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High-density lipoprotein (HDL) cholesterol as "good" cholesterol is being challenged by researchers. University of Chicago researchers said that HDL has varying degrees of quality and that poor quality HDL is actually bad for individuals.
"For many years, HDL has been viewed as good cholesterol and has generated a false perception that the more HDL in the blood, the better," said lead author Angelo Scanu, MD.
The researchers based their conclusion after reviewing published research on this subject. The findings showed that the HDL from patients with chronic diseases is different from the HDL in healthy individuals, even when blood levels of HDL are comparable.
The researchers found that normal "good" HDL reduces inflammation, whereas the dysfunctional, "bad," HDL does not.
"This is yet one more line of research that explains why some people can have perfect cholesterol levels, but still develop cardiovascular disease," said Gerald Weissmann, MD, editor-in-chief of The FASEB Journal, which published the study in its December 2008 issue.
A new meta-analysis confirms that eating soy protein can lead to a significant reduction in blood cholesterol levels, according to a study recently presented at the American Heart Association 2008 Scientific Sessions.
The researchers found reductions in total cholesterol of 9.54 mg/dL and reductions in low-density lipoprotein (LDL) cholesterol of 7.12 mg/dL, which is about a 4% and 5% reduction, respectively. The study also examined the effect in patients who had high versus normal cholesterol and found that the cholesterol-lowering effect of soy protein was considerable in both groups.
"These findings build on the body of evidence that continues to strongly justify maintaining the currently approved health claim for the role of soy protein in lowering heart disease risk," said Priscilla Samuel, PhD, lead researcher of the study.
The study further demonstrates the heart health benefits of soy protein. Research continues to indicate that consuming 25 g of soy protein daily results in reductions in total cholesterol and LDL cholesterol.
In the first study to investigate how pistachios lower cholesterol, researchers tested the effects of pistachios added to a heart healthy, moderate-fat diet on cardiovascular disease (CVD) risk factors.
For the study, the participants began with a typical diet of 35% total fat and 11% saturated fat for 2 weeks. They then tested 3 diets for 4 weeks each. The diets included, as a control, a Step I Diet with no pistachios and about 25% total fat and 8% saturated fat. The pistachio-enhanced diets were Step I Diets with 10% and 20% of the energy supplied by pistachio nuts, respectively. The 10% pistachio diet had 30% total fat and 8% saturated fat, and the 20% pistachio diet had 34% total fat and 8% saturated fat.
The findings indicated that the 20% pistachio diet lowered low-density lipoprotein (LDL) cholesterol about 12% and the 10% energy pistachio diet lowered LDL cholesterol by 9%. The relationship of total cholesterol to high-density lipoprotein (HDL) cholesterol and LDL cholesterol to HDL cholesterol may be markers of CVD risk.
The findings were recently reported in the American Journal of Clinical Nutrition.
Whereas levels of low-density lipoprotein (LDL) cholesterol among adults have fallen to some extent since 1980, harmful triglyceride levels have almost quintupled over the same 28 years.
The findings are based on an analysis of data from the US National Health and Nutrition Examination Survey II (NHANES II) conducted between 1976 and 1980, NHANES III from 1988 to 1994, and NHANES from 1999 to 2006. The data from NHANES II showed that in 1980, 48% of adults had LDL cholesterol levels above optimal (100 mg/dL or greater) levels. By 2006, the frequency had fallen to almost 41%.
Lead investigator Jerome D. Cohen, MD, cautioned that news is not all good. "Triglyceride levels are about 5 times higher than they were in the first NHANES." He said that about one third of adults have elevated triglyceride levels.
"To lower triglycerides, it is weight loss, weight loss, weight loss," Dr. Cohen emphasized. "We need to eat less, eat better, and exercise more."
F A S T F A C T: The National Cholesterol Education Program recommends that healthy adults have their cholesterol levels checked once every 5 years.