The Surprising Effects of the Mediterranean Diet on Cardiovascular Disease

Diet is known to directly affect many diseases, foremost among them cardiovascular diseases. Cardiovascular disease is a general name for a group of diseases affecting the heart and blood vessels, also called heart and vascular diseases. According to the World Health Organization (WHO), cardiovascular diseases are the leading cause of death worldwide, accounting for 38% of all deaths. The most effective dietary pattern for preventing cardiovascular diseases is the Mediterranean Diet. In this comprehensive review, we present the relationship between cardiovascular diseases and the Mediterranean Diet.

What Are the Types of Cardiovascular Disease?

Coronary Heart Disease: This cardiovascular disease results from narrowing of a vessel supplying the heart. When this narrowing leads to blockage, it can cause myocardial infarction, also known as a heart attack, or heart failure.

Cerebrovascular disease: This disease of the brain’s blood vessels results from narrowing of the vessels supplying the brain. Blockage of brain vessels can lead to a transient ischemic attack (a stroke lasting less than 24 hours and leaving no permanent damage) and paralysis (stroke). A stroke can also result from bleeding of blood vessels or a clot in the brain.

Peripheral Arterial Disease: This is disease of the blood vessels supplying the arms and legs.

Large Vessel Disease, Deep Vein Thrombosis and Pulmonary Embolism: These conditions develop when blood clots block vessels that can extend from the veins of the legs to the heart and lungs.

The main cause of blockages preventing blood flow to the heart or brain is fatty deposits on the inner walls of the blood vessels supplying these organs. Plaques made up of fat, cholesterol, calcium and other substances in the blood consequently begin to obstruct the vessel, and atherosclerosis (hardening of the arteries) develops.

What Are the Main Causes of Cardiovascular Diseases?

Blockages in the heart’s blood vessels usually result from a combination of several risk factors. Risks for cardiovascular disease include tobacco use, an unhealthy diet, obesity, physical inactivity, excessive alcohol consumption, hyperlipidemia (abnormal blood cholesterol levels), hypertension, diabetes, cardiovascular disease in family members and older age. Looking at cardiovascular risk factors, those other than genetic factors and age are modifiable. 

The American Heart Association (AHA) identifies 7 risk factors to modify for ideal heart health as “Life’s Simple 7” (Life’s Simple 7).

Life’s Simple 7 recommends the following for ideal heart health:

1. Quit smoking,
2. Increase physical activity,
3. Reach an ideal weight,
4. Develop good eating habits,
5. Lower blood sugar,
6. Lower cholesterol,
7. Lower blood pressure.

“Circulation” published a study that assessed the health and nutritional status of the US population between 2009-2011 and tracked changes over time. 7622 participants were observed for 6 years to investigate the relationship between adherence to “Life’s Simple 7” recommendations and the circulatory system. The study found that participants following the recommendations of

• “Life’s Simple 7” in at least 5 respects had, compared with participants following none of the recommendations, a cardiovascular mortality risk that was 78% lower.

Risk factors for cardiovascular disease are divided into modifiable and nonmodifiable factors. Older age, genetics and sex cannot be changed. However, modifiable risk factors can be substantially reduced through a Mediterranean Diet eating pattern that includes all food groups in a balanced, healthy way.

The other 5 elements of Life’s Simple 7, apart from its recommendations about smoking and physical exercise, can be achieved through the Mediterranean Diet.

The Mediterranean Diet Pattern in Brief

• Primarily: fruit, vegetables, olive oil, fish, whole grains, legumes, nuts, low-fat milk and dairy products
• In moderate amounts: eggs and skinless white meat
• In limited amounts: consumption of red meat is recommended

It Is Possible to Reduce Cardiovascular Disease Risk with the Mediterranean Diet!

Angel Keys, the founder of the Mediterranean Diet pattern, investigated its effects on cardiovascular diseases in 12,763 middle-aged participants through the “7 Countries Study”. This study examined the relationship between dietary patterns and cardiovascular diseases in 7 different Mediterranean countries and 7 different non-Mediterranean countries. For the first time, it showed that:

• Mediterranean populations, such as Greeks, particularly farmers in Crete, and southern Italians had lower mortality rates from cardiovascular diseases than people in northern Europe and North America. 

Atherosclerosis is now considered an inflammatory disease;

• Following a prolonged unhealthy diet, lipids, oxidized LDL (bad cholesterol) particles and free fatty acids in the blood activate the inflammatory process. Fatty tissue may be responsible for the entire process leading to cardiovascular diseases. It is also associated with insulin resistance and the development of type 2 diabetes (T2DM). Fatty tissue releases inflammatory adipocytokines in the body, such as TNF-α, IL-6, MCP-1, leptin and resistin, and increases oxidative stress that causes inflammation. The resulting inflammatory response and insulin resistance can lead to the atherosclerotic process.
• A Mediterranean Diet eating pattern is rich in antioxidant vitamins, flavonoids, minerals and fiber but contains limited saturated fat and cholesterol. It therefore reduces oxidative stress, inflammatory adipocytokines, inflammatory damage, insulin resistance and T2DM risk. Olive oil, nuts such as walnuts, hazelnuts, almonds and walnuts, and fish in the Mediterranean Diet are sources of omega-6 and omega-3. These foods raise HDL cholesterol and lower LDL cholesterol, potentially contributing to a reduction in cardiovascular disease risk.

