Recently, some high profile “nutrition experts” have been saying “Butter is Back” and creating a lot of confusion about the question of healthy oil and fat in our diets. One thing generally agreed among nutritional experts is that margarine and shortening are not healthy foods. Unfortunately, they are still very prominently used both at home and in many commercial foods. You will find them listed as “hydrogenated” oil on the label and when you do find it on the label, put the food back where you found it or put it in the garbage. More recently, some “experts” have been saying that dietary cholesterol does not raise blood cholesterol. This conclusion has been drawn on the basis of a large Metadata Study that has been widely touted. I recently listened to a physician on PBS that was getting cheers and nods of approval for saying “Butter is Back!”
But before you slather on the butter and add steak to that breakfast menu I think you should know something about metadata studies and why they are often used more to conceal than reveal the facts. A metadata study is a study of many studies. Typically, the studies have different designs and purposes with many different sizes and populations so it might seem that the more studies that are put together, the more valid the conclusions. Not so. The typical result of a metadata analysis is to dilute findings until the differences are swamped by the “noise” and variability in the studies. Metadata analysis was a favored tactic of the tobacco industry when they wanted to “prove” that smoking did not cause cancer.
In the Metadata Study on butter the large population had many different diets and since the studies weren’t controlled for differences in diet and only the differences in butter was examined, it is extremely unlikely that eating a little more or a little less butter in the Standard American Diet (SAD) would show any statistically significant difference in health. What can be said from this study is that butter is definitely not a health food. For a detailed discussion of this issue, visit the Harvard School of Public Health or download their App.
The bottom line is this: Eat more fruits and vegetables, less red meat, some fish and substitute healthy oils such as olive oil and small amounts of seeds and nuts for butter.
Ken Corliss, OD
Diplomate American Board of Optometry
(253) 845-0585