Submitted to: Experimental Biology
Publication Type: Abstract Only
Publication Acceptance Date: April 17, 1999
Publication Date: N/A
Technical Abstract: Iron absorption is enhanced by feeding saturated fats (when compared to PUFAs). Iron and Mn interact very strongly during absorption, so the purpose of the present study was to determine if fat type also affects Mn absorption. Thirty-two weanling male rats were randomly assigned to four diets that differed in the concentration of Mn and the type of dietary fat. Diets were based on AIN-96 dietary guidelines, except that 12 % of energy intake was supplied as either safflower oil or stearic acid, and diets contained no added Mn or 100 mg/kg added Mn. After consuming their respective diets for 10d, animals consumed a test meal containing 3 uCi of 54**Mn in 1 gram of diet. Whole-body 54**Mn was determined by whole-body counting for the next 10d; absorption and biological half-life were based on these counts. At the end of the experiment, animals were killed and organs were collected. A significant (p=0.016) interaction between dietary fat and Mn affected Mn absorption. Animals fed safflower oil absorbed 21.9- 30.9% of the 54**Mn regardless of Mn content of the diet. Animals fed stearate and 0 Mn absorbed 2.9-4.8% and animals fed stearate and 100 mg Mn/kg diet Mn absorbed 0.9-1.4% of the 54**Mn. Biological half-life was significantly increased in animals fed stearic acid and in animals fed low Mn. A significant (p=0.0001) interaction between dietary Mn and fat type also affect the retention of 54**Mn in the liver, brain, heart, kidney and spleen. The highest retentions of 54**Mn were in tissues of animals fed safflower oil with no added Mn, and the lowest retentions were in animals fed the high Mn. These data show that the type of fat in the diet is a major determinant of Mn absorption and retention.