New support for branched-chain amino acid supplementation in advanced hepatic failure

Nutritional supplementation with branched-chain amino acids (BCAA) has been a topic of considerable debate for more than two decades. Several studies have demonstrated that supplementation with BCAA is associated with improvement of the catabolic state commonly seen in people with cirrhosis, whereas other studies have showed an improvement in portosystemic encephalopathy in patients with liver disease. Some studies have also shown there to be no benefit in BCAA supplementation in advanced cirrhosis. A recent large clinical trial showed that long-term BCAA supplementation may be useful in preventing progressive hepatic failure and improving liver function in some patients.     

Influence of branched-chain amino acid supplementation on urinary protein metabolite concentrations after swimming

OBJECTIVE: The influence of branched-chain amino acid (BCAA) supplementation on urinary urea nitrogen, hydroxyproline (HP), and 3-methylhistidine (3MH) concentrations after 25 min of breast stroke exercise (65-70% maximum heart rate reserved, 65-70% HRRmax) followed by a 600 m crawl stroke competition was investigated in a double-blind, counter-balanced study. METHODS: Male university students (19-22 years old) majoring in physical education participated in the study. Based on the previous swimming time of a 600 m crawl stroke, the participants were divided into two groups: placebo (n = 9, BMI = 24.2 +/- 2.1 kg/m2; 12 g of glucose/day; in capsules) and BCAA (n = 10, BMI = 22.7 +/- 1.5 kg/m2; 12 g of BCAAs/day; in capsules: leucine 54%, isoleucine 19%, valine 27%) groups. The participants maintained a regular dietary intake (except the prescribed breakfast on day 15) and exercise activity at a moderate/low intensity (60-70% HRRmax, swimming and rowing, approximately 1.5 hour/day) during the 15-day study. A prescribed exercise program was performed on day 15. Urinary and blood samples were collected before, during, and after the prescribed exercise for the measurements of the urinary urea nitrogen, HP, and 3MH concentrations in urine, as well as the glucose, lactate, glutamine, alanine, and BCAA concentrations in plasma. RESULTS: Two weeks of dietary supplementation did not induce any changes in the plasma glucose and total BCAA concentrations of either group, nor in the urinary urea nitrogen, HP, and 3MH concentrations in urine. On day 15, after 25 min of breast stroke exercise and a 600 m crawl stroke competition, plasma glucose concentration decreased significantly (p < 0.05) whereas plasma lactate concentration increased significantly (p < 0.05) in both groups. The exercise program prescribed in the study did not affect urinary urea nitrogen, HP, and 3MH concentrations. Twenty hours after the competition, however, a significant increase in the concentrations of urinary urea nitrogen, HP, and 3MH was found in the placebo group (p < 0.05), but not in the BCAA group. CONCLUSIONS: The results obtained in this study suggest that swimming induced muscle proteolysis was prevented by BCAA supplementation. The mechanism could be attributed to the availability of ammonia provided by the oxidation of supplemented BCAAs during exercise.     

Update on nutritional supplementation with branched-chain amino acids

PURPOSE OF REVIEW: Branched-chain amino acids (BCAAs) have a peculiar role in whole-body nitrogen metabolism. BCAAs are not only a substrate for protein synthesis, but also modulate several components of the synthetic machinery and help to conserve muscle mass; accordingly, several conditions, characterized by protein loss and catabolic status, are likely to benefit from amino acid administration. In addition, the competitive action of BCAAs on amino acid transport across the blood-brain barrier may ultimately alter the synthesis of brain neurotransmitters, involved in neurological diseases. RECENT FINDINGS: Both putative actions of BCAAs have been tested in controlled clinical studies in the last few years. The beneficial effects on nutrition were reported to improve muscle performance, reduce protein loss during bed-rest, favor weight loss in obesity, reduce catabolism in trauma patients and improve clinical outcomes in patients with advanced cirrhosis. In this last area, the effects on nutrition might be coupled with the effects on hepatic encephalopathy mediated by improved neurotransmission, successfully tested in mania, tardive dyskinesia and spinocerebellar degeneration. SUMMARY: After 30 years of investigation with BCAAs, new studies each year provide further evidence supporting their beneficial effect in a variety of diseases. There is a need for long-term, randomized clinical studies, both in the prevention and in the treatment of various pathological conditions.     

