Women need 1.8 mg a day and men need 2.3 mg a day of manganese.
Top natural sources of manganese:
1. Blue Mussels: 5.8 mg, 251% Daily Value (DV)
2. Hazelnuts: 1.8 mg, 76% DV
3. Pecans: 1.3 mg, 56% DV
4. Brown Rice: 1.1 mg, 47% DV
5. Pacific Oysters: 1 mg, 45% DV
6. Clams: 0.9 mg, 37% DV
7. Chickpeas: 0.8 mg, 37% DV
8. Spinach: 0.8 mg, 37% DV
9. Pineapple: 0.8 mg, 33% DV
10. Soybeans: 0.7 mg, 31% DV
11. Oatmeal: 0.7 mg, 30% DV
12. Whole-Wheat Bread: 0.7 mg, 30% DV
13. Black Tea: 0.5 mg 23% DV
14. Lentils: 0.5 mg, 21%
15. Banana: 0.4 mg, 16% DV
16. Baked Potato: 0.3 mg, 14% DV
https://www.livestrong.com/article/13769669-foods-high-in-manganese/
There was no way our diet was supplying this every day, and my multivitamins and multiminerals did not have it.
Obviously there are exceptions. My supplements have always included manganese.
The dangerous takeaway is “just go buy manganese tablets” but at the levels in some tablets inadvertent toxicity may occur.
I don’t subscribe to individual supplementation of nutrients unless a deficiency has been identified.