In 2019, The Proceedings of the Nutritional Society published a study evaluating research into the relationship between the Mediterranean Diet, IL-6 and CRP (C-reactive protein), which is produced by liver and fat cells in the body and rises during inflammation. The study involved 772 participants who followed either a Mediterranean Diet or a low-fat diet. The results showed that those following the Mediterranean Diet pattern had decreased IL-6 and CRP levels whereas those following a low-fat diet were observed to have increased IL-6 and CRP levels. The Mediterranean Diet was also found to improve blood pressure and the lipid profile and reduce insulin resistance more effectively than the low-fat diet.

In 2017, European Journal of Nutrition published a systematic review and meta-analysis evaluating 29 studies on the Mediterranean Diet and cardiovascular disease risk. After examining all the studies,

• it concluded that the Mediterranean Diet reduces cardiovascular disease risk.

Let us examine the effects of the Mediterranean Diet on established cardiovascular risk factors;

Since it was first described, the Mediterranean Diet has been the most extensively researched dietary pattern. Countless studies support its effect in reducing the risk of many diseases that are cardiovascular risk factors, such as:

• obesity
• diabetes
• hypertension
• hypercholesterolemia

These risk-reducing effects are supported by numerous studies. Let us now examine each in turn:

Obesity and the Mediterranean Diet

Some of the established modifiable risk factors for cardiovascular diseases are linked to obesity. For example, an obese person is much more likely to have T2DM or hypercholesterolemia than a person of normal weight. This is because Western-style diets, containing fast food and refined products, cause weight gain and, because they are high in saturated fat, cholesterol and simple sugars, raise blood glucose, triglycerides, total cholesterol and LDL cholesterol while lowering HDL cholesterol.

In 2018, Nutrition and Dietetics published a study of participants previously enrolled in the European Prospective Investigation into Cancer and Nutrition. The study assessed anthropometric measurements and Mediterranean Diet adherence in 32,119 people. Changes over a 5-year period were examined, and the results showed that adherence to the Mediterranean Diet:

• Reduced the risk of weight gain and therefore the risk of obesity,
• Reduced waist circumference and therefore the risk of abdominal obesity.

Type 2 Diabetes and the Mediterranean Diet

The American Diabetes Association (ADA) recommends a Mediterranean Diet eating pattern to prevent cardiovascular complications in people with diabetes. Because this dietary pattern is low in simple carbohydrates such as sugar, jam or fruit juice concentrate and rich in complex carbohydrates such as fruit, whole grains or legumes, it may also reduce insulin resistance and T2DM risk in healthy individuals.

 In 2020, Nutrition and Diabetes published a study assessing Mediterranean Diet adherence in 11,991 people and their risk of T2DM after 22 years of observation. The study found that:

• As participants’ Mediterranean Diet scores increased, T2DM risk decreased. 

Hypertension and the Mediterranean Diet

In the Mediterranean Diet, foods with a high salt content are restricted while consumption of foods rich in vitamins, minerals and fiber is encouraged. It can therefore have beneficial effects on hypertension. A version of the Mediterranean Diet developed for people with hypertension and with even more restricted salt content is the Dietary Approaches to Stop Hypertension (DASH) diet. The Mediterranean Diet and the DASH diet are dietary patterns that US News & World Report has selected as the healthiest for years (see the infographic at the end of this article).

In 2019, Hypertension published a study involving 1294 healthy participants aged 65-79. They were divided into 2 groups: the first continued their usual dietary patterns, while the other followed a Mediterranean Diet. After 1 year of observation, following the Mediterranean Diet was found to:

• Reduce blood pressure and arterial stiffness, thereby effectively improving cardiovascular health.

Hypercholesterolemia and the Mediterranean Diet

Hypercholesterolemia is a major cause of cardiovascular disease. Increased total and LDL cholesterol, which contribute to plaque formation in blood vessels, usually result from diets high in cholesterol and saturated fat. Conversely, antioxidant vitamins and flavonoids in the Mediterranean Diet, which is low in saturated fat and cholesterol, reduce the oxidative stress and inflammatory damage associated with atherosclerosis.

In 2018, Environmental Research and Public Health published a study evaluating Mediterranean Diet adherence in 366 participants and examining its effect on the lipid profile. The study concluded that:

• The lipid profiles of people whose diets did not follow the Mediterranean Diet were adversely affected.

What Is the Effect of the Mediterranean Diet on Uric Acid?

In addition to the risk factors mentioned above, studies in recent years show that elevated uric acid is an important factor increasing cardiovascular disease risk. For a detailed examination of the relationship between cardiovascular deaths and uric acid levels, you can visit our related article.

In 2019, Nutrients published a systematic analysis evaluating the relationship between the Mediterranean Diet, a purine-restricted diet and a calorie-restricted diet and blood uric acid levels. The study concluded that the Mediterranean Diet was the most effective dietary pattern for maintaining balanced blood uric acid levels over the long term.

Conclusion & Summary

Countless studies investigating the relationship between the Mediterranean Diet and metabolic disorders have concluded that this eating pattern improves health and reduces cardiovascular disease risk. Thus, to help prevent both metabolic disorders that increase cardiovascular risk and Alzheimer’s disease, gout, cancer and many other diseases, we recommend following a Mediterranean Diet eating pattern that includes all food groups in balance.

Related Topics

Health Benefits and Metabolic Effects of the Mediterranean Diet – How Did It Become the World’s Best Diet?

Colorectal (Colon and Rectal) Cancer and the Mediterranean Diet

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