Eating a High-Fat Diet? Vitamins C and E
Provide Some Protection for the Heart

By Jack Challem
Copyright © 1998 by Jack Challem, The Nutrition Reporter™
All rights reserved.

Taking supplements of vitamins C and E can block some of the heart-damaging effects of high-fat foods, according to a study in the Journal of the American Medical Association.

High-fat foods rapidly boost blood levels of triglycerides, a type of fat, which prevents the heart's endothelium from momentarily relaxing while pumping blood. The endothelium is a layer of cells that line the heart and blood vessels, and impaired endothelial function is associated with all major coronary risk factors.

Gary D. Plotnick, MD, of the University of Maryland School of Medicine, Baltimore, fed 20 healthy men and women one of three breakfasts: (1) a high-fat meal consisting of an Egg McMuffin, Sausage McMuffin, and two hash brown patties, (2) a high-fat breakfast after the subjects were given 1,000 mg of vitamin C and 800 IU of vitamin E, and (3) a low-fat breakfast of cereal, skim milk, and orange juice.

Plotnick found that a single high-fat meal increased blood triglyceride levels by more than 60 percent and substantially decreased endothelial function for two to four hours. Furthermore, the decrease in endothelial function correlated with the increase in triglyceride levels, but not with fasting triglyceride levels.

However, taking vitamins C and E right before the high-fat meal helped maintain normal endothelial function. In fact, the effect of the vitamins was comparable to eating the low-fat meal, which produced no increase in triglycerides or decrease in endothelial function.
"Pretreatment with antioxidant vitamins eliminated the decrease in endothelial function following the high-fat meal," Plotnick wrote.

Reference: Plotnick GD, Corretti MC, Vogel RA, "Effect of antioxidant vitamins on the transient impairment of endothelium-dependent brachial artery vasoactivity following a single high-fat meal," JAMA, 1997;278:1682-1686.

Several other recent studies have explored the roles of vitamins and antioxidants in preventing cardiovascular diseases.

• Researchers measured the thickness of the intima in the carotid arteries of 231 people with atherosclerosis and an equal number of healthy people. The intima is the innermost layer of blood vessel walls and a thickened intima is a sign of cardiovascular disease. High blood levels of carotenoids, particularly lutein and zeaxanthin, correlated with normal intima thickness. (Iribarren C, Folson AR, Jacobs DR, et al., "Association of serum vitamin levels, LDL susceptibility to oxidation, and autoantibodies against MDA-LDL with carotid atherosclerosis," Arterioscler, Thromb, and Vasc Biol, 1997;17:1171-1177.)
  

• In an experiment with rabbits, blood flow decreased and red blood cells clumped together in small blood vessels of rabbits fed a high-cholesterol diet. However, when rabbits were also fed supplemental vitamin C, blood flow was almost normal. (Freyschuss A, Xiu R-J, Zhang J, et al., Aterioscler Thomb Vasc Biol, 1997;17:1178-1184.)
  

• Various types of heart cells, including endothelial cells, can oxidize the low-density lipoprotein (LDL) form of cholesterol and promote the development of cardiovascular disease. When human endothelial cells are rich in vitamin C, they are less likely to oxidize LDL. (Martin A and Frei B, Arterioscler Thomb Vasc Biol, 1997;17:1583-1590.)
  

This article originally appeared in The Nutrition Reporter™ newsletter. The information provided by Jack Challem and The Nutrition Reporter™ newsletter is strictly educational and not intended as medical advice. For diagnosis and treatment, consult your physician.