Diet Review: Heart-Healthy Mediterranean Diet & DASH Diet

I'm sure you've heard of the Mediterranean Diet which has been gaining quite a bit of popularity for the last few years, but many don't know that it's not actually a "diet" in the way most people think about diets. A diet in the traditional sense is a pattern of eating, not necessarily a way to lose weight. In short, the Mediterranean Diet is a healthy way of eating due to the focus on produce and healthy fats, but let's get into the details and whether it's a good option for you personally!

The Mediterranean diet is a style of eating that closely resembles the eating behaviors of people residing in Mediterranean countries. It is so named for the Mediterranean Sea, which is surrounded by an extraordinarily diverse group of countries: Italy, France, and Spain to the north, Greece, Turkey, Israel, Lebanon, and Syria to the east, and to the south, the North African countries of Egypt, Tunisia, Morocco, Algeria, and Libya. This means that there isn’t a single culture or one “diet” that encompasses the entire Mediterranean region—the spice-laden dishes of Morocco bear little resemblance to the lemon and caper-laced cuisine of southern Italy. Rather, the Mediterranean diet is about what these cuisines have in common: a daily emphasis on vegetables and fruits, beans and lentils, whole grains, more seafood than meat and poultry, and heart-healthy olive oil. This is essentially the Mediterranean way of eating.

The diet was first mentioned in the 1960s, when Ancel Keys, an American physiologist, noticed the meal patterns of people living on the Mediterranean coast and investigated the relationship between their diet and heart health. He found that diets lower in saturated fat and higher in vegetable oils seem to be cardioprotective (heart-healthy). He also noticed these diets have meal patterns rich in fruits and vegetables, grains, beans and fish. This laid the groundwork for today’s version of a Mediterranean diet, which is specifically a healthy food pattern consisting of:

• Daily whole grains, fruits, vegetables, beans, herbs, spices, nuts and healthy oils like olive oil

• Twice weekly servings of seafood

• Moderate portions of dairy and eggs

• Occasional poultry

• Very limited intake of red meats and sweets/added sugar

This dietary pattern is not just about food but also incorporates lifestyle factors like physical activity, communal dining, and stress reduction. It emphasizes local, freshly prepared plant foods such as vegetables, fruits, legumes, whole grains, nuts, and olive oil (1,2). Research has indicated that high compliance with the traditional Mediterranean Diet is associated with improved cardiovascular health outcomes, including reduced risks of coronary heart disease (CHD), stroke, and overall cardiovascular disease (CVD) - as well as decreasing risk of other chronic diseases such as type 2 diabetes & certain kinds of cancer. It also has shown improved gut and cognitive health, with its anti-inflammatory and antioxidant effects as it's so nutrient-rich. While this diet pattern does show some promise for conditions like Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD), Chronic Obstructive Pulmonary Disease (COPD) and bone health, more research is needed to confirm its efficacy in these areas (3,4).

Conversely, there are other heart-healthy diets out there that also decreased risk of CVD and more. The DASH diet was developed to combat hypertension. It focuses on vegetables, fruits, low-fat dairy, whole grains, nuts, legumes, poultry, and fish while limiting red meat, sugars, saturated fats, and sodium (5). This diet offers structured guidelines on portion sizes and food categories which can be adapted to different calorie levels - based on your personalized nutrition needs. It has primarily been studied for its potential in reducing blood pressure. Most research into other health and metabolic conditions is based on observational research. 

So - is one better than the other? Most research on the Mediterranean and DASH diets have focused on the potential positive benefits of both, and there is limited evidence available comparing them to one another. A 2023 randomized controlled trial compared the Mediterranean diet vs. DASH diet in the context of salt restriction among individuals with high-normal blood pressure or mild hypertension (6). The study found that while both diets, when combined with salt restriction, led to reductions in blood pressure compared to a control group, the Mediterranean Diet showed superiority in lowering office systolic blood pressure compared to the DASH diet and salt restriction alone. However, both dietary approaches were more effective in lowering blood pressure than salt restriction alone, highlighting their potential benefits for individuals with hypertension or elevated blood pressure levels. Like allll those diet options out there, some aspects work better for some individuals than others. Let’s take a closer look at how the Mediterranean Diet and the DASH diet compare in terms of their key features and benefits!

