Role of meal carbohydrate content for the imbalance of plasma amino acids in patients with liver cirrhosis

A Low Daily Intake of Simple Sugars in the Diet Is Associated with Improved Liver Function in Cirrhotic Liver Transplant Candidates

(1) Background: We investigated, for the first time, whether dietary simple sugar intake affects MELD score changes over time in a cohort of cirrhotic liver transplant candidates. (2) Methods: the MELD score, dietary habits using a 3-day food diary, and visceral adipose tissue index (VATI) measured with CT scan were assessed in 80 consecutive outpatient cirrhotic patients at baseline, after counseling to follow current nutritional guidelines. The MELD score was reassessed after six months and the DELTA-MELD was calculated as the MELD at the second assessment minus the MELD at baseline. (3) Results: Compared with the baseline, the MELD score of cirrhotic patients at the end of the study was decreased, stable, or increased in 36%, 8% and 56% of patients, respectively. In separate multiple linear regression models, DELTA-MELD was positively and independently correlated with the daily intake of simple sugars expressed in g/kg body weight (p = 0.01) or as a percentage of total caloric intake (p = 0.0004) and with the number of daily portions of fruit, added sugar, jam, and honey (p = 0.003). These associations were present almost exclusively in patients with VATI above the median value. (4) Conclusions: In cirrhotic patients with high amounts of visceral adipose tissue the consumption of simple sugars and fructose should be limited to improve their clinical outcome.

Nutrition Assessment and Management in Patients with Cirrhosis and Cognitive Impairment: A Comprehensive Review of Literature

Hepatic encephalopathy (HE) represents a common complication of liver cirrhosis. Protein-calorie malnutrition is frequently encountered in the cirrhotic patient and its most obvious clinical manifestation is sarcopenia. This condition represents a risk factor for HE occurrence because skeletal muscle acts as an alternative site for ammonium detoxification. Preventive intervention through an adequate assessment of nutritional status should be carried out at early stages of the disease and in a multidisciplinary team using both non-instrumental methods (food diary, anthropometric measurements, blood chemistry tests) and instrumental methods (bioimpedance testing, DEXA, CT, indirect calorimetry, dynamometry). Dietary recommendations for patients with HE do not differ from those for cirrhotic patient without HE. Daily caloric intake in the non-obese patient should be 30–40 Kcal/Kg/day with a protein intake of 1–1.5 g/Kg/day, especially of vegetable origin, through 4–6 meals daily. In patients with HE, it is also essential to monitor electrolyte balance, supplementing any micronutrient deficiencies such as sodium and zinc, as well as vitamin deficiencies because they can cause neurological symptoms similar to those of HE. In light of the critical role of nutritional status, this aspect should not be underestimated and should be included in the diagnostic–therapeutic algorithm of patients with HE.

Dietary Interventions in Liver Cirrhosis

Liver cirrhosis is associated with significant nutritional risks that often result in serious hepatic complications and poor survival rates. Diet is an important but underutilized aspect in the treatment modality of cirrhosis. Therefore, the aims of this review are to ascertain nutritional risks associated with its pathophysiology and to summarize existing evidence that support dietary recommendations for managing this patient population. Alterations in substrate utilization for energy production is a main feature of liver cirrhosis, resulting in increased catabolism of protein stores and a predisposition toward protein-energy malnutrition, even in the early stages of the disease. The body of evidence suggests that a high energy and protein (>1.2 g/kg body weight/d) diet consumed frequently and late in the evening is effective in improving nutritional status of these patients and has been associated with improved hospitalization and mortality rates. The use of branched-chain amino acid supplementation shows promise in reducing cirrhosis-related complications but are currently limited by adverse gastrointestinal symptoms and poor palatability. Furthermore exploration of dietary manipulation of branched-chain amino acid warrants further examination. Evidence is also accumulating that protein intake should not be restricted in patients with hepatic encephalopathy with earlier studies of protein restriction neglecting to account for the relative increase in fermentable fiber which would reduce the absorption of ammonia into the portal system in a way similar to supplementation with lactulose. Finally, a major finding of this review is the need to improve the quality and quantity of dietary intervention studies for patients with liver cirrhosis, particularly with the use of partial or whole dietary sources. In conclusion, dietary management of cirrhosis is not a one-size fits all approach but should be implemented earlier on in the treatment algorithm to improve the clinical prognosis of cirrhosis.

Protein tolerance to standard and high protein meals in patients with liver cirrhosis

AIM

To investigate the plasma amino acid response and tolerance to normal or high protein meals in patients with cirrhosis.

