Tuesday, March 4, 2008

Bigger than yer Britches

Shout it from the rooftops!

Low Fat Diets More Likely To Reduce Risk Of Heart Disease Than Low Carb Diets!

This gem, courtesy of Medical News Today. I was curious so I looked up the abstract.

It was a 6-week study in the journal Hypertension where they measured a number of surrogate measures of cardiovascular disease risk, in patients eating either an Atkins-style low-carbohydrate (LC) diet or an ADA-style low-fat (LF) diet.

"Brachial artery flow-mediated dilation" and nitroglycerin-mediated dilation basically measure the ability of your arteries to dilate. The loss of the ability of vessels to dilate is associated with cardiovascular disease.

Where do I begin.

First of all, this was a 6 week study, not long enough to really say anything about cardiovascular disease risk. But nevertheless, let's look at the actual data:


The LF group lost an average of 4.3 lbs over the course of the 6 weeks. The LC group lost 5.7 lbs.

The LF group's blood pressure decreased 8/5 mm Hg (systolic/diastolic). The LC group's decreased 12/6 mm Hg.

The LF group's flow-mediated dilation increased +1.9, but was reduced in the LC group by -1.4.

There was no difference between groups in nitroglycerin-mediated vasodilation.

Here's the best part (full text only): the triglyceride/HDL ratio went from 1.2 to 1.6 in the LF group, and from 1.4 to 1.1 in the LC group. Trig/HDL ratio is the best blood lipid predictor of heart disease we have, and the lower the better.


So let me get this straight. What we're looking at is data showing that LC beat or tied LF on every relevant parameter they reported except one, and somehow that means LF diets are healthier than LC? Even though overweight and hypertension are important risk factors for cardiovascular disease? Even though trig/HDL is probably the best predictor of heart disease of any of these measures?

This article wouldn't bother me if it weren't so arrogant. If it had simply reported the facts as an interesting phenomenon, instead of tacking on a politically motivated (and incorrect) interpretation, I would have just found it interesting. But the author is bigger than his britches: "LF diets may confer greater cardiovascular protection than LC diets."

The irony isn't lost on me that the paper is published in the journal Hypertension, shows that LC diets ameliorate hypertension better than LF diets, yet somehow claims LF diets are more protective of cardiovascular disease than LC. Huh?

Unfortunately, this is typical of researchers in the diet-health field and the media that report on it.

1 comment:

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