Potentially Harmful Effects of Magnesium Stearate
Magnesium stearate is formed by adding a magnesium ion to stearic acid. The compound has lubricating properties, which is why it's often used in the making of supplements, as it allows the machinery to run faster and smoother, and prevents the pills or capsules from sticking to each other.
However, previous research has shown that stearic acid suppresses T cells—your natural killer cells—which are a key component of your immune systemi. According to that study, stearic acid causes the collapse of cell membrane integrity—an effect that was found to be time and dose dependent—which, ultimately, can destroy cell function.
Naturally, when you take vitamins and other supplements, you do it with the idea of strengthening your immune system. However, if you take supplements containing magnesium stearate, you could end up doing the exact opposite as you're actually consuming chalk-like substance with each dose you take.
This filler also stimulates your gut to form a biofilm. You frequently see biofilms when you lift the lid of your toilet reservoir. Biofilms are a sort of sludge lining that acts as an effective barrier to the absorption of not only that particular vitamin but ALL the nutrients you'd normally get from food sources as well.
This is of particular concern for anyone with impaired digestion, which in today's world includes the vast majority of Americans, due to poor dietary habits.
In my view, this side effect alone is a major reason for focusing on nutritional foods, or, if you're taking a supplement, making sure it's a high quality, natural food-based supplement that does not include potentially harmful fillers and additives such as magnesium stearate.
Article from Dr. Mercola June 23, 2012