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Moving beyond survival: the triple burden of malnutrition

Dr Marko Kerac outlines the burden of malnutrition across the lifecycle from undernutrition, obesity, and micronutrient deficiency.
MARKO KERAC: Welcome to this talk on child malnutrition, a major global public health problem manifesting in three main ways, which we’ll be discussing in this session– undernutrition, overweight/obesity, and finally, micronutrient deficiency, often referred to as hidden hunger. My name is Dr. Marko Kerac, and I’m a clinical associate professor of public health nutrition working here at LSHTM in the nutrition group within the Department of Population Health.
Malnutrition is any condition in which deficiency, excess, or imbalance, of energy, protein, or other nutrients adversely affects body function and/or clinical outcome. Yet, when we talk about malnutrition, many people think first of undernutrition and children, such as this boy, shown in an advert for an old campaign fundraising for famine response. Even today, undernutrition remains a major global public health problem. Latest statistics can be found from numerous sources, including on the UNICEF website and the WHO, World Health Organisation website. According to the UNICEF/ WHO/ World Bank group joint estimates, in 2018, some 49.5 million– that 7% of children aged under five worldwide– were wasted. That is, their weight is too low for their height. They’re too thin.
149 million– 22% of children aged under five worldwide– were stunted. That is, their height is too low for their age, an indicator of more chronic, long-term malnutrition. This is an improvement from 1990, the baseline year of the Millennium Development Goals, when 253 million children– 39%– were stunted. But it’s still way higher than it should be, way higher than it could be.
The reason why undernutrition is such a serious problem is because of its strong relationship with child survival. It’s vital to appreciate that being small or thin alone is not a problem. It matters because it’s an easily measurable marker of malnutrition and is associated with functional and clinical impairments. As a child becomes progressively more undernourished, vital body functions and organ systems, including immune system function, become more and more compromised and shut down. Maternal and child malnutrition, in all its many forms, is estimated to underlie some 45% of all young child deaths each year, as shown in this pie chart. If a child has, say, diarrhoea or pneumonia but is well-nourished, chances of recovery are good.
If, however, he or she has underlying malnutrition, then the risk of death is significantly increased. Some forms of undernutrition are particularly serious. Severe Acute Malnutrition, SAM, affects some 16 million children, but accounts for at least half a million deaths per year.
Tackling undernutrition thus has a major role to play in the unfinished agenda of ensuring more children survive those vulnerable early years. The UNICEF conceptual framework, shown in this slide, helps us think through the many, often complex factors responsible for malnutrition in individuals and in communities. These include immediate causes– disease and/or inadequate dietary intake. Underlying causes– inadequate food security in families and communities, leading to inadequate access to food, inadequate care for mothers and children, poor access to health services, and an unhealthy environment. Lastly, there are basic political, economic, and institutional causes. Often the most difficult change is nonetheless vital to tackle, if meaningful and sustained improvements is to be made.
Interventions funding nutrition include better prevention activities– for example, by promoting exclusive breastfeeding for the first six months of life. And then better treatment of children who become undernourished, for example, by scale up of community-based management of acute malnutrition (CMAM) programmes. They can also be divided into nutrition-specific interventions. That’s to say, those that tackle the problem directly– school feeding programmes, for example. And then nutrition-sensitive interventions– for example, agricultural improvements, which are clearly vital to nutrition, but in a less direct way.
Once undernutrition treatment programmes traditionally focus on helping affected children survive, this growing recognition that good nutrition is also vital to helping them thrive. If not tackled early, early life undernutrition is an important cause of long-term impairments. This diagram shows how nutrition can affect an individual throughout their life course and even the next generation. For example, a low birth weight baby is at risk of poor feeding and poor catch-up growth, and is thus at risk of becoming a stunted child, who in turn becomes a stunted adolescent and a stunted adult who might not have achieved their full physical, cognitive, educational, and social potential. The first 1,000 days of life, from conception to age two years, is a particularly sensitive period.
And it is why the global Scaling Up Nutrition, SUN movement, focuses on this early life age group.
That cycle of disadvantage brings us to the second major manifestation of malnutrition– overweight and obesity. The World Health Organisation divides these as abnormal or excessive fat accumulation that presents a risk to health. BMI, Body Mass Index, is a widely used, albeit imperfect measure, whereby an individual’s weight in kilos is divided by the square of his or her height in metres. A BMI of over 25 is considered to be overweight, and over 30 is obese. This map of adult overweight in 2016 illustrates the scale of the problem globally. It’s a problem not just in high-income countries, but also in some of the world’s poorest countries and communities. Indeed, underweight and overweight can often coexist even in the same families.
This happens in many different ways, but most important here are the mechanisms described in the DOHaD literature– that is Developmental Origins of Health and Disease. Many DOHaD studies from many different settings show that early life undernutrition has a strong and causal relationship with non-communicable disease in later life. Hence, getting treatment of non-communicable conditions, like heart disease and diabetes in adulthood, once diagnosed, is really too late. Prevention should begin in utero and in infancy via improved nutrition. Optimising that early life nutrition has significant long-term benefits.
Finally, we come to micronutrient malnutrition. Micronutrients include vitamins and minerals and are needed in tiny amounts to ensure good health. The World Health Organisation calls them “magic wands” that enable the body to produce enzymes, hormones, and other substances essential for proper growth and development. Lack of individual or multiple micronutrients can occur in isolation, or it can co-exist with either undernutrition or overweight/obesity. It’s sometimes known as “hidden hunger” because it can go unnoticed until the deficiency is severe. Some micronutrient deficiencies cause a general increase in mortality and morbidity that can’t be easily identified without biochemical testing. Others have specific signs and symptoms if lacking. For example, iron deficiency is a common cause of anaemia. Goitre could be due to iodine deficiency.
And night blindness due to vitamin A deficiency. But even these are not always clinically obvious and less severe. A memorable, albeit rare, example of micronutrient deficit was highlighted in this news story about a teenage boy in the UK who lived off a very narrow and poor quality diet. Though his weight and height would not have suggested malnutrition, he was, in fact, lacking in key micronutrients, which led to visual problems described in this article.
So in this rapid overview of the major forms of malnutrition, I hope it’s clear why it matters. No surprise, therefore, that malnutrition is explicitly recognised in Goal 2 and in particular, in Target 2.2 of the Sustainable Development Goals. Target 2.2 aims to, by 2030, end all forms of malnutrition, including by 2025, the internationally-agreed targets in stunting and wasting in children under five years of age, and address the nutritional needs of adolescent girls, pregnant and lactating women, and older persons. So this is also a great reminder that though we often focus on young child malnutrition, it’s vital not to overlook other vulnerable groups.
So to conclude, malnutrition matters in all of its major forms– undernutrition, overweight/obesity, and micronutrient deficiency. Secondly, tackling malnutrition helps children survive in the short term. Thirdly, tackling malnutrition helps children thrive in the long term, and it also reduces the risk of later life non-communicable disease. And finally, malnutrition is key to many of the sustainable development goals. Towards these, programmes must address both immediate causes and upstream causes. Thanks very much for listening, and I wish all of you all the very best in your future work.

In this step Dr Marko Kerac discusses the impact of nutrition on child health. He explores the triple burden of malnutrition across the lifecycle from undernutrition, obesity, and micronutrient deficiency.

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