Vitamin E May Slow Plaque Build-Up

Source: Tufts University
October 11, 2002 (Reviewed: October 19, 2004)

The debate continues on what role vitamin E - from both foods and supplements - plays in slowing the progression of vascular degenerative disease. A group of Italian researchers say the lack of consensus among study findings may be due to differences in each study's endpoint - some look for early signs of disease, while others chronicle obvious clinical events. Writing in the American Journal of Clinical Nutrition, these researchers say that to find an effect, 'look early'. They've found an inverse association between vitamin E status and development of preclinical atherosclerosis.

Their study included 307 women between the ages of 30 and 69. Each completed an assessment of their usual diet and current health habits. Serum measurements of vitamins A, E, and C were measured, and examinations of the participants' carotid arteries were done by means of high-resolution ultrasound.

Effect of vitamin E status

The ultrasound exams revealed that 12% of the women had atherosclerotic plaque at the common carotid artery; 25% showed plaque development at the carotid bifurcation; 29% had plaque at both sites; and 34% showed no plaque.

Regression analyses showed an inverse association between tertiles of vitamin E intake and the presence of plaque at the carotid bifurcation (odds ratio, or OR=2.07; 97.5% CI 0.93, 4.59). An analysis that included only postmenopausal women (73% of the sample) showed a more pronounced association (OR=2.79, 97.5% CI 1.10, 7.07). Further, there was an inverse association between low plasma vitamin E (adjusted for plasma cholesterol) and the presence of plaque in the carotid bifurcation (OR= 2.16, 97.5% CI 1.06, 4.39).

No association was found between vitamin E status and degree of plaque in the common carotid artery, or between vitamins A or C status and plaque development.

Possible explanation for the findings

The authors say that the fact that the significant findings were limited to the carotid bifurcation makes sense, since the first signs of plaque development usually occur at this location. The common carotid artery and carotid bifurcation differ in shape, cell composition, shear stresses, and extracellular matrices, all factors that affect the development of lesions. Thicker arterial walls at the carotid bifurcation also make this a likely place for plaque to develop.

Clinical significance

The research on antioxidants and vascular disease does not yet paint a clear picture of what effect these vitamins have on arterial damage, or if supplements - at comparatively high nutrient doses - have an edge over foods in providing disease protection.

None of the women in this current study were taking vitamin E supplements, so the researchers were able to assess the effect of vitamin E from foods alone. (Those in the highest intake tertile consumed an average 8 mg/day, about half of the current US dietary recommended intake level.) The study also measured plaque formation - a sign of impending damage - rather than overt signs of disease. It's possible, suggest the authors, that vitamin E may be most effective against vascular disease in its earliest stages, before clinical signs of lesions and artery blockage become apparent.

Source

• Dietary and circulating antioxidant vitamins in relation to carotid plaques in middle-aged women. A. Iannuzzi, E. Celentano, S. Panico,  et al., Amer J Clin Nutr, 2002, vol. 76, pp. 582--587

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