This article in The Clinical Advisor (Citrus Fruit linked to Lower Ischemic Stroke Risk briefly describes the findings of a study in Stroke (Cassidy A et al. StrokeDietary Flavonoids and Risk of Stroke in Women). The study found that women who intake a higher dose of flavone from natural citrus juices are less likely to experience stroke over a 14 year period than those intaking a lower dose in juices. The same trend held for whole fruits and supplements. However, the news article author claims that total flavonoid intake is not (proportionally) related to reduction of stroke. The author did not elaborate on this confusing point, but the study article reported that it was merely the flavone subclass found in citrus fruits that reduced the risk of stroke, not the overall total flavonoid intake.
The writer of the news article did a good job of including some numbers from the study, including p-test statistical values. And while the article did not give too much detail on the study or specific reasons as to why flavone intake reduced stroke risk, the author did link the study article towards the bottom. Overall, I think the writer did a decent job of portraying the "tip of the iceberg" of the Stroke study, just enough to peak someone's interest in reading the paper. While many factors contribute to stroke risk besides possibly flavone intake, no harm generally comes from eating fresh citrus fruit, and it can be a tasty method of contributing to your health. Just don't overdo it!!!
So, if the intake vs reduction is not proportional, is there some sort of "minimum intake" to achieve the stroke reduction?
ReplyDeleteNo, the article did not address this point. A minimum intake would be quite difficult to identify, as it would likely vary depending on the person. The article also did not offer any suggestions, though this may be part of a future study. As pointed out in Lance's comment below, there are certainly some gaps in this study. More research is needed.
DeleteThis study used the data from the large Nurse's Health Study however the public (lay) article author almost seems to insinuate that the researchers found the citrus flavonoids to be the direct cause for the stroke risk reduction. Again, by using the Nurse's Health Study the researchers only found a possible association between a decreased risk in stroke risk with a higher flavonoid intakes.
ReplyDeleteThe key fact here is that this is only an association. In the lay article the reseasrchers are quoted stating that "... public health recommendations should focus on increasing citrus fruit intake.". However, it is basically left out that in in the actual study the researchers conclude the following:
"In a meta-analysis of existing cohort studies, those consuming 3 to 5 servings/day
and 5 servings/day had an 11% and 26%reduction in risk of stroke, respectively, compared with those consuming 3servings/day. However, these data could not determine which
specific fruits/vegetables or their constituents exerted these protective effects. Our findings suggest that bioactive compounds present in citrus may potentially be associated with a reduced risk of stroke. Further prospective studies are needed to confirm these associations together with further molecular mechanistic data on flavanones to inform and optimize the design of randomized trials of flavanone and citrus-based foods to potentially reduce ischemic stroke risk."
So once again it seems to me that the lay article merely offers the lay person or public only half the story. And only the doubtful person may look deeper in to the real story while most will just simply believe that citrus will save them from a stroke if they eat it. Possibly some good thought provoking info but it needs more on the limitations of the study and results.
Lance & Chris, I feel like this is a common occurrence in the Nutrition field. Any indication of a natural method for prevention of disease is jumped on and taken out of proportion by the media. It is very difficult, if not impossible, to identify just one component of a diet as a risk factor/protector because no one eats just one phytochemical or food group at a time.
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