[QuantumAphid]

The supporting study:

Flavonoid intake is associated with lower mortality in the Danish Diet Cancer and Health Cohort https://www.nature.com/articles/s41467-019-11622-x

"Dietary data were collected using a validated 192-item food-frequency questionnaire, mailed out to participants prior to their baseline visit to one of the two study centers. Participants were asked to indicate their usual frequency of intake of different food and beverage items over the past 12 months, using a 12-category frequency scale that ranged from never to 8 times or more per day."

So... 50-65 year old participants in the study responded to an annual 192 item questionnaire for 23 years. Quick: How many blueberries did you eat in the last 12 months and how frequently?

Anybody see an potential problems with this type of survey approach? Virtually guarranteed to be wildly unreliable.