Monday, May 17, 2010

Stupid Fat Study

No this isn't about "stupid fats." It's a stupid study, in my opinion.

I try to give research scientists the benefit of the doubt, because I've done lab research myself, and I know how difficult it can be to get reliable results. It's even more complex today than it was when I was in graduate school.

Nevertheless, I think this study, reported in Science Daily, really takes the cake. The SD title is "High-Fat Meals a No-No for Asthma Patients, Researchers Find."

So what did the researchers do?

They fed two different meals to 40 people with asthma and measured any resulting inflammation. Diet 1 was 1000 calories, 52% fat, and consisted of fast-food burgers and hash brown potatoes. Diet 2 was 200 calories, 13% fat, and consisted of reduced-fat yogurt.

They found that people eating diet 1 had more inflammation. So they concluded that the inflammation was caused by fat!

How can you possibly assign blame when the diets differed in so many ways?

An equally valid headline might have been "High-calorie meals a no-no for asthma patients" or "Hash-brown potatoes a no-no for asthma patients" or "Dairy products good for asthma patients" or "Eating lots of fat in combination with lots of carbohyrate a no-no for asthma patients" or "Hamburger buns a no-no for asthma patients."

Instead, they focused on the one ingredient they probably started out believing would be bad and ignored the rest.

This study was presented at the American Thoracic Society 2o10 conference in New Orleans.

One of the researchers said, "This is the first study to show that a high fat meal increases airway inflammation." No it didn't. It showed that a high-fat, high-calorie, high-carbohydrate, commercial junk-food meal increased airway inflammation.

Unfortunately, headlines are all that many people read and remember. Keep in mind that headlines can be misleading. Before accepting the conclusions in any study you think might be important for you, read as much of the full text as you are able to and then make up your own mind.

We can't depend on other people to inform us correctly. We have to take control ourselves.

Friday, May 7, 2010

ACCORD again

A couple of years ago, it was reported that intensive treatment of type 2 diabetes, aiming for a hemoglobin A1c level below 6, increased cardiovascular events compared with patients aiming for an A1c between 7 and 7.9. The study was called ACCORD, and the glucose arm of the study was stopped early because of the excess deaths in the intensive-treatment group.

On the basis of this one study, a lot of doctors told their diabetes patients who had A1c values in the normal ranges that they were too low and they should attempt to get them higher!

They seemed to apply this advice to everyone with type 2, even though the patients in the ACCORD study were older (between 40 and 79 years), had had diabetes for a median of 10 years, and already had signs of heart disease or had several risk factors for heart disease.

I've previously discussed the ACCORD trial
here, here, and here.

A conservative interpretation of the study was that aiming for a normal A1c might be harmful in older people with longstanding type 2 and pre-existing signs of or risk factors for cardiovascular disese but it would be OK for younger people who had recently been diagnosed. The idea was that if damage from high blood glucose levels has already been done, it may be too late to help by getting those levels down.

Another interpretation was that these people had been put on traditional high-carbohydrate American Diabetes Association diets, so they needed a lot of drugs to get their A1cs in normal ranges, and it was the combination of so many drugs that caused the increased cardiac events.

Another interpretation was that they'd brought the A1cs down too quickly, and that was what caused the harm.

And another was that the intensive-control group had more serious incidents of hypoglycemia.

Now comes a new interpretation of this study that says that
those who were actually able to reach the normal A1c goals had lower rates of cardiovascular events. It was the patients who were unable to reach the goals despite the intensive treatment who had increased rates of cardiovascular events.

Mortality was greater in the intensive-treatment group only when the A1c was above 7.

The new interpretation was published in the May 2010 issue of
Diabetes Care.

None of the mainstream analyses of the ACCORD study have suggested that instead of intensive treatment with drugs, patients might benefit by using lower-carb diets to get their A1c levels down. We know that works. Why can't the cardiologists understand it?

I think one thing the back-and-forth recommendations resulting from the ACCORD trial tell us is that we shouldn't forget to use common sense. If we're discussing treatment of a mentally compromised relative who is 99 and unable to understand why he shouldn't eat huge dishes of ice cream and chocolate sauce, perhaps trying to enforce a low-carb diet so the poor man would have no enjoyment in life wouldn't make sense.

One vision that haunts me is the description of an old diabetic woman in a nursing home. Everyone else got ice cream for dessert, and the nurses said, "You can't have ice cream because you are diabetic." The old woman cried all during dessert because she wanted the ice cream so much. That's cruel. Especially because they were probably stuffing her with starches like bread and potatoes.

But if we're still pretty healthy and able to manage our diabetes diet ourselves, and if we understand how harmful high blood glucose levels can be, we should make an effort to get the best A1c levels we can manage, even if some study shows that this might be harmful to some people.

We shouldn't reverse our treatment plan on the basis of one study, which is what the doctors who told all their type 2 patients to get their A1cs higher did. One study doesn't prove much. The study might have been poorly designed. The population studied might not be representative of the population as a whole, or it might not match your own situation (a study of 80-year-old male veterans might not apply to a 40-year old woman). The statistics used might have been faulty. The treatment in the study might have been different from what you are using.

There are many reasons that one study might be misleading. It's only consistent results that are significant. We shouldn't totally ignore any study. But we need to take them with a grain of salt.

Sunday, May 2, 2010

Saturated Fat and the Popular Press

The May issue of the mainstream magazine Scientific American had an article saying that dietary carbohydrates are more important than fats in terms of heart disease risk.


Many people thought t
he news would never reach the mainstream press. But it finally has. The article cites the recent meta-analysis by Krauss and colleagues that suggested that the amount of saturated fat in the diet is not related to heart disease.

I would note several caveats. First, although some of the studies in the meta-analysis used food diaries to assess intake, others used the ubiquitous "food frequency questionnaires," which may not be accurate, as discussed here.

Second, Krauss et al. suggested that the effect of saturated fat may depend on what people substitute for the saturated fat. (This assumes that no one would want to decrease calories by simply eating less saturated fat, which is what makes the most sense to me.) Eating more unsaturated fat may decrease heart disease rates, whereas eating more carbohydrates may increase heart disease rates. Not everyone agrees with this, however.

Finally, the Scientific American article says it's mostly highly processed carbohydrates that are the villains, and the author writes, "some high-fiber carbohydrates are unquestionably good for the body." Many people do, in fact, question that statement, especially in relation to people with diabetes.

The author of the Scientific American article is not urging people to pig out on saturated fats. She says that current studies "do not suggest that saturated fats are not so bad; they indicate that carbohydrates could be worse."

It takes a long time for generally accepted ideas to be thrown out. Further studies may convince people that the "healthy whole grains" that people (including those with diabetes) are currently being urged to make the focus of their diets are just as bad as white bread, pasta, and sodas.

But for now, every little nail hammered into the brittle saturated fat hypothesis of heart disease helps. Saying that high-glycemic-index carbohydrates may increase heart disease risk is a step toward accepting the idea that all carbohydrates may do the same, especially in people with a genetic propensity to insulin resistance.

Publicizing the evidence in a mainstream popular magazine will help to spread the news, because the popular press operates with a herd mentality. If one mainstream news outlet carries a story, everyone else has to report on it too.

In fact, just today I got in the mail a copy of the Harvard Medical School Focus, which included a brief comment
titled "For Heart Health: More Polyunsaturated Fat, Fewer Refined Carbohydrates." This discusses both the Krauss paper cited above and another paper that supports the idea that substituting polyunsaturated fat for saturated fat instead of carbohydrate will reduce heart disease risks.

Perhaps the brittle saturated fat hypothesis of heart disease it will soon be shattered.