One new study looks at the potential health risks of GMOs—here's what you need to know

By Lauren Mazzo
November 08, 2017
Photo: Getty Images

The '90s brought us a lot of amazing things, like Britney Spears, Friends, butterfly clips, and millennials-but the era also brought us a little thing called genetically modified organisms (or GMOs). Even though at this point, the technology and GMO foods have been around for decades, there's still a lot of confusion about what exactly these foods are doing to our bodies and the planet. (See: 5 Things You Probably Don't Know About GMOs)

In fact, an estimated 70 to 80 percent of the foods we eat in the United States contain ingredients that have been genetically modified, according to a 2013 statement by the Grocery Manufacturers Association. Yet consumer awareness about GMOs is super low. In a 2013 study by Rutgers University's School of Environmental and Biological Sciences, only 26 percent of people believed that they had ever eaten any food containing genetically modified ingredients.

Removing or reducing GMO foods from your diet may offer serious improvements in digestive issues, energy levels, weight, food allergies or sensitivities, anxiety and depression, and other chronic health conditions, according to a new peer-reviewed article published in the International Journal of Human Nutrition and Functional Medicine. The article, written by Jeffrey M. Smith, author and filmmaker behind Genetic Roulette-The Gamble of Our Lives and Seeds of Deception: Exposing Industry and Government Lies About the Safety of the Genetically Engineered Foods You're Eating, reviews existing research and also presents a new survey of 3,256 individuals who switched to a non-GMO diet.

The GMO Basics

First things first: GMOs are plants, animals, microorganisms or other organisms whose genetic makeup has been modified using genetic engineering or transgenic technology, creating a combo of genes that do not occur in nature or through traditional crossbreeding methods, according to the World Health Organization.

The Non-GMO Project lists alfalfa, canola, corn, cotton, papaya, soy, sugar beet, yellow summer squash and zucchini, animal products, microbes, and enzymes all as high-risk products for GMOs. While you won't necessarily go buy sugar beets or microbes in the store, many of these products are commodity crops that are processed into other goods. They can appear under pseudonyms such as aspartame, ascorbic acid, flavorings ("natural" and "artificial"), high-fructose corn syrup, sucrose, and xanthan gum in a food ingredient list. (Head to the Non-GMO Project's website for the full list.)

What This Particular Research Shows

Smith's article is the first research investigating the effects of reducing or removing GMOs from diets. And though this study sheds light on the possible effects of GMO foods, to date there have been no human clinical trials related to GMO consumption. (Translation: We still need a lot more research to understand how our bodies handle these modified foods.)

"I wasn't expecting it to be dramatic or even significant in terms of what people would notice when they stopped eating GMOs," says Smith. However, the survey cited in his article-conducted by the Institute for Responsible Technology (IRT, an organization that Smith founded and that educates people on GMO products)-reinforced the anecdotal evidence. It was completed by 3,256 people on the IRT mailing list. People completed a short questionnaire about which (if any) conditions or symptoms they've seen improvement in since switching to a non-GMO diet.

Smith found that a large percentage of people experienced improvements in these top 10 symptoms or conditions:

  1. Digestive problems 85.2%
  2. Fatigue 60.4%
  3. Overweight or obesity 54.6%
  4. Clouding of consciousness (brain fog) 51.7%
  5. Mood problems/anxiety/depression 51.1%
  6. Food allergies or sensitivities 50.2%
  7. Memory and concentration 48.1%
  8. Joint pain 47.5%
  9. Seasonal allergies 46.6%
  10. Gluten sensitivities 42.2%
  11. Insomnia 33.2%

A few caveats about the study: Considering all survey respondents were already on the mailing list for the organization (which maintains a stance that GMOs aren't great), it's entirely possible that these people overestimated the changes, attributed these changes to ditching GMOs when that wasn't actually the case, or were predisposed to think that there would be benefits to this dietary change.

"It's significant, but because it's a survey, it's not conclusive," admits Smith. It's worth noting that ditching GMOs was often not the only dietary change these people made. About 75 percent of people reported switching to an organic diet, 67 percent reduced processed foods, 46 percent stopped drinking soda or other sweetened beverages, 33 percent went gluten-free, 23 percent eliminated dairy, 11 percent went raw, 12 percent went vegetarian, 7 percent went vegan. Just 7 percent made no other changes other than reducing GMOs. What this means: It's tough to attribute all these health perks to ditching GMOs.

"Because of the labeling of GMO and non-GMO products in the U.S., it's hard to make just that change," says Smith. Still, when farm animals (pigs, cows, chickens) are switched to non-GMO feed, they see a relief of digestion symptoms similar to what happened in humans who switch to non-GMO foods, says Smith. Because the type of feed wasn't changing otherwise (pigs can't exactly go to Whole Foods and shop for gluten-free or dairy-free food), it suggests that the GMOs are what made the difference. It's not just anecdotal; a 2013 study published in the Journal of Organic Systems also found that GM food-fed pigs had a much higher incidence of severe stomach inflammation vs. those who ate GMO-free feed.

And, ICYMI, digestion issues seem to be everywhere these days (especially among women). GMOs could be partly to blame; incidence of digestive disorders like inflammatory bowel disease (IBD), Crohn's, and ulcerative colitis are also rising in the population in parallel with both GMOs and the use of Roundup herbicide (glyphosate), says Smith. Indeed, the use of glyphosate herbicides has increased 15-fold in the U.S. and globally since 1996, according to a 2014 study published in the journal Environmental Sciences Europe. This correlation, though, does not necessarily mean causation.

What Could Be Bad About GMOs?

Smith's article outlines a few theories for why GMOs may influence health issues-but there's still a lot of research needed, and a lot that we don't know.

  1. The process of genetic modification (literally making changes to the plant's DNA) itself can create or increase allergens, toxins, and anti-nutrients. For example, genetically modified soybeans were found to have as much as seven times the level of a natural soy allergen, plus double the normal amount of soy lectin, which can potentially block nutrient absorption, according to Smith's article.
  2. One of the main goals of genetically modifying plants is to allow the crops to survive exposure to herbicides that kill surrounding weeds. Herbicide is classified by the World Health Organization as "probably carcinogenic," according to Reuters. (Roundup gets sprayed on non-GMO plants too, which is one reason you really should consider buying organic.)
  3. Bt toxin is an insecticide produced within most genetically engineered corn varieties grown in the U.S. to kill insects so they don't ruin crops. According to Smith's research, the toxin may increase the allergenic and carcinogenic compounds in corn.

However, this is just one study, and there's a lot of conflicting literature on the topic. For example, a research review published in Critical Reviews in Biotechnology looked at 1783 original research papers, reviews, relevant opinions and reports published between 2002 and 2012 and did not find any evidence that genetically modified foods pose any harm to humans or animals. That's why one article published in the journal Environmental Sciences Europe (which was endorsed by 300 independent researchers) makes the point that there's no scientific consensus on GMO safety.

For now, just worry about the simple and definite things that can significantly impact your health: stay hydrated, getting enough sleep, stay active, and eat your vegetables.

Comments (3)

January 13, 2019
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November 9, 2017
GMO foods have been fed to livestock in the U.S. and in Europe for about 20 years, over several generations, with no evidence of any adverse effects on growth or reproduction. See: Prevalence and impacts of genetically engineered feedstuffs on livestock populations. A. L. Van Eenennaam and A. E. Young. J. Animal Sci.92:4255-4278, 2014.
November 9, 2017
It seems inappropriate to call this report "research." This voluntary survey with a very low response rate, among subscribers to an anti-GMO organization, written by an anti-GMO activist, of course came up with a high number of complaints. Who would have expected differently?