by
CNN
—
A low-carb, high-fat “keto-like” diet may be linked to higher levels of “bad” cholesterol and a double risk of cardiovascular events like clogged arteries, heart attacks and strokes, new research finds.
“Our study found that regular consumption of a self-reported low-carbohydrate, high-fat diet was associated with increased levels of LDL cholesterol — or ‘bad’ cholesterol — and a higher risk of heart disease,” said study lead author Dr. Iulia, from Iatan of the Healthy Heart Program Prevention Clinic, St. Paul’s Hospital and the University of British Columbia’s Center for Heart Lung Innovation in Vancouver, Canada, in a press release.
In the study, researchers defined a low-carbohydrate, high-fat (LCHF) diet as 45% of total daily calories from fat and 25% from carbohydrates. The study was presented Sunday at the American College of Cardiology’s Annual Scientific Session in conjunction with the World Congress of Cardiology.
“Our study rationale was based on the fact that we would see patients in our cardiovascular prevention clinic with severe hypercholesterolemia after this diet,” Iatan said during a presentation at the meeting.
Hypercholesterolemia, or high cholesterol, increases a person’s risk of having a heart attack or other adverse cardiovascular events.
“This got us thinking about the relationship between these low-carb, high-fat diets, lipid levels, and cardiovascular disease. And yet there is limited data on this relationship,” she said.
The researchers compared the diets of 305 people eating an LCHF diet to about 1,200 people eating a standard diet, using health information from the UK Biobank database, which followed people for at least a decade.
The researchers found that people on the LCHF diet had higher levels of low-density lipoprotein, also known as LDL, cholesterol and apolipoprotein B. Apolipoprotein B is a protein that encapsulates LDL cholesterol proteins and may be better at predicting heart disease than elevated LDL cholesterol levels are allowed to be.
The researchers also found that the total fat intake of the LCHF diet participants was higher in saturated fat and consumed twice as much animal sources (33%) compared to those in the control group (16%).
“After an average of 11.8 years of follow-up — and after adjusting for other heart disease risk factors such as diabetes, hypertension, obesity and smoking — people on an LCHF diet were more than twice as likely to have multiple major cardiovascular events, such as constipation in arteries that had to be opened with stenting procedures, heart attack, stroke and peripheral arterial disease,” the researchers noted, according to the press release.
The researchers said in the press release that their study “can only show an association between diet and an increased risk of major cardiac events, not a causal relationship” because it was an observational study, but their findings warrant further investigation, “Especially when about 1 in 5 Americans report being on a low-carb, semi-keto, or full ketogenic diet.
Iatan said the study’s limitations included measurement errors that arise when self-reporting dietary assessments, the study’s small sample size and that most of the participants were British and did not include other ethnic groups.
The study also looked at the longitudinal effect of diet adherence, while most people who follow a keto-like diet tend to follow it intermittently for shorter periods of time.
Most of the participants – 73% – were women, which Iatan says is “quite interesting to see, but the available literature also confirms that women are generally more dietary compliant and more interested in making lifestyle changes. ”
When asked if there were any groups who weren’t harmed by an LCHF diet, Iatan said how long people stay on the diet and whether or not they lose weight “can offset an LDL elevation.”
“It is important that every patient reacts differently. And so there really is inter-individual variability between the response. What we found is, you know, on average, patients tend to raise their LDL cholesterol levels,” she said.
Most health experts say the trending keto diet, which bans carbs to let your body burn fat for fuel, excludes healthy foods like fruits, beans, and legumes, as well as whole grains. On the keto diet, you limit your carb intake to just 20 to 50 per day—the fewer, the better. To put that in perspective, a medium-sized banana or apple has about 27 carbs—the daily ration.
Keto is short for ketosis, a metabolic state that occurs when your liver begins using stored fat to produce ketones for energy. The liver is programmed to do this when your body loses access to its preferred energy – carbohydrates – and thinks it’s starving.
The keto diet has been around since the 1920s, when a doctor stumbled upon it to control seizures in children with epilepsy who were unresponsive to other treatments.
Low-carb diets like keto rely heavily on fats to keep you full. At least 70% of the ketogenic diet is fat; some say it’s closer to 90%.
While you can get all of that fat from healthy unsaturated fats like avocados, tofu, nuts, seeds, and olive oil, the diet also allows for saturated fats like lard, butter, and coconut oil, as well as whole milk, cheese, and mayonnaise. Eating many foods high in saturated fat increases the body’s production of LDL cholesterol, which can build up in the arteries and restrict blood flow to the heart and brain.
