The mineral vanadium is essential in human nutrition; this nutrient is considered to be an ultra-trace mineral that is found in the human body and dietary sources in minute amounts. Some sources of vanadium include plant products like the buckwheat, herbs like parsley, soybeans, the seeds and oil of the sunflower, cereals like oats and whole wheat, olive oil, plants like corn, green beans, peanut oils, common vegetables like carrots and cabbage, tomatoes and lettuce, garlic, and radishes, tuberous plants like onions and beets, fruits like apples and plums, seafood, mushrooms, soy, and gelatin. People affected by disorders such as long term diabetes can benefit from vanadium supplements. Though very rarely seen, there are reports of vanadium deficiencies from time to time. Problems like manic depression have been connected to excessive levels of vanadium in the body. As far as the human nutrition is concerned, the mineral vanadium can be considered an ultra-trace mineral. Some animals require the presence of vanadium in their diets, for such animals, the deficiency symptoms can include retardation of growth, the development of bone deformities and persistent or long term infertility. The mineral vanadium is not considered essential in the diet as far as humans are concerned and no conclusive ill effects from a lack of vanadium have even been observed. The structural formation of bones and teeth in humans may be influenced by vanadium in some way - though the relationship is unclear. The control of glucose levels in individuals affected by non-insulin dependent diabetes mellitus (NIDDM) may be improved by vanadyl sulfate, which is a form of this mineral - this is based on the evidence gathered during a study of eight diabetics who were given supplements of 100 mg of vanadyl sulfate every day during a four week trial. At the same time, the long term safety issues connected to the use of such large doses of vanadium is till unknown and researchers who conducted this study caution the unsupervised use of the mineral especially in high doses. The safety of such high dosages of vanadium are questioned by many doctors of natural medicine, these experts expect that the results from future research is very likely to show that the use of such high dosage amounts will turn out to be dangerous. Though unlikely to occur, there are no reported cases of people suffering from deficiencies of the mineral vanadium. Humans do not seem to require vanadium in the diet in high amounts.