A new peer-reviewed study examined the effects of various diets on cardiovascular health, and they concluded that the Mediterranean diet and other low-fat diets were at the top. I have been focusing lately on the Mediterranean diet and overall health, and the evidence that it’s probably one of the best diets for us is becoming very strong.
As I usually do, I will review the article and determine if it provides evidence about the Mediterranean diet, other low-fat diets, and cardiovascular health.
What is the Mediterranean diet?
The Mediterranean diet is a diet that is common to the eating habits of people living in areas of the Mediterranean, including Greece, Southern Italy, and Spain. The diet generally includes proportionally higher amounts of olive oil, legumes, unrefined grains, nuts, fruits, and vegetables. It also includes moderate to high fish consumption, dairy products (generally, cheese and yogurt), moderate wine consumption, and low consumption of other meats.
Unfortunately, there is not a solid definition of this diet. In general, it is low in red meat, moderate in chicken and fish, and high in whole grains, fruits, vegetables, tree nuts, and legumes. But, it does vary from region to region around the Mediterranean.
During the 1940s and 50s, scientists observed that people who consumed the Mediterranean diet seemed to be objectively healthier (broadly defined) and suffered from lower rates of obesity than other populations that ate other types of diets that included refined grains and non-fish meats.
Mediterranean diet and cardiovascular health paper
In a paper published on 29 March 2023 in the peer-reviewed journal, BMJ, by Giorgio Karam, College of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada, and colleagues, the researchers analyzed randomized trials that examined the effect of diets, including the Mediterranean diet, on cardiovascular health.
Data for the analysis came from 40 randomized controlled trials that involved 35,548 participants who were followed for an average of 3 years. This is a very large analysis, something I look for in these types of studies.
Here are their key results:
- There was evidence of “moderate” certainty that the Mediterranean diet group had a 28% reduced risk for all-cause mortality compared to “minimal intervention,” that is, no diet or lifestyle choices that would generally be considered helpful to cardiovascular health.
- There was evidence of “moderate” certainty that the Mediterranean diet group had a 45% reduced risk for cardiovascular mortality compared to the minimal intervention group.
- There was a 35% reduction in the risk of stroke.
- There was a 52% reduction in non-fatal myocardial infarction (heart attack).
- On an absolute basis (per 1000 over 5 years), the Mediterranean diet led to 17 fewer deaths from any cause, 13 fewer cardiovascular deaths, seven fewer strokes, and 17 fewer nonfatal heart attacks.
The authors concluded:
Moderate certainty evidence shows that programmes promoting Mediterranean and low fat diets, with or without physical activity or other interventions, reduce all cause mortality and non-fatal myocardial infarction in patients with increased cardiovascular risk. Mediterranean programmes are also likely to reduce stroke risk.
This is a fairly powerful study that provides some clear advantages of the Mediterranean diet (along with other non-fat diets) for cardiovascular health. The Mediterranean diet group had a statistically significant reduction in the risk of cardiovascular deaths, strokes, and non-fatal heart attacks.
This study, though not formally a systematic review or meta-analysis (both of which are considered at the top of the hierarchy of medical research), still provides a powerful set of data to support the evidence that the Mediterranean diet may be your best choice for heart health.
Now, as I usually discuss with these types of studies, they are not randomized double-blind clinical trials. There is no way to take one group of people, make them eat a Mediterranean diet, and then monitor them for years. And, it is entirely possible that people who adhere to Mediterranean and non-fat diets engage in other healthy lifestyle choices like exercise and avoiding obesity.
Still, this is one of the best articles that I’ve read that shows a distinct reduction in risk of bad cardiovascular outcomes with those who follow these diets. As I keep reading these articles, which have captured my interest lately, I’m beginning to be convinced that the evidence is there — these diets are just better for you.
I’m giving this article a four out of five stars. It analyzes a large number of clinical studies with nearly 40,000 patients. It’s large enough that even small differences in risk can be identified, which the authors did.
Now, let me go have some pasta with a good salad.
- Karam G, Agarwal A, Sadeghirad B, Jalink M, Hitchcock CL, Ge L, Kiflen R, Ahmed W, Zea AM, Milenkovic J, Chedrawe MA, Rabassa M, El Dib R, Goldenberg JZ, Guyatt GH, Boyce E, Johnston BC. Comparison of seven popular structured dietary programmes and risk of mortality and major cardiovascular events in patients at increased cardiovascular risk: systematic review and network meta-analysis. BMJ. 2023 Mar 29;380:e072003. doi: 10.1136/bmj-2022-072003. PMID: 36990505; PMCID: PMC10053756.