Popular weight loss diet also associated with higher LDL cholesterol levels.
The ketogenic or “keto” diet, which involves consuming very low amounts of carbohydrates and high amounts of fat, is gaining popularity. However, a new study presented at the American College of Cardiology’s annual scientific session with the World Congress of Cardiology suggests that a “keto-like” diet may be associated with higher blood levels of “bad” cholesterol and to a doubly increased risk of cardiovascular disease. events such as chest pain (angina pectoris), blocked arteries requiring stenting, heart attacks and strokes.
“Our study found that regular consumption of a low-carb, high-fat diet was associated with increased levels of LDL cholesterol – or ‘bad’ cholesterol – and a higher risk of heart disease,” said said Iulia Iatan, MD, PhD, physician-scientist at the Healthy Heart Program Prevention Clinic, St. Paul’s Hospital and Center for Heart Lung Innovation at the University of British Columbia in Vancouver, Canada, and lead author of the study . “To our knowledge, our study is one of the first to examine the association between this type of diet and cardiovascular outcomes.”
Carbohydrates are the body’s first “must have” source of fuel to provide energy for daily life. Low-carb, high-fat (LCHF) diets, such as a keto diet, limit carbohydrate intake (eg, bread, pasta, rice and other grains, baked goods, potato products such as French fries and crisps, and carbohydrate-rich fruits and vegetables). By depriving the body of carbohydrates, it is forced to start breaking down fat for energy. The breakdown of fat in the liver produces ketones, chemicals that the body uses for energy in the absence of carbohydrates, hence the name ketogenic, or “ketone production.” Proponents of a ketogenic diet generally suggest limiting carbs to 10% of total daily calories, protein to 20% to 30%, and getting 60% to 80% of daily calories from fat.
Some previous studies have shown that an LCHF diet can cause high LDL cholesterol levels in some people. Although high 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 the risk of heart disease and stroke stroke have not been well studied, Iatan said.
For this study, Iatan and colleagues defined an LCHF diet as having no more than 25% of energy or total daily calories from carbohydrates and more than 45% of total daily calories from fat. They dubbed it an LCHF and “keto-like” diet because it has slightly more carbs and less fat than a strict ketogenic diet. They defined a “standard diet” as individuals who did not meet these criteria and had more balanced eating habits.
The research team analyzed data from the UK Biobank, a large-scale prospective database containing information on the health of over half a million people living in the UK and followed for at least 10 years. . When enrolling in the biobank, 70,684 participants completed a unique 24-hour self-reported dietary questionnaire and, at the same time, had their blood drawn to check their cholesterol levels. The researchers identified 305 participants whose questionnaire responses indicated that their diet during the 24-hour reporting period met the study’s definition of an LCHF. These participants were age- and sex-matched with 1,220 people who reported following a standard diet. This resulted in 73% of the participants in each group being women and the average age of the group being 54 years. Those on the 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 falls into the overweight range.
Compared to participants on a standard diet, those on an LCHF diet had significantly higher levels of LDL cholesterol and apolipoprotein B (apoB), the protein component that relies on LDL and other atherogenic lipoprotein particles. Previous studies have shown that elevated apoB may be a better predictor than elevated LDL cholesterol for cardiovascular disease risk, Iatan said. After an average of 11.8 years of follow-up — and after adjusting for other heart disease risk factors, such as diabetes, high blood pressure, obesity, and smoking — people on the LCHF diet had more twice as likely to have several major problems. cardiovascular events, such as blockages in arteries that needed to be opened with stenting procedures, heart attack, stroke, and peripheral arterial disease. A total of 9.8% of participants on the LCHF diet experienced a new cardiac event, compared to 4.3% of those on the standard diet, a doubling of the risk for those on the LCHF diet.
“Among the LCHF diet participants, we found that those with the highest levels of LDL cholesterol were at highest risk for a cardiovascular event,” Iatan said. “Our results suggest that people who are considering following an LCHF diet should be aware that it may cause an increase in their LDL cholesterol levels. Before starting this diet, they should consult with a health care provider. , monitoring their cholesterol levels and trying to address other risk factors for heart disease or stroke, such as diabetes, high blood pressure, physical inactivity and smoking, are recommended.
The study results also suggest that not everyone responds the same way to an LCHF diet.
“On average, cholesterol levels tend to increase on this diet, but some people’s cholesterol levels may stay the same or decrease, depending on several underlying factors,” Iatan said. “There are inter-individual differences in how people respond to this diet that we don’t yet fully understand. One of our next steps will be to try to identify specific characteristics or genetic markers that can predict how a person will respond to this type of diet.
A limitation of the study is that participants provided dietary information at only one time point, which must be considered when interpreting study results, Iatan said. Additionally, self-reports of food consumption can be inaccurate, although Iatan said this questionnaire has been widely validated.
Because the study was observational, it can only show an association between diet and an increased risk of major cardiac events, not a causal relationship. However, Iatan said the findings merit further research in prospective studies, especially when about 1 in 5 Americans report following a low-carb, keto-like, or whole-keto diet.
Iatan presented the study, “Association of a low-carbohydrate, high-fat (ketogenic) diet with plasma lipid levels and cardiovascular risk in a population-based cohort,” on Sunday, March 5.