There is no clear evidence that specific types of grapes are more effective than others for cognitive health. Most studies have focused on Concord grapes or grape juice, but have not directly compared different grape varieties.
Concord grape juice has been the most studied, with some evidence it may improve verbal learning and memory in older adults with mild cognitive impairment. However, results are mixed and more research is needed.
Grapes in general are rich in flavonoids and antioxidants like resveratrol, which are thought to contribute to their potential cognitive benefits. But the optimal grape variety and dose is unclear.
One systematic review found that both grape juice and freeze-dried grape powder improved various cognitive functions like attention, memory and executive function in long-term intervention studies
Whole grapes, grape juice, and other grape derivatives like wine and raisins have all shown some promise for cognitive health in epidemiological and clinical studies. But no direct comparisons have been made.
In summary, while Concord grapes have been the most studied, there is no strong evidence that any specific grape variety is superior for brain health. More research directly comparing different grape types is needed.
The current evidence suggests grapes in general, whether whole, juiced, or in other forms, may provide cognitive benefits, likely due to their polyphenol content. But the optimal grape for cognition remains unclear.