The mineral manganese is needed in trace amounts, however, it is one of the most common elements found in the earth's crust - it serves as a co-factor in many enzymatic reactions. Manganese can be found in atmospheric dust, in rain water, in fresh and sea water as well as in all animal and plant tissues. There is not a single sample of human tissue which does not contain a little manganese - some trace of the element can be detected in all tissue samples. As manganese serves as a co-factor in several important enzyme systems, it is considered to be an essential trace mineral and some amount is required in the diet. The reactions in which manganese functions as a co-factor include the synthesis of many types of protein, in the enzymatic formation of nucleic acids DNA and RNA, and in the synthesis of cartilage tissue. The mineral may be vital in processes involving the metabolism of fats, and it is known that manganese plays a role in the utilization of the insulin hormone. A preparation made from alfalfa, which is high in manganese, is reportedly a traditional African folk medicine which is still used as a treatment for diabetes and blood sugar related disorders.