To many people here in cold, landlocked Canada (and much of the US), adopting a Mediterranean dietary pattern (MedDP) sounds as realistic as swimming with penguins in Antarctica.
If it feels unattainable to you too, I have good news! It’s a flexible approach to eating that can be adapted to various cultures and cuisines. You can eat the Mediterranean way without giving up familiar foods.
Since we focus on heart health here, I start below by outlining what researchers asked volunteers to eat in four randomized controlled trials (RCTs) that found the MedDP benefitted cardiac outcomes, and how big a difference it made.
If you’ve had a heart attack, stent, bypass, or otherwise have established vascular disease, you’ll be glad to know that three of the studies were “secondary prevention” trials, looking at how people can avoid another heart event.
In part two I share 21 practical steps you can choose from to move closer to a MedDP even if you don’t have walnut and olive trees in the backyard. But first…
Why Mediterranean “dietary pattern” versus diet?
Although the word “diet” is less cumbersome, for many people it evokes painful memories of restriction, deprivation, and a short-term thinking, rather than a sustainable, enjoyable way of eating. It’s often tied to weight loss, which isn’t our focus here.
And the MedDP isn’t a “diet,” with strict rules and portions. The focus is on foods, like tomatoes and olive oil, versus nutrients like fat, carbs, and protein. There’s no calorie counting, and it doesn’t typically result in weight loss.
But if you read on, you’ll see that it can do something even better for you in the long run.
But we’re meat & potatoes people!
The MedDP also isn’t necessarily Mediterranean cuisine. If you like hummus, falafel, tzatziki, and tabbouleh, great! But if you barely know what these things are, no worries.
While the MedDP was first observed by researchers in Crete (Greece), contemporary research is based on food practices shared by the 22 countries bordering the Mediterranean, from France to Israel, Spain to Turkey.
So let’s look at the guidance given to participants in those four RCTs. You’ll see, you can even do it in a meat & potatoes household.
The Lyon Diet Heart Study
The Lyon Diet Heart Study took place in France in the late 1990’s with participants had all recently survived their first heart attack. The group randomly assigned to follow the MedDP for about five years were 50-70% less likely to die or have another heart event than the control group, who were asked to follow a “prudent Western-type diet”.
Read that again. A 50-70% reduction is a tremendous difference. Experts at the time couldn’t believe it, given how much higher in fat the MedDP is compared to the low-fat diets of the day.
The Mediterranean group in that study was asked to eat (brace yourself) plenty of bread, vegetables, fish, fruit, and poultry instead of red meat. Butter and cream were replaced with a special margarine (!) rich in alpha-linolenic acid (ALA).
(ALA is the omega-3 fat we get from plants – major sources include flax, chia, hemp, walnuts, soy, and canola oil.)
The Indo-Mediterranean Diet Heart Study
This one took place around the same time in India, with 1000 people who had “angina pectoris, myocardial infarction, or surrogate risk factors.” They reported a 52% relative reduction in total cardiac endpoints in the group assigned to the “Indo-Mediterranean” diet.
What did they mean by Indo-Mediterranean? A diet rich in fruits, vegetables, nuts, whole grains and mustard seed or soybean oil. (The control group was asked to follow a low-fat heart-healthy diet.)
I like to include this one because it shows that the MedDP isn’t just for people who live near the Mediterranean or are able to eat like they do.
Primary Prevention of Cardiovascular Disease with a Mediterranean Diet (PREDIMED)
Some cardiac nutrition experts had concerns with the design of these two studies (see page 8), including the lack of olive oil, which is so predominant in the Mediterranean region.
They also felt a primary prevention study was needed – one that looked at people who didn’t yet have heart disease, but who were at risk. Does it help prevent heart disease in the first place?
So a group of researchers in Spain conducted an enormous RCT called PREDIMED, involving almost 7500 people.
In their final report, published in 2018, they showed about a 30% reduction in major cardiovascular events (heart attacks, strokes, or death from cardiovascular causes) in the MedDP versus low-fat groups.
(There were two MedDP groups – one was given free extra-virgin olive oil every week, and one was given mixed nuts. Results were similar for both.)
PREDIMED foods
Here are the “positive recommendations” that were given to the study volunteers (taken almost exactly from the study protocol):
- Abundant use of olive oil for cooking and dressing dishes (4+ tablespoons!)
- 2+ daily servings of vegetables, at least one of them raw or as salad (their servings were about 1 cup)
- 2-3+ daily servings of fresh fruits, including natural juices (serving size not specified, but we usually use a medium-sized fruit or 1/2 cup as a serving)
- 3+ weekly servings of legumes (a serving is about 3/4-cup)
- 3+ weekly servings of fish or seafood, at least one of which is fatty fish (a serving is 100-150g / 3.5-5 oz of fish or 200g / 7 oz of shellfish)
- 3+ weekly servings of nuts or seeds (a serving is 1/4 cup or 2 tbsp of nut butter)
- Select white meats (poultry without skin or rabbit) instead of red meats or processed meats (burgers, sausages)
Sofrito
Volunteers were also asked to make a sofrito at least twice a week. You can do this! They defined sofrito simply as a sauce made from slowly simmering olive oil with finely chopped tomato, garlic and onion, often with aromatic herbs and other ingredients. They encouraged participants to use sofritos to dress vegetables, pasta, rice, fish and other dishes.
(If you Google sofrito, you’ll see that there are variations in different Latin countries throughout the world.)
It might be worth playing with sofritos! Researchers have suggested that cooking tomatoes and other vegetables this way increases the availability of bioactive compounds in the ingredients and is a significant contributor to the positive results. (See part 2 for some simple suggestions.)
