Animal protein on stunting prevention: A narrative review

Stunting has been a global problem even though adult and child obesity has not been resolved yet. Various approaches have been carried out in the nutrition field and others. The Government of Indonesia recently established an effort on stunting reduction acceleration through its Ministry of Health. The accessibility to healthy food, including sources of animal protein, become one of its strategies. This study aims to explore the efforts evolved in stunting reduction, especially regarding access, availability, and provision of animal-based products to supply the source of animal protein. The review was done narratively from scientific sources such as Pubmed and Scopus. The 193 articles were derived from the search applying keywords “protein”, “policy”, “malnutrition”, and “stunting”, and their combination using the Boolean operator. There are 193 studies screened resulting in 159 studies excluded from 3 stages, and 40 studies in the review. The articles were then reviewed systematically using Covidence, a web-based systematic literature review tool. The study results show that the availability of animal products is much better, but not yet supported by good distribution and an increase in accessibility. The government has supported this with sufficient policy, however, more thorough action is still needed. Thus, sustainable animal farming is needed as one of the strategies to provide a sufficient quantity of animal products of optimal quality to prevent malnutrition, especially stunting.


Introduction
Stunting has been a health problem that leads to various consequences in the future, not only for the children suffering from it but also for the community and the nation from a wider perspective.Stunting has become a global burden.About 22% of under-five children suffered from this globally [1], while in Asia, 21,8% are suffering from stunting [1].Indonesia is also suffering from stunting for several years.The prevalence of stunting and severely stunting keeps above 30% (36,8%, 35,7%, and 37,2% for the years 2007, 2010, and 2013 respectively) [2][3][4].Fortunately, in the year 2018, the prevalence of stunting decreased to 30,8% [5].However, the number is still very high and the trend still sloping.
Although the number of stunting in children is still high, the problem of overweight and obesity has not been solved yet.About 5,7% of under-five children are suffering from overweight in 2020, the total number is 6 million higher than the year 2000 [1].In the meantime, about 5% of children in Southeast Asia region fall in the category of overweight [6].Moreover, overweight adults globally still reach a prevalence of 39 % [7].The number said a lot that the strive to press the prevalence has not succeeded yet.
Multi-sectoral policies have been constructed and implemented to end the problems of malnutrition.However, a more comprehensive approach is still needed [8].Until recently, the double burden of malnutrition, particularly in Indonesia, is still occurring (under-five stunting in 2018: 30,8%; children overweight and obese in 2018: 8%; adults with overweight and obesity: 35,4% with the female majority [5]), which has not shown to be declining soon and still far from target (less than 30% for under-five stunting), as shown also for adult overweight and obesity (targeting for prevalence less than 16%) [3][4][5].It is an opportunity to investigate further for a more comprehensive approach to push the high prevalence down, especially in Indonesia.
Until recently, the food consumption and repetitive infection are tend to be the direct cause of malnutrition.Protein is one of macronutrient which essential for growth, and one comes from animal (rather than from plant) is believed to be more beneficial for vertical growth albeit the conflicting evidence.Animal-source protein are more complete in essential amino acids and usually carry more energy per hundred grams.Plant-source protein often lacks on sulphur amino acids, which also essential for protein construction in the body [9].However, animal-source protein also tend to be more expensive compare with plant-source protein.Therefore, some programs in overcoming stunting usually include animal-source protein in its supplemental meals provided for the children and/or the family.
Stunting needs comprehensive and multi-sectoral solutions.Global Nutrition Report 2022 has found that the most prominent type of nutrition action fall within the category of 'Leadership and governance'.This type of action needs high political leadership and good governance as foundations for policies to be effective [10].Various approaches have been carried out in the nutrition field and others.The Government of Indonesia recently established an effort on stunting reduction acceleration through its Ministry of Health.The accessibility to healthy food, including sources of animal protein, become one of its strategies.However, the policies have not yet been quite effective until recently, resulting in the number of stunting which is still very high.This study aims to explore the efforts evolved in stunting reduction, especially regarding access, availability, and provision of animal-based products to supply the source of animal protein.

Materials and methods
The review was done narratively from scientific sources such as Pubmed and Scopus.The 193 articles published in the last twenty years (2003-2023) were derived from the search applying keywords "protein", "policy", "malnutrition", and "stunting", and their combination using the Boolean operator.The final search strategy which results in the highest number of articles is "protein" AND "policy" AND ("malnutrition" OR "stunting").
