Manganese

My chiropractor suggests that I increase my consumption of foods rich in manganese. He did not recommend a supplement because you can overdo it.

HealthVitamins has an article on manganese which lists these foods:

Good natural sources of manganese include avocados, nuts and seeds, seaweed, tea, raisins, pineapple, spinach, broccoli, oranges, beans, whole grains, blueberries, egg yolks, dried peas, and green leafy vegetables.

Many herbs also contain manganese, such as alfalfa, burdock root, chamomile, dandelion, fenugreek, ginseng, hops, horsetail, lemongrass, parsley, peppermint, wild yam, and raspberry.