Protein malnutrition in man

The Role of Malnutrition in Ninety-Day Outcomes After Total Joint Arthroplasty

BACKGROUND

Research has linked malnutrition to more complications in total joint arthroplasty (TJA) patients. The role of preoperative albumin in predicting length of stay (LOS) and 90-day outcomes remains understudied. Often, an albumin cut-off ≤3.5 g/dL is used as proxy for malnutrition, although this value remains understudied. This preoperative level may be missing some patients at risk for adverse events post TJA.

METHODS

TJA patients at a single institution from 2013 to 2018 were reviewed for preoperative albumin level. In total, 4047 cases (total knee arthroplasty: 2058; total hip arthroplasty: 1989) had available data, including 90-day readmissions, 90-day emergency department (ED) visits, and postoperative LOS.

RESULTS

About 5.6% experienced a readmission and 9.6% had at least one ED visit within 90 days. Overall prevalence of malnutrition was 3.6%, and this cohort experienced a longer average LOS (3.5 vs 2.2 days, P < .0001) and was more likely to experience a readmission (16% vs 5%, P < .0001) or ED visit (18% vs 9%, P = .0005). Additionally, albumin ≤3.5 g/dL was correlated with more frequent discharge to skilled nursing facility/rehab (30.8% vs 14.7%, P < .0001), increased risk for 90-day readmission with univariable (odds ratio [OR] 1.79, P < .0001) and multivariable logistic regression (OR 1.55, P < .0001), and increased risk for 90-day ED visits with univariable (OR 1.62, P < .0001) and multivariable regression (OR 1.35, P < .0001). The optimal albumin cut-off was 3.94 g/dL in a univariable model for 90-day readmission.

CONCLUSION

Screening for malnutrition may serve a role in preoperative evaluation. An albumin cutoff value of 3.5 g/dL may miss some at-risk patients.

Infant and Preschool Psychological Development

The INCAP longitudinal study (1969–1977) was designed to test the hypothesis that nutrition supplementation improves the cognitive test performance of infant and preschool children. The hypothesis was based on a series of arguments about effects of supplementation on brain development that have not been supported by subsequent research. Both early reports of these studies and current re-examination of the data suggest effects during the preschool years, but of modest magnitude.

Protein-restricted diet alters concentration of plasma membrane glycoproteins in rat liver

Malnutrition is known to have adverse effects on the physiology and morphology of the liver. The aim of this investigation was to examine the effect of protein restriction on the content of plasma membrane proteins residing in the sinusoidal and bile canalicular domains of rat liver. Post-weanling rats maintained on low protein isocaloric diets showed marked growth retardation concomitant with reduced liver protein concentration compared to control animals. The content of leucine aminopeptidase, a bile canalicular enzyme, and asialoglycoprotein receptor, a sinusoidal receptor, in livers of protein-restricted rats was 66% and 50%, respectively, of control livers. In contrast, the relative concentrations of dipeptidyl peptidase IV and a cell adhesion molecule (GP 110), both canalicular proteins, were 160% and 121%, respectively, in rat livers upon protein restriction. After a 4-week rehabilitation period, the concentrations of all canalicular membrane proteins were similar to those in control livers, while the sinusoidal receptor was only 68% of control values. Protein restriction was found to adversely affect the concentrations of protein constituents, but not their localization in the hepatocyte plasma membrane. In general, altered concentrations of hepatocyte membrane proteins were reversed on the administration of a normal protein diet.

Prothrombin time as an index of mortality in kwashiorkor

Prothrombin time, serum albumin, aminotransferases and liver size were evaluated in 40 consecutive cases of kwashiorkor. Eleven (27.5%) of the 40 patients died. Eight out of the 11 patients who died had a prolonged prothrombin time of more than 3 s above the control compared to only 4 out of the 29 who survived (p = 0.005). Mean serum aspartate aminotransferase (AST), alanine aminotransferase (ALT) albumin, globulin and liver size were abnormal but similar in both groups. These results may indicate a predictive mortality value of prothrombin time in kwashiorkor.

