Human health

Animal source foods are advantageous for populations with elevated needs

Benefiting populations with elevated needs

The global food security challenge is less about providing sufficient food quantities and calories than about ensuring an adequate supply of essential nutrients, including quality protein and various minerals and vitamins. Meat, dairy, eggs, fish, and seafood offer convenient and comprehensive nutrient packages that support both healthy growth and aging. For pregnant and lactating women, infants, and young children, they provide nutrients that are essential for proper development, such as iron, vitamin A, zinc, and calcium. In older adults, they help combat undernutrition, functional impairment, cognitive decline, and sarcopenia. Adequate protein intake, especially from animal sources, becomes more critical with age. Additionally, animal source foods are valuable for individuals with metabolic health issues. Furthermore, intervention trials demonstrate that incorporating animal source foods into diets can prevent deficiencies, support growth, development, and overall health in various population groups.

This subsection addresses the following five questions:

What is the global food security challenge and how do animal source foods fit in?
Which vulnerable populations would benefit from more animal-sourced foods, and how?
How are animal-sourced foods associated with nutritional adequacy?
What do intervention studies tell us about the nutritional contributions of animal-sourced foods?

What is the global food security challenge and how do animal-sourced foods fit in?

Many populations, including those in high-income countries, struggle to meet recommendations for essential micronutrients. This challenge underscores the importance of focusing on nutrient quality rather than merely ensuring sufficient food quantities or caloric intake.

Animal-sourced foods are crucial in addressing several of these deficiencies, as they provide highly bioavailable forms of priority nutrients that plant-based solutions often cannot fully supply. They thus play a key role in supporting healthy growth and aging, particularly in settings where alternative dietary options may be inadequate.

Even with optimized plant-based diets, certain micronutrient needs are frequently unmet, whereas foods like eggs and milk offer comprehensive packages of essential nutrients and bioactive compounds critical for development, also in low-resource populations. Even in the US, animal source foods generate adequate dietary patterns at the lowest cost.

Although the consumption of animal-sourced foods among children and adolescents has increased globally, Sub-Saharan Africa continues to face deficiencies in iron, zinc, iodine, folate, and vitamins A, B12, and D. In high-income countries, growing advocacy to reduce the consumption of animal-sourced foods raises concerns about nutrient adequacy, especially for vulnerable groups with elevated needs.

Which vulnerable populations would benefit from more animal-sourced foods, and how?

Animal-sourced foods are essential for addressing the nutritional needs of vulnerable populations, including pregnant and lactating women, infants, children, adolescents, older adults, and individuals with metabolic health challenges. These groups are particularly at risk for deficiencies in critical nutrients like iron, zinc, calcium, vitamin B12, and vitamin D, which animal-sourced foods provide in highly bioavailable forms.

Pregnant and lactating women rely on nutrient-rich diets to support fetal development and maternal health. For infants and young children, complementary foods incorporating meat, poultry, fish, or eggs are crucial for healthy growth and cognitive development. These foods are the top sources of key micronutrients which are difficult to obtain in adequate amounts from plant-based diets alone.

In older adults, animal-sourced foods play a key role in healthy aging by addressing undernutrition, reducing risks of sarcopenia, functional impairment, and cognitive decline, and supporting overall vitality. High-quality protein from animal-sourced foods is especially important for maintaining muscle mass, while foods like oily fish, eggs, and liver provide essential vitamin D and B12, which become harder to obtain as the body ages.

For metabolically unhealthy individuals, such as those with obesity or cardiometabolic diseases, animal-sourced foods offer superior protein bioavailability and help support improved metabolic and inflammatory responses. Meeting the nutritional needs of these vulnerable groups through animal-sourced foods not only enhances individual health but also reduces healthcare costs associated with diet-related deficiencies and chronic diseases.

Further reading (summary of the scientific literature):

Pregnant and lactating women and young populations

Pregnant and lactating women, infants, children, and adolescents deserve particular attention as they often suffer from suboptimal micronutrient levels [see elsewhere]. In case nutrient adequacy is not met, consequences can be severe for individuals on (strict) vegetarian diets, as documented by clinical case reports for both (very) young individuals [see elsewhere for a literature overview] and adults [Hines 1966; Carmel 1982; Milea et al. 2000; Brocadello et al. 2007; De Rosa et al. 2012; Noh et al. 2013; Førland & Lindberg 2015; Hsu et al. 2015; Nimmagadda et al. 2018; Bachmeyer et al. 2019].

Because appropriate feeding in early childhood is critical for health throughout the course of life, 'complementary foods should be rich in nutrients and given in adequate amounts [so that] young children should receive a variety of foods including meat, poultry, fish or eggs as often as possible' [WHO 2011]. In young children, the top food sources of commonly lacking micronutrients in low- and middle-income countries are all animal sourced: iron (chicken liver), vitamin A (ruminant liver), zinc (ruminant meat or small dried fish), folate (chicken liver), vitamin B12 (ruminant liver), and calcium (small fish) [Beal et al. 2021; White et al. 2021]. For example, compared with ruminant liver, children 6–23 months would need more than 100 times the portion size of pulses to achieve a similar level of adequacy of these critical micronutrients [Beal et al. 2021; White et al. 2021].

