You are here
Experts Debate Effect of Removing Guidelines for Dietary Cholesterol
Recently the annual Dietary Guidelines Advisory Committee Report stated that cholesterol was “not a nutrient of concern for overconsumption.” But several noted doctors and scientists disagree.
“The result has been a green light for people to eat unhealthful foods,” said Dr. Neal D. Barnard, founding president of the Physicians Committee for Responsible Medicine, said in March in testimony before the advisory committee. “The committee made a scientific error on cholesterol, and to carry that mistake into the guidelines is not scientifically defensible and serves only to perpetuate confusion.”
A conclusion that eating foods high in cholesterol, such as eggs, will not affect blood cholesterol levels is flawed science, several critics have stated. Others raise concern that people will use that pronouncement as license to eat as much high-cholesterol foods as they want.
Moreover, other components in foods containing cholesterol can pose health risks, including saturated fat, they said.
“Most of the members of the public don’t differentiate between dietary cholesterol and blood cholesterol or the effects of dietary cholesterol from the risk of foods that contain it,” Barnard said in his testimony.
Dr. Michael Greger of NutritionFacts.com went a step further, stating that dietary cholesterol not only raises blood cholesterol but increases the risk of diabetes, cancers, and liver disease, including nonalcoholic cirrhosis, cancer, and hepatitis C.
Another problem, Greger testified, is that cholesterol is “correlated with other disease-promoting components in the same foods,” such as saturated fat. Removing limits on cholesterol consumption will invite people “to consume foods that should be minimized in lieu of healthier food choices.”
The U.S. Department of Agriculture updates science-based dietary guidelines every 5 years, with new guidelines expected later this year. The advisory committee wants to overturn the 2010 guidelines recommending less than 300 mg a day of dietary cholesterol, with a national average of 340 mg. One egg yolk contains about 185 mg of cholesterol.
Cholesterol occurs only in animal-based foods, with high concentrations in eggs, shellfish, and organ meats, including liver. While those foods don’t contain high levels of saturated fat, certain cuts of beef (ribs), lamb, and pork (chops), and whole-dairy products do contain elevated levels of cholesterol and saturated fat. The draft guidelines say that limiting saturated fat consumption “would further reduce the population level risk of cardiovascular disease.”
So will saturated-fat consumption increase once limits on dietary cholesterol have been removed?
Dr. Robert H. Eckel, a professor at the University of Colorado School of Medicine, co-authored the 2013 American Heart Association/American College of Cardiology evidence upon which the committee based its decision to remove dietary cholesterol limits. “The evidence we reviewed indicated that dietary cholesterol independent from the intake of saturated and trans fats alone caused no appreciable increase in blood cholesterol levels,” he said.
But he added that the advisory committee’s statement should include an asterisk to denote the need for definitive studies to decide the matter.
“I think the public’s completely confused,” Eckel said. “The right studies need to be done where the entire diet is prescribed and the only modification is in cholesterol content.”
Cholesterol is needed to produce hormones, vitamin D, and substances that help digest food. The body makes the amount of cholesterol it needs, the National Institutes of Health says. Cholesterol travels in the blood, with elevated low-density lipoprotein (LDL) cholesterol levels responsible for the buildup of plaque in arteries, resulting in cardiovascular and heart disease.
Cholesterol in the blood courses back to the liver, where it is removed and discarded. But saturated fat in the liver prevents that organ from removing the cholesterol, allowing levels to build in the blood, the NIH explains.
Dr. Lewis Kuller, of the University of Pittsburgh Graduate School of Public Health, said research studies from the 1950s through the 1970s clearly found that dietary cholesterol increases blood cholesterol. But the advisory committee, he said, relies only on research done since 1990. Modern studies survey people about what foods they consumed, compared with the earlier studies, which provided study participants with specific diets to measure the effects of dietary cholesterol.
For that reason, Kuller said the committee’s statement is “fallacious.”
“The intake of dietary cholesterol has been reduced dramatically [over the decades] primarily by efforts to convince the public to reduce their intake of dietary cholesterol,” Kuller stated in a written response to the committee guidelines. Those population-wide reductions in cholesterol represent “a major public health advance.” But that’s now at risk if limits on dietary cholesterol are removed. An increase in the nation’s average cholesterol rate of just 10 mg “can be interpreted to result in perhaps a 20 percent increase in the risk of coronary heart disease.”
A higher dietary cholesterol intake also has been linked to other health problems, including colon cancer, Kuller said.
Source: Medical Xpress; April 14, 2015.