Dieting may reverse carotid atherosclerosis

8 March 2010

MedWire News: A dietary weight-loss intervention over a 2-year period is associated with a reduction in carotid atherosclerosis, say researchers.

The observed reduction in carotid vessel wall volume (VWV) appeared to be mostly mediated by systolic blood pressure reductions brought about by weight loss, report Iris Shai (Ben-Gurion University of the Negev, Beer-Sheva, Israel) and colleagues.

At baseline, 26% of the 140 study participants were taking a lipid-lowering medication and 31% were using antihypertensives. Medication usage did not change significantly during the 2-year study.

The participants had an average body mass index of 30.4 kg/m², were aged 51 years on average, and 88% were male. They were randomly assigned to one of three diets: low fat, Mediterranean, or low carbohydrate.

At baseline, the participants’ average carotid VWV was 941.50 mm³, measured using 3-dimensional ultrasound (3DUS).

“We quantified 3DUS carotid artery VWV to evaluate changes in atherosclerosis burden because it is noninvasive, has high sensitivity for detecting changes in VWV plus plaque, and is correlated with coronary disease,” the team explains in the journal Circulation.

During follow-up, carotid VWV decreased by a significant 58.07 mm³ (4.9%) overall. The average decrease was not significantly different between the three diets, at 60.69 mm³ with the low-fat diet, 37.69 mm³ with the Mediterranean diet, and 84.33 mm³ with the low-carb diet. The researchers note, however, that their study is too small to detect any but very large differences between the diets.

In all, 95 study participants had a decrease in carotid VWV, while 45 had an increase. Those with a decrease had higher VWV at baseline than participants with an increase. They also lost more weight (5.3 vs 3.2 kg), had a larger reduction in systolic blood pressure (6.81 vs 1.11 mmHg), and a greater decrease in total homocysteine levels.

After accounting for confounders, only change in systolic blood pressure was significantly associated with decrease in carotid VWV. It also predicted reduction in carotid intima-media thickness, although this changed nonsignificantly, from 0.816 to 0.808 mm, in the cohort overall.

The study was conducted in a workplace environment, allowing strict monitoring of diet, which Shai et al admit could limit the generalizability of the findings.

But they say: “Nevertheless, we believe that similar strategies to maintain adherence could be applied elsewhere.”

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Circulation 2010; Advance online publication