The Great Cholesterol Myth (15 page)
Read The Great Cholesterol Myth Online
Authors: Jonny Bowden
Except that it didn’t.
“Greater saturated fat intake is associated with
less
progression of coronary atherosclerosis, whereas carbohydrate intake is associated with a
greater
progression [italics ours],” the authors concluded. “Women with higher saturated fat intakes had less progression of coronary atherosclerosis.”
Greater saturated fat intake was also associated with higher HDL levels, higher HDL-2 cholesterol levels, lower triglycerides, and an improved total-cholesterol-to-HDL ratio. Saturated fat, at least in this study, was hardly the dietary demon it’s been made out to be.
And if this were not a knockout punch by itself, consider what was associated with a greater progression of coronary atherosclerosis.
Are you sitting down?
Carbohydrates.
Especially the high-glycemic, processed variety of carbohydrates, which is exactly what we tend to eat when we replace saturated fat in the diet with so-called “complex” carbs such as breads, pasta, rice, and cereal.
“The findings also suggest,” wrote the researchers, “that carbohydrate intake may increase atherosclerotic progression, especially when refined carbohydrates replace saturated or monounsaturated fats.”
“Wait a minute,” you might well say. “When I take the saturated fat out of my diet and replace it with high-glycemic carbohydrates I’m actually
increasing
my risk for heart disease?”
Dr. Sinatra: The Case Against Canola Oil
Back in 1997, I wrote an article for
Connecticut Medicine
about oxidized LDL and free radicals. I was very gung ho about canola oil at the time—as were most of my colleagues—and I was emphatic in my recommendation of it.
But the paper was rejected.
A Yale professor of medicine who was on the peer review board—a biochemist, in fact—reviewed the paper and nixed it for publication. But he was kind enough to suggest some review articles on canola oil in the literature.
I read them.
My reaction: “What have I been smoking all these years?”
The success of canola oil and its reputation as the healthiest of oils is a triumph of marketing over science. It’s a terrible oil. It’s typically extracted and refined using very high heat and petroleum solvents (such as hexane). Then it undergoes a process of refining, degumming, bleaching, and—because it stinks—deodorization using even more chemicals. The only kind of canola oil that could possibly be okay is organic, cold-pressed, unrefined canola oil, and hardly anyone is using that.
Our friend Fred Pescatore, M.D., bestselling author of
The Hamptons Diet
and former medical director of the Atkins Center, is something of a cooking oil expert. Here’s what he had to say about canola oil: “I would never use this stuff!”
If you’d like to read more about the dark side of canola oil, check out the definitive paper by lipid biochemist Mary Enig and Weston A. Price Foundation president Sally Fallon. Widely available online, it’s called, tellingly, “The Great Con-Ola.”
As for my 1997 paper, I revised it, removing the recommendation to use canola oil. The paper was accepted and published.
Dr. Jonny: Good Carbs, Bad Carbs
Whenever I give a talk about healthy eating and I mention that a diet very high in carbohydrates is problematic for most people, I’m very careful to add the caveat: “I’m not talking about fruits and vegetables!” So here’s a quick cheat sheet on “good” versus “bad” carbs.
Good carbs include the following foods:
• Fruits
• Vegetables
• Beans and legumes
Bad carbs, which cover almost all carbs that come in a box with a bar code
*
, include:
• Cereals
• White rice
• Pasta
• Breads
• Cookies
• Pastries
• Snack foods
• Sodas
• Juice drinks
• Crackers
*
There are exceptions in the categories of cereal and bread, but they are few and far between. Oatmeal is one example (but not the instant kind). Ezekiel 4:9 bread is another. But by and large if you stay away from most of the foods on the above list—or keep them to an absolute minimum—you’ll be much better off healthwise.
Um, yes.
By the way, Mozaffarian and his research team didn’t just look at cholesterol. They looked at actual clinical events, such as heart attacks and deaths, from any type of cardiovascular disease. They also looked at lesser known metrics that only your doctor will appreciate (such as coronary revascularization and unstable angina).
Bottom line: Greater saturated fat intake didn’t increase the risk for any of them.
The researchers also tested what happens when you replace saturated fat with polyunsaturated fat (such as vegetable oils), the conventional dietary advice given by just about every major health organization. Maybe high-sugar carbs aren’t so good for us after all, but what about the much-touted vegetable oils, which contain the “healthy fat” our doctors keep telling us about? Swapping saturated fat for a nice helping of healthy vegetable fat has got to be just the ticket to heart health, right?
So the researchers looked at the effect of replacing saturated fat with polyunsaturated fat. Just for fun, they also took a look at what happens when you swap carbs for polyunsaturated fat.
When carbs were replaced with polyunsaturated fat there was no change in atherosclerotic progression—in terms of heart disease risk, it was a wash. But when saturated fat was replaced with polyunsaturated fat, there was a big change—but not in the expected direction. Replacing saturated fat with polyunsaturated fat actually led to an
increase
in the progression of coronary atherosclerosis!
8
(This seemingly crazy finding will make a lot more sense when we discuss those special classes of polyunsaturated fat mentioned earlier in the chapter, omega-3s and omega-6s. Stay tuned.)
