The present evidence is not supporting this! However, a new study published in a promianat medical journal suggests that a higher frequency of eating organic food was associated with a reduced risk for cancer (JAMA Internal Medicine) (1). This means that promoting organic food consumption in the general population could be a promising preventive strategy against cancer
In this study which was conducted in France the investigators enrolled 68,946 participants in the NutriNet-Santé Study online and then classified them into four quartiles according to their self-reported consumption of 16 groups of organic products. The team followed the participants for a mean of 5 years. Participants with the highest frequency of organic food intake had a 25% lower relative risk for a cancer diagnosis during follow-up compared with those with the lowest frequency. This French study reported that the risk reduction was mainly for postmenopausal breast cancer and lymphomas.
Uncertain link.
There are many studies on diet that have failed to show such results. The overall link is uncertain between cancer risk and organic food consumption as of now. It is interesting to note that another large study, United Kingdom’s Million Women Study, found that organic food consumption was linked to a slightly increased breast cancer risk (2).
On the other hand, there are many other studies that suggested that occupational exposure to pesticides was associated with different cancers, most strongly, non-Hodgkin lymphoma (type of blood cacner).
Limitations of Dietory Studies.
I have conducted dietorary studies (3). I can admit that diet is quite difficult to assess. The quantity of organic food intake is notoriously difficult to assess, and its self-report is highly susceptible to confounding by positive health behaviors and socioeconomic factors. Added to that the French study was a short study in dietory terms. It was only 5 year follow-up. The effect of diet need to be studied over longer time.
Also, diet crossover trials have shown that switching from conventionally grown to organic foods decreases urinary concentrations of pesticides. However, how far this affects cancer formation is unknown.
There will probably never be a randomized trial comparing organic food with conventionally produced food, owing to the long follow-up period needed to detect cancers and the high cost of organic food.
General advice on nutrition.
For overall health, current evidence indicates that the benefits of consuming conventionally grown produce are likely to outweigh the possible risks from pesticide exposure because of consumption. Concerns over pesticide risks should not discourage intake of conventional fruits and vegetables, especially because organic produce is often expensive and inaccessible to many populations.
It is important to limit red and processed meat and added sugars. The diet should replace refined grains with whole grains, and increases consumption of fruits and vegetables.
References:
- https://jamanetwork.com/journals/jamainternalmedicine/article-abstract/2707948
- http://www.millionwomenstudy.org/publications/375/organic-food-consumption-and-the-incidence-of-cancer-in-a-large-prospective-study-of-women-in-the-united-kingdom
- http://journal.waocp.org/?sid=Entrez:PubMed&id=pmid:19827870&key=2009.10.4.565
