Does Eating Organic Fruits and Vegetables Help Prevent Cancer?

Baskets of organic vegetables

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If you are undergoing cancer treatment or are simply interested in preventing the disease, you might be wondering whether eating organic food protects against cancer. The short answer is that yes, eating organic food could improve your chances of remaining cancer free—but it can't guarantee it. There are many variables at play that determine whether someone develops the disease. 

Organic vs. Non-Organic Foods

Conventionally grown and processed foods including, fruits, vegetables, grains, livestock, and packaged items (e.g., cereals and frozen dinners) have all been exposed to an array of chemicals that show evidence of causing cancer in humans. They also may be exposed to hormones, antibiotics, synthetic fertilizers, pesticides, and artificial additives, and could contain genetically modified ingredients.

In contrast, organic crops are grown without chemical pesticides, synthetic fertilizers, or genetically modified (GMO) seeds. Organic animal products like milk, eggs, cheese, and meats come from animals that have been raised without the use of growth hormones or antibiotics; their feed is free from GMOs, chemical pesticides, and synthetic fertilizers. In addition, organic processed and packaged foods prohibit ingredients like artificial preservatives, colors, or flavors.

Your Toxic Load

When thinking about toxicity, it’s helpful to think of your body as a barrel inside which all of your overall toxic load is held. You can only process so many toxins in a certain time period before the barrel overflows, presenting as disease. 

Whether exposure to chemicals will have a toxic, cancer-causing effect on a person depends on the types and total amounts of chemicals they have been exposed to, as well as the person’s unique physiology, genetic composition, lifestyle habits, and underlying risk factors.

In considering this in the context of your diet, exposure to the chemicals found in conventional foods is just one risk factor for developing cancer. But lessening your consumption of them is one way to reduce your risk.

In fact, a 2018 study of nearly 70,000 French adults showed that people who consume organic food had a significant reduction in the risk of cancer. Note: It could also be assumed that people who buy organic food also tend to be more health conscious overall, including being more physically active, less likely to smoke, and more likely to follow a healthful diet in general, which all play a role in a person's cancer risk.

The Impact of Pesticides

There are potentially dozens of chemicals used to produce just one conventional food product. Pesticides are worthy of a special spotlight.

Pesticides do not stay localized where they are sprayed. Rather, they are absorbed by the plant and assimilated into its cellular structure. Some herbicides, for example, are designed to mimic plant hormones, and they function by disrupting the plant’s natural growth activity. 

Because these substances are assimilated into the physical structure of the fruit or vegetable that they’re sprayed on, these foods contain what are known as “pesticide residues,” which are ingested by the people and animals that eat these items.

Link to Cancer Formation

A consensus issued by the International Agency for Research on Cancer (IARC), part of the World Health Organization (WHO), stated that some of the most widely used pesticides in the world demonstrate evidence of causing cancer. For example, the number one pesticide in the U.S. and international markets, glyphosate (commonly found in industrial pesticides and consumer products like Roundup) is noted as a "probable carcinogen," as well as a source of genotoxicity and oxidative stress.

Genotoxicity refers to damage, like mutations, occurring to a person’s genetic information stored within their cells, which may lead to cancer and other diseases.

Oxidative stress occurs when there is an imbalance between free radicals and antioxidants in your body. Having an abundance of free radicals can cause damage to DNA, proteins, and lipids, which can cause a range of disease states including cancer.

Obesity, Diabetes, and Cancer

Pesticide consumption from conventional food is a better predictor of type 2 diabetes than any other factor, according to Joseph E. Pizzorno, Jr., N.D. former advisor to Presidents Bill Clinton and George W. Bush.

These pesticides may also be responsible, in part, for the obesity epidemic because they preferentially convert calories into fat. When a person consumes more chemicals than the body can safely process and expel, they get stored in fat tissues.

While pesticides have also been connected to many other health issues, these two are of particular importance when it comes to cancer, as it is already well established that they are two of the biggest risk factors for developing the disease.

Role as Hormone Disruptors

Chemical pesticides used inside the home, on your lawn, and in conventional agriculture can increase cancer risk in other ways as well. 

Known as hormone disruptors, these substances can affect your hormonal balance by mimicking or blocking the body’s natural hormones. The presence of hormone disruptors in the body increases the likelihood of developing hormone-sensitive cancers like breast, ovarian, uterine, and prostate cancers.

Studies have shown that exposure to pesticides such as methyl bromide and organochlorines increase a woman’s breast cancer risk, as well as the risk of prostate cancer in men by acting as hormone-like compounds in the body.