The authors also apply the MeSH terms in searching articles using the Pubmed search engine.There are 193 studies screened resulting in 159 studies excluded from 3 stages, and 40 studies in the review.The articles were then reviewed systematically using Covidence, a web-based systematic literature review tool, starting from its title and abstract and then followed by reviewing full text if relevant to the research question.Since the study was a narrative review, the content of the articles included in the study is recorded for their relevancies to the research questions and used to construct a set of information to answer the research question.

Results and discussion
Stunting is the nutritional status where the height-for-age of a child falls below the -2SD based on the WHO Growth Standard chart regarding his age and sex.Stunting is chronic in characteristic and may result from low nutritional status which lasts for more than six months.The issue of growth faltering receives the majority of attention during the first "1,000 days" of a child's life, while the focus diminishes significantly when it comes to toddlers and young preschoolers.This emphasis on the early stages is justified as it is during this time that the most rapid growth and changes in body composition occur, along with the important transition from breastfeeding to complementary feeds and eventually to the family/adult diet.Additionally, there is a prevailing belief that if a child becomes stunted or wasted within the first two years, it is unlikely that they can fully recover from these conditions.[11] Identifying undernutrition, particularly the condition of stunting, at an early stage is crucial as it allows for proactive intervention and the prompt implementation of preventive measures, especially during the formative years of childhood.[12] Macronutrients as well as micronutrients tend to have a balanced role in the prevention of stunting.On the other hand, many studies show that protein consumption, especially which is animal-sourced, plays a major role in the vertical growth of children.Thus its inadequacy is often related to the large numbers of stunted children.Numerous studies have delved into the correlation between animal-source foods (ASF) and the growth of children.A comprehensive analysis of data conducted from 46 low-and middle-income countries, encompassing 112,553 children aged 6 to 23 months, revealed strong links between the consumption of ASF and child growth.These findings suggest that the high-quality proteins and micronutrients (such as zinc, iron, iodine, essential fatty acids, vitamin B12, and other nutrients) readily available in ASF may play a highly important role in promoting growth.Additionally, the concentrated form of these nutrients in ASF provides a significant advantage for young children with limited stomach capacity.Nonetheless, several studies, including both observational research and randomized controlled trials utilizing food supplements, have yielded mixed or inconclusive results when examining the relationship between ASF consumption and growth.Recent systematic reviews and meta-analyses have shed light on the challenges faced in this area.Several factors such as insignificant effect sizes, significant variations in study designs, inconsistent outcomes, and variability in sample characteristics have all contributed to a decrease in the quality of evidence linking ASF consumption to improved growth.[13] Nevertheless, ASF is still believed to be related to growth, especially height, in under-five children.
The process of child growth is complex and dynamic, and changes in growth due to dietary modifications do not happen immediately, but rather over a period of months or even years.While many studies focus on children under 24 months old, improvements in growth can still occur long after the 1000 days.Additionally, there is still much to discover about the specific periods when certain nutrients are most critical for consumption.The impact of diet on early life epigenetic changes, along with other factors, may have long-lasting effects on child growth, health, and development.However, despite a few exceptions, studies on food supplements rarely compare the relative benefits of different animalsource foods in the same context.The importance of studying whole foods has also been emphasized, as the non-protein components of animal-source foods may also influence growth outcomes.Moreover, it is crucial to consider relevant household and child factors when assessing growth outcomes [13].
Another example of ASF's role in growth improvement among under-five children is also found in Nepal.In a rural area of Nepal, a previous intervention aimed at developing the community resulted in an increase in the consumption of Animal Source Food (ASF) and overall improved growth among young children.Surprisingly, these positive changes occurred even though the intervention did not specifically include any nutrition education or focus on the child's diet or health.Building on this success, a new intervention was introduced which included a nutrition education component that targeted children and women of child-bearing age.This education program aimed to promote diversity in diet and encourage the consumption of ASF.Additionally, the new intervention provided training in livestock management [13].
The efforts to prevent stunting should not only reach children under five years of age who are highly susceptible to malnutrition but also mothers who want a baby that does not wish to fall into stunting in the future.One of the efforts is the provision of additional food and supplementation.Some studies have found that supplementation greatly increases the weight of the birth, but has no impact on the length of the birth or the circumference of the head.In addition, a recent analysis of the comparison of lipids with grain-based supplement foods in the treatment of moderate waste concluded that "more research is needed to study the advantages of ready-to-use dairy products".[14] Unfortunately, it is still necessary to evaluate the effects of animal protein supplements during pregnancy, premature babies, and full-term infants/children, as well as the assessment of linear growth after birth, and systematic consideration of variability based on several fundamental characteristics.
