Undernutrition, Overnutrition, and Malnutrition
University of Hawai‘i at Mānoa Food Science and Human Nutrition Program and Human Nutrition Program
For many, the word “malnutrition” produces an image of a child in a third-world country with a bloated belly, and skinny arms and legs. However, this image alone is not an accurate representation of the state of malnutrition. For example, someone who is 150 pounds overweight can also be malnourished.
Malnutrition refers to one not receiving proper and does not distinguish between the consequences of too many nutrients or the lack of nutrients, both of which impair overall health. Undernutrition is characterized by a lack of nutrients and insufficient energy supply, whereas overnutrition is characterized by excessive nutrient and energy intake. Overnutrition can result in obesity, a growing global health threat. Obesity is defined as a metabolic disorder that leads to an overaccumulation of fat tissue.
Although not as prevalent in America as it is in developing countries, undernutrition is not uncommon and affects many subpopulations, including the elderly, those with certain diseases, and those in poverty. Many people who live with diseases either have no appetite or may not be able to digest food properly. Some medical causes of malnutrition include cancer, inflammatory bowel syndrome, AIDS, , illnesses or conditions that cause chronic pain, psychiatric illnesses, such as , or as a result of side effects from medications. Overnutrition is an epidemic in the United States and is known to be a risk factor for many diseases, including Type 2 diabetes, cardiovascular disease, inflammatory disorders (such as rheumatoid arthritis), and cancer.
Health Risks of Being Underweight
The 2003–2006 National Health and Nutrition Examination Survey (NHANES) estimated that 1.8 percent of adults and 3.3 percent of children and adolescents in the United States are underweight.[1]
Being underweight is linked to nutritional deficiencies, especially iron-deficiency anemia, and to other problems such as delayed wound healing, hormonal abnormalities, increased susceptibility to infection, and increased risk of some chronic diseases such as . In children, being underweight can stunt growth. The most common underlying cause of underweight in America is inadequate nutrition. Other causes are wasting diseases, such as cancer, multiple sclerosis, tuberculosis, and eating disorders. People with wasting diseases are encouraged to seek nutritional counseling, as a healthy diet greatly affects survival and improves responses to disease treatments. Eating disorders that result in underweight affect about eight million Americans (seven million women and one million men).
Anorexia Nervosa
Anorexia nervosa, more often referred to as “anorexia,” is a psychiatric illness in which a person obsesses about their weight and about food that they eat. Anorexia results in extreme nutrient inadequacy and eventually to organ malfunction. Anorexia is relatively rare—the National Institute of Mental Health (NIMH) reports that 0.9 percent of females and 0.3 percent of males will have anorexia at some point in their lifetime, but it is an extreme example of how an unbalanced diet can affect health.[2]
Anorexia frequently manifests during adolescence and it has the highest rate of mortality of all mental illnesses. People with anorexia consume, on average, fewer than 1,000 kilocalories per day and exercise excessively. They are in a tremendous caloric imbalance. Moreover, some may participate in binge eating, self-induced vomiting, and purging with laxatives or enemas. The very first time a person starves him- or herself may trigger the onset of anorexia. The exact causes of anorexia are not completely known, but many things contribute to its development including economic status, as it is most prevalent in high-income families. It is a genetic disease and is often passed from one generation to the next. Pregnancy complications and abnormalities in the brain, , and immune system may all contribute to the development of this illness.
The primary signs of anorexia are fear of being overweight, extreme dieting, an unusual perception of body image, and depression. The secondary signs and symptoms of anorexia are all related to the caloric and nutrient deficiencies of the unbalanced diet and include excessive weight loss, a multitude of skin abnormalities, diarrhea, cavities and tooth loss, osteoporosis, and liver, kidney, and heart failure. There is no physical test that can be used to diagnose anorexia and distinguish it from other mental illnesses. Therefore a correct diagnosis involves eliminating other mental illnesses, hormonal imbalances, and nervous system abnormalities. Eliminating these other possibilities involves numerous blood tests, urine tests, and x-rays. Coexisting organ malfunction is also examined. Treatment of any mental illness involves not only the individual, but also family, friends, and a psychiatric counselor. Treating anorexia also involves a dietitian, who helps to provide dietary solutions that often have to be adjusted over time. The goals of treatment for anorexia are to restore a healthy body weight and significantly reduce the behaviors associated with causing the eating disorder. Relapse to an unbalanced diet is high. Many people do recover from anorexia, however most continue to have a lower-than-normal body weight for the rest of their lives.
