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Solid effort by NBC on saturated fat study, though story lacked hard numbers on findings

Using Vegetable Oils to Lower Cholesterol May Not Improve Longevity

Our Review Summary

bacon, saturated fat, diet, fatsThis story is about new evidence that may diminish the importance of limiting animal fats in people’s diets to reduce risk of deaths from heart disease. A new group of researchers re-examined a 45-year-old randomized controlled study of 9,000 people who were put in two groups: one group replaced animal fats with corn oil in their diet, the other ate animal fats. The risk of death from heart attack was higher in the vegetable-oil group, even though certain markers of cholesterol in their blood did become lower.

The story does a good job of explaining the study’s design, and some of the complex issues surrounding dietary habits and heart disease. But this story falls short by not quantifying study elements: no numbers for cholesterol level changes, no numbers for changes in risk.

 

Why This Matters

Diet appears to play a role in dozens of chronic diseases, including heart disease. Research that helps tease out which fats are truly better for people helps us further understand the issue, though it is complex and evolving. News coverage should not only be accurate, it should help readers understand how the latest study fits into the greater body of scientific knowledge.

Criteria

Does the story adequately discuss the costs of the intervention?

Not Applicable

Since this is about affordable and widely available cooking oils, this is N/A.

Does the story adequately quantify the benefits of the treatment/test/product/procedure?

Not Satisfactory

The story does not quantify. We are told the 45-year-old data showed a “lowering” of cholesterol for study participants who swapped animal fats for vegetable fats. But we aren’t given any numbers for by how much or even by what percentage.

In a similar shortcoming, one of the most counter-intuitive findings was dismissed.

“In fact, the study found that the lower the cholesterol, the greater the risk of death. But that’s a misleading association because a variety of illnesses can also cause drop in cholesterol, which is unrelated to diet.”

The story should have given us some numbers for that “greater risk.” Even if it is misleading, we are entitled to know the size of the risk found in the study.

Does the story adequately explain/quantify the harms of the intervention?

Not Applicable

The intervention in the study (eating more unsaturated fat) is unlikely to cause adverse side effects, risks, or complications, so we’re rating this N/A. The story did point out the surprising association between lower cholesterol levels and increased risk of death, though that could have been explained more clearly.

Does the story seem to grasp the quality of the evidence?

Satisfactory

The story gives us information about both the old Minnesota study and the new British Medical Journal publication. We know the old study was randomized and included 9,000 people. At the end of the story, we also learn the study has “many” limitations and some of these are mentioned.

Ideally, the story would have specifically pointed out that the study population included only residents of nursing homes and mental health hospitals, which may affect generalization. Also, given that this is decades-old data, we’re wondering how researchers took that into account, and how it might have impacted the quality of evidence.

Does the story commit disease-mongering?

Satisfactory

There was no disease mongering.

Does the story use independent sources and identify conflicts of interest?

Satisfactory

There don’t appear to be any conflicts of interest, and the story includes an independent source.

Does the story compare the new approach with existing alternatives?

Satisfactory

The story does a good job of talking about the complicated recommendations regarding diet, as well as medications, specifically statins.

Does the story establish the availability of the treatment/test/product/procedure?

Not Applicable

The different oils are widely available; this is N/A.

Does the story establish the true novelty of the approach?

Satisfactory

The story explains that the novelty is not with any treatment or discovery but rather a novel statistical examination of old data.

Does the story appear to rely solely or largely on a news release?

Satisfactory

The story does not appear to rely solely on a news release.

Total Score: 6 of 7 Satisfactory

Comments (5)

Please note, comments are no longer published through this website. All previously made comments are still archived and available for viewing through select posts.

Thomas Anderson

April 14, 2016 at 11:40 pm

Please see this letter written more than 20 years ago:
http://www.members.shaw.ca/doclink/globe-120495.jpg

Reply

Henry Blackburn, M.D.

April 18, 2016 at 7:47 am

Your critique may not have noted that the average follow-up of participants in this trial was about 1 year.
In claims with respect to mortality and coronary events this would seem to be the main limitation of the study. In any case, it was the reason that the Cochrane Group gave for not including the MCE in its meta-analysis of diet trials.
A look at the published rapid responses to the BMJ article, and to the Harvard Nutrition blog would have
pointed out other relevant limitations to that study.
An interesting finding of the study you might have mentioned was the excess total mortality for those
in the trial more than 1 year.

Reply

Henry Blackburn, M.D.

April 18, 2016 at 7:57 am

Your publishing the 20-year old comments of T. Anderson, Ph.D, who calls the American dietary guidelines and recommendations on “cholesterol,” a “hoax,” would seem to violate your commitment to “delete unfounded allegations and unverified facts?

Reply

    Gary Schwitzer

    April 18, 2016 at 8:07 am

    Dr. Blackburn,

    Thank you for your comment.

    The task of moderating comments on a news site is a complex and time-consuming job – one that the New York Times addresses today with several voices weighing in on the complexities and difficulties (http://www.nytimes.com/roomfordebate/2016/04/18/have-comment-sections-on-news-media-websites-failed?smid=tw-share). And we have only two people who moderate the thousands of comments we receive.

    That comment was approved primarily because it was a 20-year old comment on health care journalism, which is the focus of our project. Nonetheless, I understand your objection.

    Reply

Sarah J Eber

April 18, 2016 at 9:40 am

Very good! Awesome! Thank you!

Reply