Nutrition and health news in television, print and the Internet often confuse you. Coffee is good for you one morning but next morning, you are told it leads to osteoporosis. Milk is good for bones but bad for cancer patients. Margarine is better than butter…..no wait, may be butter is better after all. Fish is great food and just when you start eating it regularly, it contains toxic mercury. What does the public do when scientific research keeps contradicting itself? Such flip-flops can be maddening, especially when you’re making your best effort to live a healthy lifestyle. Why go to the trouble of making big changes when today’s recommendation may be tomorrow’s bad example?

Over the past 100 years, great strides have been made in improving the health of people the world over due to scientific advances that have helped prevent and treat many serious diseases. But scientific research is a dynamic process that moves forward slowly. Recommendations are made based on the best science available at the time. However, with new research and new results, these recommendations may be revised.

The research process is like placing stones on an old-fashioned balance scale. When enough weight accumulates on one side, the scale tips in favour of a particular recommendation. And the more weight there is on one side, the stronger the recommendation is and the more evidence it would take to change it.

If, on one side of the scale, you have over 40 studies showing that moderate alcohol intake can lower the risk of heart disease and, on the other, one or two studies that contradict those results, the scale would hardly budge. The weight of evidence would still be greatly in favour of moderate alcohol intake protecting against heart disease. Indeed, the link between alcohol and heart disease is so strong that it’s known as an established relationship. But not all links are as clear-cut as this. Often, the weight of evidence is not as great. In some cases, only a handful of studies has addressed a particular question. In other cases, a large number of studies may favour one argument, but there may also be some particularly significant studies pitching for the other side—enough to cast some doubt.

... contd.