Final answer:
Undernutrition is a lack of adequate nutritious food intake, leading to health issues. In adults, it is defined by a BMI below 18.5 kg/m², and in children as a BMI under the 5th percentile. Kwashiorkor and marasmus are severe forms of malnutrition, with poverty being a central factor in undernutrition globally.
Step-by-step explanation:
Undernutrition is the condition that results from insufficient intake of nutritious foods, leading to low body fat reserves and health issues. For adults, being underweight is determined by a BMI less than 18.5 kg/m². Children are considered underweight if their BMI is below the 5th percentile for their age group. Severe undernutrition can manifest as kwashiorkor, characterized by a swollen abdomen due to low protein intake despite adequate energy consumption, or marasmus, resulting from overall inadequate calorie intake. Common micronutrient deficiencies include Vitamin A, iron, and iodine; each affects health significantly—impacting vision, causing anemia, and leading to thyroid dysfunction, respectively. Undernutrition often arises due to a combination of poverty, uneven distribution of food, and a lack of access to quality nutrients.
Kwashiorkor and marasmus are forms of protein-energy malnutrition. Kwashiorkor often presents with edema and an enlarged liver with fatty infiltrates, while marasmus is characterized by severe muscle wasting and an absence of subcutaneous fat. Both are life-threatening conditions that require immediate attention and intervention.
Undernutrition remains a grave global challenge, especially affecting children due to their increased nutritional needs for growth and development. Wasting refers to acute weight loss in children, while stunting describes chronic height restrictions due to prolonged undernutrition. Despite being a common issue in low- and middle-income countries, undernutrition does not spare wealthier nations. It is closely linked to poverty, while in affluent countries, it often occurs in the context of food insecurity and poor dietary choices.