What you must remember is that digestion can be affected by Acidity or too much Alkalinity. Gas occurs also as part of the intestinal flora breaking down the food. Your body may just be producing more than usual because your flora is more excited and flourishing etc working more efficiently.
Be careful which Bi-Carb you put in your Vitamin C as alot of them have Aluminium. If you take Silica this will make Aluminim into a water soluble form which cannot break the blood/brain barrier. Silica is expensive and I've found most places dosages are poor. I've found Bamboo Extract to have much larger amounts in the region of 250mg
What you must remember is that digestion can be affected by Acidity or too much Alkalinity. Gas occurs also as part of the intestinal flora breaking down the food. Your body may just be producing more than usual because your flora is more excited and flourishing etc working more efficiently.