Nutritional treatment of liver cirrhosis by branched-chain amino acid-enriched nutrient mixture

The effects of branched-chain amino acid (BCAA)-enriched nutrient mixture (nutrient-mixture) on the nitrogen metabolism and nutritional state were clinically investigated in 10 patients with liver cirrhosis. Nutrient-mixture-supplemented diet was prepared by adding 150 g nutrient-mixture daily to low-protein diet, and comparisons were made with a regular diet (control diet). Each diet supplied 2,100 kcal energy and 80 g protein per day. Patients were given control diet for 2 weeks and thereafter treated successively with nutrient-mixture-supplemented and control diet each for 2 weeks. Nitrogen balance improvement and positive balance were observed during the feeding of nutrient-mixture-supplemented diet. The composition of nitrogen compounds in urine and the fecal nitrogen excretion did not alter during the test period. Plasma aromatic amino acid (AAA) concentrations decreased and BCAA/AAA molar ratios increased significantly during the 1st and 2nd week of nutrient-mixture-supplemented diet administration. Plasma methionine concentration also decreased in the 1st week. Plasma pre-albumin levels rose significantly during the 1st and 2nd week of nutrient-mixture-supplemented diet administration, and the number connection test improved significantly following the supplemented diet. These results suggest that the use of nutrient-mixture in the nutritional treatment of liver cirrhosis had no deleterious effects on nitrogen metabolism and is useful for the improvement of plasma amino acid imbalance and protein-energy malnutrition.     

Role of branched-chain amino acids in liver disease: the evidence for and against

PURPOSE OF REVIEW: There is ample evidence that patients with liver disease have an ongoing energy and protein catabolism. Nutritional management in these patients must receive high priority. The administration of branched-chain amino acids to patients with liver disease has been a controversial subject. This review is an update on the data available from various studies involving branched-chain amino acids supplementation in patients with chronic liver disease and associated complications. RECENT FINDINGS: This review summarizes the results of nutritional interventions involving branched-chain amino acids supplementation carried out in different centres around the world. It is interesting to note that no toxic effects of branched-chain amino acids supplementation have been reported in any of these trials. SUMMARY: Administration of branched-chain amino acids stimulates hepatic protein synthesis in patients with chronic liver disease and this could contribute significantly to improving their nutritional status, and result in a better quality of life. The beneficial role of branched-chain amino acids supplementation in patients with chronic hepatic encephalopathy has been clearly documented in some studies but the exact mechanism of action is still not clear.     

The branched-chain amino acid antagonism in chicks

The effects of dietary supplements of branched-chain amino acids on growth, food consumption and metabolism in chicks were investigated. When an adequate diet contained 1.20, 1.60, 2.25, 3.75, or 5.00% leucine, increasing leucine content caused reduced food consumption and weight gains, coupled with impaired efficiency of food utilization. When the diet deficient in branched-chain amino acids contained 0.98, 1.46, 2.25, 3.75, or 5.00% leucine, increasing leucine resulted in increased food consumption and reduced efficiency of food utilization when levels of leucine up to 3.75% were fed. Excess leucine depressed plasma concentrations of isoleucine and valine. Excesses of isoleucine or valine caused smaller depressions of concentrations of the other two branched-chain amino acids. All these effects were seen during the first 8 days of experiment, after which they diminished or disappeared. Muscle branched-chain amino acid aminotransferase (BCAT) (L-leucine:2-oxoglutarate aminotransferase, EC 2.6.1.6) activity was increased in chicks fed excess leucine but not in those fed excess isoleucine or valine. Hepatic alpha-ketoisocaproic dehydrogenase (KADH) (2-oxoisocaproate:lipoate oxidoreductase, EC 1.2.4.3) activity and muscle polyribosomal aggregation were unaffected by diet. When chicks were fed diets containing either 0.98 or 2.25% leucine, production of 14CO2 from [1-14C]isoleucine and [1-14C]valine was increased in chicks fed the higher level of leucine. The increase was small in both cases, representing approximately 2% of consumed isoleucine and valine. Increased production of 14CO2 was observed within 12 hours of feeding excess leucine; however, BCAT increased only after 2 to 4 days. No differences were seen in excreted 14C or in the relative distribution of 14C along the small intestine. We conclude that the chick is able to adapt in part to excesses of dietary leucine and that the branched-chain amino acid antagonism may involve increased catabolism of the limiting branched-chain amino acids.     

