Everything Causes Cancer ...

There ' s no cure, there ' s no answer.-- Joe JacksonThe ever-reliable John Ioannidisriffs on nutritional epidemiology. I would say that if there is one reason why Jane and John Q. Public are skeptical of science it ' s because they keep hearing contradictory or changing advice about what to eat. As Ioannidis explains rather wonkily, and I will try to explain more accessibly, there are some fundamental problems with trying to sort out how diet affects health. In the first place, whatever effects there may be will take a long time to manifest. Maybe eating a lot of doughnuts will cause you to become yellow, have only four fingers, and say " D ' oh " a lot, but if so it ' s not going to happen overnight. Following cohorts of people for 30 years or more is difficult and expensive.Even if you do it, asking people to report on what they eat is the only practical way to measure it. You can ' t watch 5,000 people eat every day and record everything. And people just don ' t remember very well and don ' t report very accurately. Furthermore, what questions should you ask? Studies typically try to assess the effects of specific foods or categories of food, but any particular eating habit is likely to be associated with others. Is it really the hazelnuts (to use one of Ioannidis ' s examples), or do people who eat a lot of hazelnuts also tend to have other habits or circumstances relevant to health? Ioannidis points out (not sure where gets the info, there ' s no citation) tha...
Source: Stayin' Alive - Category: American Health Source Type: blogs