Malnutrition involves deficiency of not only the macronutrients i.e. fats, proteins, carbohydrates but also results in subphysiological concentration of most micronutrients.
Based in part on the antidepressant effects of sleep deprivation, it has been hypothesized that MDD involves deficiency in sleep homeostatic processes the S-deficiency hypothesis of depression [ 21, 22].
Nutritional status derangement has a multifactorial origin, typically occurring during a continuity involving deficiency in dietary intake and/or increased requirements due to a disease state, from complications of an underlying disorder such as impaired absorption, excessive nutrient losses, and altered nutrient utilization or a combination of the aforementioned factors [ 2, 8, 10].
(Diseases involving deficiencies of particular vitamins are discussed in nutrition: Deficiency diseases: Vitamins).
Skeletal lesions in infants and adults indicative of scurvy suggest that initial colonisation phases in the Pacific islands involved precarious times involving deficiencies of key nutrients.
Many involve deficiencies of 'micronutrients' -- substances like vitamin A and iodine that the human body cannot make itself but that are needed, often in only tiny amounts, to orchestrate a whole range of essential physiological functions.
Clinical error is now widely recognized as a systems problem; that is, adverse events affecting individual patients are usually caused by a sequence of events in the macro- and micro-environment that involve deficiencies in the structure and organization of health care, and are not simply a consequence of human error by the responsible clinician who is the terminal link in the chain.
The underlying mechanisms of impulsivity are not well understood but putatively involve deficiencies in norepinephrine and dopamine (DA) transmission 5, 6, 7, 8, together with functional abnormalities in the prefrontal cortex (PFC) and striatum 9, 10, 11, 12, 13, 14, 15.
Another large group of congenitally caused disorders involves hormone deficiency or insensitivity, such as lack of growth hormone production or resistance of receptors to estrogen or testosterone.
*Homocystinuria, occurring in one baby in 275,000, involves a deficiency of an enzyme that converts homocysteine into cystathionine, needed for normal brain development.
The pathogenesis of IRDS involves a deficiency of all elements of pulmonary surfactant, in particular dipalmitoyl phosphatidylcholine, along with surfactant inhibition and a global immaturity of lung architecture commensurate with the degree of prematurity.