Expression of liver-specific genes coding for plasma proteins in protein deficiency

Protein deficiency leads to a decreased concentration of plasma proteins, although it is not clear whether this response is caused by alterations in gene transcription or in post-transcriptional events. The aim of this study was to investigate the expression of some liver-specific genes coding for plasma proteins in rats kept on a protein-free diet for 30 days. Cloned cDNA probes for the albumin, transthyretin, retinol-binding protein and prothrombin genes were used in Northern hybridizations to total liver RNA to compare their transcript levels in protein-deficient and control animals. Liver polysomes were also isolated and fractionated from the two groups of animals to examine the possible effects of protein deficiency on translation of the mRNAs. The results indicate that the albumin and transthyretin mRNAs are present in lower amounts in protein deficiency. The distribution profile along sucrose gradients shows that all mRNAs are undergoing translation, but in protein-deficient animals a small but consistent fraction of each mRNA is also present in the non-polysomal, low molecular weight fractions.

Liver function in protein-energy malnutrition measured by cinnamic acid tolerance and benzoic acid tolerance: effect of carnitine supplementation

1. Rats fed on a protein-depleted diet for 8 weeks were repleted for 5 weeks on high-protein (HP), high-protein + 20 g DL-carnitine/kg (HP + C), or low-protein + 20 g DL-carnitine/kg (LP + C) diets. At 4 and 8 weeks of depletion, and 1 and 5 weeks of repletion, rats from each treatment group were given a benzoic acid tolerance test (BATT) or a cinnamic acid tolerance test (CATT) as a measure of liver function. 2. BATT and CATT measured the molar percentage of a test dose (1 mmol/kg body-weight) of benzoic acid or cinnamic acid excreted in the urine as hippuric acid within 24 h. Liver weight, liver lipid levels, and carnitine concentration in plasma and liver were also measured following liver-function testing. 3. BATT and CATT were severely impaired in protein-depleted rats, but returned rapidly to control levels following protein refeeding. Correlations of BATT and CATT with liver lipid concentration were high (r -0.49 and -0.62 respectively), and both tests show promise as clinical tests for liver function in protein-energy malnutrition. 4. Carnitine supplementation was required to return liver carnitine concentration of protein-depleted rats to control levels during repletion, but was not associated with accelerated reduction in liver fat concentration in protein-repleted rats.

[Chronologic studies of the effects of a hypoproteinic diet followed by an equilibrated diet on delta-6 and delta-5 desaturations of linoleic acid in liver microsomes in the rat]

A low protein diet affects amounts of linoleic and arachidonic acids in hepatic microsomal phospholipids of growing rats. Are the changes related to modifications in microsomal delta 6- and delta 5- linoleic acid desaturase activities? Two groups of Wistar rats weighing 80 +/- 5 g at the beginning of the experiment were used: Control group (T) was fed on a 16% gluten + 4% casein diet for 53 days; Experimental group (E) was fed on a 4% gluten + 1% casein diet for 26 days (MP) then Control diet for 27 days (RE). After 2, 14 and 26 days of MP and 2, 15 and 27 days of RE, rats of each group were sacrificed. Protein and water contents of liver, quantitative fatty acid, composition of total lipids in liver and hepatic microsomes were determined. delta 6- and delta 5- linoleic acid desaturase activities were estimated from incubation of liver microsomes with [1-14C] C 18: 2 n-6 or [2(14)C] C 20: 3 n-6 respectively. The low protein diet stops practically ponderal growth. The fatty-acid compositions of microsomal total lipids of E rats were affected in comparison with values of T rats. These modifications persist after 27 days of RE. The C 20: 4 n-6/C 18: 2 n-6 ratio in microsomal total lipids was slightly different between T and E rats but increased strongly during refeeding. Same modifications take place in the fatty-acid composition of hepatic total lipids. After two days of MP, delta 6- and delta 5- desaturase activities were depressed, phenomenon that not persist in the course of MP. These enzyme activities increase to higher values than those of the T after two days of RE.

