Potassium (K) organic
anion salts, such as
potassium citrate or
potassium malate in plant foods, may counteract low-grade
metabolic acidosis induced by western diets, but little is known about the effect of other minor plant
anions. Effects of K
salts (
chloride,
citrate, galacturonate or
tartrate) were thus studied on the
mineral balance and digestive fermentations in groups of 6-week-old rats adapted to an acidogenic/5 %
inulin diet. In all diet groups, substantial amounts of
lactate and
succinate were present in the caecum, besides SCFA. SCFA were poorly affected by K
salts conditions. The KCl-supplemented diet elicited an accumulation of
lactate in the caecum; whereas the
lactate caecal pool was low in rats fed the
potassium tartrate-supplemented (K TAR) diet. A fraction of
tartrate (around 50 %) was recovered in urine of rats fed the K TAR diet.
Potassium citrate and
potassium galacturonate diets exerted a marked alkalinizing effect on urine pH and promoted a notable citraturia (around 0.5 micro mol/24 h). All the K organic
anion salts counteracted Ca and Mg hyperexcretion in urine, especially
potassium tartrate as to magnesuria. The present findings indicate that K
salts of unabsorbed organic
anions exert alkalinizing effects when metabolizable in the large intestine, even if K and finally available
anions (likely SCFA) are not simultaneously bioavailable. Whether this observation is also relevant for a fraction of SCFA arising from dietary fibre breakdown (which represents the major organic
anions absorbed in the digestive tract in man) deserves further investigation.