A popular weight-loss diet is also associated with higher levels of LDL cholesterol, according to research published in March 2023. <\/p>\n\n\n\n
The ketogenic or \u201cketo\u201d diet, which involves consuming very low amounts of carbohydrates and high amounts of fats, has been gaining popularity. However, a new study presented at the American College of Cardiology\u2019s Annual Scientific Session Together With the World Congress of Cardiology suggests that a \u201cketo-like\u201d diet may be associated with higher blood levels of \u201cbad\u201d cholesterol and a twofold heightened risk of cardiovascular events such as chest pain (angina), blocked arteries requiring stenting, heart attacks and strokes. <\/p>\n\n\n\n
\u201cOur study found that regular consumption of a self-reported diet low in carbohydrates and high in fat was associated with increased levels of LDL cholesterol\u2014 or \u201cbad\u201d cholesterol\u2014and a higher risk of heart disease,\u201d said Iulia Iatan, MD, PhD, attending physician-scientist at the Healthy Heart Program Prevention Clinic, St. Paul\u2019s Hospital and University of British Columbia\u2019s Centre for Heart Lung Innovation in Vancouver, Canada, and lead author of the study. \u201cTo our knowledge, our study is one of the first to examine the association between this type of dietary pattern and cardiovascular outcomes.\u201d <\/p>\n\n\n\n
Carbohydrates are the body\u2019s first \u201cgo-to\u201d source for fuel to provide energy for daily life. Low-carbohydrate, high-fat (LCHF) diets, like a keto diet, restrict consumption of carbohydrates (e.g., bread, pasta, rice and other grains, baked goods, potato products such as fries and chips, and high-carbohydrate fruits and vegetables). By depriving the body of carbohydrates, it is forced to start breaking down fat for energy instead. The breakdown of fat in the liver produces ketones, chemicals that the body uses as energy in the absence of carbohydrates\u2014hence the name ketogenic, or \u201cketone producing.\u201d Proponents of a ketogenic diet generally suggest limiting carbohydrates to 10% of total daily calories, protein to 20% to 30% and obtaining 60% to 80% of daily calories from fat. <\/p>\n\n\n\n
Some previous studies have shown that an LCHF diet can lead to elevated levels of LDL cholesterol in some people. While elevated LDL cholesterol is a known risk factor for heart disease (caused by atherosclerosis, a buildup of cholesterol in the coronary arteries), the effects of an LCHF diet on risk for heart disease and stroke have not been well studied, Iatan said.
For this study, Iatan and her colleagues defined an LCHF diet as consisting of no more than 25% of total daily energy or calories from carbohydrates and more than 45% of total daily calories from fat. They dubbed this an LCHF diet and \u201cketo-like\u201d because it is somewhat higher in carbohydrates and lower in fat than a strict ketogenic diet. They defined a \u201cstandard diet\u201d as individuals not meeting these criteria and having more balanced eating habits. <\/p>\n\n\n\n
The research team analyzed data from the UK Biobank, a large-scale prospective database with health information from over half a million people living in the United Kingdom who were followed for at least 10 years. Upon enrollment in the biobank, 70,684 participants completed a one-time self-reported 24-hour diet questionnaire and, at the same time, had blood drawn to check their levels of cholesterol. The researchers identified 305 participants whose questionnaire responses indicated that their diet during the 24-hour reporting period met the study\u2019s definition of an LCHF. These participants were matched by age and sex with 1,220 individuals who reported eating a standard diet. This resulted in 73% of the participants in each group being women and the group\u2019s average age was 54 years. Those on an LCHF diet had an average body mass index (BMI) of 27.7; those on a standard diet, 26.7. A BMI of 25 to 30 kg\/m-2 falls within the overweight range. <\/p>\n\n\n\n
Compared with participants on a standard diet, those on an LCHF diet had significantly higher levels of both LDL cholesterol and apolipoprotein B (apoB), the protein component that sits on LDL and other atherogenic lipoprotein particles. Previous studies have shown that elevated apoB may be a better predictor than elevated LDL cholesterol for risk of cardiovascular disease, Iatan said. After an average of 11.8 years of follow-up\u2014and after adjustment for other risk factors for heart disease, such as diabetes, high blood pressure, obesity and smoking\u2014people on an LCHF diet had more than two-times higher risk of having several major cardiovascular events, such as blockages in the arteries that needed to be opened with stenting procedures, heart attack, stroke and peripheral arterial disease. In all, 9.8% of participants on an LCHF diet experienced a new cardiac event, compared with 4.3% of those on a standard diet, a doubling of risk for those on an LCHF diet. <\/p>\n\n\n\n
\u201cAmong the participants on an LCHF diet, we found that those with the highest levels of LDL cholesterol were at the highest risk for a cardiovascular event,\u201d Iatan said. \u201cOur findings suggest that people who are considering going on an LCHF diet should be aware that doing so could lead to an increase in their levels of LDL cholesterol. Before starting this dietary pattern, they should consult a health care provider. While on the diet, it is recommended they have their cholesterol levels monitored and should try to address other risk factors for heart disease or stroke, such as diabetes, high blood pressure, physical inactivity and smoking.\u201d <\/p>\n\n\n\n
The study\u2019s findings also suggest that not everyone responds to an LCHF diet in the same way.
A limitation of the study is that participants provided dietary information at only one point in time, which should be considered when interpreting the study findings, Iatan said. Moreover, self-reports of food consumption can be inaccurate.
Because the study was observational, it can only show an association between the diet and an increased risk for major cardiac events, not a causal relationship. However, Iatan said the findings merit further research in prospectively designed studies, especially when approximately 1 in 5 Americans report being on a low-carb, keto-like or full keto diet. <\/p>\n\n\n\n
The American College of Cardiology (ACC) is the global leader in transforming cardiovascular care and improving heart health for all. As the preeminent source of professional medical education for the entire cardiovascular care team since 1949, ACC credentials cardiovascular professionals in over 140 countries who meet stringent qualifications and leads in the formation of health policy, standards and guidelines. More about ACC you may find here.<\/a>.<\/p>\n\n\n\n