Kwashiorkor revisited: the pathogenesis of oedema in kwashiorkor and its significance

Cicely Williams, in her original description of kwashiorkor, implied that deficiency of protein in the baby's food could be a main cause of the syndrome. The hallmark of kwashiorkor is oedema. According to the 'classical' theory, an inadequate intake of protein leads to a low plasma albumin concentration, which in turn causes oedema. This theory has been contested from several points of view: that hypoalbuminaemia is not the major factor determining the presence of oedema, and that there is no real evidence of dietary protein deficiency. The resolution of this question is of some importance from the point of view of public health diagnosis and prevention. A crucial point in the argument is the pathogenesis of oedema, which is discussed in some detail. Although it is clearly multifactorial, with electrolyte disturbances--potassium deficiency and sodium retention--playing an important role, it is contended that the classical theory is essentially correct. On the dietary side, recent experimental work supports the earlier view that the development of oedema depends on a relative deficiency of protein with a relative excess of energy. Comparisons of intakes with requirements are unconvincing in view of uncertainty about the validity of the estimates of children's needs for protein.

Nitrosamine metabolism in kwashiorkor rats

The in vitro metabolism of nitrosodimethylamine (NDMA) was studied in liver tissue obtained from male weanling kwashiorkor wistar rats. The elimination of this compound and that of nitrosomorpholine (NMOR) from the blood, after a single intravenous dose, was also investigated. N-demethylase activity in liver microsomes of the test animals was not significantly different from that of the controls although the activity of this enzyme per gram wet liver tissue was considerably reduced in the model animals. On the other hand, the glutathione (GSH) content in liver cytosol of the kwashiorkor animals was much higher than that of the controls. The elimination of NDMA and NMOR from the blood of the experimental animals over 8 hr following i.v. administration of the carcinogens, showed that the clearance rate of each nitrosamine was significantly lower in the kwashiorkor rats.

Hepatic function in rats with dietary-induced fatty liver, as measured by the uptake of indocyanine green

1. The hepatic uptake of indocyanine green (ICG) has been measured in rats receiving a 50 g protein/kg diet for 6, 12 or 20 d or a choline-deficient diet for 2 or 6 d. 2. There was no effect on ICG uptake on the choline-deficient diet, although all the rats developed an intense fatty infiltration of the liver by 6 d. 3. The rats on the 50 g protein/kg diet showed impaired uptake of ICG at 6, 12 and 20 d, which appeared to be related to the extent of fatty infiltration. 4. It is concluded that ICG uptake is predominantly a function of the periportal zone of the liver lobule, and therefore likely to be sensitive to insults that exert their predominant effect in this zone.

Urinary free amino acids pattern in protein-energy malnourished Sudanese children

The urinary free amino acid pattern in a morning urine sample of Sudanese children suffering from Kwashiorkor and marasmus were determined before and during the course of treatment up to the 2nd week. The urinary amino acid/total urinary N (3.62) was found to be almost constant for Kwashiorkor patients, while the mean for marasmic patients was found to be 27. The concentration of leucine, valine, phenylalanine, methylhistidine, lysine, hydroxylysine and beta-amino-isobutyric acid was elevated in marasmic children, while the concentration of most of these amino acids was at a lower level in Kwashiorkor patients. The significance of these differences was discussed in relation to the biochemical detection of these deficiencies in field nutrition surveys.

Selective deficiency of hepatic triglyceride lipase and hypertriglyceridaemia in kwashiorkor

1. Serum postheparin lipolytic activities (PHLA), triglyceride and free fatty acid concentrations were determined in children with kwashiorkor before and after treatment and also in normal control children. 2. Using the range (571-1650 mumol/l) of serum triglyceride of the control children as normal, five (20%) of the twenty-five children with kwashiorkor had low (less than 570 mumol/l), thirteen (52%) had normal (571-1650 mumol/l) and seven (28%) had high (more than 1650 mumol/l) serum triglyceride levels. 3. The serum PHLA did not show any definite correlation with the level of circulating triglycerides, although the lowest levels of PHLA were found in the malnourished children with highest triglyceride level. 4. While the hepatic PHLA in the malnourished children was significantly less than control value, the extrahepatic PHLA did not differ significantly. 5. After treatment, serum PHLA rose significantly and the mean levels were within normal range. 6. Our findings suggest that a defect in catabolism of very-low-density lipoprotein caused by a low hepatic PHLA may cause hypertriglyceridaemia in children with kwashiorkor.

