This article was in the New York Times. Mainstream media is doing exactly what industry wants, that is, reporting what looks like science but is really product promotion. What has happened to journalism?
Blueberries May Promote Heart Health, New York Times, 3 June 2019
“Researchers estimate that eating a cup of blueberries a day reduced the risk of any cardiovascular event by 13 percent.”
First of all, eating a cup of blueberries a day (they found that a half cup wasn’t enough), as I found, is economically unrealistic. Second, “heart health” was not their primary endpoint. It wasn’t even a secondary endpoint. It was a projection based on secondary endpoints. In fact, they didn’t even find a positive effect on their primary endpoint (see below). Third, 13 percent is small, like really small.
Here was the study. I’m beginning to suspect articles in this journal:
Blueberries Improve Biomarkers Of Cardiometabolic Function In Participants With Metabolic Syndrome — Results From A 6-Month, Double-blind, Randomized Controlled Trial, American Journal of Clinical Nutrition, 28 May 2019
The primary endpoint* was insulin resistance. Did eating a cup of blueberries improve insulin resistance? No, it did not. The rest of their measurements are all results of fishing expeditions. You will always be able to find some positive effect from an intervention. Do these effects result in less disease and a longer life? Their study was not designed to answer that question, but that didn’t stop them. Those measurements, and there are a lot of them, are there as distractions.
Insulin resistance, pulse wave velocity, blood pressure, NO [nitric oxide], and overall plasma thiol status were unaffected. Likewise, a half cup per day had no effect on any biomarkers.
Also, the blueberry eaters had to limit consumption of other “anthocyanin-rich foods and other foods known to modify vascular function.” They’re saying that lots of foods we eat do the same thing as blueberries. Here are foods listed in the study that participants had to limit:
Blackcurrant, blackberry, cranberry, bilberry, black raspberry, cherry, grapes, strawberry, red raspberry, red currant, lingonberries, black olives, dark chocolate, oily fish (salmon, mackerel, tuna, herring), tea (including herbal), coffee (instant or filter), hot chocolate, alcohol, cabbage, radicchio, black beans, beets, broccoli, carrot, cauliflower, celery, cucumber, lettuce, Brussels sprouts, parsley, potato, radish, spinach.
They should have mentioned watermelon which has a stong nitric oxide effect.
Another giveaway that this study is more advertisement than science is how they word the conclusion. Treatments (in this case a cup of blueberries a day, not a half cup mind you) are never indicated by the results of one small study – a study that didn’t even show good on their primary endpoint!
Conclusions: Despite insulin resistance remaining unchanged we show, to our knowledge, the first sustained improvements in vascular function, lipid status, and underlying NO bioactivity following 1 cup blueberries/d. With effect sizes predictive of 12–15% reductions in CVD risk, blueberries should be included in dietary strategies to reduce individual and population CVD risk.
The study was funded by the US Highbush Blueberry Council.
The study used freeze-dried blueberries. I looked around and found these on Amazon for $8.15 or $6.79 per ounce. I’m guessing one ounce is about a cup. They ate a cup a day. That makes this intervention even more expensive than if they used fresh or frozen blueberries. (Frozen run around $1.50/cup. These freeze-dried are over 4 times that.)
* Wikipedia: “The primary endpoint of a clinical trial is the endpoint for which subjects are randomized and for which the trial is powered. Secondary endpoints are endpoints that are analyzed post hoc, for which the trial may not be powered nor randomized.”