Vegetable vs. animal based digestive enzymes
Animal based enzymes are produced from the stomachs and pancreas of pigs, cows, ox, etc. These are not recommended because:
1.) Animal enzymes work in an alkaline environment (pH above 7). These enzymes cannot survive and do their job of digestion in the acid pH of the stomach. So when you take these supplemental enzymes you are getting little to no therapeutic effect because they must pass through the stomach which they were never intended to do. In his book Enzyme Nutrition, Dr. Howell explains how vegetable based enzymes from aspergilli can tolerate acid from the stomach and predigest food so as to minimize the amount of enzymes being secreted (and used up) by your body.11 This is why we recommend this type of enzyme.
2.) Animal glands are toxic, laden with chemicals, drugs, and possibly even viruses, and parasites. For the same reasons we have previously discussed not eating animal products, also applies to taking animal based enzymes.