Numerous studies have shown that vegans consume insufficient calcium and vitamin D, not only owing to the absence of dairy products but also due to calcium bioavailability problems in plant-based diets [28]. Vitamin D insufficiency exacerbates calcium shortage further owing to impaired intestinal absorption.

Beer and Wine Isinglass, a gelatin-based substance derived from fish, is used as a clarifying agent in some beer and wine. Other non-vegan ingredients sometimes used are casein (from milk) and egg whites.

One of the primary reasons people quit veganism is health concerns. While veganism can be a healthy and sustainable diet when done correctly. Some individuals may experience inadequate nutrition and deficiencies due to a lack of knowledge about plant-based sources of essential nutrients.