Pathogenesis of oedema in protein-energy malnutrition: the significance of plasma colloid osmotic pressure

1. Rats were made oedematous by feeding them low-protein diets (protein: energy (P:E) 0.005) ad lib., and measurements were made of plasma and interstitial fluid colloid osmotic pressures (πp and πi respectively) and interstitial fluid hydrostatic pressure (Pi) before, and at the onset of, oedema formation. Taken together as (πp − πi + Pi) these forces oppose capillary pressure (Pc) and thus determine rates of transcapillary water filtration. Interstitial fluid was sampled, in non-oedematous and oedematous animals, from perforated capsules implanted subcutaneously for the measurement of Pi. Blood, plasma and interstitial fluid volumes were also determined.

2. In Expt I comparisons were made between animals fed on a control diet (P:E 0.210) and the lowprotein diet. In normal animals the ratio πp:πi was approximately 2, but in protein deficiency it was increased since reductions in the absolute value of πi matched those in πp. These changes were observed 2 weeks after the start of the experiment and became more exaggerated when oedema appeared (weeks 18–22).

3. Pi was normally negative with respect to atmospheric pressure but increased to values close to zero when oedema formation occurred.

4. Despite the reductions in πp that were seen in the protein-deficient animals the sum of the forces opposing filtration (πp − πi + Pi) did not change significantly during the experiment.

5. Plasma and interstitial fluid volumes expressed per kg body-weight (measured using 125I-albumin and 35SO42−) were unchanged as πp initially decreased in the protein-deficient animals but increased markedly with the onset of oedema.

6. In Expt 2 comparisons were made between animals fed the low-protein diet ad lib. and others fed on the control diet in restricted amounts so that weight loss was the same in the two groups of animals.

7. The wasting induced by restriction of the control diet did not produce reductions in πp or πi and values for Pi were normal. Changes in the animals fed on the low-protein diet were similar to those observed in Expt I. By using 51Cr-labelled erythrocytes it was shown that the expansion in plasma volume that occurred when oedema appeared in the protein-deficient animals was mainly due to a reduction in total erythrocyte volume. Blood volume did not increase significantly.

8. It was concluded that in the hypoproteinaemia induced in the experimental animals reductions in the value of πp, which might otherwise result in an imbalance of forces that would produce excessive rates of transcapillary water filtration, were compensated for by reductions in πi. Increases in Pi also compensated but were quantitatively less important.

9. The significance of the results is discussed in terms of the pathogenesis of oedema in kwashiorkor and the concept of an oncotic threshold for oedema formation in hypoproteinaemia.

Total body water in malnutrition: the possible role of energy intake

1. Total body water (TBW) was measured using tritiated water in sixty-five children. The measurements were distributed throughout rehabilitation in order to define the effect of changing energy intakes. 2. Oedematous children had a high TBW which decreased to the normal range during loss of oedema providing they were not receiving more than maintenance amounts of energy during this period. 3. Marasmic children who had not received greater than maintenance amounts of energy had a normal TBW. 4. Treatment with a high-energy diet was associated with an initial increase in TBW. 5. The possible mechanisms for this phenomenon are discussed.

High energy feeding in protein-energy malnutrition

The use of a high-fat diet in malnourished children produced accelerated growth of lean tissues as well as adipose tissue, and resulted in rapid nutirtional rehabilitation in 25 seriously malnourished babies. Such diets are easy to prepare and relatively cheap, and they offer important advantages over conventional feeding in the hospital treatment of malnourished children.

[Protein levels of bean and cassava flour mixture. 2. Digestibility and biological value]

Através da elaboração de balanço nitrogenado, o autor determinou o valor biológico da farinha de feijão pura e de duas combinações diferentes desta com a farinha de mandioca, comparando-as com a caseína. O estudo foi realizado considerando-se dois períodos diferentes de adaptação. — se aceitarmos um período de adaptação de urna semana como válida, observamos diferença significativa ao nível de 5%, somente entre os valores biológicos do feijão puro puro e da Mistura I. — considerando-se que o período de adaptação não deve ser menor que 12 dias, os valores biológicos do feijão puro e das duas misturas estudadas são inferiores ao da caseína, ao nivel de significancia de 5%. O coeficiente de digestibilidade dos alimentos não pode ser responsável pelas diferenças dos valores biológicos obtidos e do nivel de crescimento dos animais.

