Research article: organic food consumption

A recently published scientific article from France.:

The frequency of organic food consumption is inversely associated with cancer risk: results from the NutriNet-Santé prospective Cohort

by J Baudry, KE. Assmann, M Touvier, B Allès, L Seconda, P Latino-Martel, K Ezzedine, P Galan, S Hercberg, D Lairon and  E Kesse-Guyot., published in the JAMA Internal Medecine : JAMA Intern Med. Published online October 22, 2018. doi:10.1001/jamainternmed.2018.4357.


Summary of the paper and comments

While organic foods are less likely to contain pesticide residues than conventional foods, few studies have examined the consumption of organic food in relation to cancer risk.

Our aim was to prospectively investigate the association between organic food consumption and the risk of cancer in a large cohort of French adults.

The design is a prospective cohort study with 4.56 years follow-up in population-based French adult volunteers.

Data are from 68,946 participants (78% women, mean age=44y) with available information on organic food consumption frequency and dietary intake. For 16 food products, participants reported their consumption frequency of labeled organic foods (never, occasionally, most of the time). An organic score ranging from 0 to 32 points was computed. A total of 1,340 first incident cancer cases were identified during follow-up of 4,56 years (2009-2016), among which 459 breast cancers, 180 prostate cancers, 135 skin cancers, 99 colorectal cancers, 47 non-Hodgkin lymphomas and 15 other lymphomas. The risk of cancer in association with the organic score (modelled as quartiles (Q)) was estimated using Cox proportional hazards models, adjusted for potential cancer risk factors.

Results: After adjustment for confounding factors, high organic scores were inversely associated with the overall risk of cancer (HRQ4 vs. Q1=0.75, 95%CI=0.63-0.88, P-trend=0.001, This means an overall cancer risk reduction by 25%. The decrease in cancer risk was –8% (95%CI=-12%–4%) for a 5-point increase in the organic score. We observed reduced risks for specific cancer sites (Non Hodgkin Lymphomas (- 86%), lymphomas (- 76%) and post-menopausal breast (- 34%)) among individuals with a higher frequency of organic food consumption. Skin cancer was borderline significantly reduced (-37%). When stratifying by various factors, significant associations were detected in women, older individuals, low and high educated individuals, individuals with a family history of cancer, participants with low to medium overall nutritional quality, former smokers and all BMI strata

General comments. A higher frequency of organic food consumption was associated with a reduced risk of cancer, and especially for some sites. If these findings are confirmed (regarding lymphomas, in the middle-aged UK women of the Million Women Study, there was a 21% lower risk of lymphomas among regular organic consumers compared to non-consumers), further research is necessary to determine the underlying factors potentially involved in this inverse relationship.

One possible major explanation for the negative association between organic food frequency and cancer risk is that the prohibition of synthetic chemical pesticides in organic farming leads to a lower frequency or absence of contamination in organic foods as compared to conventional foods  and results in significant reductions in pesticide levels in urine. In 2015, based on experimental and population studies, the IARC (WHO) has recognized the carcinogenicity of a certain number of pesticides. Another potential impact of organic foods could be due to the highest content of such foods in various antioxidants and protective fatty acids  that are not accounted for in the present calculations due to the lack of a specific composition database.

Full article