Facts About GMOs: What a Functional Nutritionist Wants You to Know

When it comes to understanding the facts about GMOs, there’s a lot of mixed information out there. 

Some people see genetically modified foods as a scientific breakthrough that helps feed a growing population, while others worry about their long-term effects on health and the environment. 

Over the past 30 years, genetically modified organisms have become widespread, now appearing in roughly 70% of packaged foods found in grocery stores. Their rise raises important questions – how are these engineered crops influencing our environment, society, and economy, and what effects might they have in the long run?

As a functional nutritionist and registered nurse, I focus on helping people understand the science behind their food choices and how those choices support overall health. While many GMO crops are approved for consumption, some research has linked genetically modified foods to potential adverse effects such as reduced fertility, developmental and cognitive concerns, and certain organ abnormalities. Because of these findings, experts emphasize the importance of continued long-term studies and clear labeling of GMO products, allowing consumers to make informed choices about what they eat.

In this article, we’ll explore what GMOs are, how to identify them on food labels, and when it might make sense to choose organic or non-GMO foods.

Interested in supporting your gut health naturally? Check out my post, Your Guide to the Best Probiotics for Acne, Weight Loss, and Gut Health, to learn how probiotics can help balance digestion, immunity, and overall well-being.

What are GMOs? 

A GMO (short for genetically modified organism) is a plant, animal, or microbe whose DNA has been changed using modern science. 

Genes can be added, removed, or adjusted to give the organism new traits, like making a plant resist pests or grow faster or larger. 

The three most common reasons farmers grow GMO crops include: 

1. To resist specific insects that damage crops 
2. To tolerate herbicides that are used to control weeds 
3. To resist plant viruses 

These genetic changes are meant to make crops stronger, more productive, and easier to grow. While “GMO” is the most common term, you might also see them referred to as genetically engineered (GE) foods, bioengineered foods, or genetically modified crops. 

It’s important to note that while GMOs can offer benefits for farming and food production, their use also raises questions about long-term effects on health, the environment, and biodiversity. 

Risks of GMOs

While GMOs have supported crop yields and food availability, research continues to raise valid questions about their effects on human health. Most safety studies have been short-term and are often conducted by the same corporations that produce GMO crops, limiting independent verification.

Below are several key findings and concerns documented in peer-reviewed research:

1. Organ and Tissue Effects
   Reviews of animal studies have shown possible organ abnormalities, including liver and kidney changes, stomach inflammation, and intestinal alterations after long-term exposure to herbicide-tolerant or insect-resistant GM foods.While some studies showed no difference from non-GMO diets, others reported cellular or tissue damage, suggesting that more rigorous human studies are needed.
2. Herbicide Exposure
   GMO crops designed to tolerate herbicides have contributed to a major increase in herbicide use, particularly glyphosate. Residues of glyphosate and related chemicals have been linked to reproductive and developmental toxicity, endocrine disruption, and metabolic disorders in several population studies and toxicology reviews.Chronic low-level exposure may also contribute to gut microbiome imbalance and oxidative stress, mechanisms that can influence long-term health outcomes.
3. Allergic Reactions and Immune Concerns
   Some genetically modified foods can introduce new proteins that trigger allergic or immune reactions. A well-known example is when a Brazil nut gene was added to soybeans, causing allergic responses in people with nut allergies.Animal studies also found signs of gut irritation and immune changes after GMO consumption, though more human research is needed to confirm these effects.
4. Nutrient and Hormonal Changes
   Genetic modification can unintentionally alter nutrient composition. GMO soybeans, for example, showed significant differences in isoflavone and trypsin inhibitor levels compared with non-GMO soy, which could influence hormone balance and protein digestion.These findings suggest that GMO foods may not always be “substantially equivalent” to their traditional counterparts, a standard often used for safety approval.
5. Environmental and Ecosystem Effects
   Pest-resistant genes in GMO crops can spread to nearby weeds, creating “superweeds” that are harder to control.
   Insect-resistant plants may harm beneficial insects, disrupt pest balance, and affect other species in the food chain.Beyond these immediate effects, scientists are still uncovering how GMOs may influence soil health, water quality, and biodiversity over time, suggesting that the full environmental impact may be broader than we currently understand.
6. Limited Long-Term Human Data
   Only one controlled human feeding study has been published, making it difficult to determine how GMO DNA or proteins behave in the digestive system.Experts, therefore, call for independent, long-term, and multi-generational studies to assess potential impacts on chronic disease risk and overall health so consumers can make informed choices.Ready to take charge of your health? Learn how functional nutrition can help you manage symptoms, reduce inflammation, and feel your best again. Schedule your complimentary 15-minute consultation today. 

How to Identify GMOs on Food Labels 

If you’re wondering how to identify GMO foods, the good news is that food labeling has become clearer in recent years. 

