RDA is above 1.4 milligrams for adults
There are no recommendations on daily intake in the UK, but the World Health Organisation notes a daily intake of 2.5 mg as the absolute minimum requirement. The USA recommendations are 2.3 mg for men and 1.8 mg for women.
Manganese is an essential trace-mineral.
As little as 5% of the manganese in food actually gets into your blood. It competes with iron for absorption.
Food processing removes as much as 90% of the manganese.
Where do you get manganese?
It is in all kinds of plant food – vegetables and salad, pulses, nuts, whole grains, eggs, avocados, pears, bananas, and pineapple, and in tea and coffee.
It is in at least 20 enzyme systems; is needed for making haemoglobin, bones, cartilage and hormones; it is essential in maintaining blood sugar levels, proper brain function and a healthy nervous system and supports the efficient use of vitamins B1, C, E and biotin.
Too much manganese
Taking too much milk or fizzy drinks means that there is excess calcium and phosphorus around, and these disrupt the absorption of manganese.
Too little manganese
Deficiency is unusual, but symptoms include low blood sugar, reduced fertility and poor growth of bone and cartilage.
Supplements usually take the form of multi-mineral products. Surprisingly, tea can provide about half of the normal daily requirement.