Way back in 1946, the esteemed British medical journal the Lancet declared in an editorial that organic fanatics were making health and nutrition claims way beyond what the science supported. Oh how little has changed since then.
The media is once again pronouncing organic food superior based on science fad and the findings of a single study taken well beyond what the evidence shows.
The latest salvo in this debate is a simple study of processing tomatoes (the kind used to make paste and sauces) grown over the past decade by a group of California researchers. The researchers, led by Dr. Alyson Mitchell, report that irrigated processing tomatoes grown using organic methods contained roughly twice as much of two flavonoid antioxidants, quercetin and kaempferol.
These are the two most abundant “flavonoids” in our diet “linked” to reduction in some forms of cancer and lower blood pressure, which reduces the risk of heart disease and stroke. Link means “far from provent” in science, but the media thrives on rumor. Hence, the river of newspaper ink spilled in the past month on how organic vegetables and fruits “really are better for you” because they are “full of antioxidants.”
Whether the findings have any bearing on your health or on flavonoid levels in organic tomato paste at your local market are both completely unknown.
For example, the organic tomatoes used twice as much irrigation water as the conventional ones – in a state that is already desperately short of fresh water. They were also provided one-third more nitrogen and 3-fold more phosphorus each year than the conventional tomatoes via cow manure fertilizer. Yet California only has enough animal manure to support about 10 percent of its current produce production. Unless the organic tomato paste you buy is grown specifically under these conditions with the same tomato variety, who knows what the flavonoid levels will be.
If you really want to be sure to get “more” flavonoids, Unilever Research and the University of Exeter have developed a GM line of tomatoes that produce as much as 78-fold more flavonoids without special growing requirements. Now that’s a difference!
But even that may not mean much. While there is evidence that eating some fruits and vegetables is healthful, consuming lots, or more flavonoids or antioxidants has yet to show any health benefits whatsoever.
In a new follow-up study of more than 3,000 breast cancer survivors followed for over 7 years published in the July issue of the Journal of the American Medical Association, women who ate up to 12 servings of fruits and vegetables each day had exactly the same recurrence and new cancer rate as women who ate only five a day. This lack of change in cancer incidence despite a doubling of consumption in antioxidants is a fly in the organic sauce. Perhaps they are suggesting we can get the benefits of 5 servings of fruits and vegetables by eating only two servings of organic – which would be good considering organics cost twice as much.
All of this assumes that flavonoids and antioxidants truly have anti-cancer benefits, and no studies have yet actually shown that. In fact, it was not long ago that beta-carotene, another vegetable antioxidant, was thought to protect against cancer. Then a clinical trial was started to see if it really did. The study was halted early after it was discovered that those consuming more beta-carotene had increased cancer risk.
At this point, the entire “antioxidant” theory of cancer prevention is faring poorly. Just this month the U.S. Food and Drug Administration told tomato product manufacturers that they can no longer proclaim on food labels that lycopene, another high-profile tomato “antioxidant,” might reduce the risk of prostate or other cancers. The agency reviewed 81 studies supposedly supporting this claim and found “no credible evidence supporting a relationship between lycopene consumption, either as a food ingredient, a component of food, or as a dietary supplement, and any of the cancers evaluated in the studies.”
What about the claim that antioxidants lower blood pressure, and, thus, the risk of heart disease and stroke? Scores of media reports treat this claim as if it was irrefutable. Yet here, too, the science is far less clear than the media portrays.
Studies have shown that in people with high blood pressure, a diet rich in fruits and vegetables lowers blood pressure slightly (3-4 mm of Hg). Just precisely what in that diet is responsible for this slight drop has been the big question, with many assuming a role for flavonoids and other antioxidants. But new research published last December in the New England Journal of Medicine indicates it could be the nitrates, not the antioxidants, which lower blood pressure. Daily nitrate supplements equal to the amount found in a quarter pound of spinach lowered blood pressure in study subjects by an amount equal to the drop seen in the dietary studies. If it is nitrates that lower blood pressure, not the “antioxidants”, conventional vegetables are the healthier option. Studies repeatedly show that regular, non-organic vegetables have between 10-50 percent more nitrates than organic ones.
So if you’re worried about protecting yourself from cancer and high blood pressure, the science says you’d be best off eating a balanced diet that includes a variety of fruits and vegetables and forgetting the organic hype and high prices.
Dennis T. Avery is a senior fellow for Hudson Institute in Washington, DC and the Director for Global Food Issues. He was formerly a senior analyst for the Department of State. Readers may write him at Post Office Box 202, Churchville, VA 24421.
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