Research finds chicken, beef raise cholesterol levels in equal measures compared to vegetable diet
Eating chicken and other white meats may be just as bad for your heart as a diet rich in red meats such as beef, lamb and pork, according to new research.Red meat has become a demonized ingredient in recent years, after a landmark study in 2012 found its high saturated fat content increases the risk of early death.
In 2015, the International Agency for Research on Cancer listed red meat in Group 2A: a probable carcinogen. White meat has been held up as the healthier, leaner alternative – fueling the uptick in consumption of poultry, as sales of burgers and chops dwindle.
But a small new study calls that into question. Researchers at the University of California, San Francisco, United States (U.S.), found both white and red meat drive up levels of ‘bad’ cholesterol in the blood in equal measures, raising the risk of heart disease.
The effect was observed whether or not the diet contained high levels of saturated fat, according to the findings published in the American Journal of Clinical Nutrition.Saturated fats, found in foods including butter, cheese and cream, increased blood cholesterol to the same extent with all three protein sources.
Study senior author, Prof. Ronald Krauss said: “When we planned this study, we expected red meat to have a more adverse effect on blood cholesterol levels than white meat, but we were surprised that this was not the case – their effects on cholesterol are identical when saturated fat levels are equivalent.”
Krauss, a senior scientist at Children’s Hospital Oakland Research Institute (CHORI), California, said the meats studied did not include grass-fed beef or processed products such as bacon or sausage, or fish. But he said the results were notable as they indicated that restricting meat altogether, whether red or white, is more advisable for lowering blood cholesterol levels than previously understood.
The study – dubbed Animal and Plant Protein and Cardiovascular Health trial – involved 113 people aged between 21 to 65 years-old.
The participants were randomly put into either a high saturated fat or low saturated fat diet group.In their respective groups, the participants ate red meat, white poultry meat, and then no meat in separate four week periods which were balanced out by periods in between where participants went back to their normal diet.
Corn-fed beef was the main red meat source, followed by pork, while chicken was the main white meat source, followed by turkey. They were given the food which was carefully put together by researchers in the lab and were not allowed to drink alcohol, take vitamins, eat processed meats or change their exercise routine during the study. Blood samples were collected at the start and finish of each diet, which found that eating high amounts of saturated fat increased concentrations of large LDL particles.
LDL particles are essential for carrying lipids, including cholesterol, around the body in the bloodstream.There is stronger evidence that small LDL particles, which are still needed to transport nutrients, are a risk factor for developing cholesterol problems.
Red and white meat also increased amounts of large LDL in comparison to diets that exclude meat. For this reason, standard LDL cholesterol tests, which may primarily reflect levels of larger LDL particles, may misrepresent levels of larger LDL particles, and overestimate the cardiovascular risk of higher meat and saturated fat intakes.
High cholesterol can block blood vessels and cause heart disease, which causes more than a quarter of deaths in the US and UK. Red meat, a source of iron and vitamin B12, has become less popular due to concerns about heart disease and cancer.
Government dietary guidelines have encouraged eating poultry as a healthier alternative to red meat and generally leaner cuts – those that have less saturated fat.But there had been no comprehensive comparison of the effects of red meat, white meat and non-meat proteins on blood cholesterol until now, according to the researchers.
Krauss said a diet that includes non-meat proteins such as vegetables, dairy, and legumes – including beans – show the best cholesterol benefit.He said: “Our results indicate that current advice to restrict red meat and not white meat should not be based only on their effects on blood cholesterol.
“Indeed, other effects of red meat consumption could contribute to heart disease, and these effects should be explored in more detail in an effort to improve health.”
What is high cholesterol? Cholesterol is a fatty substance that is vital for the normal functioning of the body. But too much can cause it to build up in the arteries, restricting blood flow to the heart, brain and rest of the body. This raises the risk of angina, heart attacks, stroke and blood clots.
Cholesterol is made in the liver and is carried in the blood by proteins. The first – high-density lipoprotein (HDL) – carries cholesterol from cells to the liver where it is broken down or passed as waste. This is ‘good cholesterol’.‘Bad cholesterol’ – low-density lipoprotein (LDL) – carries cholesterol to cells, with excessive amounts then building in the artery walls.
High cholesterol can be genetic but it is also linked to a diet rich in saturated fat, as well as smoking, diabetes, high blood pressure and a family history of stroke or heart disease.
Blood cholesterol is measured in units called millimoles per litre of blood, often shortened to mmol/L.A healthy adult’s overall level should be 5mmol/L or less, while their LDL level should be no more than 3mmol/L. An ideal level of HDL is above 1mmol/L.
Cholesterol can be lowered by eating a healthy, low-fat diet; not smoking; and exercising regularly.If these do not help, cholesterol-lowering medication like statins may be prescribed.
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