Selenium + Fluoride

• Strategies to increase dietary intakes of a nutrient

  • fortification
  • supplementation
  • Dietary diversification
• Organic form


  Selen methionine and selenocysteine (protein)
• Inorganic form 


  Selenite, selenised yeast
• RDI 


  Female = 60micrograms/day

  Male = 70 micrograms/day
• Is selenium absorbed easily?

  Yes - 80% is and isn‘t regulated
• Tissue/blood levels reflect intake
• Wheat used in NZ is imported from Australia due to their higher selenium levels in the soil
• Plant levels reflect soil content

  • grains (wheat) vary by soil content
  • fruit and veges are poor sources
  • some plants accumulate selenium for example Brazil nuts, mushrooms, garlic
• Over the 2 weeks of consuming 2 brazil nuts a day there was a signif increase in plasma selenium
• the Brazil nuts were proven to be as bioavailable as the tablets therefore, for optimal health 2 Brazil nuts should be consumed a day
• White muscle disease in sheep 1959:

  • Stillborn or die in the first few days
  • unsteady gait and arched back
  • “drenching” includes selenium supplement
  • white patches found in their muscles
• Keshans disease in humans in 1935

  • low in selenium and enterovirus
  • cardiomyopathy in children and pregnant women
• Why has china had it and not NZ?

  china - lots of rice

  NZ - more meats, more imported foods, less cereals
• There have been no public health strategies implemented in NZ regarding selenium
• toxicity

  • from diet is very rare
  • effects: pallor, lassitude, irritability, indigestion, and giddiness
  • selenised yeast supplement
• Fluoride

  • low levels in NZ soil
  • too much is considered bad
• A milligram per kilogram is 1 ppm
• Some good sources of fluoride

  • black tea
  • fish
• How much fluoride is absorbed in the diet ?

  100%
• Excretion 


  Via the kidney in the urine
• AI 


  3 mg/day for female

  4 mg/day for male
• What is fluoridation?


  Fortification of fluoride in water
• Dental caries

  One of the most preventable chronic diseases in the world
• dietary factors

  • eating frequency
  • CHO foods
  • sequence of food eaten
  • clearance time of food
  • presence of Ca, P, F
  • acidity
• Fluoride

  • inhibits bacteria
  • inhibits demineralization
  • enhances remineralization
• Toxicity

  • rare from the diet
  • skeletal fluorosis (brittle ones)
  • dental fluorosis (cosmetic)