
Dietary Cholesterol Makes LDL
Cholesterol More RadicalBy Judy McBride April 4, 2000A little extra cholesterol in our diets
may render the bad LDL cholesterol in our bloodstream more
susceptible to oxidation. Thats what happened to the LDL from a group of
older men and women in a study reported in the March issue of
Atherosclerosis. And thats not good: Evidence suggests that oxidized LDL cholesterol is
more apt to provoke the plaques that build up in arteries and increase risk of
heart attack and stroke. The researchers concluded that the current recommendation to limit dietary
cholesterol is both valid and prudent, noting that their findings support those
of an earlier study by others. This study was led by Ursula S. Schwab and Alice
H. Lichtenstein at the Jean Mayer USDA
Human Nutrition Research Center on Aging at Tufts University in Boston. Schwab, who is now back in Finland, Lichtenstein and colleagues designed
30-percent-fat diets that differed only in the type of fat. One was rich in
polyunsaturated fat from corn oil; the other was rich in saturated fat from
beef tallow. Otherwise, the foods were identical. And by adding extra cholesterol to each diet--ranging from around 220 to 330
milligrams, depending on the volunteers total calorie intake--they
approximately doubled the cholesterol content. Thats considerably more
than the 300-milligrams recommended by the Dietary Guidelines. Thirteen men and women between the ages of 46 and 78 ate each of four diets,
the corn oil with and without the extra cholesterol and beef tallow with and
without extra cholesterol. The type of fat didnt significantly affect the susceptibility of the
volunteers LDL to oxidation in a test-tube assay. But the extra
cholesterol increased oxidation susceptibility by 28 percent during the corn
oil diet and 15 percent during the beef tallow diet. The volunteers began the study with moderately elevated LDL
cholesterol--each having levels greater than 130 milligrams per deciliter.
Adding the extra dietary cholesterol prompted a further rise in their total as
well as their LDL cholesterol, regardless of the type of fat in the diet. Scientific contact: Alice H. Lichtenstein, Jean Mayer
USDA Human Nutrition Research Center on
Aging at Tufts University, Boston,
Mass., phone (617) 556-3127, fax (617) 556-3103,
[email protected].
U.S. Department of Agriculture |