For years, the nutritional message was clear: Eat more fruits and vegetables. They are rich in fiber, vitamins, minerals, antioxidants, and plant compounds that have been linked to better health and a reduced risk of some chronic diseases. But in recent years, another question has arisen: Does it also matter how the fruits and vegetables were grown? Is there a health difference between organic and conventional produce?
A new study published in The American Journal of Clinical Nutrition examined exactly this question. The researchers analyzed data from more than 31,000 adults in France, from the large NutriNet–Santé cohort study, and examined whether replacing conventional fruits and vegetables with organic fruits and vegetables is associated with a lower risk of cancer over the years. The most prominent finding was in the field of breast cancer: Replacing 100 grams per day of conventional fruits and vegetables with organic fruits and vegetables was associated with an approximate 10% decrease in the risk of postmenopausal breast cancer.
It is important to emphasize right at the outset: The study does not prove that eating organic fruits and vegetables prevents cancer. This is an observational study, and therefore it can show an association, but cannot definitively prove cause and effect. Still, this is an important and interesting study, because it touches on one of the most practical questions in modern nutrition: We want to encourage the consumption of fruits and vegetables, but these very foods may be a significant source of exposure to pesticide residues.
What did the researchers examine?
The researchers used data from the NutriNet–Santé study, a large French study that tracks the dietary and health habits of adults over time. Participants completed detailed dietary questionnaires, in which they were asked not only how many fruits and vegetables they eat, but also how often each food they consume is organic.
This is a significant advantage compared to previous studies, in which organic food consumption was sometimes measured by a very general question, such as "Do you eat organic food?". Here, the researchers were able to estimate more accurately how much of each participant's fruit and vegetable consumption was organic and how much was conventional.
The study included 31,179 participants. About 75% of them were women, and the average age was 53. The follow–up lasted an average of 7.3 years. During this period, 1,718 cases of cancer were diagnosed, including 284 cases of postmenopausal breast cancer.
The researchers attempted to neutralize many factors that might affect cancer risk, including age, sex, education, income, smoking, alcohol consumption, physical activity, body weight, family history of cancer, overall diet quality, and consumption of various foods. In the analysis of postmenopausal breast cancer, the researchers also took into account factors such as age at menarche, use of hormone therapy, and number of childbirths, factors that can affect the risk of breast cancer.
The central finding: The strongest association was for postmenopausal breast cancer
When the researchers examined the replacement of conventional fruits and vegetables with organic fruits and vegetables, a relatively small association was found with the overall risk of cancer: Each replacement of 100 grams per day was associated with an approximate 2% decrease in the overall risk of cancer. However, this association was borderline and did not appear with the same consistency across all forms of analysis.
In contrast, for postmenopausal breast cancer, the result was clearer. Each replacement of 100 grams per day of conventional fruits and vegetables with organic ones was associated with an approximate 10% decrease in risk. When the participants were divided into five groups according to the level of replacement to organic, the group that consumed the highest proportion of organic fruits and vegetables was at a significantly lower risk compared to the group that consumed the lowest proportion.
No clear association was found for prostate cancer, colorectal cancer, or skin cancer. This does not necessarily mean there is no association at all. It is possible that the study did not have enough statistical power for each type of cancer individually, or that the effect is more relevant to types of cancer that are influenced by hormonal mechanisms.
The main hypothesis is reduced exposure to pesticides. Organic food generally contains fewer residues of synthetic pesticides compared to conventional produce. Previous studies have also shown that people who eat more organic food tend to excrete lower levels of breakdown products of certain pesticides in their urine.
Some pesticides may affect biological mechanisms relevant to cancer development. They may affect oxidative stress, DNA damage, epigenetic changes, chronic inflammation, hormonal disruption, and alterations in metabolism. Such mechanisms may be particularly relevant in postmenopausal breast cancer, where hormones, adipose tissue, inflammation, and metabolic health play a significant role.
The researchers specifically refer to the possible effect of pesticides as endocrine disruptors, meaning substances that can interfere with the body's hormonal activity. Some of them may mimic estrogenic activity, affect androgen receptors, disrupt thyroid hormone activity, or affect progesterone activity. All of these do not prove that pesticides in food cause breast cancer, but they provide a possible biological explanation for the finding observed in the study.
In addition, there is growing interest in the link between pesticides and the gut microbiome. The microbiome affects the immune system, inflammation, hormone breakdown, metabolism, and even the risk of chronic diseases. This is still an evolving field of research, but it is possible that in the future it will turn out to be an important part of the link between environmental exposure and cancer risk.
Is it now mandatory to buy only organic?
No. The most important message still remains: Eat enough fruits and vegetables. People should not reduce their consumption of fruits and vegetables just because they cannot afford to buy organic. The benefits of a plant–rich diet are well established.
However, this study suggests that when it is economically and practically possible, choosing organic produce may be a logical way to reduce exposure to pesticide residues. This may be particularly relevant for people who eat a lot of fruits and vegetables, and for postmenopausal women seeking to reduce risk factors for breast cancer.
The practical approach does not have to be extreme. One can start with the fruits and vegetables that are eaten the most at home, or those that tend to contain more pesticide residues. It is not necessary to turn the entire basket organic in one day. Even a partial replacement can be a reasonable step. In addition, diversifying the diet and choosing seasonal produce can also help reduce exposure.
What are the study's limitations?
The study has several important limitations. First, it is an observational study and not a randomized trial. People who choose organic food may differ from people who do not choose it: They may be more health–conscious, undergo more screening tests, engage more in physical activity, or adhere to other healthy habits. The researchers tried to account for many factors, but it is always possible that unmeasured factors exist.
Second, the dietary data were based on self–reporting, and self–reporting is not perfect. Third, the population in the study was predominantly female, French, and relatively health–conscious, so it is not certain that the results would be identical in every country and every population. In addition, for some types of cancer, the number of cases was relatively small, making it difficult to draw strong conclusions from them.
Still, the study also has significant advantages: It is large, prospective, detailed, and examined not just "how many fruits and vegetables are eaten", but what happens when the same amount of fruits and vegetables comes more from an organic source and less from a conventional source.
Ultimately, this study reminds us of an important point: Everything we put into our mouths can affect our health, not only in terms of calories, vitamins, or fiber, but also in terms of the substances that accompany food on the way from the field to the plate. Therefore, when we choose fruits and vegetables, it is worth thinking not only about the quantity we eat, but also about their source, how they were grown, and the question of whether they might contain pesticide residues.
The message is not to stop eating conventional fruits and vegetables or to panic over every apple that is not organic. Fruits and vegetables are still a central part of a healthy diet. But the study does reinforce the importance of making more informed choices: When it is economically and practically possible, priority should be given to organic produce, especially for foods we eat frequently and for fruits and vegetables that tend to carry more pesticide residues.
Cancer is almost never caused by a single factor alone. It develops from a combination of genetics, hormones, diet, inflammation, metabolism, the microbiome, and environmental exposures over years. Therefore, even if organic produce is not a "magic shield", it can be another practical way to reduce the daily environmental burden on the body. In this sense, choosing cleaner food is not a trend, it is part of a broader way of thinking about health, prevention, and responsibility toward our bodies.
Dr. Dalit Dmean–Medina is a functional and integrative physician