Bulimia Nervosa
, like anorexia, is a psychiatric illness that can have severe health consequences. The NIMH reports that 0.5 percent of females and 0.1 percent of males will have bulimia nervosa, or otherwise known as bulimia, at some point in their lifetime.[3]
Bulimia is characterized by episodes of eating large amounts of food followed by purging, which is accomplished by vomiting and with the use of laxatives and diuretics. Unlike people with anorexia, those with bulimia often have a normal weight, making the disorder more difficult to detect and diagnose. The disorder is characterized by signs similar to anorexia such as fear of being overweight, extreme dieting, and bouts of excessive exercise. Secondary signs and symptoms include gastric reflux, severe erosion of tooth enamel, dehydration, electrolyte imbalances, lacerations in the mouth from vomiting, and peptic ulcers. Repeated damage to the esophagus puts people with bulimia at an increased risk for esophageal cancer. The disorder is also highly genetic, linked to depression and anxiety disorders, and most commonly occurs in adolescent girls and young women. Treatment often involves antidepressant medications and, like anorexia, has better results when both the family and the individual with the disorder participate in nutritional and psychiatric counseling.
Binge-Eating Disorder
Similar to those who experience anorexia and bulimia, people who have a binge-eating disorder have lost control over their eating. Binge-eating disorder is not currently diagnosed as a distinct psychiatric illness, although there is a proposal from the American Psychiatric Association to categorize it more specifically. People with binge-eating disorder will periodically overeat to the extreme, but their loss of control over eating is not followed by fasting, purging, or compulsive exercise. As a result, people with this disorder are often overweight or obese, and their chronic disease risks are those linked to having an abnormally high body weight such as , cardiovascular disease, and Type 2 diabetes. Additionally, they often experience guilt, shame, and depression. Binge-eating disorder is commonly associated with depression and anxiety disorders. According to the NIMH, binge-eating disorder is more prevalent than anorexia and bulimia, and affects 3.5 percent of females and 2.0 percent of males at some point during their lifetime.[4] Treatment often involves antidepressant medication as well as nutritional and psychiatric counseling.
Orthorexia Nervosa
was coined in 1997 by physician Steven Bratman.[5] The term uses “ortho,” in its meaning as straight, correct and true and refers to a fixation on eating proper food.[6] Fixation on ‘healthy eating’ by those with orthorexia nervosa often results in behaviors that end up damaging one’s well-being such as extreme weight loss or a refusal to dine out with friends. Orthorexia nervosa like anorexia nervosa involves restriction of the amount and variety of foods eaten, however those with orthorexia nervosa do not have an incessant fear of weight gain but instead have an obsession with “feeling pure, healthy and natural.”[7] People affected by orthorexia nervosa tend to follow diets tied to a philosophy or theory and believe that their theory of eating is the best.[8] [9] Such diets often have a redemptive quality that involves denying oneself of “bad” or “wrong” foods.[10] In extreme cases, affected individuals may also fear contamination or harm from water and electricity leading them to use filters to purify their environment from electrical emissions. Orthorexia nervosa has similar physical consequences to anorexia nervosa despite the lack of motivation for weight loss by affected individuals.
Although awareness of orthorexia nervosa is increasing, it is not formally recognized in the Diagnostic Statistical Manual and thus it is difficult to get an estimate of how many persons are affected by orthorexia nervosa. Additionally, the lack of formal diagnostic criteria makes it impossible to know if orthorexia nervosa occurs with other types of existing disorders like anorexia or a form of obsessive-compulsive disorder (OCD) or if it’s a stand-alone eating disorder. Studies show that many persons with orthorexia nervosa also have OCD. Many experts view orthorexia nervosa as a variety of anorexia or OCD. Treatment usually involves psychotherapy and weight restoration as needed.[11] OCD may be a consequence of malnutrition, being underweight and a starved brain thus weight restoration may resolve the OCD.
Warning signs and symptoms of orthorexia nervosa:[12]
- Compulsive checking of ingredients lists and nutritional labels
- An increased concern about the health of ingredients
- Cutting out an increasing number of food groups such as all sugars, all carbohydrates, all dairy or all animal products
- An inability to eat anything but a narrow group of foods that are deemed ‘healthy’ or ‘pure’
- Unusual interest in the health of what others are eating
- Spending hours per day thinking about what food might be served at upcoming events
- Showing high levels of distress when ‘safe’ or ‘healthy’ foods are not available
- Obsessive following of food and ‘healthy lifestyle’ blogs on social media
- Body image concerns may or may not present
The Healing Process
With all wounds, from a paper cut to major surgery, the body must heal itself. Healing is facilitated through proper nutrition while malnutrition inhibits and complicates this vital process. The following nutrients are important for proper healing:[13]
- Vitamin A. Helps to enable the epithelial tissue (the thin outer layer of the body and the lining that protects your ) and bone cells form.
