Animal-based foods in the human diet

Abstract

The role of animal-source foods (ASFs) in the human diet remains one of the most complex and controversial debates in nutritional science. This article synthesizes historical, epidemiological, and experimental evidence regarding their impact on health. Archaeology and evolutionary biology demonstrate that ASFs were central to the human diet for millions of years, providing essential nutrients—such as vitamin B12, heme iron, retinol, and long-chain omega-3 fatty acids—whose bioavailability is not replicated by plant-based sources. However, modern controversy stems from epidemiological studies and clinical trials characterized by methodological limitations and frequent conflicts of interest.
The evidence is most consistent regarding the risks associated with processed meats—classified as carcinogens by the IARC and linked to increased cardiovascular risk—whereas findings for unprocessed red meat are less conclusive. Dairy products present a "nutritional paradox," showing inverse associations with type 2 diabetes and hypertension, likely explained by the food matrix. Fish emerges as a particularly beneficial source of EPA and DHA, and eggs have been rehabilitated as important foods for neurodevelopment and cognitive health. The conclusion is that ASFs fulfill critical nutritional roles, yet their effects depend on the specific food type, preparation method, production system, and overall dietary pattern. Universal recommendations to simply consume "more" or "less" ASF lack robust support; the primary risks differ between high-income countries (excessive processed meat intake) and low-income countries (micronutrient deficiencies). Dietary patterns associated with longevity—such as the Mediterranean and traditional Japanese diets—include moderate amounts of unprocessed ASFs within a framework rich in vegetables and fiber. Future research points toward multi-omic approaches integrating genetics, microbiota, and metabolism to better understand the interplay between food and health.