Older adults and healthy aging

In older adults, the role of animal source foods in healthy aging is of particular importance and more research is needed to weigh potential benefits against harms [Kouvari et al. 2016]. Recent studies suggest that a higher intake of animal source foods contributes to addressing the wide prevalence of undernutrition [Borkent et al. 2020], functional impairment [Yuan et al. 2020; Miyazaki et al. 2023], cognitive decline [Gao et al. 2022; Anderson & Alpass et al. 2024], and sarcopenia [Rondanelli et al. 2015], and may parallel lower mortality [Meroño et al. 2021; Kurata et al. 2023]. In a Japanese cohort, the consumption of milk in middle age has been associated with a lower prevalence of frailty later in life for men (but not for women) [Hong et al. 2024]. Fish consumption is associated with a lower risk of cognitive impairment and decline in a dose-response manner [Godos et al. 2024]. Frequent consumption of eggs has been related to a lower risk of Alzheimer’s dementia, possibly based on a higher intake of choline [Pan et al. 2024].

Low intake of protein is of particular concern in older populations [Langsetmo et al. 2020; Borkent et al. 2023], whereby the intake of animal protein over plant protein seems favourable to combat sarcopenia [Campbell et al. 2023]. A vegan diet should not be recommended without protein supplementation as it may lead to lower muscle mass and a higher risk for loss of physical function due to sarcopenia [Domić et al. 2022]. For more on the importance of protein quality when comparing animal source foods with plants, see elsewhere. The Irish Food Safety Authority specifically recommends animal source foods and, to a lesser extent, legumes and nuts to supply older adults with sufficient high-quality protein [FSA Ireland 2021]. Avoiding animal source foods increases the risk of inadequate protein intake, as strategies to improve the anabolic properties of plant-based foods are often not feasible for older adults [Domić et al. 2022].

In addition, elderly are more reliant on the few dietary sources of vitamin D (oily fish, eggs, liver, butter, meat), since their capacity to form 7-dehydrocholesterol in the skin is decreasing with advancing age [Bender 2002]. They especially benefit from high-quality protein supply [Bauer et al. 2013; Paddon-Jones et al. 2015; Medonça et al. 2020], which is more complicated when using plants only [Berrazaga et al. 2019]. Aging populations also become more vulnerable to B12 deficiency [Green et al. 2017]. Moreover, it is known that higher levels of total cholesterol and iron serve as biomarkers for longevity in Swedish centenarians [Murata et al. 2023].

The metabolically unhealthy

Finally, the metabolically unhealthy are an important target population group that would benefit from sufficient intake of animal source foods. They suffer from inflammatory conditions and perturbed endocrine responses (in particular hyperinsulinemia), which can at least be partially mediated via higher protein bioavailability [cf. Wolfe et al. 2008]. In Ireland, for instance, >80% of older adults are abdominally obese, while >50% are at high risk of cardiometabolic disease [FSA Ireland 2021]. The societal impact is gigantic, also because of the very high costs related to the treatment of such diseases.

How are animal-sourced foods associated with nutritional adequacy?

Very low intake of animal-sourced foods among vulnerable populations is often linked to decreased nutrient intake and compromised health. In contrast, various studies highlight the associations between the consumption of animal-sourced foods and improved nutrient intake and health outcomes in different groups with elevated needs.

Higher meat consumption can be linked to reduced anaemia among elderly, as well as decreased stunting in young children. Dairy consumption is, for instance, associated with an improved status of B-vitamin and vitamin-D biomarkers in older adults. Intake of fish is linked to improved nutritional outcomes, including a better vitamin D status in maternal diets and children's diets. Egg consumption is associated with higher intake of various nutrients, including choline. It is important to underline, however, that such associational data is not necessarily proof of causal relationships.

What do intervention studies tell us about the nutritional contributions of animal-sourced foods?

Intervention trials have shown that the incorporation of animal source foods in the diet can enhance nutritional resilience across different life stages, especially when the baseline intake is low. Their administration can help to improve the physical, behavioural, and cognitive outcomes of children, mitigate deficiencies in young females, enhance muscle synthesis in young men, and tackle poor bone health and sarcopenia in older adults.

In Kenia, the administration of meat improved the performance of school children. Seafood, rich in long-chain omega-3 fatty acids, protein, and many other nutrients, contributes to improved responses in risk factors for chronic disease and has potential to reduce inflammation. Dairy products have demonstrated various health benefits, including improved vitamin K2 status, enhanced cognitive outcomes in school children in Ghana, and better bone health in various young and adult population groups. In rural Ecuador, it has been shown that eggs contribute to a reduction in stunting and improved plasma levels of essential nutrients like choline and DHA in infants.

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