In the United States, under the National Bioengineered Food Disclosure Standard, companies must tell you when a product is made with genetically modified ingredients. 

Instead of GMO, you’ll usually see the word “bioengineered” on the packaging. 

Here’s what to look for when reading a label: 

• Text that says “bioengineered food” or “contains a bioengineered ingredient.” 
• A bioengineered food symbol (shown below)
  
• A QR code or website link that lets you scan or visit to view GMO information
• A phone number to call or text to get disclosure information 

As of 2022, these requirements apply to foods that meet the definition of “bioengineered” – meaning they contain detectable genetic material that has been modified and could not be naturally found. 

If you prefer to avoid GMOs altogether, look for Non-GMO Project Verified or USDA Organic labels – both guarantee that the food is not genetically modified. 

Foods labeled USDA Organic are automatically non-GMO, since genetic engineering is not allowed in organic farming standards.

List of GMO Foods

When looking at the facts about GMOs, it’s important to note which foods are most likely to be genetically modified. 

The U.S. Department of Agricultural Marketing Service (AMS) created an official list of bioengineered foods to help identify crops that are available in a genetically modified form. 

While some GMO crops are designed for pest or herbicide resistance, research has shown that many GMO ingredients appear in highly processed foods and offer little nutritional value. In some cases, herbicides like glyphosate and glufosinate-ammonium can interact with soil microorganisms and reduce the crop’s nutrient content.

This list of GMO foods is used for consumers to understand which foods may be GMOs. 

Grains & Legumes

• Corn – Commonly modified for pest and herbicide resistance.
• Soybeans – One of the most widespread GMO crops, used in oils, protein powders, and processed foods.
• Alfalfa – Often used as livestock feed and genetically modified for herbicide tolerance.

Vegetables

• Potatoes – Modified to reduce bruising and resist pests.
• Eggplant (BARI Bt Begun varieties) – Engineered to resist insects in certain regions.
• Squash (summer varieties) – Designed to resist plant viruses.
• Sugarbeet – Modified for herbicide resistance; used in sugar production.

Fruits

• Apple (Arctic™ varieties) – Developed to resist browning after slicing.
• Papaya (ringspot virus–resistant varieties) – Engineered to protect against viral plant disease.
• Pineapple (pink-flesh varieties) – Created to enhance color and sweetness.

Other GMO Foods

• Canola – Modified for improved oil quality and herbicide resistance.
• Cotton – Engineered to resist pests; cottonseed oil is used in food products.
• Sugarcane (Bt insect-resistant varieties) – Developed to reduce crop loss from pests.
• Salmon (AquAdvantage®) – The first genetically modified animal approved for food, designed to grow more efficiently.

The Truth About PLU Codes and GMOs

You may have heard the claim that the small stickers on fruits or vegetables, called PLU codes, can tell you whether a food is genetically modified or not. 

Price Look-Up (PLU) codes were created in the 1990s to help grocery stores identify and price produce. The system is voluntary and managed by the International Federation for Produce Standards, not the government. 

The claim that has been circling the internet states that: 

• A four-digit code means conventionally grown 
• A five-digit code starting with 9 means organic 
• A five-digit code starting with 8 means genetically modified 

The “8” prefix for GMO foods was suggested decades ago, but never adopted by retailers. In other words, a banana labeled #84011 doesn’t actually mean it’s genetically modified; it’s just a pricing system. 

PLU codes were initially used by manufacturers, with the hope of it being an easy way to identify GMOs; however, because it was voluntary, the system never took off. 

If you truly want to know how to identify GMO foods, look for official labels instead. The USDA Organic seal and Non-GMO Project Verified logo are the only reliable indicators that a product is non-GMO. 

The Best Ways to Avoid GMOs (And When it Matters Most) 

When it comes to the facts about GMOs, many people want to know how to make smarter choices at the grocery store. The truth is, you don’t have to avoid every GMO food to eat well, but knowing where they’re most common and how to spot them can help you shop more confidently. 

• Know the high-risk foods: The most common GMO crops include corn, soy, canola, cottonseed, sugar beets, and alfalfa. These ingredients are often found in packaged snacks, oils, and sweeteners. Choosing more whole foods and fewer processed items is an easy way to limit bioengineered foods in your diet. 
• When organic matters: Foods labeled USDA organic are always non-GMO, since genetic modification isn’t allowed in organic farming. Prioritize organic for high-risk crops or foods made with corn and soy, two of the biggest sources of GMOs in the U.S. 
• Balance cost and benefit: If buying all organic isn’t in your budget, focus on the foods you eat most often. Use resources like the EWG’s Dirty Dozen and Clean Fifteen to decide when organic makes the biggest difference. 
• Read the labels: GMOs often show up in ingredient lists as corn syrup, soy lecithin, vegetable oil, and maltodextrin. Watching for these can help you avoid them without overhauling your entire diet.
• Buy foods labeled non-GMO: Look for packaging that says Non-GMO Project Verified or GMO-free. These labels ensure the product was made without genetically modified ingredients.
• Shop local when you can: Buying from farmers’ markets or local co-ops is an easy way to support small farms that typically grow non-GMO crops and use fewer chemicals. Take the time to talk to the farmer and understand how the food is grown. 

