Monday, September 15, 2008

BOOKS: The Heart Revolution

The wordy subtitle of this book tells what it's about: "the extraordinary discovery that finally laid the cholesterol myth to rest and put good food back on the table". The book is a quick read (I did it cover-to-cover in one cross-country flight), but a very useful one. The author, Dr. Kilmer McCully, was a highly regarded research pathologist at Mass General, where he did pioneering work on the link between an amino acid called homocysteine and heart disease. He begins with this remarkable assertion:
In the past, fats and cholesterol in the diet were blamed for causing heart disease. But years of medical research have produced no convincing evidence that these components of foods actually cause hardening of the arteries. In fact, scientists have proven that pure cholesterol does not cause arteriosclerosis and that elevation of blood cholesterol is a symptom -- not a cause -- of heart disease. Discoveries about a substance in our bodies, homocysteine, are revolutionizing our understanding of the cause of the nation's number one killer. We have learned that deficiencies of B vitamins in the diet -- folic acid, vitamin B6, vitamin B12 -- trigger heart disease by raising levels of homocysteine in the blood. Now there is a way to prevent heart disease and to achieve a longer, healthier life. All you have to do is improve your diet.
That's the book in a nutshell. It expands in an interesting, convincing, and readable way on the research behind this, and it gives substantial dietary advice. One of the real eye-opening parts for me was seeing the crucial connection to fresh food. Some vitamins, especially two of the three B vitamins crucial in controlling heart disease, are very perishable. They are available in a variety of foods, but are rapidly broken down by time, heat, and processing. Thus, even vitamin-rich vegetables can lose the majority of their vitamin B content by the way they are cooked, through other processing, or even just sitting around too long. Thus, my desire in recent years to get a lot of fresh produce at the local farmer's market has even more marked health benefits than I had realized. Another factor is the distinction between pure cholesterol and oxy-cholesterol, only the latter of which is unhealthful. Pure cholesterol (the kind found in meat and eggs) is perfectly healthy, but oxy-cholesterol, which only arises when foods are excessively heated (especially deep frying) or processed (especially the powdered version of milk and eggs used in many processed foods), is to be avoided.

The front story is how this homocysteine thing works, and what sort of diet can control it. But there's a fascinating back story, and this book only tells parts of it. The back story is the interplay between food, medicine, and politics. McCully talks about the cholesterol myth (cholesterol as the explanatory factor of heart disease), how it arose, and how it has persisted despite its failure to adequately explain heart disease. Most of us have heard of the "French paradox", how the French have lower rates of heart disease despite eating eggs, cheese, butter, and pâté de foie gras -- i.e., everything "wrong" according to the cholesterol theory. The French experience is perfectly consistent with the homocysteine theory, however. Whole dairy products (not non-fat) and meats (especially organ meats) are great sources for B vitamins. Other evidence against the cholesterol theory is piled on (e.g., the incidence of heart disease has been declining in America since the late 1960s, despite cholesterol levels staying fairly consistent). McCully dissects the FDA food pyramid, explaining which parts of it are sound, and which parts of it are outright damaging to health, and he shows flashes of anger at the politics behind the workings of government that have allowed misguided and refuted recommendations to persist.

Where McCully shows impressively charitable restraint is in not discussing the affect those politics had on his own career, which was unjustly derailed for many years because his research bucked the widely-accepted cholesterol theory. We get only a sketch of that story in a foreword to the book written by Michelle Stacey, who had profiled McCully for the New York Times Magazine in 1997. There's undoubtedly an interesting story there in the politics of research funding (she notes, for instance, that the cholesterol theory leads to a multi-million dollar pharmaceutical solution, while the homocysteine theory may be addressed completely by fresh food, supplemented by over-the-counter vitamins if needed).

In any event, this is recommended reading for everyone concerned about their health. If you're not already eating more fresh food and avoiding processed food as much as possible, this book will give you a compelling reason to do so.

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