Both of them are more of a “dietary pattern,” emphasizing choice and flexibility rather than a strict set of rules or foods to restrict. Both diets emphasize whole foods, vegetables, legumes, whole grains, and fruits as key components of a healthy eating pattern. Both include limited consumption of processed foods, sugars, and saturated fats without strict avoidance. Both can have improvements in adherence with the incorporation of a client’s culturally and regionally relevant foods. This may take extra consideration from the practitioner or client in recommending specific changes to make the dietary pattern more relevant. 

Now let's discuss the differences. The Mediterranean Diet traditionally emphasizes physical activity, communal dining, and stress reduction as integral components, while the DASH diet primarily focuses on dietary factors (I will go into this in a bit more detail later, but the former is my preferred approach). The Mediterranean Diet allows for diversity in food choices, serving sizes, and food group variation, while the DASH diet provides more structured guidelines. Some individuals prefer, or have better adherence with, flexibility vs. structure when it comes to dietary changes. The Mediterranean Diet promotes healthy fats from sources like olive oil and fatty fish, while the DASH diet focuses on reducing total and saturated fats, emphasizing low-fat dairy. The DASH diet strongly emphasizes reducing sodium intake, whereas the Mediterranean Diet, while generally lower in sodium due to its emphasis on whole foods, does not have specific sodium restrictions. The DASH diet was developed specifically to address hypertension and has extensive research supporting its effectiveness in lowering blood pressure.

The Mediterranean diet is beneficial for people looking to lower their risk of heart disease, stroke, high blood pressure (hypertension), high cholesterol and/or diabetes. Other possible benefits, although not as well demonstrated, include better control of rheumatoid arthritis, cancer risk reduction, improved cognition and lessened risk of depression. There is no denying that eating in accordance to the Mediterranean diet requires a shift in thinking: Portion sizes are smaller, less meat defines a serving size, and a meal often has several equally weighted dishes on the plate. When the Mediterranean diet is followed along with careful attention to estimated calorie needs, it’s been shown to reduce weight gain, decrease waist circumference and ultimately induce weight loss.

So, we know that diets that promise quick results often fail to deliver and are not advisable. Studies comparing different types of diets have not found a single "best" weight loss diet for all people. However, any diet will help you to lose weight if you eat in a caloric deficit and are able to stick with it (following a very restrictive diet may help you lose weight quickly, but it's easy to gain the weight back as soon as you stop following the diet). Therefore, it is important to choose an eating plan that includes foods you like. "Fad" diets often promise quick weight loss (more than 1 to 2 pounds per week) and may claim that you do not need to exercise or give up your favorite foods. Some fad diets cost a lot of money because you have to pay for seminars, pills, or packaged foods. Fad diets generally lack any scientific evidence that they are safe and effective, instead relying on "before" and "after" photos or testimonials. In contrast, the Mediterranean and DASH diets offer well-researched health benefits. The Mediterranean diet emphasizes plant-based foods, olive oil, and lifestyle practices, leading to improved cardiovascular health and reduced risks of various diseases. The DASH diet focuses on fruits, vegetables, low-fat dairy, and limits on sodium and saturated fats, and is aimed at reducing hypertension. Both diets share a plant-forward focus that can decrease blood pressure, but differ in structure and guidelines.

Overall, I really like that the Mediterranean diet is less "rigid" and it promotes general healthy eating - whole foods like whole grains, vegetables, fruits, legumes, nuts, seeds, and heart-healthy fats. Processed foods, red meat, added sugar, and refined grains are restricted or consumed in moderation. Additionally, the Mediterranean diet focuses on lifestyle factors such as community, movement, and purpose - so, a whole-person health approach! Right up my alley.