A meta-analysis of 18 research studies suggests that people who are exposed to certain levels of pesticides (e.g., those who manufacture or apply them chemicals) are up to four times more likely to develop and/or die of prostate cancer.

People who are not involved in the manufacturing or application of pesticides may still experience negative health ramifications from cumulative exposure to pesticides over a lifetime in the foods they eat, water they drink, and lawn chemicals and insect/rodent sprays they use at home.

Also of concern is the exponentially cumulative effect of all of the different chemicals, aside from just pesticides, that you come in contact with in daily life. This has lead certain cancer-related organizations to urge people who are concerned about their cancer risk to find alternatives to using these chemicals and products that contain them.

Other Chemicals in Non-Organic Foods

A primary component in chemical fertilizers, nitrogen, is known to have negative health effects as well. In addition to being highly toxic to marine life, the accumulated increase of nitrates found in certain fruits and vegetables as well as drinking water has been linked to an increase of thyroid cancer, for example, as well as hormone-sensitive cancers (chemical fertilizers may also act as hormone disruptors).

Growth hormones administered to conventionally raised livestock can influence a person’s cancer risk by acting as hormone disruptors in the body, which, as stated previously, can increase the likelihood of developing hormone-sensitive cancers that affect the breasts, uterus, ovaries, and prostate.

Science and Debate

Despite evidence showing that consuming pesticides and other chemicals found in conventional food is not completely "safe," foods with these substances remain on the market. This can be confusing when you're weighing just how important it is that you go organic.

The answer as to why is not a simple one, but one of the most important points to consider as a consumer is the science that is reviewed when making decisions about substances that can be used in food production.

The Environmental Protection Agency (EPA) is in charge of approving new pesticides in the U.S. It is also responsible for setting “tolerance” levels, or the maximum pesticide residue that is allowed on any crop that is still deemed to be safe for people to consume.

When reviewing new pesticide applications and setting tolerance limits, the EPA relies on pesticide manufacturers to submit their own scientific studies proving their products' safety. Unfortunately, this does not free supporting research from potential bias.

Other points to keep in mind about manufacturer's research:

  • Each pesticide is studied in isolation rather than in combination with the dozens of different chemicals used to produce a conventional crop and the hundreds of chemicals a person is exposed to on a daily basis. This is problematic as chemicals often have a synergistic effect that could be exponentially more harmful than that of one chemical alone, and the tolerance limits for such combinations are not known.
  • These studies don’t account for the long-term health outcomes of the chemicals in question, as the cumulative effect of consuming these chemicals over a lifetime is rarely taken into account. 

Among four of the largest agricultural producing nations—the U.S., China, Brazil, and the European Union—the U.S. lags behind the other three in banning the use of harmful pesticides.

Should I Go All Organic? It's Expensive

Besides the potential for chemical exposure and associated cancer risk, studies have shown that organic foods are often higher in nutritional value than non-organic foods. But a large assortment of organic food isn't always available at every supermarket, and it does cost a bit more than non-organic options.

Some organic is better than none. That said, pregnant women, children, and sensitive populations like those undergoing cancer treatment and people prone to chronic illnesses should eat as much organic food as possible to reduce their risk of adverse health outcomes. 

If you have to pick and choose what on your list is organic, favor buying organic animal products like beef, poultry, milk, and eggs. They are exposed to more chemicals than plants, and those chemicals bio-accumulate in the animals’ tissues. 

You may be able to find a larger variety of organic foods for less money at local farmers markets or by joining a food co-op or community-supported agriculture program (CSA), which allows you to buy directly from a local organically run farm.

If you're shopping on a tight budget, you may be able to reduce your costs and exposure to chemicals by buying the organic fruits and vegetables on the "Dirty Dozen" list, which is compiled annually by the Environmental Working Group.

This list ranks the foods that are exposed to the greatest amounts of pesticides and should be avoided when conventionally grown. Similarly, the report has a list of "Clean 15" fruits and vegetables considered safer to purchase when conventionally grown.

Remember that the nutritional benefits of eating fresh fruits and vegetables over processed and packaged foods cannot be overstated. If buying organic just isn't feasible, conventionally grown produce is the next best choice to avoid diseases associated with poor diet, such as cancer.

Whether you're buying organic or conventional foods, you should always thoroughly wash produce to reduce surface residues.

A Word From Verywell

The correlation between cancer incidence and exposure to chemical pesticides, synthetic fertilizers, growth hormones, and other chemicals found in conventional foods is well-established. What isn't known is exactly how much exposure could cause a person to get the disease. Nevertheless, reducing your exposures (in your diet and from other sources) is a good idea, and it may reduce your risk of cancer and other chronic illnesses.

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