Thursday, August 1, 2013

A lesson in what we truly know...

I find it humorous when people tell me something is a scientific fact, particularly when it pertains to diet.  If you have been paying attention to the popular news media as of late, you may have noticed that cholesterol and saturated fat have been given a mea culpa.  After spending more than 30 years being demonized as the cause of heart disease and atherosclerotic plaques, it turns out that cholesterol and saturated fat really aren't that bad for you.  Of course, 30 years ago, we knew cholesterol and saturated fat were as bad for society as Keeping up with the Kardashians would eventually become.  The problem is that what we knew 30 and even 60 years ago turned out to be wrong, and foolish people continue to pass it around as gospel.  Here are some snippets from a paper from 1953 found here.

1) "Atherosclerosis may be readily produced in the rabbit and in the chicken by feeding a diet containing large amounts of cholesterol...while feeding cholesterol to man, or the monkey, has very little effect on the blood even when enormous doses of cholesterol are given."

2) "The cholesterol-fortified diet commonly used to produce hypercholesterolemia and subsequent atherosclerosis in the rabbit...corresponds to about 15 gm of cholesterol in a 3000 calorie diet for a man...Even when concentrating on foods of naturally high cholesterol content, it is difficult to devise a diet to provide, experimentally, as much as 2gm of cholesterol in the daily diet."

3) "That dietary cholesterol is not important for man would be predicted from the fact that the biliary output of cholesterol from the human liver is from 10 to 20 times as much as the daily amount of cholesterol in any diet of natural foods."

4) "Controlled experiments on men clearly show that serum cholesterol changes in direct relation to a change in the total amount of fat in the diet.  Both animal and vegetable fats show this effect and the addition or removal of cholesterol from the diet does not change the result. The cholesterol level may fall, however, if the diet is almost exclusively pure fat and is free of carbohydrate."

5) "In the classification of the U.S. Department of Agriculture, by far the largest proportion of the total fats, from 45 to 50 percent in recent years, is "fats and oils as such, excluding butter."  This means cooking and salad fats and oils- lard, corn oil, cottonseed oil, hydrogenated vegetable oil shortening, margarine, mayonnaise, etc."

All of this evidence more or less exonerates cholesterol yet it was ignored.  In 1977 the government began a decades long attack on cholesterol and saturated fat.  The government and AMA recommended that we limit our cholesterol intake and saturated fat intake despite the evidence listed above.  Could there be anything worse than that?  Actually there can, the person who wrote the above paper was Ancel Keys, the physician whose work was used to form the very recommendations put out in 1977.  Despite the fact that there was no evidence that cholesterol was bad the government still recommended limiting cholesterol consumption along with saturated fat.  In addition, despite the evidence that most of the fats people were eating in this 1953 study were vegetable in origin, we were told to avoid saturated animal fats and replace them with...wait for it...vegetable oils.

Regardless, Keys still came to the conclusion that we should limit fat consumption as a whole which turned out to be wrong.  One of his assertions in this paper that sticks out to me is that controlled studies show a direct relationship between serum cholesterol and fat consumption, but when carbohydrates are kept low, aka fat is upwards of 80% or more of total energy intake, serum cholesterol drops.  I wouldn't consider myself a genius or anything, but I find it hard to call something a direct relationship when putting one of the variables at it's highest causes the other one to drop like a rock.  Ironically, in this same paper, Keys brushed off a low carb high fat diet as not rooted in reality.  Well, in reality, a high fat/low carbohydrate diet is more than likely the diet we subsisted on for millions of years.  As an illustration of this concept, I would like you to go home and devise a suitable diet calorie-wise and do so without bread, pasta, cereal or any other processed foods.  It's nearly impossible to come up with a 2000-3000 calorie diet that doesn't involve a large number of processed foods OR a lot of animal fats.  Since processed foods weren't around a few thousand years ago, I'll let you guess as to whether or not animal fats were a significant part of our ancestor's diet considering Cocoa Puffs certainly wasn't.  This is what is so interesting about using an evolutionary template, it not only looks at current data, it looks at whether the current data jives with what the reality was prior to recent history.  You know, the type of history that started more than fifty years ago.

So whatever became of Ancel Keys?  In 1955 President Dwight Eisenhower survived his first heart attack and decided to begin following the recommendation of Keys.  Six more heart attacks later and he finally succumbed to the last one in 1969, how did that advice serve him?  As for Keys, he got his picture on the cover of Time magazine in 1961 and Americans soon started snapping in line and following his advice.  Fifty-two years later and heart disease is still the leading cause of death in the United States.  Whether or not you agree with Keys' conclusions, you have to wonder how long you have to follow advice before you realize it's bad.  The truth of the matter is, we obviously don't know exactly what is causing heart disease and diet appears to only be one of many factors involved in it's progression.  In addition, the notion that high serum cholesterol is a major causative factors, at least what we consider high, is probably also false.  It's simply based on the notion that cholesterol is part of the plaques that form on blood vessel walls.  If only someone would have brought that up years ago...Oh yeah, Keys brought it up in the paper cited at the beginning of this blog post.  That's the problem, people read something in it's entirety and ignore the parts that don't fit their narrative.  Interestingly enough, calcium is also found in the plaques on blood vessel walls yet we were told to supplement to make sure we were getting enough.  Recent studies are showing that people who supplement with calcium are more likely to have cardiovascular disease than people who don't.  It shouldn't come as any surprise that we seem to be wrong on so many levels, the Earth was flat once upon a time too.