Submitted to: Biological Trace Element Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/24/2003
Publication Date: 12/1/2003
Citation: Droke, E.A., Briske-Anderson, M., Lukaski, H.C. 2003. Fatty acids alter monolayer integrity, paracellular transport, and iron uptake and transport in Caco-2 cells. Biological Trace Element Research. 95:219-232.
Interpretive Summary: Many components of the diet potentially impact the ability of an individual to absorb and utilize the iron in foods. We have been examining the effects of different fatty acids on non-heme iron (iron not from meat) uptake and utilization in animals and have found that certain fatty acids, such as stearic acid, enhance, whereas other fatty acids, such as linoleic acid, retard iron absorption and utilization. We have expanded this research to include the use of cells in culture to determine the effects of different fatty acids on the cellular uptake and transport of iron. A cell line that mimics intestinal cell function was incubated under controlled conditions with media varying in iron content and fatty acid composition. A radioactive tracer of non-heme iron was used to measure inorganic iron uptake into and the transport of iron out of cells. Under conditions of low iron in the medium, stearic and palmitic acid, facilitated iron uptake and transport compared to linoleic acid. These findings indicate that specific saturated fatty acids promote iron uptake and use when iron is limiting. This information provides additional evidence that these saturated fatty acids may be the unknown factors in the diet that are responsible for boosting inorganic iron absorption and utilization when meat is consumed. This information is useful to dieticians who plan diets for individuals at risk for iron deficiency, including children and pregnant women.
Technical Abstract: The Caco-2 cell line was used as a model to determine if the type of fatty acid, unsaturated versus saturated, either suppresses or enhances the cellular acquisition (uptake) and transport of 59**Fe in the human intestine. Cells were cultured in either a lower iron (medium with 1% fetal bovine serum) or higher iron (medium with 10% fetal bovine serum) medium. Fatty acids (stearic acid, palmitic acid, linoleic acid or oleic acid) wer complexed to bovine serum albumin for supplementation; albumin was included as a control. The iron containing medium and/or fatty acids had varied effects on monolayer integrity and paracellular transport. Oleic, palmitic and stearic acids enhanced iron uptake to a greater extent in cells grown in a lower iron medium. The type of medium the cells were grown in did not influence the fatty acid effect on iron transport. Oleic acid slightly increased transport when compared with linoleic acid, but the enhancement was less than for stearic acid and palmitic acid. These data suggest that unsaturated versus saturated fatty acids affect iron uptake and transport differently in the human intestine. In addition, growth of the intestinal cells in medium varying in iron concentration is an important determinant in the influence of dietary fat on iron uptake and transport.