s a lot of sneaky stuff that makes you go “Hmm…” It’s just circumstantial, sure. There are no smoking guns, but it’s worth considering:
Before being allowed to purchase GM seeds, customers (including farmers, scientists, and other researchers) must sign an agreement that limits what they’re allowed to do with them. For instance, customers can’t replicate the genetic alterations – a perfectly reasonable kind of patent protection. These legally-binding end-user agreements also forbid the seeds from being used in independent research, thereby severely limiting independent researchers from conducting any meaningful tests unless they get permission.
Following previous stints as VP at Monsanto, lawyer for Monsanto, and administrator at the USDA, Michael Taylor, is now the chief commissioner of foods at the FDA. As chief commissioner, Taylor will be protecting all of us from dangerous food.
It certainly brings to mind Gertrude’s famous line from Hamlet, “The lady doth protest too much,” doesn’t it?
At any rate, you can simply avoid GMOs, and sticking to a Primal way of eating gets you most of the way there. After all, the most prevalent GMOs in the United States are:
Soybeans – 93% are GM
Corn – 86% are GM
Sugar beets – 95% are GM
Canola – 87% are GM
Cotton – 93% are GM
Hawaiian papaya – 80% are GM
Processed food – In 2003, it was estimated that 70-75% of processed food contained GMOs. That number is probably higher now.
Potatoes and alfalfa – Unknown, but at least some are genetically modified.
Almost without exception, the fruits, the vegetables, the nuts and the seeds you come across and which form the foundation of many of your meals and snacks are not GMO. No need to worry about those. If you’re eating processed foods, however, even so called “healthy snacks,” you’ll likely be eating GMOs.
Unless you’re still cooking with canola, sneaking corn tortillas, eating out at places that cook with soybean oil, making papaya smoothies every morning, and losing bets that have you eating articles of clothing made with GMO cotton, you’re avoiding 99% of genetically modified food simply by going Primal. You’re definitely not eating diets consisting of 11% or 22% or 33% GM corn or soy, so I really wouldn’t worry too much about the occasional bite. Stick to organic potatoes when you eat them and you’re golden. Of course, conventionally-raised, grain-fed livestock are eating almost entirely GMO feed, but I’m unaware of any evidence that this affects the health of those who eat their meat and milk (and grass-fed and pastured animal products are healthier, anyway). Anyone know?
Is there a bottom line to all this? A definitive answer? No; not yet.
But I think at the bare minimum, GM foods should be labeled so that people can make decisions about the food they and their families are eating. With so much uncertainty, I think the only fair thing to do is give people a choice in the matter. Not everyone avoids grains and legumes in general, like us.
Well, I hope this was helpful. I’ll probably get criticized from both sides – for not completely and unequivocally condemning GMOs and for failing to pledge my undying support. Not everything has a clear conclusion, though. So it goes.
By all means, though, get it going in the comment section! I want to hear evidence and arguments from both sides. Just try to be respectful, and Grok on!
Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending three decades researching and educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates Primal/paleo, keto, and Whole30-friendly kitchen staples.