The contribution of terrestrial animal source food to healthy diets for improved nutrition and health outcomes

How was this report designed? 

In April 2023, the Food and Agriculture Organization of the United Nations (FAO) published a report titled “The contribution of terrestrial animal source food to healthy diets for improved nutrition and health outcomes - An evidence and policy overview on the state of the knowledge and gaps”.  This report, produced with the assistance of a multidisciplinary committee and external reviewers, synthesizes the evidence on the effects of terrestrial animal source foods (TASF) on human nutrition and health. In addition to providing a robust systematic review of over 500 studies on the impacts of TASF on health, the report includes an analysis of some 250 current policy documents and dietary guidelines.

What is a terrestrial animal source food (TASF)?

In this report, the FAO defines TASF as all food products obtained from terrestrial animals, including animal production and farming as well as hunting. Categories of TASF include eggs and egg products, milk and dairy products, meat and meat products, food from hunting and wildlife farming, and insect and insect products.

Nutrient composition and value

This report underscores that TASF contain several macronutrients, micronutrients, and bioactive compounds that have unique and important contributions to human health. In fact, they can provide a large proportion of the recommended nutrient intake across the lifespan. The intake of TASF has also been shown to counteract the effects of the anti-nutrients contained in plant-based foods.

The vital contributions of TASF, as a part of a healthy diet, towards nutrition and health are highlighted, as TASF contribute critical nutrients that play a key role in ensuring food health: 

• High-quality, digestible proteins, that contain important amino acids, such as indispensable (essential) amino acids and some with roles in human health (such as carnitines, creatine, taurine, etc.);
• Long-chain fatty acids and ratios of fatty acids that are important for human health;
• Various critical micronutrients in bioavailable forms, including vitamins, such as B12, and minerals, such as the iron in meat or the calcium in milk.

Specifically, milk and dairy products are described as nutrient-dense foods that not only contain high-quality protein (primarily casein and whey), but a wide range of micronutrients such as highly bioavailable calcium, phosphorous, potassium, magnesium, vitamin B complex, as well as zinc and selenium. Additionally, dairy’s unique natural food matrix includes compounds that enhance its digestion and absorption, such as β-lactoglobulin which may enhance vitamin A absorption, casein which acts as a carrier for calcium and phosphorus, as well as lactoferrin which binds iron and play a key role in immunity. 

Effects of TASF on health and nutrition over the life course 

Overall, the evidence suggests that TASF in the context of a healthy and balanced diet, can contribute to improved nutrition, health, and cognition. In fact, data supports that TASF intakes at appropriate levels benefit several health outcomes, including reducing the levels of both infectious and noncommunicable diseases, across the lifespan. 

Much of the evidence on the role of TASF across the lifespan pertains to milk and dairy products, which have been more thoroughly researched: 

• Milk and dairy consumption during pregnancy promote healthy weight of infants at birth and may also benefit birth length and foetal head circumference, with some evidence suggesting greater effects if the intervention starts in the first trimester;
• Infants and young children have limited gastric capacity and consequently, may need nutrient-dense, easily absorbable foods (such as TASF) as a part of complementary feeding to support growth and development;
• In school-age children and adolescents, dairy intake was linked to increased height and lower risks of obesity/overweight;
• In adults, findings largely indicate that consumption of milk and yogurt reduces the risk of all-cause mortality, hypertension, stroke, type 2 diabetes, colorectal cancer, breast cancer, obesity, osteoporosis, and fractures;
• Preliminary evidence suggests that milk and dairy products may play a role in mitigating sarcopenia, fractures, frailty, dementia, and Alzheimer’s disease.

As a consequence, the FAO encourages governments of various countries to update national dietary guidelines to reflect the important contributions of TASF, in appropriate quantities, at all stages of life to mitigate the risks of micronutrient deficiencies and the burden of noncommunicable diseases.

Emerging Topics

Despite being increasingly present in the marketplace, TASF alternatives and imitation products, including plant-based foods and cell-cultured meat, remain a novel topic in regards to health. However, this report states that:

• “Evidence suggests that these products cannot replace TASF in terms of nutritional composition.”
• “Plant-based meat alternatives that are widely available on the market have been found to be deficient in some essential nutrients and high in saturated fat, sodium and sugar.”

The consumption of insects as a source of nutrients is also addressed, though cultural barriers and individual preferences reduce acceptability. Moreover, concerns with food safety must be considered as the scale of insect farming increases.

On the topic of sustainability, in their report, the FAO notes that assessments of TASF in healthy diets need to consider factors such as regional variations in natural resources, background health and nutrition as well as people’s nutritional needs over the lifespan, the availability and accessibility of foods, and the ecosystem roles of the livestock. Moreover, emerging evidence on sustainability of diets shows that greater diversity of species in the diet (plant-based foods, TASF, and aquatic food) contributes to higher nutrient adequacy.