Why do some people who are deficient in a mineral have a negative response when introducing the mineral to their body, and why does potassium gluconate sometimes help ease the reaction? Does the potassium interfere and slow down progress with the minerals?

It comes down to genetics and genetic mutations. Some people have reactions due to their genetics and the genetic mutations they have. Others are lucky and don’t have reactions, but they can still be deficient.  

And then the potassium helps because once you start fixing the deficiencies and improving methylation, there’s an increase in the production of adrenaline and aldosterone. And then this can lead to low potassium. Aldosterone retains sodium and wastes potassium. So then supplementing with potassium can help counteract this.  But again, it depends on the person and their genetic profile.

And the potassium doesn't interfere with progress or interfere with the build up of the minerals. But the potassium shouldn't be taken at the exact same time as the minerals. Only 30-60 minutes later if necessary, if you have a reaction. Don't take the potassium at the exact same time as the iodine, selenium and molybdenum.