Foods to limit
PREDIMED participants were also advised to “eliminate or drastically limit” the following foods:
- cream
- butter, margarine
- cold meat, paté, duck
- carbonated and/ or sugared beverages
- pastries, industrial bakery products (such as cakes, donuts or cookies), industrial desserts (puddings, custard)
- French fries or potato chips
- out-of-home pre cooked cakes and sweets.
To help with consistent follow through, the MedDP groups had individual and group sessions with a study dietitian every three months, totalling 32 visits!
Other recommendations:
- Eat 2 main meals per day (seated at a table, lasting more than 20 minutes); (Isn’t that interesting?)
- For usual drinkers, the main source of alcohol should be wine during meals (maximum 300 mL, 1-3 glasses of wine per day), bigger for men: 150 mL, than for women: 100 mL).
- Eat as much as you like of nuts (raw and unsalted), eggs, fish (recommended daily), seafood, low-fat cheese and whole-grain cereals.
- Limit consumption (=<1 serving per week) of cured ham, red meat (after removing all the visible fat), chocolate (only “black” chocolate, with more than 50% cocoa), cured or fatty types of cheese.
Damn. That’s last one is tough. Of course, it’s impossible from just this study to know which of the recommendations made the difference. 😉
Just kidding. The consistent theme in Mediterranean and other cardiac nutrition studies is a diet rich in not-too-processed plant-based foods.
Other research suggests that full-fat cheese and dark chocolate are okay in greater amounts than above, but I digress.
CORDIOPREV
This last one is kind of PREDIMED for secondary prevention, involving patients with established coronary heart disease, also in Spain. The final report was published in the Lancet medical journal in May 2022.
After seven years of a high-intensity dietary intervention, they found that participants who adopted the MedDP were 26% less likely to have another major cardiovascular event, compared to those on a heart-healthy low-fat diet.
Similar to the others, by major cardiovascular event, they meant heart attack, need for another stent or bypass, stroke resulting from a blocked artery, peripheral artery disease, or cardiovascular death.
There were 502 people in the MedDP group and 500 advised to follow the low-fat diet. 87 people in the MedDP group had a reoccurrence, compared to 111 in the low-fat group. That’s 28·1% vs 37·7%, or 26% fewer.
26% might not seem like a lot, but it’s the kind of number that gets the attention of researchers trying to reduce the scourge of heart disease.
There is a great visual of this in the Lancet, but it’s copyrighted, so I’m not sharing it. You can see a tiny version of it here. Zoom in and squint. 😂
The lines in that chart represent people having cardiac events over the years, with the blue line for the folks assigned to the low-fat diet climbing faster and gradually pulling away from the red line, which represents people in the MedDP arm. It’s quite obvious that there’s a difference.
It’s important to note that like PREDIMED this was a “high intensity intervention”. Participants had at least 12 interactions with study dietitians every year, between individual face-to-face visits, group sessions, and phone calls.
That’s much more support than people usually get in a cardiac rehab (CR) program! Other studies use intense protocols like this too, so don’t feel bad if you find it hard to stay consistent after having one class or appointment.
How would someone do if they weren’t getting this much dietary support? Well, patients in the same CR program at the same time had a 20% mortality rate over six years of follow-up, compared to 8% for those in the CORDIOPREV study. Large drug studies in similar patients typically report higher rates of major cardiovascular events.
(However, take the comparison with a grain of salt. Patients not in the study weren’t randomly assigned to the usual CR program. It’s possible they didn’t volunteer because they were sicker, older, or unable to spare the time, which might have limited their ability to develop heart-healthy habits in general. And just 17.5% of study participants were women, another problem altogether. But hopefully all that work with the dietitians paid off to some degree!)
CORDIOPREV foods
The recommendations given to volunteers was almost the same as PREDIMED above, except that they were more specific with certain guidance:
- 6 servings of grains and potatoes, preferably whole grains, per day
- 2 servings of dairy per day
- Less than one carbonated beverage per day
- Less than one serving of red meat per week
- 2-4 eggs per week
- One serving or fewer of commercial bakery products, sweets, and pastries per week
- No butter and margarine at all
Which study is best?
Don’t get too hung up on the different results from study to study. They’re different populations and designs. The foods weren’t exactly the same, but they had commonalities: Lots of vegetables, fruit, olive and other unsaturated fat rich oils, nuts, fish, legumes, whole grains, more white than red meat, and wine with meals in moderation, if any alcohol. Limited sugary and other processed foods.
An RCT is better evidence than the typical observational study we see so often in nutrition. RCTs can actually demonstrate cause and effect. We don’t get much of that for nutrition and cardiac outcomes. It just takes too long.
Having four of them means that the MedDP doesn’t look better because goat herders in Greece walk so much, or because people in Spain relax and enjoy meals with loved ones. Those things undoubtedly help with heart health, but these studies prove that the dietary pattern itself also benefits the cardiovascular system.
We still have much to learn about the nuances of the MedDP. How much red meat is best? What if it’s lean? Grass-fed? Does dairy play a protective role? Cheese too? Sweetened yogurt?
So far all we can say with confidence is that this pattern in general supports better cardiovascular health. The details you can work out based on what foods you like, tolerate, and have access to.
How can you do it where you live?
Practically speaking, if you’re far away from Greece, Spain, or France, what does that look like?
Just like the folks running the study in India, you can adapt these recommendations to your local and cultural foods and preferences.
What if you can’t possibly eat that much fish? What if you aren’t used to cooking with lentils or beans? What if there’s no good fruit in your grocery store this time of year?
If you have access to a Registered Dietitian who specializes in heart health, take advantage! Go to as many classes from them as you can. Meet with them individually to discuss your unique health situation.
And to get you going, I wrote up answers to those questions and 21 practical strategies for the average Canadian or American in part two of this series. Read on…
