Nourishing the dysfunctional gut and whey protein

Protein metabolism and requirements in the ICU

The critically ill patient is highly catabolic, loosing significant amounts of protein and muscle. This proteolysis may induce a loss of 20% of the muscle mass in 10 days of hospitalization. Muscle loss may be assessed measuring urinary nitrogen excretion, muscle mass by ultrasound, bioimpedance, computerized tomography or MRI. To reduce the negative nitrogen balance, protein can be administrated enterally, or parenterally through amino acids as a part of parenteral nutrition. ESPEN guidelines recommend to administer 1.3 g/kg/day of protein to critically ill patients but this recommendation should be adapted according to clinical conditions. Elderly, obese, trauma, burn, acute kidney injury patients should receive larger amount of protein.

Achieving Protein Targets in the ICU Using a Specialized High-Protein Enteral Formula: A Quality Improvement Project

BACKGROUND

To meet protein needs in critical illness (CI), guidelines suggest ≥1.2-2.5 g protein/kg/d; however, most intensive care unit (ICU) patients receive ≤0.7 g/kg/d. Higher protein enteral nutrition (EN) formulas may be part of the solution to provide prescribed protein. Our objective was to demonstrate that an EN formula with 37% protein can deliver ≥80% of prescribed protein, without overfeeding calories within the first 5 days of feeding and to describe ICU clinicians' experience.

METHODS

This quality improvement (QI) project included patients requiring exclusive EN for up to 5 days from 6 Canadian ICUs. Rationale for choosing formula, patient's BMI (kg/m² ), nutrition targets, daily protein and energy delivered, feeding interruptions, and general tolerance were recorded.

RESULTS

Forty-four of 49 patients received the formula ≥2 days. Average protein prescribed was 137.5 g/d (82.5-200) or 1.9 g/kg/d (1.5-2.5). Average protein delivered was 116.9 g/d (33.5-180) or 1.6 g/kg/d (0.4-2.4). Seventy-five percent to 83% of patients received ≥80% prescribed protein on days 2-5. Average energy prescribed was 1638.6 kcal/d (990-2500) or 17.8 kcal/kg (11-26). Average energy delivered was 1523.9 kcal/d (693.0-2557.5) or 17.3 kcal/kg/d (1.35-64.7). The formula was well tolerated with no gastrointestinal symptoms reported in 38 (86%) patients. The most common reasons to prescribe the formula were obesity and use of fat-based medications.

CONCLUSIONS

We demonstrated in a QI study that a high-protein EN formula was tolerated in a small, heterogeneous group of ICU patients and effective in meeting protein targets without overfeeding.

Gastric Emptying and Gastrointestinal Transit Compared among Native and Hydrolyzed Whey and Casein Milk Proteins in an Aged Rat Model

Little is known about how milk proteins affect gastrointestinal (GI) transit, particularly for the elderly, in whom digestion has been observed to be slowed. We tested the hypothesis that GI transit is faster for whey than for casein and that this effect is accentuated with hydrolysates, similar to soy. Adult male rats (18 months old) were fed native whey or casein, hydrolyzed whey (WPH) or casein (CPH), hydrolyzed blend (HB; 60% whey:40% casein), or hydrolyzed soy for 14 days then treated with loperamide, prucalopride, or vehicle-control for 7 days. X-ray imaging tracked bead-transit for: gastric emptying (GE; 4 h), small intestine (SI) transit (9 h), and large intestine (LI) transit (12 h). GE for whey was 33 ± 12% faster than that for either casein or CPH. SI transit was decreased by 37 ± 9% for casein and 24 ± 6% for whey compared with hydrolyzed soy, and persisted for casein at 12 h. Although CPH and WPH did not alter transit compared with their respective intact counterparts, fecal output was increased by WPH. Slowed transit by casein was reversed by prucalopride (9-h), but not loperamide. However, rapid GE and slower SI transit for the HB compared with intact forms were inhibited by loperamide. The expected slower GI transit for casein relative to soy provided a comparative benchmark, and opioid receptor involvement was corroborated. Our findings provide new evidence that whey slowed SI transit compared with soy, independent of GE. Increased GI transit from stomach to colon for the HB compared with casein suggests that including hydrolyzed milk proteins in foods may benefit those with slowed intestinal transit.

