Foods That Improve Memory Naturally | Dr. Neal Barnard Exam Room Live Q&A

Dark, leafy greens such as spinach, kale, and swiss chard are well known as great sources of nutrition. Studies suggest that dark, leafy greens may have a protective effect on cognitive decline and that one serving per day of green leafy vegetables may help slow cognitive decline with aging. In general, a higher intake of vegetables may even contribute to larger brain volume.
Berries are another great source of antioxidants and may also have benefits for brain health. A mixture of berries may be helpful for cognitive functioning as well as overall brain volume.

https://blog.ochsner.org/articles/food-and-brain-health-whats-the-connection/