From what I've been reading, digestive enzyme supplements are not New Age, but are part of the very New Age-friendly U.S. supplement market.
Scientific support for these supplements is lacking and some the side effects to taking them are diarrhea, nausea and intestinal cramping.
For those who are unfamiliar with digestive enzymes, they aid in the chemical breakdown of food into smaller, absorbable components. The human body produces a variety of enzymes to break down food except in the case of some plant substances. These substances are more popularly known as dietary fiber which is a nondigestible substance whose health benefits derive from its inability to be absorbed.
" . . . The term 'digestive enzymes' is a catchall that includes a variety of compounds with different purposes—similar to 'vitamins' or 'probiotics'," writes Tamara Duker Freuman, MS, RD, CDN, a registered dietitian specializing in digestive disorders, Celiac Disease and food intolerances, for US News Health.
"Just as we can't draw sweeping generalizations about whether taking vitamins is beneficial (it would depend on which vitamin in which individual), so too with digestive enzymes: It depends on which enzyme and in what population."
She goes on to describe a handful of circumstances in which taking digestive enzymes is necessary. One of these is for pancreatic insufficiency, a condition in which the pancreas is unable to produce normal amounts of digestive enzymes. This condition is often found in people with cystic fibrosis. It is treated with prescription enzymes that are specially coated to protect them from being absorbed before they reach the intestines.
People suffering from lactose intolerance, which is the inability to break down and absorb milk sugar, are also prescribed lactose enzyme supplements.
People following high fiber diets, such as vegans and vegetarians who consume mostly beans and vegetables, will take digestive enzymes to help them to tolerate this diet.
Beyond these few circumstances, however, the benefits of supplemental digestive enzymes "become murkier," Freuman writes.
"The notion that large swaths of the population suffer from 'enzyme deficiencies' is advanced by some in the health arena—and particularly so by profit-oriented marketers of digestive enzyme supplements. In fact, apart from lactase, overt digestive enzyme deficiencies are rare, and they generally occur in malnourished, ill individuals—not in gassy but otherwise well people."