METHODS

The plasma amino acid response to a 20 g mixed protein meal was compared in 8 biopsy-proven compensated cirrhotic patients and 6 healthy subjects. In addition the response to a high protein meal (1 g/kg body weight) was studied in 6 decompensated biopsy-proven cirrhotics in order to evaluate their protein tolerance and the likelihood of developing hepatic encephalopathy (HE) following a porto-caval shunt procedure. To test for covert HE, the “number connection test” (NCT) was done on all patients, and an electroencephalogram was recorded in patients considered to be at Child-Pugh C stage.

RESULTS

The changes in plasma amino acids after a 20 g protein meal were similar in healthy subjects and in cirrhotics except for a significantly greater increase (P < 0.05) in isoleucine, leucine and tyrosine concentrations in the cirrhotics. The baseline branched chain amino acids/aromatic amino acids (BCAA/AAA) ratio was higher in the healthy persons and remained stable-but it decreased significantly after the meal in the cirrhotic group. After the high protein meal there was a marked increase in the levels of most amino acids, but only small changes occurred in the levels of taurine, citrulline, cysteine and histidine.The BCAA/AAA ratio was significantly higher 180 and 240 min after the meal. Slightly elevated basal plasma ammonia levels showed no particular pattern. Overt HE was not observed in any patients.

CONCLUSION

Patients with stable liver disease tolerate natural mixed meals with a standard protein content. The response to a high protein meal in decompensated cirrhotics suggests accumulation of some amino acids but it did not precipitate HE. These results support current nutritional guidelines that recommend a protein intake of 1.2-1.5 g/kg body weight/day for patients with cirrhosis.

Branched-chain amino acids in liver disease: new aspects of long known phenomena

PURPOSE OF REVIEW

To provide an overview of findings on the role of branched-chain amino acids (BCAAs) in the pathophysiology, pathobiochemistry, and treatment of liver cirrhosis and its complications that have been published since or were not included in the last review on this topic in 2007 in this journal.

RECENT FINDINGS

There has been continued interest in the potential of oral BCAA supplements in improving energy metabolism, nitrogen metabolism, carbohydrate metabolism, insulin resistance, severity of liver disease, serum albumin levels, quality of serum albumin, or postoperative complication rates. Unfortunately, many trials suffer from lacking or inadequate controls or small sample size. In a fine example of scientific perseverance, Dutch researchers uncovered the long-known phenomenon of ingested blood being highly comagenic in patients with cirrhosis to be due to the low biologic value of blood protein. The absence of isoleucine and the abundance of leucine in the hemoglobin molecule by way of BCAA antagonism leads to impaired protein synthesis and azotemia paving the way for hepatic encephalopathy.

SUMMARY

Recognizing hypoisoleucinemia and BCAA antagonism following gastrointestinal bleeding, and its successful treatment by isoleucine infusion has advanced our understanding of the role of BCAA in liver cirrhosis.

Biological variation of free plasma amino acids in healthy individuals

BACKGROUND

Biological variation data for free plasma amino acids are lacking from the more comprehensive databases. Therefore, we determined the intra- and inter-individual components of variation in healthy subjects. These data were used to define desirable goals for imprecision, bias and total error, indices of individuality and reference change values.

METHODS

Plasma samples were collected from 11 volunteers at weekly intervals over 5 weeks. Free plasma amino acids were analyzed by reversed-phase HPLC and analytical and biological variation data were derived using ANOVA.

RESULTS

Intra-individual coefficients of variation ranged from 9.5% to 46.4%, with lower values among the essential amino acids. The mean inter-individual coefficient of variation was 46.6% and was higher than intra-individual values for all amino acids. Thus, indices of individuality were below 0.8. Reference change values ranged from 30.9% to 128.4% and total error values ranged from 15.2% to 61.0%.

CONCLUSIONS

Plasma amino acids exhibit relatively low intra-individual coefficients of variation, with essential amino acids showing tighter homeostatic control. Analytical quality goals can be reasonably achieved with current methods. Reference intervals are of limited value in the detection of unusual results in an individual. Therefore, comparison of serial results by means of the reference change values is recommended.

Branched-chain amino acids induce neurotoxicity in rat cortical cultures

The higher risk for amyotrophic lateral sclerosis (ALS) among professional soccer players, recently reported in Italy, has stimulated investigations in the search for environmental factors that may be at the origin of the increased susceptibility to the disease. Here we studied if high concentrations of branched-chain amino acids (BCAAs), widely used among athletes as dietary integrators to improve physical performance, may be related to an excitotoxic neuronal cell damage. Our results show that (i) high concentrations of BCAAs are neurotoxic and increase excitotoxicity in cortical neurons; (ii) neurotoxicity is brain area specific, being detected in cortical, but not in hippocampal neurons; (iii) it is related to NMDA receptor overstimulation, since it is abolished in the presence of MK-801, a specific NMDA channel blocker; (iv) it depends on the presence of astrocytes. We describe here a possible biological link between an environmental factor (high dietary intake of BCAAs) and the increased risk of ALS among soccer players.