[Criteria for indirect evaluation of protein status of organisms]

The value of the determination of blood protein and amino acids is discussed. The results suggest that the serum albumin concentration is perhaps not very sensitive index of the protein value. But the level of plasma amino acids may yield valuable information of the protein state. However, there is no evidence that the use of the plasma amino-acid level as an indicator of the protein value is exclusively profitable. Determination of the urea level in the blood under standardized experimental conditions may be a good indirect estimation of the adequate protein ratio in an individual. Various enzyme activities seem to be no conclusive indices of the state of protein nutrition. A simple determination of the urinary nitrogen might perhaps be a satisfactory method for evaluating the protein quality for an individual. The determination of urinary urea closes not seem to be a more valuable indicator than the protein state. It has been shown that the diameter of the myofibrils depends on the adequate protein ratio in the feed. The weights of several muscles and different organs are also in agreement with the supply of protein. Furthermore, the author discusses the correlation of the nitrogen concentration in a single leg of the rat to that in the total body as a possible indirect method for determining the protein value.

The effect of work level and dietary intake on water balance and the excretion of sodium, potassium and iron in a hot climate

1. The dietary intake, and urinary, cutaneous and faecal loss of water, sodium, potassium and iron have been studied in young men living and performing moderate work in a hot climate. The dietary intakes of K and Fe were lowered during part of the study.

2. The subjects were already somewhat acclimatized to heat; further acclimatization was achieved when they were performing work, and this was assessed in terms of the increase in their rate of sweating.

3. The subjects tended to be in marginally negative Na balance, partly owing to lowered Na intakes. Intakes and outputs of K were in balance. Losses of K in sweat amounted to 15% of intake when the dietary level was reduced.

4. The subjects were slow in adapting to changes in Fe intake, 8 d being an insufficient period for adaptation after their intake had been halved. Losses of Fe in sweat were approximately 0·3 mg/d, or one-third of the estimated requirement for absorbed Fe.

5. It is concluded that Fe losses in sweat could be a significant factor in Fe depletion if dietary Fe was low or unavailable, as there was no evidence that a low intake and absorption affected sweat losses.

Liver structure and function following small bowel resection

The observation that patients with extensive small bowel resection have impaired hepatocellular function with reduced BSP clearance and fatty change in biopsies from the liver led to a systematic study of liver structure and function following proximal and distal small bowel resection in the rat. While anaesthesia and surgery impaired BSP clearance per se, small bowel resection further reduced BSP clearance with impairment of both uptake and excretion phases of BSP excretion. The increased BSP retention was more marked after distal than after proximal small bowel resection, but in both experimental groups the abnormalities of BSP excretion spontaneously returned to normal three to four weeks after surgery. Circulating liver enzymes were normal but serum alkaline phosphatase was significantly depressed, particularly after distal resection. Isoenzyme studies showed that the depression of serum AP was due to a reduced intestinal isoenzyme. While serum levels remained consistently depressed up to eight weeks after proximal resection, in parallel with mucosal regeneration, serum AP returned to normal two to four weeks after ileectomy. While these minor changes in hepatic structure and function would normally be of little clinical importance, the additional insult of hepatic dysfunction may well be important in malnourished patients after extensive small bowel resection.

Serum transferrin of pregnant mothers related to birth weight of their infants

In a study of 81 pregnant mothers and their newborn infants the maternal serum transferrin concentration at about 24 weeks of gestation was shown to have a low but significant correlation with infant birth weight (r=0.33; P<0.01). Maternal undernutrition is suggested as a possible cause of low serum transferrin levels.

Glucose tolerance and insulin sensitivity in malnourished children

1. In malnourished, compared with recovered children, fasting blood glucose concentrations were low and there was impaired peripheral glycolysis as shown by a failure of blood lactate to rise after glucose was injected intravenously.

2. Homogenates of muscle biopsies from malnourished and recovered children produced equal amounts of lactate when incubated anaerobically with various substrates, but when compared with homogenates of biopsies from normal children the pattern suggested an impairment of glycolysis.

3. The rate of glucose disappearance after intravenous glucose was slow in the malnourished child and there was possibly diminished sensitivity to exogenous insulin.

4. Isocaloric diets relatively high or low in fat were fed to children who had recovered from malnutrition. Glucose tolerance, insulin sensitivity, fasting plasma insulin and insulin response to intravenous glucose were all the same in children on either diet.