I think, first, it’s important to understand fundamentally what is the difference in organic versus non-organic farming. Then, once we are on the same page regarding the definitions we can move on to interpreting the research findings. In order to understand what ‘organic farming’ means, I have reviewed the definitions and guidelines supplied by USDA NOP (US Organic certifying body ‘National Organic Program’), Soil Association (UK Organic certifying body), ACO (Australian Certifying body), Eco Cert (European certification) and then summarised them at a high level in the below diagram. (1,2,3,4)
Firstly, the science is conflicting. From afar a study published in the British Journal of Nutrition by Leifart et al. appears to show a significant difference in the nutritional content of organic versus non-organic fruits and vegetables (5). This study reviewed 343 peer-reviewed publications and concluded:
In conclusion, organic crops, on average, have higher concentrations of antioxidants, lower concentrations of Cd (toxic metal) and a lower incidence of pesticide residues than the non-organic comparators across regions and production seasons.
The theory behind the higher antioxidant levels in the organic produce found in the above review was that organic fruits and vegetables have to fend for themselves and in doing so, produce more phytonutrient antioxidants to protect themselves against bugs. And taking a step further, science shows these antioxidants are particularly helpful in reducing free radical damage and reducing the chances of developing many chronic illnesses when incorporated in the human diet.
The problem I have with this study is that it’s findings are of stark contrast to another systematic review and it was funded by the European government and an Organic Charity called Sheepdrove (6,7). Whilst I want to believe it, I just can’t get my head around the fact the study has been funded by a charity who owns and operates what appears to be a business that would significantly benefit from good publicity surrounding Organic farming.
In the 2012 Systematic Review performed by a group of researchers at Stanford University found no difference in the nutrients when it conducted a review on 240 studies (6). They did, however, make comment about pesticides and bacteria in their conclusion:
The published literature lacks strong evidence that organic foods are significantly more nutritious than conventional foods. Consumption of organic foods may reduce exposure to pesticide residues and antibiotic-resistant bacteria
This paper reported no conflicts of interest and received funding from a university grant – no organic bodies or companies to benefit from a particular result were involved. Personally, out of the two large systematic reviews, this one appears to be from a more believable source…who knows what studies were omitted out of the first study (or included) to result in the “Organic Is Superior” finding.
It appears the macronutrients between Organic and Conventional produce are not dissimilar. At a micronutrient level, there appears to be conflicting findings, however the strongest paper without any conflict of interest reports no significant nutrient differences between organic and non-organic fruits and vegetables. This means they found no significant difference in calories, carbohydrates, fibre, sugars, protein or vitamins/minerals, etc.
However, given conventional farming can use any number of over 300 permitted artificial pesticides, it is highly probable that in consuming non-organic (conventional) produce you are exposing your body to artificial pesticides, herbicides and fertilisers which you would otherwise be avoiding if you were consuming organic produce. Are these at a level that will effect your health? There’s no evidence to suggest that the artificial pesticide levels are harmful (they fall within ‘safe limits’), but I wouldn’t recommend being the study cohort to test this over the coming decades. We can certainly learn a lot by looking at areas of the world that have the highest number of centurions and highest quality of life: The Okinawan’s (9).
Okinawans have less cancer, heart disease and dementia than western populations, and women there live longer than any women on the planet. Coincidentally, they do gardening well up into their 100’s, plant medical gardens, eat a largely plant-based diet and consume organic fruit and vegetables free from any artificial pesticides/residues. Of course, there are no doubt other aspects of their peaceful lives that contribute to their longevity (sense of purpose, close family connections, etc.) but this is certainly a very relevant lifestyle factor worth considering.
Putting the nutrient, and perhaps chemical composition, of the foods aside it also appears that organic farming is more sustainable from an environment point of view and has less affect on animals and humans living nearby the crop farms.
So for these reasons my preferred option is organic, despite not an overwhelming amount of evidence in support of them from a true nutritional point of view…yet! In saying that, I am a big believer that non-organic produce is still better than not consuming fruits/vegetables at all! So in other words, if you cannot afford organic produce or access it in your area then do not shy away from standard produce.
If budget is an issue and you can only buy some organic produce, here is a list of the best plants to source as organic. These are the plants that typically have the highest concentrations of pesticides if farmed conventionally:
Detergents or retail fruit and vegetable washes seem to make no real difference (8).
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