If you have high levels of C-reactive protein (CRP), a marker in blood for inflammation that is strongly associated with heart disease, trying to lower your LDL-cholesterol through modest diet changes alone may not work.
Kirsten Hilpert, doctoral candidate in the nutrition option of Penn State's Integrative Biosciences program, conducted a small study of the Step 1 diet's effect on men and women with moderately elevated cholesterol. She found that those who also had elevated CRP levels couldn't lower their LDL-cholesterol numbers with the Step 1 cholesterol-lowering diet, even when soy protein, a food with an approved FDA heart health claim, was added to the diet.
The National Cholesterol Education Program Step 1 diet, the first level of treatment for high cholesterol, is a low fat diet that restricts total fat to 30 percent of calories with saturated fat less than 10 percent.
Hilpert notes, "Although there are specific dietary factors, like soy, that have been shown to lower blood cholesterol, not all people experience this benefit. Our study suggests that if your CRP is elevated, you may not be able to reap the full benefit of the Step 1 Diet with or without soy."
The study is detailed in a paper, Lipid Response to a Low-Fat Diet with or without Soy Is Modified by C-Reactive Protein Status in Moderately Hypercholesterolemic Adults, published in a recent issue of the Journal of Nutrition. Hilpert's co-authors are Dr. Penny Kris-Etherton, distinguished professor of nutrition, and Dr. Sheila West, assistant professor of biobehavioral health.
Hilpert points out that in recent studies other researchers noticed that only individuals with low CRP levels experienced significant reductions in total cholesterol when consuming the DASH diet, a low-fat, low sodium diet shown to reduce high blood pressure.
The Penn State researchers decided to see if CRP status had the same effect when subjects consumed a cholesterol-lowering diet. Their study is among the first to test whether or not CRP status can predict a person's lipid response to a cholesterol-lowering diet including soy.
They recruited 32 older, overweight people with moderately elevated cholesterol. The participants included 14 men and 18 women, six of whom were receiving hormone replacement therapy. Their LDL cholesterol was in the 124 to 211 mg/dl range.