Oats and wheat are high in manganese. Healthy people don't need to worry about getting too much manganese from food. Other foods with high manganese are shellfish, nuts, legumes (like soybeans, kidney beans, and chickpeas), brown rice, leafy green vegetables (spinach and kale), and fruits such as pineapple. Manganese toxicity has never been observed from manganese in food. It does occur from some water and industrial sources and high-dose supplements.