You don’t need to fear GMOs, but you can make informed decisions based on your preferences and priorities. Whether you choose organic, non-GMO, or a mix of both, being aware of what’s in your food helps you stay aligned with your values and health goals. 

What “Organic” Really Means

When you see USDA Organic on a label, that product is not allowed to be made with GMOs. That’s a legal rule of organic farming. So if you’re trying to avoid GMO foods, choosing organic is one of the most reliable shortcuts.

Here’s why that matters:

• Organic = non-GMO by definition. In the “non GMO vs GMO” conversation, organic already answers that. GMO seeds and genetic engineering are not allowed in certified organic crops.
• Organic also limits many synthetic pesticides. Conventional crops, including many GMO crops, can be grown with certain herbicides and pesticides. Organic rules restrict most of those and focus more on soil health and natural pest control. Some studies show organic foods can have lower pesticide residues and certain heavy metals.
• Does organic mean “no chemicals ever”? No. It means stricter rules about what can be used, not zero inputs. But for shoppers who worry about both genetic modification and chemical exposure, organic often feels like the safer bet.

So the key takeaway is simple: If you’re asking “how do I avoid GMO foods,” the most direct answer is “buy organic when you can,” especially for high-risk crops like corn and soy.

The Facts About GMOs: FAQs 

Are GMOs safe?

Research on long-term health effects is limited. We don’t fully know what we don’t know yet, and some studies have raised questions about how GMOs and the herbicides used with them may affect health and the environment. For that reason, many people choose to be cautious and limit their intake when possible.

You can use resources like the Non-GMO Product Finder to choose options you know are safe. 

What are the pros and cons of GMOs?

• Pros: The pros of GMOs are higher yields, better pest resistance, and longer shelf life.
• Cons: The cons of GMOs are more herbicide use, possible environmental impact, potential long-term health effects,  and limited transparency for shoppers.

How can I identify GMO foods? 

Look for the words “bioengineered food” or the bioengineered symbol on packaging. If you want to avoid GMOs, choose foods labeled USDA Organic or Non-GMO Project Verified.

What are the most common GMO foods?

Corn, soybeans, canola, cottonseed, sugar beet, alfalfa, papaya, apples, and potatoes are the most common GMO foods in the U.S.

What is the difference between non-GMO and organic?

Non-GMO means the food was not made with genetically modified ingredients. Organic means no GMOs and stricter rules about pesticides and farming practices. All organic foods are non-GMO, but not all non-GMO foods are organic.

Purchasing organic means it will automatically be non-GMO. 

How can I avoid GMO foods?

Buy organic when possible, limit processed foods made with corn or soy, and look for verified non-GMO labels.

Are GMOs dangerous?

Current research suggests approved GMO foods are safe to eat, but we don’t know what we don’t know. Genetically modifying crops to resist pests or tolerate herbicides may create a greater toxic burden for the body, and long-term effects on human health and the environment remain unclear.

Do GMOs affect the environment?

They can. Some GMO crops may help reduce waste or pesticide use, but others can contribute to weed resistance and lower biodiversity.

Key Takeaways 

When it comes to the facts about GMOs, the goal is to help you understand what they are and how to make choices that feel right for your health and values. 

Genetically modified organisms are created by altering a plant or animal’s DNA to improve traits like pest resistance or crop yield. While research shows that approved GMO foods are considered safe to eat, ongoing studies continue to explore their long-term effects on human health and the environment.

Here’s what to remember:

• GMOs are everywhere. The most common ones in the U.S. include corn, soy, canola, cottonseed, sugar beet, and alfalfa.
• Labels can help. Look for the word bioengineered, the BE symbol, or choose products with USDA Organic or Non-GMO Project Verified seals.
• Organic = non-GMO. Organic foods cannot be produced with genetic modification, making them a reliable choice if you want to avoid GMOs.
• Awareness matters. Even if you don’t avoid GMOs entirely, understanding where they show up helps you make informed, balanced decisions.

At the end of the day, food isn’t just about single ingredients, it’s about patterns. Paying attention to quality, variety, and how foods make you feel is the foundation of eating well.

Ready to take charge of your health? Learn how functional nutrition can help you manage symptoms, reduce inflammation, and feel your best again. Schedule your complimentary 15-minute consultation today.