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• Children: IQ declines, clumsiness, gait issues, headache, behavioral changes, seizures, cognitive & behavioral problems
• Adults: peripheral neuropathies, motor weakness, chronic renal insufficiency, systolic hypertension, anemia • Non-essential; no known function in human physiology; toxic
Absorption, Transport, & Excretion
• Exposure: inhalation, ingestion (fish), cutaneous, injection (tattoo pigments), dental amalgams
• Absorption: 80% inhaled, ~0% in GI; excretion: fecal & urinary
Toxicity
• Primarily through reaction with sulfhydryl groups
• Inhaled vapor: nervous, digestive, & immune systems
• Inorganic salts: skin, eyes, GI tract, & kidneys Health Effects
• Essential; helps maintain metabolism of glucose, fat, cholesterol
Absorption, Transport, & Excretion
• Absorbed, bound in blood to transferrin, transported by albumin
Deficiency/Toxicity
• Deficiency: glucose intolerance, glycosuria, hypercholesterolemia, decreased longevity, decreased sperm counts, impaired fertility (50-200mg/dL)
• Toxicity: dermatitis, skin ulcers, eczema (cutaneous contact); airway irritation & obstruction, lung cancer (inhaled), target organ effected is lungs
+6 form is much more toxic produces toxic radicals
+3 form is responsible for contact dermatidis • Essential; a component of metalloenzymes; an enzyme activator
Absorption, Transport, & Excretion
• Absorption: 2-15% of dietary intake; affected by iron, calcium, phosphates, & fiber
Deficiency/Toxicity
• Deficiency: blood clotting defects, hypocholesterolemia, dermatitis, heart & bone problems, stunted growth (in children)
• Toxicity: nausea, vomiting, headache, disorientation, memory loss, anxiety, compulsive laughing or crying Health Effects
• Essential; part of cellular antioxidant defense system against free radicals; involved in metabolism of thyroid hormones
Absorption, Transport, & Excretion
• Exposure: food, drinking water
• Absorption: >50% of dietary intake; excretion: urine, feces, sweat
Deficiency/Toxicity
• Deficiency: cardiomyopathy, muscle weakness, osteoarthritis
• Toxicity: rare; only from 1 form of selenium, not present in food; causes nausea, vomiting, hair loss, nail changes, diarrhea
• Keshan Disease endemic cardiomyopathy, shows to be treated with selenium supplementation 