Stewart's approach: Just a heresy or another lens into acid‐base physiology?

Strong ion difference: Questionable stewardship

“…This is a pivotal element of his approach. It is stated (equation 1, 4 equation 4.3.4, p. 57 6 ) that where K w is the ion product for water (see also Vasileiadis et al 1 ). Formally, this is correct.…”

“…A follow‐up 1 to a recent discussion of urinary acidity 2,3 focused on Stewarts's theory of ‘strong ion difference’ (SID) 4‐6 . The comments of Vasileiadis et al 1 warrant a reevaluation of Stewart's approach.…”

“…b b The recent comment 1 , that ‘common sense’ can be used, at least partly, to validate a scientific theory, is surprising. Common sense is a deceptive scientific guide informing us that the earth is flat, the sky is blue, and the light travels at infinite speed.…”

Strong ion difference: “ὃ οὐ κινούμενον κινεῖ”a or the unmoved physico‐chemical mover

“…One could, however, in promoting the pathophysiological priority of regulating [H + ] in the organism, refer to [SID] as a physiologically dependent variable, which is mobilized each time as a control mechanism, to serve this priority. In our previous paper, 11 we have also referred to the regulation of [Na]/[Cl] on either side of a semipermeable membrane, under the physico‐chemical constraints acting on the Donnan equilibrium, created by the distinct physiological composition of the separated fluids. It does not matter how one approaches this issue.…”

“…Although we have referred to this issue in our previous paper, 11 it would be appropriate to point out something: according to Prof. Bie, the food and the metabolic substrates present in it (the processing of which provides the energy as well as the structural elements that the organism needs) are treated as bearing (or creating during their catabolism) a specific proton load, which, as an independent variable, affects the acid‐base status of the organism. We will simply refer to the relevant Figure, 1 noting that in the case of “H + generating metabolism,” the final metabolic product appears to be a strong anion (Cl − , derived from the HCl dissociation, eventually excreted by the kidneys; we presume that the increased Cl − in urine might, most probably, lessen the urine [SID]), while in the case of “H + consuming metabolism” (ie alkalinizing effect), the final metabolic product appears to be a strong cation (K + , resulting from the dissociation of KOH, also excreted by the kidneys)!…”