Can Eating Organic Food Prevent Cancer?

Does the consumption of  ‘clean’ foods do a better job at preventing cancer than, say, what the majority of the U.S. population eats—namely produce and processed foodstuffs containing pesticide and herbicide residue, antibiotics, and growth hormones?

Until recently there haven’t been large studies to help answer this important question. Now, outcomes from a new French-led investigation called NutriNet-Santé Prospective Cohort Study have been published in JAMA Internal Medicine and help provide answers.

But before I dig in, I want to take you back to 1991 when I was diagnosed with chronic lymphocytic leukemia (CLL). Back then it was hard to find local organic produce, even in the Washington, DC area where I live. About the only place guaranteed to find a decent selection was a small chain called Fresh Fields (soon thereafter acquired by Whole Foods Market). Over time, other markets with organic food offerings began popping up.

A quarter century ago, hard evidence linking diet and cancer was nowhere to be found. But the idea of eating clean food (and filtered water) seemed like a sensible thing to do, so I switched to a whole foods, predominantly plant-based diet. I never looked back.

My diet has not changed much over the last couple decades. What I eat and why can be found here.

When I eat has been the most dramatic change for me, as I have been following a 16-18 hour intermittent fasting program for over a year.

I continue to consume mostly organic produce. It’s still expensive to eat organic foods, but as consumer demand for ‘clean’ food increases, and competition to grow and market organic foods rises, these items will become more affordable.

Should you be purchasing organic foods exclusively—especially produce—to help prevent cancer, manage active disease, or to ensure a deep and durable remission and long-term survival?

We’ll get to that, but first: the French study.

Study Details—Design and Numbers

Trial: NutriNet-Santé Prospective Cohort Study 

Lead investigator: Julia Baudry, PhD, from Institut National de la Sante et de la Recherche Medicale

Design: Population-based prospective cohort study 

Number of participants: 68,946 

Gender: women: 78%; men: 22% 

Mean age: 42 

Main outcomes and measures: Study estimated the risk of cancer in association with the organic food score (modeled as quartiles) using Cox proportional hazards regression models adjusted for potential cancer risk factors. 

Incidence of Cancer: After a mean follow-up time of 4.6 years, 1340 first incident cancer cases were recorded, as follows: breast: 459; prostate: 180; skin cancer: 135; colorectal: 99; non-Hodgkin lymphomas: 47; other lymphomas: 15.

Study Strengths: Prospective study design, large sample size, and detailed questionnaire of organic food frequency, and clinical validation of cancer cases. 

Study Limitations and Potential Biases: Some limitations included: (1) Analysis based on volunteers who were likely health conscious individuals, limiting ability to generalize finding. (2) Participants were predominantly female, well-educated, and exhibited healthier behaviors as compared to the general French population. “These factors may have led to a lower cancer incidence herein than the national estimates, as well as higher levels of organic food consumption in our sample.” (3) Follow-up time was short, perhaps limiting causal interpretation and statistical authority for specific sites, including colorectal cancer. (5) Cannot exclude the possibility of non-detection of some cancer cases.

Funding: Dr. Baudry was funded by the French National Research Agency, with support from the French Ministry of Health, French Institute for Health Surveillance, National Institute for Prevention and Health Education, and additional government institutions.  

Study Conclusions

There was an association between the regular intake of 16 organic products (vegetables, produce, meat, fish, ready-to-eat-meals, dietary supplements, and other products) with a 73% decreased incidence of non-Hodgkin lymphoma, and 21% less occurrence of post-menopausal breast cancer.

Most interesting and powerful is that the study showed a reduced cancer risk even among those who ate poorly, consuming unhealthy diets, while also consuming organic food.

The study authors’ written conclusion and relevance:

“A higher frequency of organic food consumption was associated with a reduced risk of cancer. Although the study findings need to be confirmed, promoting organic food consumption in the general population could be a promising preventive strategy against cancer.”

Correlation Does Not Prove Causation…

…but clearly, these numbers are statistically significant for at least two populations of malignant disease.

Unless or until the organic food industry bands together to invest in larger epidemiological studies, we will never know for sure the real impact of organic versus conventional food on cancer prevention.

Ultimately we must investigate all paths to ‘cancer prevention’, but we must also study the impact of clean organic foods for those undergoing active cancer treatment, and measure duration of disease-free progression, remission,  and overall survival.

Should You Buy Organic?

If you like the way organic produce tastes as compared to its conventionally grown counterparts, and you can afford the investment, then yes, buy all organic.

I choose not to purchase all of my food organic. I only buy organic produce known to have high levels of pesticide and herbicide residue in their conventionally-grown forms. Berries, for instance, are super foods for cancer. But they are also known to have high concentrations of pesticide residue. Apples, peaches and other produce falls into the same category. If I cannot find these organically grown items, I do not buy or consume them at all.

Essentially, I follow the EWG’s (Environmental Working Group) Shopping Guide to Pesticide in Produce, because I trust EWG as our best resource to avoid harmful chemicals.

Bottom Line

If you are reading this, you are probably a cancer survivor, care for someone hosting cancer, or someone who would otherwise like to avoid it altogether. Science moves along at glacial speed.

Do not wait for all the evidence to unfold. You live in the here and now. Follow EWG’s guidance and consume ‘clean foods’ while avoiding compromised, conventionally-grown foods known to be laden with detrimental pesticide and herbicide residue such as glyphosates (think: Roundup), a well-known hormone disrupter.

Photo credit: BigStock.com/MihailoK