Manganese (Mn) Atomic No. 25 Atomic mass.55

Distribution Total body contents = 12 – 20 mg Mainly concentrated in liver and kidney Human Blood Contains 5-20 ug/dl

Dietary source Best: Nuts, Grains, Legumes, Soybean, Coffee & Tea Good: Fruits, Vegetables Poor: Meat, Sea food, Poultry and Fish

RDA 2.5 – 5.0 mg/day provides a margin of safety Infants 0 – 0.5 = 0.5 – 0.7 0.5 – 1.0 = 0.7 – 1.0 Children 1 – 3 = 1.0 – 1.5 4 – 6 = 1.5 – 2.0 7 – 10 = 2.0 – 3.0 11+ = 2.5 – 5.0 Adults 2.5 – 5.0

Absorption and Excretion Poorly absorbed (3-4 %) Mostly from small intestine Transmanganin, a globulin binds and transports Major uptake site are mitochondria Excreted mostly in feces via bile Very little through kidneys

Important functions Essential for many species including human. Vital component of many enzyme system Protein metabolism, Hexokinase,Arginase, Choline Esterase and Pyruvate Kinase Energy metabolism, Oxidatative Phosphorylation Synthesis of muco-polysaccharides (cartilage) Glyco-proteins (prothrombin) Gluconeogenesis Probable role in Hb and Cholesterol synthesis

Factors Affecting Absorption High Amount of dietary Iron , Calcium and Phosphorous interfares with Mn absorption from GIT.

Related Diseases Deficiency in human not yet established In animals Poor reproduction Growth retardation Congenital malformation Abnormal bones and cartilage Impaired glucose tolerance

Related Diseases Toxicity in human seen when exposed to Mn dust for a long duration. Excessive amounts accumulate in liver and CNS which leads to Neuro- muscular disorder – Parkinsonism Anorexia,impotence and leg cramps are the early sighns of over dose.

MOLYBDENUM (Mo) Atomic No. 42 Atomic mass.96

Dietary sources Some rich sources include organ meat , legumes, and whole-grain cereals. Molybdenum content of foods varies with the concentration of the element in soil.

Safe and adequate intake For adults is approximately between 0.15 and 0.50 mg per day. Excessive intake i.e. 10 -- 15 mg/ day, produce gout like, symptoms.

Distribution Mostly concentrated in liver and kidney

Important functions of Molybdenum Essential component of the enzymes; Xanthine oxidase Aldehyde oxidase, and Sulfite oxidase, needed for the oxidation of xanthines, aldehydes, and sulfites, respectively.

Important functions of Molybdenum Mo is present in nitrate reductase in plants and nitrogenase in micro-organisms, where it functions in nitrogen fixation.

Related disease In areas where the soil has a high molybdenum content cattles develop a syndrome called “Teart” which is characterized by: Weight loss, Brittle bones and De-pigmentation.

SELENIUM (Se) Atomic No. 34 Atomic mass.79

Dietary sources Good dietary sources include Both animal and plants sources Seafood, Liver and Kidney are best sources Meat and Milk are poor sources. Cereals , pulses, vegetables , and fruits are fair sources

Safe & adequate dietary intake A level of 0.1ug per gram of diet is considered adequate for optimal growth and reproductions, with 50 to 200 µg. Per day being safe and adequate for adults A level of selenium in excess of 5 ppm in foods is considered dangerous. Toxicity occurs when the drinking water contains more than 2 µg/L or the diet has more than 3 µg per gram.

Distribution Selenium is widely distributed throughout the body, with highest concentrations found in the kidneys liver, pancreas, and pituitary. The amount of selenium in foods is proportional to the soil content in the area where the food is grown.

Important functions Although recognized as an essential element for many animal species, selenium has not yet been clearly established as essential for humans. The best known biochemical function of this element is as part of the enzyme glutathione peroxide, which protects vital components of the cell e.g. membrane lipids and hemoglobin) against oxidative damages.

Important functions It may also be involved in other important biologic processes, immune mechanisms and mitochondrial ATP synthesis. Required for normal growth and development in animals.

Deficiency manifestation Liver necrosis Pancreatic degeneration, Muscular Dystrophy, Heart enlargement, Cardiac arrythmias, RBC fragility and infertility are the deficiency manifestations of selenium

KESHAN DISEASE Naturally occuring Se deficiency disease in human. Reported in Keshan province of N.E China. Low contents of Se in soil is the basic reason. Disease is characterized by acute or chronic heart enlargement , cardiac arrhythmias and ECG changes.

Related disease in animals A syndrome termed alkali disease has been reported among cattle consuming feed high in selenium. Concentrations in the range of 5 to 15 ppm have been shown to be toxic to animals. Deficiency occurs when the concentration is less than 0.02 to 0.05 ug per gram of diet

Related disease in animals Selenium has been found to cure some, but not all, of the deficiency symptoms produced in animals by vitamin E deficiency, It is thought that this is due to the similarity between the action of selenium and that of vitamin E as antioxidants.

Selenium Toxicity Chronic Toxcity ………..Selenosis Its Signs are : Dullness Weight Loss Hair Loss Impaired Vision and Liver Necrosis Not seen in human, however Glass, ceramic and paints industry workers are at risk

Protective Role Selenium supplementation is thaught to reduce the risk of cancer in human.

Interference from other elements Sulfur is an antagonist to selenium in that it competes with this element for reactive sites in enzymes.