Some companies promote Krebs Cycle intermediates, consisting of calcium carbonate, citrate, malate, fumarate, glutarate, and succinate, however when comparing their 650 mg tabs to standard 500 mg calcium carbonate tabs, Dr. Ronald Roth found the absorption of calcium carbonate tablets somewhat superior for those with normal stomach acid levels or when taken with meals. In contrast to calcium carbonate, these so-called krebs cycle calcium formulations may also be less tolerated by those suffering from allergies, or a faulty immune system... Full Text