It has been shown that supplementation during pregnancy and infancy/childhood has a positive effect on child weight, food-based supplementation during childhood also improves the weight-for-age scores and reduces the risk of retardation.However, it has been shown that only the supplementation of animalsource foods during childhood/infancy, not of formulas, increases height in age.It is important to point out that there is a lack of high-quality studies on the linear growth results, making it difficult to draw definitive conclusions.However, this does not diminish the benefits of balanced supplements, including proteins and energy, in restoring the health of children with low nutrition.In addition, the potential benefits of supplementation in cognitive outcomes should be assessed separately.[14] The World Health Organization (WHO) continues to support the use of animal proteins in nutritional supplements to address malnutrition.Despite this, further research is needed to establish solid evidence of significant benefits beyond weight gain.Thus, future policy-related studies should give priority to investigating these potential benefits.
The problem of malnutrition, particularly stunting, cannot be separated from the issue of food insecurity.The lack of accessibility and availability of food is directly related to the consumption of food, which leads to poor nutritional status.Food insecurity is a complex issue that affects the world on a global scale.To address this problem, we need to simultaneously achieve various objectives.Firstly, we must ensure that enough nutritious and diverse food is produced and made available to all individuals.Additionally, these individuals must have the means to physically and economically access this food.It is important to note that food security is closely connected to poverty alleviation and overall health and well-being.However, it is crucial to acknowledge that agricultural production can have negative impacts on natural vegetation and biodiversity, as well as contribute to greenhouse gas emissions.This creates a conflict with other Sustainable Development Goals, such as protecting terrestrial ecosystems and combatting climate change.Therefore, it is essential to understand the synergies and trade-offs between these different sustainability objectives and how they can be influenced by policy interventions.Scholars and policymakers have been actively discussing and researching these topics on a global scale [15].
Animals and plants are important sources of certain vitamins, meat is a good source of B12 and green leaf vegetables are rich in folate.However, animal products generally provide a higher amount of minerals that can be easily absorbed by the body compared to plants.The Food and Agriculture Organization (FAO) has introduced methods such as protein digestibility corrected amino acid (PDCAAS) and digestible indispensable amino acid (indispensable amino acid) scores to assess protein quality in diet.However, these indexes do not take into account the specific amino acid requirements of tissue synthesis or the important role of amino acid synthesis in human nutrition and metabolism.Animal-derived foods such as meat, dairy products, eggs, birds, seafood, and other foods contain more balanced amino acids compatible with human tissue, compared to plant-derived foods such as rice, wheat, corn, potatoes, vegetables, cereals, beans, peaches, processed soybeans, nuts, seeds, etc.For example, beef meat has a protein content of 63-68%, whereas most plant-based foods (excluding legumes) have only a protein content of 10-15% [16].
Efforts to enhance the quality of complementary feeding and promote a wider range of nutritious foods have proven effective in enhancing child growth.These initiatives typically concentrate on educating and counseling caregivers to improve their understanding, behaviors, and preferences when it comes to providing diverse and nutritious complementary foods.However, it is important to recognize that limited dietary diversity may also stem from challenges related to the availability, accessibility, and affordability of food, as well as time constraints and convenience factors.Numerous studies have highlighted affordability as a significant obstacle to consuming more nutritious foods and a deciding factor in food choices within low-and middle-income countries [17].
In Bangladesh, India, and Pakistan, most of the household expenditure is devoted to food.In each country, an average of 53 per cent, 57 per cent, and 45 per cent of the total expenses of households are spent on food, respectively.Interestingly, Pakistani households spend relatively little on food, compared to Indian and Bangladeshi households.Most of the food consumed in these countries comes from purchases, accounting for 82% to 89% of the total food expenditure.Even in rural areas, local production and other sources contribute less than 25 per cent of total food expenditure.In the specific food category, cereals account for a large proportion of household food expenditure, between 21 and 27 %.Vegetables also play an important role, accounting for between 8 and 11 per cent of food expenditure.In Bangladesh and Pakistan, meat, fish, and eggs are widely consumed, and more than 90% of households have consumed these foods in one to two weeks.In India, however, only about 50 per cent of households consume these animal foods.Nuts and seeds are consumed more frequently in Bangladesh than in other countries, while milk is consumed more frequently in Pakistan and India than in Bangladesh.In terms of affordability, foods from animals tend to be less accessible than foods from plants.Chicken and livestock meat (such as beef, goats, and mutton) are often one of the least affordable ways to fill the food shortage, with a few exceptions, such as the availability of protein in Pakistan.On the other hand, plant-based foods, such as legumes, nuts, and bananas, are the most affordable and nutritious options analyzed per kilogram of calories [17].
