It is estimated that nearly one in three persons globally suffers from at least one form of<unk> : wasting, stunting, vitamin or mineral deficiency, overweight, obesity, or diet-related noncommunicable diseases. Undernutrition is more common in developing countries. Stunting is more prevalent in urban slums than in rural areas. Studies on<unk>  have the population categorised into different groups including infants, under-five children, children, adolescents, pregnant women, adults and the elderly population. The use of different growth references in different studies leads to variances in the undernutrition prevalence reported in different studies. Some of the growth references used in studies include the National Center for Health Statistics (NCHS) growth charts, WHO reference 2007, Centers for Disease Control and Prevention (CDC) growth charts, National Health and Nutrition Examination Survey (NHANES), WHO reference 1995, Obesity Task Force (IOTF) criteria and Indian Academy of Pediatrics (IAP) growth charts. In children The prevalence of undernutrition is highest among children under five. In 2020, 149 million children under five years old were stunted, 45 million were wasted, and 38.9 million were overweight or obese. The following year, an estimated 45% of deaths in children were linked to undernutrition. The prevalence of wasting among children under five in South Asia was reported to be 16% moderately or severely wasted. In Asia, India has one of the highest burden of wasting with over 20% wasted children. However, the burden of undernutrition among under-five children in African countries is much higher. A pooled analysis of the prevalence of chronic undernutrition among under-five children in East Africa was identified to be 33.3%. This prevalence of undernutrition among under-five children ranged from 21.9% in Kenya to 53% in Burundi. In Tanzania, the prevalence of stunting, among children under five varied from 41% in lowland and 64.5% in highland areas. Undernutrition by underweight and wasting was 11.5% and 2.5% in lowland and 22.% and 1.4% in the highland areas of Tanzania respectively. In South Sudan, the prevalence of undernutrition explained by stunting, underweight and wasting in under-five children were 23.8%, 4.8% and 2.3% respectively. Vitamin A deficiency affects one third of children under age 5 around the world, leading to 670,000 deaths and 250,000–500,000 cases of blindness. In adults As of June 2021, 1.9 billion adults were overweight or obese, and 462 million adults were underweight. Globally, two billion people had iodine deficiency in 2017. In 2020, 900 million women and children suffered from anemia, which is often caused by iron deficiency. Certain groups have higher rates of undernutrition, including elderly people and women (in particular while pregnant or breastfeeding children under five years of age). Undernutrition is an increasing health problem in people aged over 65 years, even in developed countries, especially among nursing home residents and in acute care hospitals. In the elderly, undernutrition is more commonly due to physical, psychological, and social factors, not a lack of food. Age-related reduced dietary intake due to chewing and swallowing problems, sensory decline, depression, imbalanced gut microbiome, poverty and loneliness are major contributors to undernutrition in the elderly population. Recent increase There has been an increase in world hunger over the past decade. In 2015, 795 million people (about one in ten people on earth) had undernutrition. In 2020, one in nine people in the world—or 820 million people worldwide—was hungry. These increases are partially related to the ongoing COVID-19 pandemic, which continues to highlight the weaknesses of current food and health systems. It has contributed to food insecurity, increasing hunger worldwide; meanwhile, lower physical activity during lockdowns has contributed to increases in overweight and obesity. In 2020, experts estimated that by the end of the year, the pandemic could double the number of people at risk of suffering acute hunger. Similarly, experts estimate that the prevalence of moderate and severe wasting could increase by 14% due to COVID-19; coupled with reductions in nutrition and health services coverage, this could result in over 128,000 additional deaths among children under 5 in 2020 alone. Other major causes of hunger include manmade conflicts, climate changes, and economic downturns.
Malnutrition
Terry's nails
Overnutrition
Nephrotic syndrome  Nephrotic syndrome  1
Low milk supply
Protein–energy malnutrition
Undernutrition in children
Bile acid malabsorption