This story reports on a recent well done randomized, placebo-controlled clinical trial that finds high doses of resveratrol can have an effect on the production of a biomarker associated with Alzheimer’s disease. The story also highlights some modest gains in patients’ ability to perform daily tasks. However, the story seems to reach farther than the evidence and could easily mislead readers who are looking for ways to fight the symptoms of Alzheimer’s — for themselves or loved ones. The headline, “New Evidence Resveratrol May Slow Alzheimer’s,” is particularly off base, as there’s no evidence presented in this study to indicate a slowing of Alzheimer’s progression. The story’s characterization of brain shrinkage in the resveratrol group as a “positive sign” is similarly problematic, as it’s far from clear that a shrinking brain is a good thing for anyone. An independent source would likely have helped this story provide a more thorough and accurate evaluation of the study and its implications. A competing CNN story did feature such a perspective and, perhaps as a result, was better.
Alzheimer’s affects more than 5 million people in the United States, and that number is expected to double over the next 35 years. It is the sixth leading cause of death in the United States. And while the number of patients diagnosed is great, the number of people affected is even greater. It is difficult for loved ones to watch a friend or family member lose his or her sense of self, to say nothing of the financial and emotional burden that comes with increased responsibilities for taking care of Alzheimer’s patients as the condition advances. New tools and treatments that can slow the progress of Alzheimer’s are important and worth covering. But it is also important to present the limitations of new studies, so as to avoid giving a false impression of the findings to doctors, patients and their loved ones.
The story does not mention cost at all. But in this case we’ll rule this Not Applicable since the story clearly indicates that the supplements studied are not on the market.
The story has a fundamental flaw. The key finding of the study is that high doses of resveratrol can have an effect on the production of amyloid-beta40, a biomarker that declines as Alzheimer’s disease advances. Specifically, the study looked at 119 patients with mild to moderate Alzheimer’s disease. Patients who received the high doses of resveratrol did not see declines in the biomarker, whereas patients who received a placebo did see declines in amyloid-beta40. Couching that as “new evidence resveratrol may slow Alzheimer’s,” as we see in the headline, is misleading. More accurate is the line in the eighth paragraph: “How resveratrol may be affecting the Alzheimer’s disease process isn’t clear yet.” And it’s not until the last line of the story that readers find: “We need more studies to see if it really does have benefit and then it could be turned into more effective drugs that can better target Alzheimer’s.” That’s a qualifier that should have found placement much higher in the story.
Another concern is the story’s reporting on brain volume decline in the resveratrol group, which it says is “a positive sign, as the disease can cause inflammation and swelling that can interfere with nerve connections.” Characterizing a shrinking brain as a “positive sign” seems problematic at best. The study itself says that the “The etiology and interpretation of brain volume loss observed here and in other studies are unclear.” And in the news release issued for the study, Dr. Turner acknowledges, “We’re not sure how to interpret this finding.”
And finally, the story also points to “slight improvements” among patients receiving resveratrol — but doesn’t explain exactly what that means. More on this below in “Quality of Evidence.”
The story doesn’t mention side effects, but the study itself reported that adverse effects included nausea, diarrhea, and weight loss. In addition, there are some concerns that resveratrol may affect blood clotting, which would be important information for patients taking blood thinners. It’s worth noting that this absence of potential harms in the story is particularly problematic, given that a key goal of the study was to determine whether high doses of resveratrol are safe. Moreover, weight loss is already a significant concern among Alzheimer’s patients, so anything that would exacerbate that is definitely worth paying attention to.
The story does note the size of the study and the maximum dosage that patients received. However, the story doesn’t provide much in the way of critical evaluation of the results. For example, while the story says that “men who were treated [with resveratrol] showed slight improvements in their ability to maintain certain daily activities on their own, such as dressing and bathing themselves,” it doesn’t mention the fact that the study included five tests that measured patient’s mental processes — and found slight improvements in only one of them. There was no difference between the resveratrol group and the placebo group on the other four tests.
Similarly, the study looked at many different measures in the spinal fluid and plasma, as well as many different brain volume measures. And when looking at so many different outcomes, the authors were bound to come out with one or two positive results by chance. So-called “correction for multiple comparisons” is designed to address this problem, but wasn’t performed in this study as far as we could see.
Lastly, the point of a phase 2 study is to look at safety, not benefits, but the story never communicated this key limitation or explained the purpose of this type of study. As the paper itself notes: “This phase 2 study has limitations….The altered biomarker trajectories must be interpreted with caution. Although they suggest [central nervous system] effects, they do not indicate benefit. A larger study is required to determine whether resveratrol may be beneficial.”
Inclusion of an independent perspective would likely have brought attention to many of these concerns.
No disease mongering here.
While several of the study authors have ties to the pharmaceutical industry, it’s not clear whether any of those companies are developing resveratrol-based drugs or supplements, and the study itself was funded by the NIH. Regardless, the story does lack input from any experts who weren’t involved in the study, which is necessary to meet our standard here. The story would have been much stronger if it had included outside experts who could have placed the work in context and helped readers understand how this work fits into the broader scheme of Alzheimer’s research and treatment.
While there are a paucity of treatment options for Alzheimer’s, there are some pharmaceuticals on the market, such as cholinesterase inhibitors. The story doesn’t mention any of them, or explore how these may compare to, or be compatible with, the use of resveratrol.
In addition, so many small clinical trials in Alzheimer’s have made headlines like this one, only to come up totally negative when studied in a properly powered trial. We wish the story had shown some awareness of that fact.
The story does make clear that this study does not mean people should begin drinking red wine or taking resveratrol supplements to combat Alzheimer’s disease, and notes that more studies are needed to determine benefit or to create drugs for clinical use.
This study is, as the story notes, “the largest and longest study of resveratrol in people with mild to moderate Alzheimer’s disease.” We’ll rate the story Satisfactory for that reason, but we wished for additional context. A quick internet search turned up dozens of other studies on resveratrol and Alzheimer’s — and a quick paragraph on what those other studies have told us would have been both interesting and useful.
This story technically meets our standard here since it includes quotes from an interview with the lead author — quotes that weren’t included in a news release about the study and which indicate original reporting. But we’d note that the news release on this study is actually much more careful in its presentation of the results than this more sensational news story. The news release is more accurate in claiming, “Resveratrol impacts Alzheimer’s disease biomarker,” and says nothing about “slow[ing] Alzheimer’s.” The release also includes cautionary language sprinkled throughout the text, whereas the lone caveat in this story comes only at the very end.