This story does a reasonably good job of describing what happened in this study about the LDL-lowering effect of avocados. But that’s mainly thanks to an American Heart Association press release upon which the article is largely based. The story doesn’t provide any of the context that might have been gleaned from an actual conversation with the study researchers or an outside independent expert. And perhaps as a result, it fails to provide the broad perspective on what the findings mean in terms of outcomes that matter to people — things like heart attacks and strokes.
Obesity and cardiovascular disease are reaching near epidemic proportions in the United States, and the average American diet is a major contributing factor. The study reported on here suggests that modest changes in diet could have important public health implications. If found about a 10% reduction in LDL cholesterol when participants ingested a moderate-fat diet with the addition of an avocado. That’s roughly half the LDL cholesterol drop seen with the starting dose of one of the statins.
The article does not mention a direct price for avocados, but it does mention that avocados tend to be expensive in many parts of the country at certain times of the year.
The reduction in LDL or “bad” cholesterol levels are clearly stated for each study group referenced in the article. However, we’re never told what the participants’ baseline LDL cholesterol values were, so it’s difficult to know how meaningful these changes are. The competing NBC story, by comparison, told us that an LDL level below 100 is considered healthy, so the reader has some context from which to judge the 13-point drop seen in the study.
The story also fails to communicate any bottom line assessment of what the findings mean for outcomes that matter to readers — for example, their risk of suffering a heart attack or stroke. It doesn’t explain that LDL is one of many factors that may affect the likelihood of suffering heart disease. To provide the appropriate context, the story might have communicated how the changes seen in the study would affect an individual’s 10-year risk of suffering a heart attack or stroke.
The story mentions that avocados are typically consumed in the U.S. as guacamole, which is often eaten with corn chips that are high in calories and sodium. We’ll call that good enough for a satisfactory rating on this criterion. The story could have gone one step further, as NBC did, and note that consumers should compensate for the extra calories from avocados by reducing intake of nutrient-poor calories. Otherwise they’re likely to gain weight.
The story does a good job telling the reader about the methods of the study and the three diets. The number of participants and a bit about their demographics are also provided. The results of the study are provided in absolute terms and importantly are placed in context with a quote from the American Heart Association press release: “Although these findings demonstrate that an avocado a day alongside a moderate-fat diet has the potential to reduce bad cholesterol, the team notes that their research was a controlled feeding study. That is not the real-world,” says Kris-Etherton, “so it is a proof-of-concept investigation.”
Given the presence of these caveats, we’ll rate this satisfactory, although we’d love to have seen some discussion of the fact that the primary outcome — LDL cholesterol — is an intermediate marker of heart disease risk. See our primer on this topic. Thus, the findings are not as strong as those of some other studies that assessed the number of heart attacks and strokes that occurred after dietary changes.
The story does not resort to disease mongering to make its case.
The story includes quotes from the principal author that help place the study in context, and it notes that the story was funded by Haas Avocado Board. However, the researcher’s quotes are taken directly from a press release, whereas the other outlets that covered this story all spoke directly with the study author. Additional useful information could have (and, we think, should have) been gleaned by speaking with someone who was not affiliated with the study. That’s why we’re rating this unsatisfactory.
We would have liked to have seen a brief listing of other foods that provide healthier fats somewhere in the story to provide a bit of balance. The story does note: “Still, the team believes their findings indicate that people should consider replacing saturated fatty acids in their diet with healthier fats from avocados and other sources. Kris-Etherton adds:“We need to focus on getting people to eat a heart-healthy diet that includes avocados and other nutrient-rich food sources of better fats.” However, other stories we reviewed about this study mentioned specific foods that are high in monounsaturated fats.
More importantly, given the ubiquity of statin drugs, we would have liked to have seen some comparison of the effects seen in this study with those attained via statin therapy. An independent expert could have easily provided that information, had the story consulted one.
The story does note that avocados are available but somewhat expensive at certain times of the year. We’ll call this satisfactory, although the story could have noted that some areas may lack access to more exotic fresh produce such as avocados.
The role of foods high in monounsaturated fats in reducing total and LDL cholesterol has been known for quite some time, and the authors note that “It is known that monounsaturated fats can help lower levels of bad cholesterol.” However, the story does not specifically establish the novelty of studying the LDL-lowering properties of avocado. Is this first time this issue has been studied? The story doesn’t tell us.
The story uses several quotes directly from this American Heart Association news release without noting that’s the case. For example:
The story does list the news release in the reference list of sources, but if you’re going to rely on a canned statement, we’d expect to see some acknowledgment of that fact in the text of the story.
There also doesn’t appear to be any information contained in the article that isn’t also in the news release.
It’s clear that the three competing stories that covered this study at least spoke with study researcher Penny Kris-Etherton.