Glanced at the study. The supplement appeared to be 90mg of curcumin, taken twice daily.

A quick google search says there are about 15 mg per tablespoon. That would mean you'd need to eat about 6 tbsp of turmeric to get a comparable amount. Probably even more so, since I don't think turmeric is pure curcumin. For reference, the average curry or other dish using turmeric in my household takes about 1 tbsp, so at a glance I would consider it impractical to get that much naturally through your food.

My next curiosity would be whether a smaller amount can show similar benefit, or whether it needs to be at a level only available in a supplement.