I should probably elaborate a little on baking soda.
Carbonate is a a key ion in the bodies pH balance. A deficiency of this ion changes the balance of hydrogen ions and thus changes the bodies pH. For example when a patient is too acidotic in hospital (which can happen for a number of different reasons), the treatment includes administering intravenous bicarbonate. This is common and happens in every intensive care unit on a daily basis. Carbonate balance (as all ions) is controlled by the kidneys.
My theory is that PFS affects the adrenals to some extent. The adrenals produce numerous steroids. A key steroid is aldosterone which acts on the kidneys to maintain water balance, ion balance and pH.