- A vegetarian or vegan diet can help lower levels of cholesterol in the body while also helping combat climate change, says a new meta-study.
- In particular, according to the study, plant-based diets lower the levels of a lipoprotein— which is gaining interest as a better indicator of heart health than “bad” cholesterol.
- Since the body makes most of its cholesterol — and it does not come from diet — drugs such as statins that control cholesterol production remain important.
A new study indicates that a vegetarian or vegan diet can reduce levels of dietary cholesterol in the body. In particular, the study shows that such diets reduce levels of lipoprotein which may be a better predictor of cardiovascular disease than low-density lipoprotein (LDL) or “bad” cholesterol.
The study finds that plant-based diets are associated with a 7% reduction in total cholesterol and a 14% reduction in all artery-blocking lipoproteins, thereby reducing the risk of cardiovascular disease for people who maintain such a diet for at least five years.
Lipoproteins are particles composed of fats, or lipids, and proteins. The lipids they contain include cholesterol and triglycerides. Some cholesterol lipids, such as high-density lipoprotein (HDL), or “good” cholesterol, protect against heart disease. An excess, on the other hand, of low-density lipoprotein (LDL) increases cardiovascular disease risk.
The reduction in risk that resulted from plant-based diets was roughly equivalent to about a third of the cholesterol-reducing effect of medications such as statins.
The authors of the study also noted the climate-change benefits a wider adoption of plant-based foods would provide.
The study is a meta-study — or study of studies — that analyzed the results of 30 different randomized trials published between 1980 and 2022 investigating the effect of plant-based diets on cholesterol.
The results are published in the European Heart Journal, accompanied by an editorial.
Cholesterol and plant-based diets
Senior investigator of the study, Dr. Ruth Frikke-Schmidt, pointed out the importance of cholesterol, even though it is often discussed in a negative light:
“Cholesterol is a cornerstone for, e.g., cell membranes, bile, and hormones,” Dr. Frikke-Schmidt said.
However, a traditional Western diet contains much more cholesterol than is needed, which results in too-high plasma levels and [a] risk of atherosclerosis and heart attacks. A plant-based diet with less cholesterol is still sufficient to meet the needs of the body.”
Dr. Frikke-Schmidt also pointed out that vegetarian and vegan diets appear to encourage the liver to produce more LDL receptors, “thereby, [the body] can more efficiently catch cholesterol from the bloodstream.”
Perhaps the study’s most interesting finding, according to Dr. Yu-Ming Ni, a cardiologist who was not involved in the study, was that while overall cholesterol levels did not drop spectacularly, “What was very interesting was the drop in the cholesterol of apoB [apolipoprotein B].”
“It reflects a tendency towards a reduction in the actual particle counts themselves, which in research has potentially been a more accurate risk factor for predicting cardiovascular risk in some patients,” he said.
What a plant-based diet has to do with climate change
One of the study’s major findings is that vegetarian and vegan diets — in addition to promoting health — benefit the environment. Dr. Frikke-Schmidt said:
“The Institute of nutrition at the Technical University in Copenhagen estimates that 20-35% of the impact on the climate can be reduced by limiting the amount of meat products, and reduced with 45-50% if only vegan diets are produced and used.”
“These estimates are based on all available scientific literature in the field and incorporates use of land, use of water, and other resources. You can also get more info on this topic from the EAT Lancet commission report,” she explained.
Why diet alone is not the answer
Most cholesterol is not diet-based, explained Dr. Devin Kehl, a noninvasive cardiologist who was not involved with this study.
“The body produces about 80% of its cholesterol, and the remainder is ingested via diet,” he said.
Nonetheless, he added, “the reduction of animal fats in one’s diet, as demonstrated in this data set, does lead to reductions of cholesterol concentrations in the bloodstream.”
Dr. Kehl cautioned, “However, [plant-based diets] should not be seen as a substitute for cholesterol reducing medications, when these are deemed appropriate by one’s cardiologist.”
The liver produces the body’s own cholesterol, and medication such as statins inhibit this production. Cholesterol gets stored in the gall bladder as bile.
“Bile is kind of like a soap of the body,” said Dr. Ni.
When a person eats, hormones cause the gallbladder to excrete the bile into the intestinal tract.
“[It] basically picks up the fats in your food, helps to digest them, and helps to collect those very important fat-soluble vitamins that are important for our daily functioning, among other things,” said Dr. Ni.
These are then reabsorbed in the intestinal tract, along with some cholesterol. The rest leaves the body in the stool.
“We recycle a very significant portion of our cholesterol every day,” added Dr. Ni.
Reducing saturated fats in your diet
Dr. Kehl said the study, while in line with existing research, “adds to our body of evidence supporting that reduction of saturated fat in one’s diet does promote improvements of the serum cholesterol profile.”
The key to cardiovascular health and cholesterol control, according to Dr. Ni, is living by the American Heart Association’s Essential 8™.
“First and foremost, diet exercise, stress management, and sleep. To me, that’s always the focus, and I spend a lot of my time with my patients talking about those basic elements of cardiovascular health.”
— Dr. Yu-Ming Ni
Dr. Frikke-Schmidt’s personal takeaway is:
“An important message from me is that plant-based diets are a key instrument for changing food production to more environmentally sustainable forms, while at the same time reducing the growing burden of cardiovascular disease globally.”