nutritional disorders
Overview of Undernutrition
Risk Factors for Undernutrition
Undernutrition is caused by social, cultural, and political factors. Poverty remains the leading cause of undernutrition in low, middle-, and high-income nations. War, civil unrest, overpopulation, unsafe housing conditions, infectious diseases, pandemics, and urbanization can all contribute to undernutrition. Undernutrition is of special concern at certain times (ie, during infancy, early childhood, adolescence, pregnancy, breastfeeding, and old age) because these conditions involve rapid growth and/or increase the need for nutrients. Infants and children are particularly susceptible to undernutrition because of their high demand for energy and essential nutrients. According to the World Health Organization (WHO), in 2020, 149 million children > 5 years were estimated to be stunted (too short for age) and 45 million were estimated to be wasted (too thin for height [ Risk factor references ]). The Because vitamin K does not readily cross the placenta, neonates may be deficient, so they are given a single injection of vitamin K within 1 hour of birth to prevent Blood loss , a life-threatening disorder. Infants fed only breast milk, which is typically low in Inadequately fed infants and children are at risk of Protein-Energy Undernutrition (PEU) (PEU—previously called protein-energy malnutrition) and deficiencies of During adolescence, nutritional requirements increase because the growth rate accelerates. Anorexia Nervosa may affect adolescent girls in particular. Requirements for nutrients increase during pregnancy (to support the metabolic demands of pregnancy and fetal growth) and breastfeeding. Aberrations of diet, including Pica (consumption of nonnutritive substances, such as clay and Older adults are at high risk of undernutrition because their nutritional needs increase but energy requirements decrease. This disparity requires consumption of nutrient-dense foods. Aging—even when disease or dietary deficiency is absent—leads to sarcopenia (progressive loss of lean body mass), starting after age 40 and eventually amounting to a muscle loss of about 10 kg (22 lb) in men and 5 kg (11 lb) in women. Undernutrition contributes to sarcopenia, and sarcopenia accounts for many of the complications of undernutrition (eg, decreased nitrogen balance, increased susceptibility to infections). Causes of sarcopenia include the following: Decreased physical activity Decreased food intake Increased levels of cytokines (particularly interleukin-6) Decreased levels of growth hormone and mechano growth factor (insulin-like growth factor-3) In men, decreasing androgen levels Aging decreases basal metabolic rate (due mainly to decreased fat-free mass), total body weight, height, and skeletal mass; from about age 40 to age 65, mean body fat (as a percentage of body weight) increases to about 30% (from 20%) in men and to 40% (from 27%) in women. From age 20 to 80, food intake decreases, especially in men. Anorexia due to aging itself has many causes, including Reduced receptive relaxation of the stomach’s fundus Increased release and activity of cholecystokinin (which produces satiation) Increased leptin (an anorectic hormone produced by fat cells) Diminished taste and smell, which can decrease eating pleasure but usually decrease food intake only slightly Depressive Disorders (a common cause) Loneliness Inability to shop or prepare meals Dementia None Some chronic disorders Use of certain medications Occasionally, Anorexia Nervosa (sometimes called anorexia tardive in older patients), paranoia, or Institutionalized older patients are at particular risk of Protein-Energy Undernutrition (PEU) . They are often confused and may be unable to express hunger or preferences for foods. They may be physically unable to feed themselves. Chewing or swallowing may be very slow, making it tedious for another person to feed them enough food. , and inadequate exposure to sunshine contribute to Vitamin D Deficiency and Dependency and osteomalacia. Diabetes Mellitus (DM) , some chronic disorders that affect the gastrointestinal tract, intestinal resection, and certain other gastrointestinal surgical procedures tend to impair absorption of fat-soluble vitamins, vitamin B12, calcium, and iron. Gluten enteropathy, pancreatic insufficiency, or other disorders can result in Liver disorders impair storage of vitamins A and B12 and interfere with metabolism of protein and energy sources. Renal insufficiency predisposes to protein, iron, andvitamin Ddeficiencies. Anorexia causes some patients with cancer or depression and many with AIDS to consume inadequate amounts of food. Infections, trauma, hyperthyroidism, extensive burns, and prolonged fever increase metabolic demands. Any condition that increases cytokines may be accompanied by muscle loss, lipolysis, lowalbuminlevels, and anorexia. Iron Deficiency can occur in people who follow an ovo-lacto diet (although such a diet can be compatible with good health). People who follow a vegan diet may develop Some fad diets result in vitamin, mineral, and protein deficiencies; cardiac, renal, and metabolic disorders; and sometimes death. Very low calorie diets (<400 kcal/day) cannot sustain health for long. A fruit-only diet is not recommended because it is deficient in protein, sodium, and many micronutrients. Many medications (eg, appetite suppressants,digoxin,glucagon-like peptide-1 [GLP-1] receptor agonists) decrease appetite; others impair nutrient absorption or metabolism. Some medications and other substances (eg, stimulants) have catabolic effects. Certain medications can impair absorption of many nutrients; eg, antiseizure medications can impair absorption of vitamins. Patients with alcohol or substance dependency may neglect their nutritional needs. Absorption and metabolism of nutrients may also be impaired. People with IV drug use disorders typically become undernourished, as do people with Alcohol Use Disorder and Rehabilitation who consume 1.World Health Organization (WHO): Infant and young child feeding, 2021. Accessed September 20, 2023. 2.Unicef: Under-Five Mortality, 2023. Accessed September 20, 2023. 