Can a Mediterranean diet help ward off heart disease, dementia and cancer?

For some time, researchers have suggested that a Mediterranean diet — rich in fresh fruits and vegetables, beans, nuts, whole grains, and fish — may help reduce the risk of heart disease and increase life expectancy. A growing body of scientific evidence now supports this notion. Recent studies have linked reduced rates of cardiovascular disease, dementia and cancers to Mediterranean diets. Medical News Today reviewed the evidence and spoke to experts about the science behind the benefits of this diet.

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Several recent studies suggest that the Mediterranean diet can help ward off several diseases and chronic conditions. Photo credit: Cameron Whitman/Stocksy.

Over the years, many diets have been proposed for maintaining good health or reducing the risk of specific diseases, but few have stood up to rigorous scientific scrutiny.

One exception, however, seems to be the Mediterranean diet.

Increasingly, studies show that there are significant health benefits for people who follow this diet. Not only has research shown that it reduces cardiovascular disease, but it may also benefit cognition, decrease the risk of diabetes, lower the risk of certain cancers, and ease symptoms of multiple sclerosis.

The Mediterranean Diet is an umbrella term referring to diets based on the historical eating habits of people living around the Mediterranean Sea.

According the American Heart Associationwho recommends this type of diet for cardiovascular health, its main characteristics are:

  • high consumption of vegetables, fruits, whole grains, beans, and legumes
  • low-fat or fat-free dairy products, fish, poultry, non-tropical vegetable oils and nuts
  • limited added sugars, sugary drinks, sodium, highly processed foods, refined carbohydrates, saturated fats, and fatty or processed meats.

The Harvard School of Public Health adds to these recommendations, emphasizing the importance of healthy fats – olive oil, avocados, nuts and oily fish.

He advises people to eat red meat only occasionally, but to get their protein from fish or seafood at least twice a week and to eat small amounts of poultry, eggs and dairy products. almost every day.

Although water should be a person’s main drink, people can also drink one or two small glasses of red wine every day, according to the traditional Mediterranean diet.

The researchers add, however, that a healthy diet should also be combined with some form of enjoyable physical activity on a daily basis.

Dr. Scott Kaiser, geriatrician and director of geriatric cognitive health at the Pacific Neuroscience Institute at Providence Saint John’s Health Center in Santa Monica, California, said:

“Research supports the benefits of adopting healthy lifestyles and indicates the critical importance this can play in shaping our future individual and collective health. (…) Start by including lots of fresh vegetables – especially leafy greens – then enjoy fresh fruits – like berries – and other antioxidant-rich foods, along with fish, olive oil and other brain-healthy omega-3 foods. .”

Mediterranean diets have long been associated with benefits for cardiovascular health. In the mid-twentieth century, the Seven Countries Study showed that diets in the Mediterranean and Japan in the 1960s were associated with low rates of coronary heart disease and all-cause mortality.

Since then, research has shown that this type of diet not only benefits cardiovascular health, but also reduces the risk of many other health problems.

And recently, the evidence for the many health benefits of following a Mediterranean diet has been mounting. But what makes Mediterranean diets so healthy, exactly?

“The Mediterranean diet is characterized by high fruit and vegetable content, high fiber content, high levels of ‘good fats’, moderate intakes of fish and meat, low amounts of highly processed foods and foods sweet,” noted Dr Eamon Laird, a visiting research fellow at Trinity College, Dublin, Ireland.

“These food components provide high amounts of fibre, good fats, antioxidants, polyphenols, vitamins and minerals – choline, vitamin C, potassium, B vitamins, fish vitamin D, etc. – (and) proteins that provide health benefits throughout a large number of organ systems and tissues,” he explained.

Much research has investigated the effect of a Mediterranean diet on the risk of cardiovascular disease (CVD).

A meta-analysis of multiple studies published in March 2023, with a pooled sample of over 700,000 participants, found that by closely adhering to a Mediterranean diet, women reduced their risk of CVD by 24% and their risk of death from any cause by 23%.

According to Dr. Laird, “(w)omens are also much more likely to stick to the diet than men, which could explain why we see more health benefits in women.”

The meta-analysis seems to confirm the conclusions of previous research. For example, in 2015, another meta-analysis found that the Mediterranean diet could be a major factor in the prevention of cardiovascular disease.

And it’s the whole diet, rather than any particular aspect, that seems to have this effect, says Dr. Joanna Hodges, assistant professor of nutritional sciences at Pennsylvania State University. DTM.

