A New Organic Stew

by Howard Fienberg
April 22, 2002

A classic canard from supporters of organic food is that it is more healthy for you than regular, pesticide-grown food. Decent scientific evidence to support this position has never materialized and some supporters have had to admit that the health claims of organic food seem hollow.


So organic food proponents must have been elated by a New Scientist report last month that eating organic food may help reduce your risk of heart attacks, strokes and cancer. Was this the evidence they’ve been searching for?


Scottish researchers (from the Dumfries and Galloway Royal Infirmary and the University of Strathclyde) published a study in the European Journal of Nutrition comparing the levels of salicylic acid (SA) in organic and regular varieties of vegetable soups. They discovered that the organic soups contained almost six times the amount of SA as the regular ones.


What’s the big deal about SA? It is, according to the New Scientist, responsible for the anti-inflammatory action of aspirin, and helps combat hardening of the arteries and bowel cancer. The researchers speculate that SA in the diet may help to prevent these conditions.


Souped Up Numbers


Unfortunately, a look at the study raises some jarring questions.


Why didn’t the researchers test the vegetables directly? A more rigorous design would have been to compare specific vegetables, organic versus ordinary, to look for the difference in SA levels. Why did they instead test soup, which is a combination of many different vegetables?


In all, the researchers looked at 11 different organic soups and 24 different regular soups. Commercial soups all use different ingredients and the information available on exactly how much of each ingredient is in the final product is often poor. Why did the researchers not design a properly controlled study where they cooked the soups themselves, with the same types of ingredients in each one, organic versus ordinary?


To Your Health?


Another big question revolves around salicylic acid itself. The kind of SA in vegetable soup is not necessarily comparable to that in aspirin, where the researchers are speculating it has an effect. The active ingredient in aspirin is not ordinary SA, but a soluble version more easily absorbed in the stomach called methyl salicylate. Thomas Coles, research leader at the New Zealand Institute for Crop & Food Research, says that because the SA component of vegetable soups (organic or ordinary) is determined by what has happened to the vegetables prior to being cooked, the amount of SA will inevitably vary. That makes it of little use to patients trying to prevent blood clotting, which requires a finite, known amount of aspirin (and thus, methyl salicylate) to be taken regularly.


If consumers want SA in their soup, it would presumably be cheaper and more effective to crumble aspirin tablets and add the crumbs into their soup than to fuss over organic or ordinary varieties.


Salicylic acid also has its own down side. Coles also points out that some people suffer from a disease called acute porphyria, which makes them effectively allergic to SA. If organic growers intend to tout the health benefits of the increased levels of SA in their organic food, should they not also slap warning labels on their produce, saying May contain high levels of salicylates; should not be consumed by persons with salicylate intolerance?


Amount Matters


Such questions on their own would ordinarily be more than enough to demonstrate the value in a study (or, in this case, the absence thereof). However, even disregarding all the above questions, one problem still remains: scale.


What did the researchers find exactly? The organic soup they tested had an average of 117 nanograms of SA per gram of soup, while the regular soups averaged 20 nanograms/gram.


What does that mean for the consumer? According to their research, a typical 400-gram serving of organic vegetable soup would thus contain 46,800 nanograms of SA versus the 8,000 nanograms of SA found in an equivalent serving of ordinary vegetable soup. That looks like an impressive difference at first glance.


However, let’s look at the scale more closely. A nanogram is a billionth of a gram (that’s 9 zeros). Or 0.000000001% of a gram. So for our comparison above, the differential of 3,880 nanograms favoring the organic soup is mind-bogglingly minute. The 400 gram organic soup serving would have 0.000047 grams or 0.00047% of a gram of SA. The equivalent regular soup serving would have 0.000008 grams or 0.00008% of a gram of SA.


Alex Avery, director of research for the Center for Global Food Issues, laughed at the tiny amounts. He wished he could have seen the researchers arguing about the physiological differences involving thousandths and ten-thousandths of a gram while holding a straight face.


Scientists may yet discover tangible evidence that organic food is healthier for us than regular food. Unfortunately, this study doesn’t show any.  

See the original:

return to Howard Fienberg's page