Original URL: http://www.theregister.co.uk/2014/04/04/organic_food_health_cancer/

Organic food: Pricey, not particularly healthy, won't save you from cancer

Study of 'organic' food consumption and cancer risk showed some interesting results

By Dr Pan Pantziarka

Posted in Science, 4th April 2014 09:04 GMT

Comment One of the primary drivers of the growth in organic food sales over the last couple of decades is the perception that organic food is healthier than conventionally farmed food.

It stands to reason, doesn’t it? After all conventional crops depend on chemicals and organic food doesn't.

And we all know that chemicals, in this case mainly pesticides, are bad for you. Ergo organic food should be healthier, and the strong growth in organic food sales (up 2.8 per cent last year, after a few years of downturn during the recession) attests to how popular opinion has accepted this assertion.

This is why the results of a new UK study that looked at cancer risk and the consumption of organic food is so damned inconvenient. Where organic food advocates have pushed organics as a way of reducing cancer risk, the study shows that it makes little difference one way or another. Hence uncomfortable headlines from the likes of the Daily Mail: Eating organic foods does NOTHING to reduce the cancer risk among women, says new study.

6,000 eaters probed

Fruit and vegetables on display on the shelves of a supermarket

Organic, not organic? Makes no difference. Pic by Daniel Cukier (C) Attribution-NoDerivs

The study in question appears in the latest edition of the British Journal of Cancer and is by Oxford University cancer epidemiology boffin Dr Kathryn Bradbury and co-workers. Part of the Million Women Study funded by Cancer Research UK and the Medical Research Council, this particular bit of research tracked 623,080 middle-aged British women for almost 10 years and looked at their pattern of organic food consumption and the incidence of 16 different cancer types, as well as overall cancer incidence.

Based on their reported eating habits the women were put into three groups: never, sometimes, or usually/always eating organic food. The headline result showed that eating organic food was not associated with overall cancer incidence one way or another (in fact there was a tiny increased overall risk of about 3 per cent, but it’s the sort of noisy result one can ignore). Look at the specific cancer types and the results are mixed, with some showing increased or decreased risks, but again nothing to be alarmed (or pleased) about.

Of course this has upset some, especially the British Soil Association, the guardian of all things organic in the UK (including being the premier organic certification body in the country).

According to Peter Melchett (aka Lord Melchett or the 4th Baron Melchett, ex-Greenpeace head honcho and now Policy Director at the Soil Association) the study is flawed because certain confounding variables weren’t addressed and because, according to him, the authors don’t understand what pesticides are found in food or how they get into food.

However, he was quick to pick out one of the results for particular attention – the numbers show that there is an apparent 21 per cent decrease in non-Hodgkins lymphoma risk among the women who reported "usually or always" eating organic food.

However, there were other numbers that were not picked out by the Soil Association, the most alarming of which was the apparent 9 per cent increase in the risk of breast cancer. This was a result that the study authors subjected to a series of additional tests and the results still stood. More alarming still was the 37 per cent increase in the risk of developing a soft tissue sarcoma, a form of cancer which is rare and hard to treat. Why no mention of those figures at the Soil Association?

It's all relative

Of course the fact is that all of these figures are dealing with relative risk, which is standard practice in epidemiological studies. To get some perspective, the chances of getting non-Hodgkins lymphoma is about 2.1 per cent, so if the results of this study hold true, then sticking to an always organic diet will reduce that to 1.66 per cent.

The figures for breast cancer are around 12.3 per cent life-time risk, and this will be increased to 13.4 per cent if you go the all organic route. And if you really want to trade punches with the proponents of organic, you can point out that a high-organic diet will lead to more cancers as the incidence of breast cancer is much higher than the incidence of non-Hodgkins.

However, it’s unlikely that this finding is going to do much to dissuade the faithful that the benefits of organics have been over-sold. After all, this is not the first negative study when it comes to organics and health. A systematic review published in the Annals of Internal Medicine in 2012 found that: "The published literature lacks strong evidence that organic foods are significantly more nutritious than conventional foods".

There were differences reported to do with pesticide residues but nothing to cause alarm. In terms of nutrient content, there was one statistically significant nutrient where organics outdid conventional produce: phosphorous. Now, if you’re starving, then eating organic is the better choice, but if you’re not, then increased phosphorous is pretty much irrelevant as it’s abundant in the diet no matter where it comes from.

Of course it’s the pesticide residues that ultimately drive the idea that organics are better for us. This ignores the fact that even organic food uses pesticides, for example rotenone and pyrethrin, some of which are considered carcinogenic or otherwise hazardous to health.

And, just to throw in some numbers, a study by the United States Department of Agriculture in 2012 found that 4 per cent of organic food samples had pesticide residues above the 5 per cent EPA limit, which technically meant they would have failed the organic certification they carried.

But leaving that aside, the chemophobia of much of the population is stoked by the use of in vitro studies which show that certain pesticides are carcinogenic. However, there is a huge difference between the inside of a petri dish and the inside of a human.

Pesticides are amongst the most heavily regulated chemical agents in the world, and if there was a link to cancer incidence then we would expect to see it in studies such as this one, and in studies that looked at farm workers and others who have greater exposure to pesticides.

One recently published paper looked at the incidence of cancer in agricultural workers in France during the period 2005 – 2009 (the AGRICAN study). It reported that overall agricultural workers were healthier than the general population, with reduced cancer incidence compared to the general population in the same areas. So where are the bodies (so to speak)?

There are, of course, problems with this new study in the UK. For one there was no stratification by type of organic diet – so, for example, we don’t know whether the lymphoma result was skewed by an excess of vegans or carnivores.

And the categories of "never", "sometimes" and "usually/always" are by necessity coarse and difficult to quantify – for example how can you tell how much non-organic food the "usually" group eats?

But for all that, this is study with a large sample size and if there was a positive signal that eating organic protects against cancer you’d expect to see it.

The upshot? It’s probably true to say that spending the pennies (or pounds) you save by eating non-organic on eating MORE fruit and veg is a healthier bet than forking out the extra for "organics". ®