Oxidized Cholesterol-Another Heart Disease Risk
The Scienfitic Evidence that Supports the Link
Aug 27, 2009
There is extensive evidence suggesting that oxidized dietary cholesterol may play a key role in atherosclerosis - a disease characterized by hardening of the arteries.
Zhen You Chen, Ph.D. and colleagues of Hongkong University found new evidence that oxidized cholesterol increases the risk of heart attacks, by boosting total cholesterol levels. When a person ingests a meal high in oxidized dietary cholesterol, the cholesterol oxidation products (COPs) called oxycholesterols, are incorporated in the circulating low-density lipoprotein or LDL-C/"bad" cholesterol and in high-density lipoprotein or HDL-C/"good" cholesterol. This merger makes LDL-C more susceptible to oxidation (rancidity).
Oxidized cholesterol attracts monocytes (white blood cells) that become "foam cells" as they engulf the noxious particles which in turn gets deposited in the intima - innermost lining of blood vessels. The typical Western diet with its highly processed food content is replete with oxidized fat that can contribute to heart disease. Their investigation was presented in the 238th National Meeting of the American Chemical Society.
All fats including cholesterol from dietary and endogenous sources (produced daily by the liver) are subject to outside/"exogenous" and self-oxidation/"auto-oxidation". Food processing involving temperature e.g. cooking,
irradiation, addition of antioxidants such as butylated hydroxy acid, (BHA), vitamin E, vitamin C, trolox, etc., exposure to oxygen during storage can significantly preserve or destroy cholesterol. In a study conducted by Nam and colleagues, irradiated and aerobically packaged raw meats such as turkey, beef, and pork contained high cholesterol oxidation products after 7 days of storage.
Lee Hu and colleagues found that adding antioxidants (vitamin C, vitamin E, BHA, and trolox) inhibited the formation of COPs with vitamin C being the most pronounced in eggs and BHA in meat products.
Reducing Your Dietary Oxycholesterol Intake
While it is impossible to completely eliminate oxidized fats from your diet, you can minimize the amount of these harmful fats by implementing these strategies:
- Increase your intake of fresh whole foods - fruits, vegetables, whole grain breads and cereals, nuts, seeds, etc. They contain antioxidant vitamins (vitamin C and E) and the antioxidant mineral - Selenium. They also contain phytochemicals - plant chemicals that confer health beyong vitamins and minerals. Some of these phytochemicals act as antioxidants themselves, but many act in synergy with other protective compounds in the foods, or enzymes produced by the body. Together they enhance the immune system and the body's ability to fight oxidation.
- Select and prepare foods properly. The best way of preparing meats are boiling, steaming/braising, roasting (covered with some fluid). Eat grilled meats sparingly. Marinate meat to be grilled in some vitamin C - rich juice like lemon juice to preserve fats (cholesterol). Trim off charred parts of grilled meat.
- Restrict your total fat intake to less than 30 grams per day.
- Restrict intake of processed or convenience foods. Nutrition labels only itemize calorie, macronutrient (protein, carbohydrate, fat, water), vitamins, and mineral contents, but not the fat radicals in the product.
References
Zhen Yu Chen et al. "Little known type of cholesterol may pose greatest risk of heart disease risk" Annual Meeting of the American Chemical Society, August 16-20, 2009 Washington,DC, USA
Staprans I et al. "Oxidized cholesterol in the diet is a souce of oxidized lipoprotein in human serum" Journal of Lipid Research April 2003;44:705-715
Staprans I et al. "The role of dietary oxidized cholesterol and oxidized fatty acids in the development of atherosclerosis" Molecular Nutrition Food Research November 2005; 49(11):1075-1082
Nam KC et al. "Cholesterol oxidation products in irradiated raw meats with different packaging and storage time" Meat Science August 2001;58(4):431-435
Lee Hu et al. "Inhibition of cholesterol oxidation in marinated foods as affected by antioxidants during heating" Food Chemistry May 2008;108(1):234-244
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