Since the ancient time milk and its products are serving as a central component of the human diet because of their nutrient rich content and variegated functional bioactive molecules. Nonetheless, the advent of lactose intolerance, milk allergies, and environmental sustainability factors has expedited the transition from conventional milk derived from animal sources to the alternative milk derived from plants and cereals. This review article critically analyses the ingredients of milk obtained from Lactalia species, such as, cow, Buffalo, goat, and camel, and the milk processed from plants, for e.g., soy milk, almond milk, oat milk, rice milk, coconut milk, and millet milk, in association to its nutritional factors, fermentation potential, health benefits, and possible risks. Plant-based milk especially millet milk is a new and sustainable source of high-quality protein (gluten-free), fiber, and slowly digested carbohydrates, which can help in regulating glucose and cholesterol in the bloodstream; however, it amino acids profile may require complementation to match animal-derived proteins. This review focuses on the mechanisms—such as lipid metabolism, calcium absorption, gut microbiota modification, and antioxidant effects—that underlie the health-promoting qualities of milk and its fermented variants. It also covers possible negative consequences resulting from different biological mechanisms, including casein allergy as an immunological reaction to milk proteins, lactose intolerance as a result of decreased lactase activity, and possible hormonal modulation linked to phytoestrogens in some plant-based milk substitutes. Fermentation is highlighted as an integral step with increased benefits for digestibility due to the reduction in the level of anti-nutrients, improvement in the level of probiotics, and overall functionality improvement for both animal and plant sources of milk. Moreover, the mechanisms pertaining to the diseases are examined in detail with the identification of potential milk constituents responsible for the development and prevention of cardiovascular diseases, osteoporosis, and cancers. Lastly, the sustainability issues for milk products are examined with millet milk being identified as the novel renewable milk source. In conclusion, this review contains the throughgoing information set pertaining to the availability, tolerance potential, and environment effects, both for the animal and plant-based of milks including their fermented forms.
Rathee et al. (Sun,) studied this question.