How does Dietary Cholesterol affect Cholesterol Level

            Since nearly all tissues of the body have the ability to produce cholesterol, dietary cholesterol is defined as coming from the food we eat. It is found in meat, poultry, seafood and dairy products. Egg yolks and organ meats are high in cholesterol. Shrimp and crayfish are somewhat high in cholesterol. Chicken, turkey and fish contain about the same amount of cholesterol as do lean beef, lamb and pork. Plants don’t produce cholesterol, so foods and oils coming from plants are cholesterol free.

Cholesterol gets a bad rap because it is necessary for the formation of cell membranes and the synthesis of essential compounds such as bile acids and steroid hormones. In fact the body makes enough cholesterol to maintain itself. Therefore, dietary cholesterol is surplus cholesterol – cholesterol that the body does not need.

The relationship between dietary cholesterol and the concentration of blood cholesterol is not linear. For every additional 100mg of cholesterol consumed up to a total intake of 500mg per day, there is a 2-3% increase in the concentration of blood cholesterol. In contrast further increases in cholesterol intake beyond 500mg per day have little additional effect on the plasma level. It has been estimated that if cholesterol intake is greater than 500mg per day, a reduction in intake to 250mg per day will reduce blood total cholesterol by 5-7% which may be predicted to translate into a 10% reduction in the risk of coronary heart disease.

The American Heart Association recommends an intake of cholesterol < 300 milligrams/day for the healthy adult population and < 200 milligrams/day for adults with elevated blood LDL-cholesterol levels. Dietary cholesterol increases the concentration of both LDL (bad) and HDL (good) cholesterol in most people, although the relative increase in the two fractions may vary markedly between people. A low-fat diet and high-cholesterol intake (600mg/day) from shrimps in persons with normal levels of cholesterol raised LDL cholesterol by 7% but also raised HDL by 12% and decreased triglycerides by 13%. The LDL cholesterol to HDL cholesterol ratio dropped ( a good thing). In contrast, the low fat high-egg diet (cholesterol intake 600mg/day) raised LDL by 10% and HDL by 8% (and increased the ratio of LDL to HDL - a bad thing). In one study it was concluded that moderate shrimp consumption by persons with optimal levels of cholesterol did not affect overall lipoprotein profile and shrimp consumption could be included in ‘heart healthy’ guidelines.

Egg yokes contain lots of cholesterol. Eggs combined with sausages or fried in butter and eaten with buttered toast, can certainly contribute to high blood cholesterol levels, but it is the accompanying saturated fat that is the culprit. The main message to those with high blood cholesterol should be to find alternatives to saturated fat. Fast foods have loads of saturated fat even if fried in ‘no cholesterol vegetable oil’ which is made from partially-hydrogenated vegetable oils (trans fats). This oil may not have cholesterol, but is high in saturated and trans fatty acids.

So cholesterol found in the foods we eat is not as much of a problem as the saturated and trans fats in the food or used to prepare the food.