Protein-Energy Malnutrition And Metabolism

Discussion in 'Articles & Scientific Studies' started by Amazoniac, Mar 12, 2016.

  1. Amazoniac

    Amazoniac Member

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    Authoritarians,

    Thought that this might interest some. Keep in mind that those observations were on children, but most of those effects can be perceived in adults as well when there are chronic sub-optimal intake of nutrients..

    http://www.oxfordjournals.org/our_journals/tropej/online/mcnts_chap7.pdf

    "As the tissue cells break down, potassium and nitrogen are lost in equal proportions initially. Later there is increased loss of potassium in diarrhoeal stools causing a cellular deficit of potassium."

    Liver
    "Fatty liver is characteristic of kwashiorkor. The fat content of the liver may be as high as 50 per cent of the total wet weight. As recovery occurs, fat gradually disappears. Electron microscopy of liver tissue obtained by biopsy reveals that after 3 weeks of treatment on a balanced diet the liver cells are still not visibly normal, even though serum protein levels have reached normal levels. Recognizable liver pathology can be identified even after 10-12 weeks of treatment. Total recovery eventually occurs and liver biopsy 5 years later on light microscopy has shown no signs of residual damage. There are two obvious reasons for the fatty liver. There is an increased flux of fatty acids from adipose tissue for the production of energy. At the same time there is decreased hepatic synthesis of P-lipoproteins which normally transport triglycerides from the liver. The synthesis of the apo-protein part of this fat transporting mechanism is particularly sensitive to lack of protein in the diet."

    Pancreas
    "There is a marked atrophy of the acinar cells, and exocrine secretion is reduced in keeping with the atrophic changes. Enzyme activity of the pancreatic juice has been reported to be as low as 50 per cent of normal. Recovery takes place within the first few days of instituting treatment. Investigation of B cell function reveals that in both kwashiorkor and marasmus insulin secretion is abnormally low after oral administration of glucose. Improvement occurs after 3-6 weeks of treatment, though there are instances where an abnormal response persisted up to 10 months after recovery from malnutrition."

    GI tract
    "Striking morphological changes occur in the jejunum, especially in kwashiorkor. In particular, villous atrophy may be severe. Enzyme activity is reduced within the cells in keeping with the morphological changes. The enzymes most affected are the ones located in the brush border. Of these, lactase has been studied extensively because it is more severely affected and because most diets used for recovery are based on milk and contain large quantities of lactose. Besides these morphological changes, the small intestine also suffers from bacterial overgrowth with invasion of the proximal gut by the bacterial flora of the distal part of the small intestine. Malabsorption of fat has been correlated with bacterial degradation of bile salts so that the concentration of conjugated bile salts in the gut lumen falls below the critical level necessary for forming micelles with fat. Intestinal permeability is increased as measured by the inert sugars lactulose and L-rhamnose. Decreased L-rhamnose recovery in urine indicating malabsorption, and increased lactulose recovery indicating permeability serve as independent predictors of mortality. Improvement in intestinal permeability is slow to occur with nutritional therapy, and can lag much behind improvement in weight."

    "Some atrophy of the gastric mucosa is common in the majority of cases. Fasting gastric pH is often in the neutral range. Thus the function of the stomach acid as a barrier to intestinal contamination is much reduced. This is supported by the observation that fasting stomach contents in children suffering from PEM have high bacterial and fungal counts."

    "..With regard to protein digestion, it has been found that even though faecal nitrogen excretion in malnourished children is on average twice the normal, there is no serious malabsorption of nitrogen. More than three-quarters of the nitrogen in the diet is absorbed and is usually sufficient to allow the initiation of a cure except in very severe diarrhoea."

    Heart
    "The heart muscle suffers in the general atrophy of all muscle tissue. Cardiac output is reduced in accord with the reduced body metabolism. Doppler echocardiograms show reduced thickness of septum and posterior cardiac wall compared to age matched controls. The total left ventricular mass and cardiac output are reduced in proportion to decrease in body size. Institution of treatment, by stimulating metabolism, can often precipitate congestive cardiac failure."

    Immune System
    "Profound changes occur in cell-mediated immunity, the complement system, and in the function of polymorphonuclear lymphocytes. The thymus is consistently reduced in size. Seroconversion in response to vaccination seems to be preserved. The complement system shows consistent abnormality with decreased C3 levels."

    Muscle
    "The muscle compartment of the body comprises a large mass of protein which is both labile and sensitive to dietary changes. Muscle wasting is an early result of PEM. Electron microscopy shows depletion of myofibrils, mitochondrial swelling, glycogen depletion and disorganization of sarcomere. At recovery the average muscle mass is usually about twice that during the malnourished state. Muscle and fat biopsies in malnourished Peruvian infants at the time of admission and again 4-9 months later, after recovery, show that there is a gross reduction of muscle cell size in malnourished infants. Improvement takes place with recovery, but the cell size continues to remain subnormal after recovery."

