This BBC story doesn't give very clear answers, and highlights that science is a political process, like so much in the modern world.

Some new research has been published, which shows that organic foods are "higher in nutrients and lower in pesticides" than conventional foods. The story refers to the new research as a meta-analysis, meaning that existing research data was re-analysed, rather than being based on new sampling and measurement of food content. There is nothing wrong with meta-analyses, as the original studies tend to be focussed on specific nutrients and pollutants, and only by combining them can broader conclusions about the health benefits of food be drawn.

The conclusions of the new research differ from the last two studies on this subject, mainly due to the existence of new and more comprehensive input data.

Some scientists, however, disagree with the results, including Prof Tom Sanders, head of the Diabetes and Nutritional Sciences Division at King's College London's School of Medicine. He says "This article is misleading because it refers to antioxidants in plants as if they were a class of essential nutrients, which they are not. In terms of macro-nutrients (protein, carbohydrate, fat), the organic products contained less protein. Other nutrient differences were trivial and well inside the normal range of variation that occurs with different varieties, soil types and variations in weather."

It seems that the progress in nutritional science in recent years has largely passed Prof Sanders by. The claimed health benefits of organic foods are not that they contain more macro-nutrients (protein, carbohydrate and fat), as he suggests, but that they contain more good micro-nutrients (antioxidants, vitamins and minerals, for example), and less pesticides and heavy metals. Using Prof Sanders criteria, the most healthy meals would be things like steak and chips (fries), and not many nutritionists would claim that was a super-healthy meal. We could all live on super-concentrated meals like astronaut food and get all the macro-nutrients that we need, and I don't think that we would be healthy as a result.

The new story does contain some sensible stuff, of course, such as the statement that "Ultimately, we all need to eat more fruit and vegetables, regardless of whether they are organic or not, to form part of a healthy balanced diet, which will help protect health."

The real problem that the statements by Prof Sanders and others highlight, however, is the way science works. Just because a study shows evidence of something (whether that a new kind of subatomic particle exists, that global warming is real, or that organic food is more healthy than non-organic food) does not mean that it is automatically accepted into the accepted body of scientific "knowledge". Sometimes vital and ground-breaking research is simply ignored by other scientists. Often scientists disagree, and perform additional research to disprove the disputed findings, but even if the attempts to disprove fail, the disputed research may not be accepted for decades (or longer). The history of science is full of examples of this. Sometimes the root cause is that some scientists simply cannot understand the new research; sometimes because they have vested interests in the new research being wrong.

A good example of politics in science is the fact that Albert Einstein (a very clever scientist and the author of some key scientific work) never accepted quantum mechanics (which is the cornerstone of much modern science and technology), because it is based on the uncertainty principle (first postulated by Heisenberg - that is the original Heisenberg, not the methamphetamine king from Breaking Bad). Einstein said that he couldn't accept "that God throws dice". Science eventually moved on despite objections from Einstein and others, but the development and acceptance of quantum mechanics was delayed by the objections.