A new, much-ballyhooed study showing that the most avid consumers of organic food had fewer cancers than those who never eat such products illustrates the difficulty of establishing cause and effect when evaluating diet and health. It is effectively impossible to prove beyond a doubt in a laboratory that any given food reduces the risk of developing an illness as complex as cancer.
"Diet is complex," Nigel Brockton, the director of research at the American Institute for Cancer Research (AICR), told AFP. Researchers, like the French team behind Monday's study, must then follow a large test group and wait for cancers to develop in some of the subjects.
They then hope that after the fact, they can isolate a specific behavior among all those who are sick that made the difference. Thousands of studies on diet and illness have been conducted for decades. Even the findings of the largest are sometimes disputed, like one in 2013 that purportedly showed the sweeping benefits of the so-called Mediterranean diet in combatting heart ailments.
That study was retracted from the prestigious New England Journal of Medicine earlier this year over criticism of the methods used. Only one major study on the nexus between organic food and cancer had been carried out before the latest effort published in the Journal of the American Medical Association (JAMA) Internal Medicine.
That 2014 research, known as the Million Women Study, used a test group of 600,000 British women. It found no overall difference in cancer risk between those who ate organic food and those who didn't. It only found that organic food lovers had a reduced risk of developing non-Hodgkin's lymphoma. So then, how does one approach the new study by the French team? It is certainly more detailed than the Million Women Study, though it looked at 69,000 women - roughly 10 percent of the sample size.