Based on an extensive literature review the jury is still out on this one – as far as evidence based medicine is concerned:
Organic food: buying more safety or just peace of mind? A critical review of the literature.
Magkos F, Arvaniti F, Zampelas A.
Int J Food Sci Nutr. 2003 Sep;54(5):357-71
Consumer concern over the quality and safety of conventional food has intensified in recent years, and primarily drives the increasing demand for organically grown food, which is perceived as healthier and safer. Relevant scientific evidence, however, is scarce, while anecdotal reports abound. Although there is an urgent need for information related to health benefits and/or hazards of food products of both origins, generalized conclusions remain tentative in the absence of adequate comparative data. Organic fruits and vegetables can be expected to contain fewer agrochemical residues than conventionally grown alternatives; yet, the significance of this difference is questionable, inasmuch as actual levels of contamination in both types of food are generally well below acceptable limits. Also, some leafy, root, and tuber organic vegetables appear to have lower nitrate content compared with conventional ones, but whether or not dietary nitrate indeed constitutes a threat to human health is a matter of debate. On the other hand, no differences can be identified for environmental contaminants (e.g. cadmium and other heavy metals), which are likely to be present in food from both origins. With respect to other food hazards, such as endogenous plant toxins, biological pesticides and pathogenic microorganisms, available evidence is extremely limited preventing generalized statements. Also, results for mycotoxin contamination in cereal crops are variable and inconclusive; hence, no clear picture emerges. It is difficult, therefore, to weigh the risks, but what should be made clear is that ‘organic’ does not automatically equal ‘safe.’ Additional studies in this area of research are warranted. At our present state of knowledge, other factors rather than safety aspects seem to speak in favor of organic food.
However studies do show that children eating conventionally grown food have notable levels of pesticides in their urine (Eating Organic Dramatically Lowers Children’s Exposure to Organophosphate Pesticides. Crit Rev Food Sci Nutr. 2006;46(1):23-56.) and that an organic diet helps men create better functioning sperm. (Human semen quality in relation to dietary pesticide exposure and organic diet. Juhler RK, Larsen SB, Meyer O, Jensen ND, Spano M, Giwercman A, Bonde JP. Arch Environ Contam Toxicol. 1999 Oct;37(3):415-23. )
A note of caution about evidence based medicine: lack of evidence is often due to a lack of research. Ask yourself this – who funds scientific research and what agenda do they have?
Most sources agree that conventional farming is unhealthy for the planet as a whole. Also, organically raised cattle in the UK has never had an outbreak of BSE.
A variety of nutrients have been shown to be depleted by pesticides. Those most affected are: vitamins B and C and beta-carotene. Conventional food is also higher in heavy metals such as aluminum, mercury and lead. On the other hand organically grown food has been found to be significantly higher in chromium, selenium, magnesium and calcium.
US sources state the highest pesticide residue is found in the following foods: apples, peaches, melons, strawberries, green beans, squash and spinach.
I tend to recommend that you also choose organic – corn, broccoli, root vegetables and coffee. Coffee is one of the most sprayed crops in the world!
The bottom line is we need a minimum of 5 serves of vegetables and a couple of pieces a fruit a day. If you can’t afford organic – look for what is freshest and wash or peel food.