Discussions regarding the role of animal-source foods in healthy and environmentally sustainable diets are often polarizing. To bring clarity to this important topic, Beal (Global Alliance for Improved Nutrition) and co-authors critically reviewed the evidence related to the health benefits and risks of animal-source foods, environmental benefits and risk, and the role of alternative proteins and protein-rich foods. Published in The Journal of Nutrition, the authors conclude that the amount and type of animal-source foods that is healthy and environmentally sustainable will depend on the local context and health priorities.
Animal-source foods include meat, fish, eggs, and dairy, whereas plant-source foods include all foods derived from plants. Higher income countries tend to consume the most amounts of animal-source foods compared to lower income countries such as South Asia and Sub-Saharan Africa. Animal-source foods can have both positive and negative health consequences. Excess consumption of processed meat, red meat, and saturated fat has been implicated in increased risk of diet-related noncommunicable diseases. Similarly, environmental scientists have noted that production of animal-source foods can have substantial negative environmental impacts related to land use, soil health, water quantity and quality, biodiversity, and climate change. Animal-source foods are rich in nutrients that are commonly lacking in plant-source foods, and consuming appropriate quantities in the context of a balanced diet contributes to diet quality and nutrition security. Increasing consumption of animal-source foods in low- and middle-income countries is an important strategy for addressing micronutrient deficiencies and other forms of undernutrition. Thus, these synergies and trade-offs between nutritional and environmental aspects of animal-source foods are important considerations.
It is widely recognized that animal- and plant-source foods have complimentary nutrient profiles. Whereas animal-source foods provide an abundance of bioavailable nutrients such as iron, zinc, calcium, vitamins B12 and D, choline, and high-quality protein and omega-3 fatty acids, the array of nutrients in plant-source foods is often lacking. Although the production of animal-source foods can negatively impact the environment when produced inappropriately, careful integration of cropping systems and livestock can improve environmental outcomes and overall efficiency, while improving food security and nutrition for populations worldwide.
Regarding animal-source foods, there is no one-size-fits all approach when it comes to both health and environmental sustainability. Rather, it depends on the local context and health priorities that will inevitably change over time as populations develop; as nutritional concerns evolve; and as alternative foods from new technologies become viable, sustainable, affordable, and accessible. Populations consuming high levels of meat would generally benefit from reduced consumption. In contrast, those who consume low levels of animal-source foods and at increased risk of undernutrition would generally benefit from increased consumption.
Efforts to increase or decrease animal-source food consumption should consider the nutritional and environmental needs and risks in the local context, and importantly, involve local stakeholders impacted by policy change. All animal-source foods have a role to play in certain contexts to optimize the use of the various ecological conditions and accommodate diverse cultural traditions across the globe. Ruminant livestock and dairy have the potential to be sustainably produced where rangelands make up a large portion of the available land, whereas aquatic animal-source foods could be prioritized in areas with access to large bodies of fresh or salt water. At the individual level, healthy and sustainable diets can take many forms, ranging from plant-exclusive diets to those rich in a diversity of animal- and plant-source foods.
Beal T, Gardner CD, Herrero M, Iannotti LL, Merbold L, Nordhagen, S, Mottet A. Friend or Foe? The Role of Animal-Source Foods in Healthy and Environmentally Sustainable Diets. The Journal of Nutrition, Volume 153, Issue 2, February 2023, Pages 409-425, doi.org/10.1016/j.tjnut.2022.10.016.
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