If you’re confused by these findings, you’re hardly alone. The
American Journal of Clinical Nutrition
devoted an entire editorial to the findings titled “Saturated Fat Prevents Coronary Artery Disease? An American Paradox.”
9
But it’s only a paradox if we refuse to question the bedrock belief of fat theology that saturated fat consumption increases the risk for heart disease. The research is showing that it does not.
We worry deeply about the wholesale, unqualified recommendation to reduce saturated fat at all costs, because it invariably means that people will replace it with processed carbohydrates. That switcheroo is just about guaranteed to both reduce HDLs and increase triglycerides, and if you’re trying to prevent heart disease, those are very bad outcomes indeed.
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In the Nurses’ Health Study, for example, refined carb-ohydrates and their high glycemic load were independently shown to be associated with an increased risk for coronary heart disease.
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We worry deeply about the wholesale, unqualified recommendation to reduce saturated fat at all costs, because it invariably means that people will replace it with processed carbohydrates.
Glycemic index is a measure of how quickly a given amount of food raises your blood sugar (and keeps it elevated). Glycemic load is a related (and more accurate) measure of the same thing. High-glycemic foods—such as most white breads, white rice, and cereals—are simply those that send your blood sugar on a roller–coaster ride. Low-glycemic foods include most fruits and vegetables as well as beans and legumes.
Now don’t misunderstand us. If you wanted to swap some saturated fat out of your diet and trade it for some low-sugar, high-fiber, nutrient-rich carbohydrates, such as Brussels sprouts or kale, no one would complain. Substituting saturated fat with low-glycemic carbs such as vegetables doesn’t increase the risk of heart attacks at all, but substitution of saturated fat with high-glycemic carbs does—by a fair amount, actually. A study in the
American Journal of Clinical Nutrition
found that replacing saturated fats with high-glycemic index carbs was associated with a 33 percent increase in heart attack risk.
12
Because most people replace saturated fat with exactly these kinds of processed, high-glycemic (high-sugar) carbs (e.g., breads, cereals, and pasta), the conventional wisdom to cut out saturated fat and consume lots of carbs instead is starting to look like an increasingly boneheaded notion. Although it’s not perfect, saturated fat does a number of good things in the body. Its wholesale replacement by the worst kind of carbohydrates is turning out to be a cure worse than the disease.
13
A recent Dutch study added to the list of accumulating research showing that when you substitute high-glycemic carbohydrates for saturated fat you actually increase cardiovascular risk.
14
But the Dutch researchers had an interesting take on this, one that appreciates that an accumulation of saturated fat in the body is not necessarily the best thing in the world.
They pointed out that eating a high amount of carbs causes your body to hold on to the saturated fatty acids that you’re also consuming—and those saturated fats get preserved, stored in your body rather than burned for energy. Meanwhile, all those extra carbs you’re eating get converted into more saturated fatty acids in the liver. Now you’ve got a serious excess of saturated fatty acids—you’re holding on to the ones you’re eating, and your liver is creating even more of them, fueled by the carbs you’re consuming. Because large amounts of saturated fat can lessen the anti-inflammatory actions of HDL cholesterol,
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this isn’t a good situation.
However, the Dutch researchers correctly noted that cutting saturated fat out of the diet is not the most effective way to combat the accumulation of saturated fatty acids in the body. It’s far better, they suggested, to reduce dietary carbohydrates. This way, your body makes fewer saturated fatty acids, and its tendency to hold on to those you do eat is reduced. “Attention should be shifted from the harmful effects of dietary saturated fat per se to the prevention of the accumulation of saturated fatty acids (in the body),” the authors wrote. “This shift would emphasize the importance of reducing dietary carbs, especially carbs with a high glycemic index, rather than reducing dietary saturated fat.”
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Carbohydrates have a nasty effect on cholesterol particle size, which, as you’ve seen, is of significantly greater importance than total cholesterol, LDL, or even HDL. Two researchers from the Department of Atherosclerosis Research, part of the Children’s Hospital Oakland Research Institute in California, decided to test the effect of dietary carbohydrates on the size and density of both LDL and HDL. They found that people who ate more carbohydrates—particularly simple sugars and starches with a high glycemic index—had significantly greater levels of those angry, dense, atherogenic particles of LDL (pattern B). They also had the greatest number of small, dense HDL particles.
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We want to propose a different way of looking at fat intake. We think what we are about to suggest goes a long way toward explaining the contradictory findings, or apparently contradictory findings, on saturated fat, diet, fat reduction, and cardiovascular disease.
To do this, we have to briefly introduce the other two categories of fats besides saturated: monounsaturated fats and polyunsaturated fats. (Remember, all fatty acids fall into one of these three broad categories.)
*
Monounsaturated fat is the fat that’s predominant in olive oil (as well as in nuts and nut oils, such as macadamia nut oil). Its health benefits have been well documented and are noncontroversial. Monounsaturated fat is the primary fat consumed in the highly touted Mediterranean diet, and it’s generally accepted that this kind of fat is perfectly healthy. For that reason, we won’t spend much time on it, because it is pretty irrelevant at this point to the case we’re about to make.