Children under the age of five often face a range of nutrition problems, including protein-energy malnutrition and deficiencies in essential nutrients, especially in low-and middle-income countries.Poor dietary habits, such as consuming low-energy weaning foods, can contribute to malnutrition and stunted growth among young children.In Indonesia, there is a wide variation in the adequacy of energy and macronutrient intake among under-five children, indicating disparities in nutrient consumption.Specifically, Indonesian children tend to have insufficient intake of carbohydrates and fats.However, studies that specifically examine the adequacy of specific types of carbohydrates and fats, such as fiber and essential fatty acids (EFAs), are rare.Consumption of EFAs, for instance, is crucial for supporting the growth of children under the age of two.Protein is also important for linear growth, and inadequate protein intake has been linked to higher rates of stunting.Surprisingly, more than half of the studies included in this review reported excessive protein intake among Indonesian children.This suggests that factors other than protein inadequacy may be contributing to child malnutrition in Indonesia.The mixed reporting of energy and macronutrient intake also suggests that undernutrition in Indonesian children is not solely caused by inadequate macronutrient consumption, but is likely linked to deficiencies in essential micronutrients, which are not regularly assessed or reported [18].
Protein from animal-source recently closely related to meat from livestock such as beef, chicken, and mutton.On the other hand, marine-source food is still rarely discussed for its role in supplying protein from animal-source food.Aquatic foods encompass a wide range of organisms, including microorganisms, plants, and animals, as well as innovative plant-and cell-based foods that originate from aquatic sources.This diverse category includes various types of aquatic life such as finfish, crustaceans like shrimp, crabs, octopus, and squids, mollusks like sea snails, cockles, and clams, as well as aquatic plants for example water spinach and seaweed.Aquatic foods can be obtained through farming or by being caught in the wild, and they can be sourced from different types of water bodies such as inland lakes, rivers, and wetlands, coastal areas like estuaries and mangroves, as well as marine environments.This broad range of sources ensures a wide variety of aquatic foods throughout the year and across various geographic regions [19].
AASFs (Aquatic Animal Source Foods) have different manners by which they add to working on human well-being.First and foremost, they assist with decreasing the lack of fundamental micronutrients, for example, iron, vitamin A, and calcium, which are able to prompt different sicknesses.Besides, AASFs are a rich wellspring of omega-3 long-chain polyunsaturated unsaturated fats, explicitly DHA and EPA, which are useful for heart well-being, mind capability, and eye well-being.Also, AASFs can supplant the utilization of red and handled meats, which are known to adversely affect well-being.It is critical to take note that these pathways might cover specific people or essentially benefit explicit populaces in light of geological area or age and orientation gatherings.The third pathway, specifically, is connected with the sustenance progress, which happens when segment and monetary changes lead to dietary and epidemiological movements that line up with Western food frameworks.To acquire a superior comprehension of how AASFs can add to further developing eating regimens and general wellbeing, it is important to investigate oceanic food strategy drives and ventures that plan to build admittance to a different scope of sea-going food sources and the supplements they offer [19].

Conclusions
Stunting has been a health problem that leads to various consequences in the future, not only for the children suffering from it but also for the community and the nation from a wider perspective.Stunting has become a global burden.Stunting needs to be resolved comprehensively, with multi-sector cooperation and collaboration as well as interdisciplinary work.Protein consumption has been evidenced to be playing a major role in improving growth, especially vertical growth, albeit more studies are always needed.The needs of more studies on animal protein roles in stunting prevention is due to conflicting evidence whether it really beneficial for the linear growth of children.Protein from animalsourced food is considerably preferable to give a valuable supply for children's growth, due to its content of essential amino acids, digestibility and its role in organ development.Unfortunately, consumption is still limited, and often less than daily needs.On the other hand, protein from aquatic animal-sourced food is still abundant and rarely brought into the discussion of stunting prevention.There is a promising condition that aquatic animal source food can play a bigger role in the future to prevent stunting, as a complementary animal protein source besides livestock.More thorough studies on availability, accessibility, and the ratio of risk-to-benefit for stunting prevention are still highly needed.