Fecal Excretion and Apparent Absorption of Macro elements

Fecal Excretion and Apparent Absorption of Macro elements 

The excretion of macro elements occurs via the feces, urine, and stveat, though the first two routes represent the main pathways. Typically, fecal excretion accounts for only 2-7% of the sodium intake. The apparent absorption rate of sodium has been found to vary between 93 and 98%. On average, the apparent absorption rate of macro elements by ovolactovegetarians is lower 

Element (w) n(m) Excretion by feces % Apparent absorption rate, %  

Fecal excretion of the macro elements was, on average, 3% for sodium, 19% for potassium, 28% for ash, 36% for phosphorus, 69% for magnesium, and 84% for calcium. The apparent absorption rate is negatively correlated with fecal excretion of the macro elements. The real absorption rate of all these elements is higher than the apparent absorption rate, mainly due to the salivary, biliary and pancreatic excretion of absorbed macro elements into the intestine. 

Macro element Intake Measured by the Duplicate Portion Technique and the Basket 

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