“(The study) concludes that no specific component of the Mediterranean diet has been shown to be as beneficial as the whole diet (in preventing cardiovascular disease),” she told us.

There is also growing evidence that diet can improve cognitive function. A study published in March 2023 which used data from the UK Biobank just reported that people with higher adherence to a Mediterranean diet had up to 23% lower risk of dementia compared to those with lower adherence to a diet Mediterranean.

The study, which used data from more than 60,000 people, concluded that the Mediterranean diet reduced the risk of dementia even in people with a genetic predisposition to dementia.

The authors conclude that adopting a diet rich in healthy plant-based foods may be a strategy to reduce the risk of dementia.

Another study, also published in March 2023, looking at post-mortem Alzheimer’s disease, found that those who followed a Mediterranean or MIND diet, particularly high in leafy greens, had a significantly higher beta-amyloid load. weak.

Beta-amyloid is believed to be responsible for many symptoms of Alzheimer’s disease.

The diet may also benefit people with multiple sclerosis (MS). A preliminary study to be presented at the 75th Annual Meeting of the American Academy of Neurology in April 2023 found that people with MS who followed a Mediterranean diet had a 20% lower risk of cognitive impairment than those who followed it. followed the least.

The diet has been shown to both reduce the risk of certain cancers and improve the effectiveness of certain cancer treatments.

A review of 2019 found that high adherence to the Mediterranean diet was associated with lower rates of several cancers, including breast, colorectal and prostate cancers.

This study concluded that the antioxidant and anti-inflammatory properties of the components of the diet “prevent and neutralize DNA damage and slow the development of various forms of cancer”.

For prostate cancer, recent research has shown that a diet rich in colorful fruits and vegetables both reduces the risk of developing prostate cancer and speeds up recovery in those undergoing radiation therapy for the disease.

The studies, conducted in South Australia, found that diets high in lycopene And selenium reduces the risk.

Tomatoes, melons, papayas, grapes, peaches, watermelons and cranberries are high in lycopene, and white meat, fish, shellfish, eggs and nuts contain high levels of selenium. All of these are recommended in the Mediterranean diet.

And it’s not just prostate cancer patients whose treatment may be more successful with a Mediterranean diet.

A recent study presented at UEG Week 2022 found that diet was significantly associated with a better response to immunotherapy drugs in people with advanced melanoma.

Although the exact mechanism by which the Mediterranean diet benefits health is unclear, there is growing evidence that the diet may have five main effects:

  • lower lipids
  • protecting against oxidative stress, inflammation and platelet aggregation
  • alter hormones and growth factors involved in cancer pathogenesis
  • restriction of specific amino acids
  • influence the gut microbiome to produce metabolites beneficial to metabolic health.

Dr. Laird explained to DTM how certain components of the diet are beneficial to health:

“Omega-3 fatty acids, phytosterols, resveratrolvitamins and polyphenols may help reduce levels of inflammation (PCR, inflammatory cytokines), and can improve endothelial function. By reducing inflammation levels, improving blood flow, improving insulin sensitivity, and improving lipid metabolism, you also default to reducing some of the major risk factors for cardiovascular disease, cognitive decline, cancers and diabetes.

Studies have shown that these nutrients are best consumed in their natural form as part of a healthy diet, such as the Mediterranean diet.

Although they can be obtained through supplements, there may be side effects to taking excessive amounts.

The Mediterranean diet is just one of many diets that have health benefits. Others include the MIND, Nordic, and DASH diets.

“The common thread running through all (healthy) diets is a strong influence of plant foods, which we believe (…) has many benefits for increasing dietary fiber, antioxidants, phytonutrients, vitamins and minerals,” said said Kate Cohen, dietitian. at the Ellison Clinic in Saint John’s, part of the Ellison Institute for Transformative Medicine and Providence Saint John’s Health Center in Santa Monica, California.

So, the key to any healthy diet is to incorporate plenty of vegetables, whole grains, and healthy fats. Most importantly, any dietary changes made must be long-term and sustainable to provide health benefits.

“In the long term, it (the Mediterranean diet) can be difficult to follow in its true form, especially for those used to processed diets. A good approach would be to slowly incorporate components into your current diet and build slowly – again, variety is the spice of life and we should have a varied and diverse diet and not just rely on one diet to meet all of our needs and requirements and tastes – the food must be enjoyed too!”

– Dr. Eamon Laird

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