- Vitamin C. Helps form collagen, an important protein in many body tissues.
- Protein. Facilitates tissue formation.
- Fats. Play a key role in the formation and function of cell membranes.
- Carbohydrates. Fuel cellular activity, supplying needed energy to support the inflammatory response that promotes healing.
Learning Activities
Technology Note: The second edition of the Human Nutrition Open Educational Resource (OER) textbook features interactive learning activities. These activities are available in the web-based textbook and not available in the downloadable versions (EPUB, Digital PDF, Print_PDF, or Open Document).
Learning activities may be used across various mobile devices, however, for the best user experience it is strongly recommended that users complete these activities using a desktop or laptop computer and in Google Chrome.
- Prevalence of Underweight among Children and Adolescents: United States, 2003–2006. Centers for Disease Control and Prevention. http://www.cdc.gov/nchs/data/hestat/underweight/underweight_children.htm. Updated November 6, 2015. Accessed April 15, 2018. ↵
- Eating Disorders. The National Institute of Mental Health. https://www.nimh.nih.gov/health/statistics/eating-disorders.shtml#part_155061. Accessed April 15, 2018. ↵
- Eating Disorders. The National Institute of Mental Health. https://www.nimh.nih.gov/health/statistics/eating-disorders.shtml#part_155061. Accessed April 15, 2018. ↵
- Eating Disorders. The National Institute of Mental Health. https://www.nimh.nih.gov/health/statistics/eating-disorders.shtml#part_155061. Accessed April 15, 2018. ↵
- Mathieu J.(2005). What is orthorexia? Journal of the American Dietetic Association, 105(10), 1510-1512. Bratman, S. Health Food Junkie. Yoga Journal. 1997, September/October, 42-50. Available at https://www.orthorexia.com/original-orthorexia-essay/. ↵
- Donini LM, Marsili D, Graziani MP, Imbriale M, Cannella C. (2004). Orthorexia nervosa: a preliminary study with a proposal for diagnosis and an attempt to measure the dimension of the phenomenon. Eating and Weight Disorders, 9(2), 151‐157. ↵
- Mathieu J. (2005). What is orthorexia? Journal of the American Dietetic Association, 105(10), 1510-1512. Bratman, S. Health Food Junkie. Yoga Journal. 1997, September/October, 42-50. Available at https://www.orthorexia.com/original-orthorexia-essay/. ↵
- Donini LM, Marsili D, Graziani MP, Imbriale M, Cannella C. (2004). Orthorexia nervosa: a preliminary study with a proposal for diagnosis and an attempt to measure the dimension of the phenomenon. Eating and Weight Disorders, 9(2), 151‐157. ↵
- Orthorexia. (2017, February 26). National Eating Disorders Association. https://www.nationaleatingdisorders.org/learn/by-eating-disorder/other/orthorexia ↵
- Mathieu J. (2005). What is orthorexia? Journal of the American Dietetic Association, 105(10), 1510-1512. Bratman, S. Health Food Junkie. Yoga Journal. 1997, September/October, 42-50. Available at https://www.orthorexia.com/original-orthorexia-essay/. ↵
- Orthorexia. (2017, February 26). National Eating Disorders Association. https://www.nationaleatingdisorders.org/learn/by-eating-disorder/other/orthorexia ↵
- Orthorexia. (2017, February 26). National Eating Disorders Association. https://www.nationaleatingdisorders.org/learn/by-eating-disorder/other/orthorexia ↵
- MacKay D, Miller AL. (2003). Nutritional Support for Wound Healing. Alternative Medicine Review, 8(4), 359–77. https://www.ncbi.nlm.nih.gov/pubmed/14653765. Accessed April 15, 2018. ↵
The sum of all processes involved in how organisms obtain nutrients, metabolize them, and use them to support all of life’s processes.
A disease that results in an irreversible loss of mental function.
Eating disorder characterized by under eating and excessive weight loss.
A disorder affecting the bones that is characterized as a loss in bone mass, increased bone fragility, and increased risk of fractures.
The organ system composed of a collection of glands that produce and secrete hormones.
Eating disorder characterized by alternating cycles of overeating and undereating.
Abnormally high blood pressure.
Eating disorder characterized by a fixation on eating healthy food.
A group of tissues that performs a specialized function.