Influence of Bovine Whey Protein Concentrate and Hydrolysate Preparation Methods on Motility in the Isolated Rat Distal Colon

Whey protein concentrate (WPC) and hydrolysate (WPH) are protein ingredients used in sports, medical and pediatric formulations. Concentration and hydrolysis methods vary for whey sourced from cheese and casein co-products. The purpose of this research was to investigate the influence of whey processing methods on in vitro gastrointestinal (GI) health indicators for colonic motility, epithelial barrier integrity and immune modulation. WPCs from casein or cheese processing and WPH (11% or 19% degree of hydrolysis, DH) were compared for their effects on motility in a 1 cm section of isolated rat distal colon in an oxygenated tissue bath. Results showed that WPC decreased motility irrespective of whether it was a by-product of lactic acid or mineral acid casein production, or from cheese production. This indicated that regardless of the preparation methodology, the whey protein contained components that modulate aspects of motility within the distal colon. WPH (11% DH) increased contractile frequency by 27% in a delayed manner and WPH (19% DH) had an immediate effect on contractile properties, increasing tension by 65% and frequency by 131%. Increased motility was associated with increased hydrolysis that may be attributed to the abundance of bioactive peptides. Increased frequency of contractions by WPH (19% DH) was inhibited (by 44%) by naloxone, implicating a potential involvement of opioid receptors in modulation of motility. Trans-epithelial electrical resistance and cytokine expression assays revealed that the WPC proteins studied did not alter intestinal barrier integrity or elicit any discernible immune response.

Emerging trends in nutraceutical applications of whey protein and its derivatives

The looming food insecurity demands the utilization of nutrient-rich residues from food industries as value-added products. Whey, a dairy industry waste has been characterized to be excellent nourishment with an array of bioactive components. Whey protein comprises 20 % of total milk protein and it is rich in branched and essential amino acids, functional peptides, antioxidants and immunoglobulins. It confers benefits against a wide range of metabolic diseases such as cardiovascular complications, hypertension, obesity, diabetes, cancer and phenylketonuria. The protein has been validated to boost recovery from resistance exercise-injuries, stimulate gut physiology and protect skin against detrimental radiations. Apart from health invigoration, whey protein has proved its suitability as fat replacer and emulsifier. Further, its edible and antimicrobial packaging potential renders its highly desirable in food as well as pharmaceutical sectors. Considering the enormous nutraceutical worth of whey protein, this review emphasizes on its established and emerging biological roles. Present and future scopes in food processing and dietary supplement formulation are discussed. Associated hurdles are identified and how technical advancement might augment its applications are explored. This review is expected to provide valuable insight on whey protein-fortified functional foods, associated technical hurdles and scopes of improvement.

Safety and Tolerability of Enteral Protein Supplementation for Infants With Brain Injury

BACKGROUND

We hypothesized that enteral protein supplementation in infants with brain injury would be safe and well tolerated and improve growth.

MATERIALS AND METHODS

Twenty-five infants with perinatal brain injury were randomized to a high-protein (4 g/kg/d) or standard-protein diet and followed for 12 months.

RESULTS

The whey protein powder was well tolerated by 9 of the 13 infants in the high-protein group, and no adverse events related to the supplement were seen. The protein group had higher serum urea nitrogen at 10 and 30 days after study initiation but no difference in bicarbonate levels at either time point. Infants in the protein group maintained their weight z score from birth to 3 months of age, while infants in the standard group had a significant decrease in their weight z score over the same time period.

CONCLUSION

These results suggest that enteral protein supplementation may reduce growth failure in infants with brain injury.