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Is following a Mediterranean diet enough to lower cholesterol levels? Image credit: Sara Remington/Stocksy.
  • High cholesterol is responsible for about 2.6 million deaths globally every year.
  • Previous studies have suggested that certain diets, such as the Mediterranean diet, can help lower ‘bad’ cholesterol levels.
  • Researchers from Lausanne University have found contrary evidence suggesting following the Mediterranean diet may not have as much impact on cholesterol levels as previously reported.

Researchers estimate that high cholesterol causes about 2.6 million deaths around the world each year.

High cholesterol is caused by an increased level of low-density lipoprotein (LDL) cholesterol, also known as “bad” cholesterol, in the body.

Although genetics and some medications can cause heightened LDL cholesterol levels, most times the main culprit is an unhealthy diet.

Over the past few years, scientists have found that certain diets, such as the DASH diet, Therapeutic Lifestyle Changes (TLC) diet, vegan diet, and Mediterranean diet, can help lower “bad” cholesterol levels.

Now, however, researchers from Lausanne University in Switzerland have found contrary evidence, suggesting that following the Mediterranean diet may not have as much impact on cholesterol levels as previously reported.

The study was recently published in the journal Nutrients.

The Mediterranean diet is considered very healthy thanks of its focus on vegetables, fruits, legumes, whole grains, and healthy fats, and its emphasis on fish and seafood for protein.

Previous research has shown that some of the foods emphasized in the Mediterranean diet can help lower LDL cholesterol. These include whole grains, olive oil, fish high in omega-3 fatty acids, and nuts.

A study published in May 2017 discovered that adherence to the Mediterranean diet — particularly when enriched with virgin olive oil — decreased LDL cholesterol amounts in people at high risk for cardiovascular disease.

Research published in July 2020 found that switching study participants with overweight and obesity to a Mediterranean diet resulted in a reduction in their cholesterol.

Similarly, a study published in June 2020 found people with hypercholesterolemia — an increased amount of LDL cholesterol — who followed a combination of the Mediterranean diet and Portfolio Diet lowered their LDL cholesterol levels by 25%.

Finally, a systematic review of 13 studies on the Mediterranean diet and high cholesterol published in March 2021 found that the diet offered favorable effects on high-density lipoprotein (HDL) cholesterol.

HDL cholesterol is considered the “good” cholesterol, and higher amounts of this type of cholesterol in the body may help lower a person’s risk of cardiovascular disease.

For this study, researchers conducted three cross-sectional studies using data from people living in Lausanne, Switzerland. The dietary intake of about 4,200 study participants was assessed through a food frequency questionnaire.

Scientists measured how adherent study participants were to the Mediterranean diet, as well as their LDL and HDL cholesterol and triglyceride levels. Triglycerides are a type of fat found in the bloodstream. High triglyceride levels coupled with low HDL and/or high LDL cholesterol levels can increase a person’s risk of heart issues.

Upon analysis, the researchers found that no matter how high a participant’s adherence to the Mediterranean diet was, it did not affect their lipid profile, which is a measurement of a person’s cholesterol and triglyceride levels.

Scientists reported there were no significant differences between how adherent a person was to the Mediterranean diet and study participants diagnosed with incident dyslipidemia, which is an imbalance of lipids in the blood.

Researchers said that adherence to the Mediterranean diet was positively related to HDL cholesterol and negatively linked to triglyceride levels in participants who were not diagnosed with dyslipidemia. However, there were no significant associations reported for total and LDL cholesterol.

Overall, the researchers commented in their study that their results highlight the need for more research on long-term dietary investigations across populations, and also question the one-diet-fits-all approach for a specific medical treatment, such as lipid imbalance.

After reviewing this research, Monique Richard, a registered dietitian nutritionist, owner of Nutrition-In-Sight, and national media spokesperson for the Academy of Nutrition Dietetics, not involved in the study, told Medical News Today the results were not surprising.

“As registered dietitian nutritionists, my colleagues and I understand the bio-individuality and numerous other factors that influence lab values and biomarkers that measure cholesterol levels, such as genetics, ethnicity, activity, nutrient adequacy, prescription medication/medication interactions, metabolic cofactor functioning, bowel movements, gut health, gallbladder and bile duct functionality and more,” Richard told us.

“One specific pill, diet, or exercise is not, and never will be, a ‘cure-all’ or ‘one size fits all’,” she cautioned.

“I do think it is important to note that even though a conflict of interest was not disclosed, it is noted that a funding source of the study included GlaxoSmithKline — a pharmaceutical company that makes cholesterol-lowering medication,” Richard pointed out.

Dr. Yu-Ming Ni, a board-certified cardiologist and lipidologist at MemorialCare Heart and Vascular Institute at Orange Coast Medical Center in Fountain Valley, CA, also not involved in the study, agreed with Richard’s viewpoint:

“From a short-term standpoint, there really isn’t a one-size-fits-all diet. From a long-term standpoint, we’ve been looking to find which diet is the best. I still think that if you stick to the Mediterranean diet, which has the most data, you’re not going to be wrong.”

Dr. Ni, however, also told MNT he feared people would read this study and assume the Mediterranean diet provides no benefits.

“You’re throwing the baby out with the bathwater when you say something like that — that’s what I don’t want people to think,” he continued. “I think there’s some subtle differences in cholesterol. I just don’t think that it’s going to be just because one study says that maybe there isn’t a difference depending on adherence, I wouldn’t say that you shouldn’t do Mediterranean diet anymore.”

When it comes to lowering high cholesterol, Dr. Ni advised everyone ought to remember it comes down to more than just adhering to a specific diet.

“Whenever I counsel my patients about what’s a healthy lifestyle, I mean it — it’s a way of living,” he told us. “It’s not just what you put in your mouth. As much as that is important, and I would argue for some people it is the most important factor that leads to their risk for heart disease. [But] it’s not the only thing — it’s everything else, too.”

“If you’re thinking about eating differently in a more healthy way, a Mediterranean diet is a great choice,” Dr. Ni added. “Maybe that works for you, maybe that doesn’t. And if not, then, you can explore other dietary options.”

For readers looking to lower their cholesterol, Richard advised meeting with a registered dietitian nutritionist to learn more about their needs, goals, what may be going on with their cholesterol, and other factors that may be influencing them.

“Fiber is our friend with a capital ‘F’,” she continued. “If you have a healthy gut and are able to up the insoluble and soluble fiber, it will help sweep out excess cholesterol. The basic [minimal] recommendation is 25–35 grams of fiber a day. Only about 5–9% of Americans are currently meeting that recommendation. Get it from fruits, vegetables, nuts, seeds, beans, and whole grains.”