    Brain and the Nervous System
    "Metabolic and biochemical functions of the brain may be altered, and several of these, like catechol amine metabolism, are related to higher mental functions. Hence at a time when a large number of components are being formed and assembled, the vulnerability is greatly increased, as for example during the period of the growth spurt of the brain."
    "When magnetic resonance imaging technique was applied to children admitted with severe kwashiorkor brain shrinkage was found in every one of those investigated. White and grey matter were found to be equally affected. Following three months of treatment the changes in brain show improvement in keeping with gain in weight and improvement in serum protein levels."

    Carbohydrate Metabolism
    "Low blood sugar is a common accompaniment of PEM. Two types of hypoglycemia have been identified - asymptomatic, from which recovery occurs with feeding; and the profound irreversible type, associated with severe mal nutrition, hypothermia or infection. As a general rule, if the child has hypothermia it is almost certain that hypoglycemia is also present."

    Fat Metabolism
    "Fat malabsorption is common in PEM, but the degree is rarely serious enough to cause steatorrhoea. Probably the most serious result of fat malabsorption is the impairment of absorption of fat-soluble vitamins.
    It has been found that vegetable fats are better absorbed than animal fats
    and this is the rationale behind the use of cottonseed oil as a source of energy in the treatment of kwashiorkor."

    Protein Metabolism
    "Protein digestion, though inefficient because of low levels of pancreatic trypsin is sufficient for recovery to occur when an adequate diet is being fed. On average, absorption of nitrogen from a milk-based diet is 70-80 per cent as compared to 90 per cent in the normal child. Similarly, in the absence of complicating infection, nitrogen is well retained, being in the range of 20-40 per cent of the intake. Thus, protein repletion through a greatly enhanced anabolism is usual as soon as sufficient protein is given. Nitrogen retention continues to be high until a normal growth rate has been attained."
    "Albumin synthesis and its level in plasma are very sensitive to protein intake. There is an immediate fall when dietary deficiency occurs, and a rise when the deficiency is corrected. Serum albumin levels are also sensitive to infection. The longitudinal study of Ugandan children referred to earlier showed that a combination of respiratory infection, diarrhoea and malaria caused a dramatic fall in serum albumin."

    --
    Defense Mechanisms
    "The child with malnutrition is susceptible to infection. The body's defenses are unable to mount an adequate response to microbial challenge so that the mildest infection tends to spread and become generalized. In severe cases the clinical response to infection, like fever and phagocytosis, may be absent and the first sign of widespread infection may be sudden deterioration in the general condition, refusal to take food and hypothermia."

    "Studies of the body's defense mechanisms reveal adequate capacity for humoral immunity. Thus immunoglobulin levels in the blood are normal and there are normal numbers and proportions of B lymphocytes, which produce immunoglobulins. Secretory IgA in salivary and naso-pharyngeal secretions, and in the gastrointestinal tract, is reduced and does not rise in response to antigenic challenge. This impairment of secretory antibody response in malnourished children explains their slow recovery from enteric infections and viral illnesses like measles. In contrast to humoral immunity, cellular immunity (T-cell function) is profoundly impaired. T-lymphocytes are reduced in number to about a third of normal and various tests of their functions also show impairment. In keeping with the lowered cellular immunity, all lymphoid organs show atrophy, especially the thymus. Several studies have now established that in protein-energy malnutrition and/or deficiency of single nutrients that take part in nucleic acid metabolism generally there is atrophy of lymphoid tissue and dysfunction of cell mediated immunity. Deficiencies of single nutrients can impair the production of key proteins. A useful clinical sign for assessing the involution of lymphoid organs is the size of the tonsils in malnourished children. Phagocytic function is also inefficient and several workers have emphasized its correlation with iron deficiency, especially lower levels of serum transferrin."

    "Accompanying deficiency of micronutrients often compounds the difficulty. Of the micronutrients vitamins A, C, E and B6 and folic acid are important to consider. Metals like zinc, selenium, iron, copper have influences on immune response, and many are deficient in severe malnutrition."
     
  2. Makrosky

    Makrosky Member

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    I don't get it. All of this is related to low protein intake? Please clarify.
     
  3. OP
    Amazoniac

    Amazoniac Member

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    Yes, protein and/or energy deficient diets, but I think that that can happen to a lesser degree in chronic sub-optimal intake. And also, as the article suggests: "Deficiencies of single nutrients can impair the production of key proteins."
     
  4. 800mRepeats

    800mRepeats Member

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    Interesting read. Helpful to see some of the body-wide effects gathered all in one place. Thank you.
     
  5. Sofia

    Sofia Member

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    Very interesting!
     
  6. Cloudhands

    Cloudhands Member

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    I couldnt see the study, did they give any quantities of protein? Also as far as the kwashiorkor and nafld, theres a million other variables not taken into consideration, for example pufa levels, and what foods they were eating etc
     
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