A song by the Lovin' Spoonful asks "Did you ever have to make up your mind? Pick up on one and leave the other behind?" When a new idea comes along, how can we tell if it is right or wrong, especially in a complex field such as human medicine? How can we tell whether a voice in the wilderness is a Galileo or Einstein, correctly seeing things that others can't, or an L. Ron Hubbard promoting a Scientology that is baseless? Ultimately time will tell, but when the stakes are our own health, time is not on our side. How do we decide? We need to look at whether the idea seems to make sense, and look for corroboration from sources we trust or think we can believe.
Recently I read the book Grain Brain by Dr. David Perlmutter. (You may still be able to find a TV segment featuring him on Dr Oz's web site.) He is a board-certified neurologist and nutritionist, apparently the only doctor in the U.S. who is both, so he should know what he's talking about. His theory is that the low-fat, low-cholesterol, high-carbohydrate diet containing wheat gluten currently recommended by most experts is harmful and is responsible for many brain problems, insulin resistance and diabetes, obesity, and heart problems. though the focus of the book is on the brain. The book is fairly easy to read, and he backs up his assertions with an average of 25 references per chapter. One has to ask whether this is for real, the beginning of a reversal of "conventional wisdom". Everyone is aware of the "epidemic" in diabetes and obesity, in spite of 40+ years of promotion of low-fat high-carb. Something is obviously wrong.
Many people have become aware of gluten in connection with celiac disease, but this is different. The theory is that gluten sensitivity is common in people who do not have celiac, that our human genome is not adapted to it, and that consumption of gluten has dramatically increased in a short time.
Many people have become aware of inflammation as a proposed cause of coronary artery disease. Dr. Perlmutter extends this concern to brain disease, and not just vascular but neural disease.
He also contends that rather than being harmful, dietary and serum cholesterol and LDL and certain fats are essential to neurological health. (This is consistent with recent Alzheimer's research I have seen.) He also contends that carbohydrate consumption, rather than fat consumption, causes obesity, insulin resistance, and diabetes. There are very convincing studies showing a direct, not inverse, relationship between cholesterol levels and brain function. They seem to show that high cholesterol levels significantly improve cognitive function.
I can't summarize the whole book here - you'll need to read it before it will make sense. He cites many studies to back up these conclusions, and points out studies which directly contradict the low-fat, low-cholesterol advice we have received for the last 40 years or so. His information does not seem to have the vague, unscientific, conspiracy-theory flavor of many of the "detox" and "cleansing" promoters.
Large studies are essential because they try to control for extraneous factors to zoom in on proving specific facts. We can consider anecdotal evidence but must be cautious and understand it does not conclusively prove anything. With that in mind, here's my own anecdotal evidence. My parents were both diagnosed with Alzheimer's Disease within a year or two, and it progressed in both of them at a similar pace. My father died of AD and artery disease a year ago, and my mother will die of AD eventually. Why both of them? Did they have something environmental or dietary in common? Well, yes. In the 1970's, Dad was diagnosed with high cholesterol, and went on a low-cholesterol and fairly low-fat diet. Mom did all the cooking, so she ate the same diet (we all did). As far as I know, they tried to maintain that diet all their lives. Current research indicates that AD begins developing years or decades before symptoms appear, and progresses exponentially. So if Grain Brain is correct, it's quite possible that both were affected in the same way, beginning way back then.
Is there corroborating evidence from other experts? Some. The studies cited by Dr. Perlmutter sound convincing, but they are narrowly focused and have not received much public attention or comment. In a recent web article, heart surgeon Dr. Dwight Lundell proclaims the same reversal of theory concerning heart health that Dr. Perlmutter proposes for brain health: low-fat, low-cholesterol, high-carb is wrong. And the molecular mechanisms he explains are exactly or nearly the same. It will be interesting to see if this line of thought gains momentum. (On the other hand, it's hard to know whether to trust individual experts or not: although Lundell has terrific credentials and experience, he's been in trouble with medical authorities and has drawn his share of criticism.)
So if Grain Brain is correct, why has it taken so long to realize it? One possibility is "confirmation bias". We tend to notice evidence that which confirms our opinions, and it takes a lot of evidence to change our minds. (See this and other articles on the Less Wrong web site for more information.) Dr. Perlmutter also points to "publication bias" in which respected journals are reluctant to publish controversial papers. Maybe. Part of the problem is that the underlying biochemistry is complex and variable, and it is nearly impossible to do long-term, double-blind studies on thinking humans.
At this time, none of this fits in with the official positions of the American Medical Association, the Heart Association, the Alzheimer's Association, or any other large organization. In a lecture I attended last night, Maria C. Carillo, Ph. D., Vice President, Medical & Scientific Relations of the Alzheimer's Association talked about a "heart-head connection", meaning that what is good for the heart is good for the brain, but only in the sense that heart health promotes good oxygenation and nutrition of the brain. Her description of what is healthy for the heart was low fat, low cholesterol. As far as I know, the Association has not made any statement regarding the Grain Brain theory.
We hear constantly about the need to follow a "heart healthy" diet - probably everyone is in favor of that idea. Now the question seems to be about exactly what that means. The low-fat, low-cholesterol, high-carb diet is coming under attack, and it's only now getting publicized. Is this like the Paleo diet? Yes, in many ways, but it has different foundations. Is this like the Atkins diet? Yes, in many ways, but it is more specific about wheat gluten.
So what to do? Keep doing what we've been doing, and hope the advice of the last 40+ years is right? Or believe the recent studies that say it may be horribly backwards? Sometimes the heretic is right.
