Malnutrition

Malnutrition is a lack of or imbalance in vitamins, minerals or other nutrients.

Types of malnutrition include:
 * undernutrition
 * when not enough essential nutrients are consumed or they are excreted more quickly rapidly than they can be replaced


 * micronutrient-related malnutrition
 * deficiency in specific nutrients, for example iron or vitamin B12


 * overnutrition
 * people consume too much, the wrong things, don't exercise enough, or take too many dietary vitamins or other nutrients

Signs and symptoms

 * unexpected weight loss – clothes, dentures, or jewellery may become loose
 * tiredness fatigue, and lethargy, which may include sleepiness
 * Depression, anxiety, or mood changea
 * loss of appetite, medically known as the symptom anorexia (which is different to the eating disorder anorexia nervosa)
 * loss of interest in food and/or drinks
 * loss of muscle strength or muscle wasting
 * Dizziness
 * stunted growth (in children)

Further complications caused by malnutrition include:
 * increased risk of illness
 * increased risk of infections
 * slower wound healing
 * increased risk of falls
 * lower quality of life
 * reduced independence
 * reduced ability to carry out activities of daily life

Possible causes and risk factors

 * Lack of food including starvation
 * Poverty
 * overnutrition risk is increased by being more than 20% overweight or having a diet high in fat and salt
 * Eating disorders
 * Disease-related malnutrition - due to reduced dietary intake, malabsorption, inability to eat, increased nutrient losses or increased energy expenditure caused by certain diseases
 * Examples of illnesses that can cause malnutrition include diarrhea, and cancer.

Treatment

 * A healthy, balanced diet helps prevent malnutrition
 * Tube feeding or IV nutrition, for instance when a patient is unable to eat enough or for diseases like irritable bowel disease or burns that are known to cause malabsorption or increase nutrition requirements

ME/CFS
Very severe ME can cause malnutrition, for example patients who are physically unable to eat enough due to extreme exhaustion and post-exertional malaise, gastrointestinal symptoms of ME/CFS, or food intolerances.

Diet and nutritional deficiencies
ME/CFS cannot be diagnosed until medical tests have been carried out to rule out certain nutritional deficiencies, including iron, vitamin B12, and vitamin D, but these can occur after diagnosis. 

Nutritional deficiencies identified in people with ME/CFS include:
 * Lack of dietary fibre in 95%
 * unhealthy fat intake in 70%
 * inadequate fruit and vegetable intake in 70%
 * low intake of calcium, iodine, selenium and vitamin D was common
 * low vitamin D levels in 60% of those not taking supplements was found in one study
 * low circulating levels of vitamin E were found in CFS patients, but only in lower quality studies
 * Deficiencies that have been found in some studies but not others include various B vitamins, vitamin C, magnesium, sodium, zinc, L-tryptophan, carnitine, coenzyme Q10, and essential fatty acids.

A review by Jones and Probst stated that "unhealthy dietary intake [was] not significantly associated with fatigue severity or functional impairment" in chronic fatigue syndrome patients, and found that avoiding dairy or grains was common, and was usually not based on a diagnosed allergy or intolerance.

Notable articles

 * 2021, Life-Threatening Malnutrition in Very Severe ME/CFS - (Full text)
 * 2017, Role of dietary modification in alleviating chronic fatigue syndrome symptoms: A systematic review - (Full text)
 * 2017, Vitamin and mineral status in chronic fatigue syndrome and fibromyalgia syndrome: A systematic review and meta-analysis - (Full text)
 * 2005, Nutrient intake is unrelated to nutrient status in patients with chronic fatigue syndrome - (Full text)

Learn more

 * Malnutrition - British Dietetic Association
 * Poor Nutrition - CDC
 * Malnutrition - Symptoms - NHS
 * Dietary Guidelines for Americans 2020–2025 - MyPlate and Consumer Resources
 * Malnutrition - World Health Organization fact sheet