Do GMOs cause infertility?

From 1996 to approximately 2014, the use of GMO crops in the United States, such as corn, soybeans, and cotton increased heavily, leveling off at over 75% of planted acres from 2015-2020 [1, 2]. Genetically modified soybeans make up 94% of all soybeans planted, while GMO corn equates to 92% of the US’s corn crop. GMO sugar beets comprise 99.9% of all sugar beet crops in the United States—this equates to practically every crystal of beet sugar (as opposed to cane sugar) used in the US.

This data makes our opening question even more relevant—does the consumption of these foods have an influence on our fertility?

The biggest issue with GMO crops’ introduction into our food chain is that we don’t have much evidence on how they affect humans.

There are studies investigating their effect on animals and on human cells outside of the body, but not on humans directly. Additionally, it’s important to ask how these foods affect animals and, in turn, how the foods produced from these animals affect humans. 70-90% of genetically modified crops are used for animal feed [3].

We have some preliminary information that is important to be aware of. There is evidence that GMO foods may affect the important production of mucus in the small intestine [4], as well as structures, called crypts, that influence the health of the small intestine lining [5]. It may also be that GMO corn contributes to differences in gender weight distribution, kidney and liver toxicity, and triglyceride balance [6].

The functions of the intestines and liver are surely important for fertility. But, the research on fertility, specifically, is minimal. In 2014, a team of researchers in Lanzhou, China, published a paper called “Hypothetical Link Between Infertility and Genetically Modified Food.” This paper poses the idea that genetically modified foods may be linked to infertility, specifically in the ways that they affect the relationship between hormones and metabolism, endometriosis, hormone-related tumors, and finally, their effects on sperm, egg, and embryo [7].

But, to maintain perspective, there is a strong body of evidence showing no physiological differences between GM and non-GM foods. The American Medical Association and The World Health Organization maintain that genetically modified foods are safe, even during pregnancy [8].

This puts the consideration of fertility, and overall health, in relation to GMOs at a difficult crossroads.

Until we learn more, I believe it’s prudent to do our best to avoid these foods during the family-building years.

Practically, this means being aware of the most common foods that are genetically modified. I’ve already mentioned sugar beets, corn, and soy, but a few other crops are commonly GM:

canola
cotton (cottonseed oil is in some processed foods and used for frying in restaurants, while cottonseed meal is used as animal feed)
potatoes
papaya
summer squash
alfalfa
apples
coconuts

Does this mean NEVER eat these foods again? No, definitely not. It simply means do your best to buy these foods organic when possible (GMO foods are not able to be certified as organic) and avoid them when eating out.

Foods derived from these products may be GMO. This includes:

soybean oil
soy protein powder
textured soy protein
soy sauce
high fructose corn syrup (in virtually all processed foods, most notably in imitation maple syrup, ketchup, salad dressings, store-bought mayonnaise, and sodas)
corn starch
dextrose
corn oil
corn muffins/cornbread
corn tortillas
aspartame (made from genetically modified bacteria)
most beer contains GM corn derivatives
margarine, commercial shortening, many brands of mayonnaise, and lots of cereals, crackers, chips, baked goods, bread, and other processed foods contain canola or cottonseed oil

Finally, keep in mind that conventionally raised meat, dairy products, farmed fish, and eggs are from animals fed GM corn, soy, cottonseed, and alfalfa.

While conventionally grown wheat is usually heavily sprayed with glyphosate, it is not genetically modified. So, look for organic wheat, barley, rye, and spelt. Blue corn and popcorn are not genetically modified at this time, so enjoy air-popped popcorn or popcorn prepared in heat-safe oils (lard, tallow, coconut, red palm) in a stainless steel pot or pan with a lid.

Tips for reducing exposure to GM foods

As I mentioned above, certified organic foods cannot be knowingly grown from genetically modified seeds. But, it is possible for genetically modified seeds to contaminate non-GMO crops, even those that are organically grown. This occurrence has been documented in numerous cases.

If you want to be rigorous about avoiding GMOs, avoid soy, corn, corn, and beet sugars, and corn, cottonseed, soy, and canola oils, whether organic or not. Make exceptions for things such as “non-GMO verified” on the label of miso, any blue corn, and any popcorn.

Along with avoiding the foods above, buy organic and ideally pasture-raised meat, dairy, and eggs to avoid GM corn, soy, and cottonseed meal commonly found in animal feed. Source wild-caught fish to avoid the GMO-based feeds given to farmed fish and to avoid the genetically modified salmon that is being produced on some fish farms.

It’s a great idea to source foods as locally as possible via an organic community-supported agriculture vegetable and meat box and farmer’s markets.

Get to know the farmers in your area and their practices—this not only supports your efforts to avoid GMOs but also your local food economy. And, though CSA boxes are a higher initial cost, they are highly economical over the long term and will help save you and your family money throughout the year.

Pay close attention to the ingredients in sweetened products. Avoid anything with dextrose, high fructose corn syrup, and sugar from sugar beets. The best sweeteners are raw honey, organic grade B maple syrup, blackstrap molasses, and organic dehydrated cane juice, in moderation. The less refined the sugar is, the better.

To avoid genetically modified vegetable oils in restaurants, ask for your food to be prepared in butter or 100% olive oil, and ask for your salad to be undressed and served with a side of extra-virgin olive oil and vinegar or lemon. Be aware that many restaurants use a ‘restaurant blend olive oil’ that is actually olive oil mixed with another, less expensive oil such as canola or soy oil. Remember that mayonnaise is usually made with canola, soybean, corn, and/or cottonseed oil, so ask before ordering something with mayonnaise. I like to carry a small bottle of homemade dressing or olive oil with me when I go out.

Buy GMO-free beer…this usually means finding beer from small breweries or certified organic beer. See https://foodbabe.com/cleanbeer/. If you’re a home brewer, do not use any priming sugar product unless it comes with organic certification or a non-GMO verified label. You can prime your brew with homemade solutions made from sugars such as maple syrup, palm sugar, and barley malt.

Finally, non-organic baby formula usually contains GMOs from corn, soy, and cottonseed in various forms. Breastfeed if at all possible, or learn how to make homemade formula (https://mtcapra.com/product/homemade-goat-milk-formula-kit/). If you can do neither, then buy a baby formula that is non-GMO verified.

Resources

Genetic Literacy Project: https://geneticliteracyproject.org/
Secret Ingredients Movie
https://www.youtube.com/watch?v=sJMapopxGrQ
Basic video on identifying GMOs: http://www.youtube.com/watch?v=-LAKFhDguuw
Another documentary: Genetic Roulette, The Gamble of our Lives: www.geneticroulettemovie.com

References

About Victoria LaFont Jackson

Victoria LaFont is an opera singer turned marketing-obsessed scientist. Her nutrition-focused copywriting and coaching have helped hundreds of clinicians go from burnout to career bliss.

Victoria bases her work on a bias-conscious interpretation of the research literature translated into precise content. She has reported on and studied evidence-based medicine for over a decade.

Previously, she operated a successful clinical practice and formulated and scaled a supplement business—Truly Healthy Protein Powder—from product idea to company sale. She has contributed to HealthMeans.com, Food Revolution Network, and the Nutritional Therapy Association. She is also a faculty member for the University of Western States’ Human Nutrition and Functional Medicine master’s program.

You can find Victoria in the weight room, playing disc golf, or creating videos for her successful monthly marketing membership at www.thelafontagency.com.