A study published in the American Journal of Clinical Nutrition has reported that eating red and white meat has equally negative effects on blood cholesterol levels. This is in contrast to popular belief that red meat has a worse effect on blood cholesterol than white meat.
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The aim of the study was to investigate whether levels of atherogenic lipids and lipoproteins (lipids and lipoproteins that promote the formation of fatty deposits in the arteries) differed in diets rich in red meats compared with diets in which protein is derived from white meat or nonmeat sources.
The study was led by researchers at the Children’s Hospital Oakland Research Institute (CHORI), which is the research department of UCSF Benioff Children’s Hospital Oakland.
Plant-based protein is best
Study participants included healthy men and women aged 21 to 65 years old who had a body mass index (BMI) of 20 to 35kg/m2, a blood pressure level of <150/90, and who were not using vitamin supplements or drinking alcohol, amongst other criteria.
The participants were given experimental diets that substituted red meat for white meat or non-meat protein sources and were followed for four weeks at a time. In between these experimental diets were breaks of two to seven weeks, during which participants consumed their normal diet.
For each experimental diet, blood samples were collected for plasma lipid, lipoprotein particle subfractions, apolipoproteins, and glucose level analysis. Body weight, blood pressure, and hip and waist circumference were also taken.
The researchers discovered that consuming high levels of red meat or white poultry caused higher blood cholesterol levels when compared to diets that sourced protein from plant sources.
This surprising discovery was also apparent in diets that included a high amount of saturated fats, which increased blood cholesterol to the same extent as red, white, and plant protein sources.
Observational studies suggest that red meat intake is associated with increased cardiovascular disease risk, whereas no such association has been observed with regular consumption of poultry. Conversely, plant protein sources and vegetarian dietary patterns appear to be cardioprotective.”
‘We were surprised [by the findings]’
Dietary guidelines currently recommend eating white meats instead of red meats as a source of protein, as red meat has associations with cardiovascular disease (CVD).
Senior author of the study Ronald Krauss, MD, a senior scientist and director of Atherosclerosis Research at CHORI and a UCSF professor of medicine said there had been no comparison between the effects of red meat, white meat, and nonmeat proteins on blood cholesterol, and the results were very different to what he and the research team had expected.
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.”
The study, named the APPROACH (Animal and Plant Protein and Cardiovascular Health) trial, references the current literature suggesting contrary results this new study’s findings.
It notes that saturated fatty acids (SFAs) increase plasma concentrations of low-density lipoprotein (LDL) cholesterol and as such there is a widespread belief that “the SFA content of red meat contributes to its association with CVD risk.”
Although the study did not include grass-fed beef, fish, or processed meats such as bacon or sausage, the results suggested that restricting dietary intake of red and white meat is better for lowering blood cholesterol levels than it is currently thought. In fact, proteins derived from plant sources were best for lowering blood cholesterol levels, according to Krauss.
Concentrations of large cholesterol-enriched LDL particles increased in diets with high levels of saturated fats. Large cholesterol-enriched LDL particles are not as strongly associated with CVD risk as smaller LDL particles, and it was found that levels of large LDL particles also increased with higher intakes of red and white meats. This is in comparison to diets that do not include meat products.
“Our results indicate that current advice to restrict red meat and not white meat should 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,” said Krauss.
The study made the following conclusion:
The findings are in keeping with recommendations promoting diets with a high proportion of plant-based food but, based on lipid and lipoprotein effects, do not provide evidence for choosing white or red meat for reducing CVD risk.”
Bergeron, N., et al. (2019). Effects of red meat, white meat, and nonmeat protein sources on atherogenic lipoprotein measures in the context of low compared with high saturated fat intake: a randomized controlled trial. The American Journal of Clinical Nutrition. doi.org/10.1093/ajcn/nqz035.