So often I hear people say, "Oh, I heard that "fill in the blank" is bad for you", or "Oh, I heard that "fill in the blank" is so good for you". People often use statements such as these because they belive them to be true. Usually, their source is some sort of media outlet, but I am here to tell you that these sources are not reliable and do not reflect concrete, scientific evidence. Studies we hear about on the news are usually based on only one study that was formatted into a press release and paraphrased by a reporter. What many people do not know, is that not all studies are credible, and most importantly, not all studies are able to be replicated.
In science, a study must be replicated many, sometimes hundreds or thousands of times, before it is accepted as a credible statement in the scientific community. The ones we hear about on the news are usually a one time study that shows some type of interesting data. What you need to be asking yourself when you hear these statements are:
Who conducted the study? (The beef industry loves to fund studies against soy!)
How was the study conducted? (Was it conducted in a reliable way?)
Has the study been replicated? (9 times out of ten, they're not!)
What are some possible faults with the study? (Could the study have false-positive or false-negative-results?)
All of these are things that the scientific community take into consideration, but the media does not. It is so irritating to me when I hear people say they know something is scientifically proven, when they are merely talking about something they read or heard in some media source. In science, nothing is proven! We just collect data to construct theories and make educated guesses.
Another thing I notice is that studies, even scientific ones, like to isolate specific nutrients, or compounds in such high amounts that we would never consume in our diets. For example, studies love to point out negative effects of soy protein isolate in high doses, yet if you are consuming a whole foods diet, you would never come near the amounts they are studying. Even when they study specific vitamins and minerals, they are usually studying them in a concentrated form that, unless you take a mega-dose supplement, you would never be able to replicate in a whole foods diet.
What does all this mean? Don't believe everything you hear and ask questions. Most importantly, NEVER take anyone's word, unless they are a doctor, or scientist, about any type of scientific data, because 9 times out of 10, they have no idea what they are talking about!!! Eat a varied, whole foods diet and don't worry about what the "studies" are saying!