This short story describes an observational study of 15,482 people from 39 countries around the world who were already diagnosed with heart disease and almost all taking medication for it. The people who reported eating a Mediterranean diet–heavy on fruits and vegetables and low on red meat–showed a reduced risk of heart attack, stroke or death, compared to those who said they ate a Western diet with more meat and animal fats.
This story does include quantified benefits, including a helpful statistic about “how many people out of 100” would likely develop heart disease, stroke, or die. However, it doesn’t provide much analysis that wasn’t already in the news release. A robust discussion of the study’s many limitations would have been useful, for example. For more about the limits of observational studies, see our guide.
This matters because cardiovascular disease is a common cause of death. People love the idea that just adding a few healthy foods or taking a vitamin will reduce their risk of a disease while they still make poor dietary choices (hamburger and French fries). Media reports about a study like this, likely to interest a lot of people–and possibly affirm not-so-healthy dietary choices–should include a robust discussion of the study’s caveats, as well as a discussion of past studies on the topic, so people are fully informed.
The story does not talk about costs. Eating fresh fruits and vegetables–and fresh seafood, especially–is associated with higher costs in many countries.
The story helped clarify the somewhat confusing data points in the study by quantifying the benefits this way (italics added by us):
“Over nearly four years, 1,588 (about 10 percent) of the study participants suffered either a heart attack or stroke, or died. Those who ate more foods in the Mediterranean diet category were 3.5 times less likely to experience one of these three events than people whose diets more closely resembled the Western standard.
In fact, every one-point increase in a participant’s Mediterranean diet score was linked with a 7 percent reduction in risk of heart attack, stroke, or death. Look at it this way: if 100 people ate the highest proportion of Mediterranean foods and 100 ate the least, there would be three fewer heart attacks, strokes, or deaths among those who ate more foods from the Mediterranean diet. These findings held for every geographical region.”
We applaud the writer for including the 100 people example to help readers understand the risk reduction.
Because this is a story about a study of dietary habits, this is N/A.
The story explained the way the study was conducted, which is important. But, the story does not mention some key limitations, including that the short survey did not include as many foods as typically measured in diet studies, and the study did not account for possible benefits of olive oil. To put it another way: What if eating olive oil has a positive effect by itself? If that accounts for the three fewer bad outcomes, then the rest of the diet differences are not statistically significant.
There was no disease mongering.
The story would have been stronger if it had included analysis from at least one independent source who had no connection to this study. Especially considering that many of the study’s authors, including the source who was indirectly quoted in the story, received support from a variety of pharmaceutical companies, including GlaxoSmithKline, which is mentioned in this story.
The story did an adequate job of explaining the two diets, and it mentioned medication, which is another approach to preventing heart disease.
Both Western and Mediterranean foods are widely available. However, Western foods are known to be cheaper and more widely available in low-income areas, and that could have been mentioned.
Novelty is addressed with these statements, “Surprisingly, the results suggest it might be possible they can have their cake and eat it, too.” and “Now here’s the interesting part: eating more foods thought to be less healthy — those typical of Western diets —did not link to an increase in heart attacks, strokes, or deaths. Eating more healthy foods was the key, even if some unhealthy foods were also consumed along the way.”
We saw quite a few repeated phrases from the news release here and the story. It appears it did rely very heavily on the release, especially considering there wasn’t an outside source commenting on the study, nor direct quotes.