Enriched branched-chain amino acid formula versus a casein-based supplement in the treatment of cirrhosis

An orally administered branched-chain amino acid (BCAA) rich supplement (T), Travasorb-Hepatic was compared to a casein based supplement (E), Ensure, in a randomized double-blind cross-over study in eight malnourished, stable cirrhotics unable to achieve a daily dietary protein intake of 1.0 g/kg. Doses of antiportal systemic encephalopathy drugs remained constant and a baseline 1000 kcal, 40 g dietary protein intake was encouraged. To this diet, supplemental protein was added in daily 20-g increments to a maximum of 60 g supplemental protein. Mental status, asterixis, and number connection tests were assessed daily and an antiportal systemic encephalopathy index calculated. There was no significant difference in the mean intake of dietary protein (T, 33.7 +/- 4.0 g; E, 26.7 +/- 10.8 g), supplemental protein (T, 43.1 +/- 8.3 g; E, 47.9 +/- 7.1 g), or N2 balance (T, 4.2 +/- 3.7 g; E, 3.4 +/- 4.4) between treatment trials. The antiportal systemic encephalopathy index improved on E, with no significant change in the BCAA:aromatic acid molar ratio. This ratio improved on T (1.02 +/- 2.0 to 2.7 +/- 1.1), but was not accompanied by improvement in the antiportal systemic encephalopathy index. The improved protein tolerance in both groups was not further increased by a highly enriched BCAA formula compared to one with a moderate BCAA content from a natural dietary protein source. Thus, both conventional casein-based supplements and enriched BCAA formulas are well tolerated and can be safely and effectively used as an integral part of diet therapy.     

The optimal branched-chain to total amino acid ratio in the injury-adapted amino acid formulation

Several recent studies have suggested that solutions containing increased amounts of branched-chain amino acids (BCAA) might be useful in the treatment of patients with trauma and/or sepsis. In this study we investigated the optimal amount of BCAA in a balanced nutritional solution in an injured rat laparotomy model. The amino acid content of a standard BCAA-enriched amino acid solution was enriched to 40, 45, and 50% by the addition of equimolar amounts of the three BCAA. Rats were infused with either 3.6 cal/100 g body weight/24 hr or with 18 cal/100 g body weight/24 hr with either a 40, 45, or 50% BCAA mixture and evaluated for nitrogen balance, plasma amino acid levels, and levels of plasma blood urea nitrogen, creatinine, glucose, albumin, and blood ammonia. Nitrogen balance was negative in rats receiving only 3.6 cal/100 g body weight/24 hr, but was least negative in the group receiving 45% BCAA. Nitrogen balance was positive in groups receiving 18 cal/100 g body weight/24 hr, but was most positive in groups receiving 40 or 45% BCAA-containing solutions. Plasma amino acid patterns were least distorted in the 40 and 45% formulations. Blood ammonia was highest in the 40% BCAA group and plasma albumin was best maintained in the 45% BCAA group regardless of the amount of caloric supply. The results suggest that a 45% BCAA-enriched solution is the most appropriate in this injured rat model.     

Standard or branched-chain amino acid infusions as short-term nutritional support in liver cirrhosis?

The metabolic effects of selected and branched-chain amino acid (BCAA)-enriched parenteral solutions were studied in liver cirrhosis. After 3 days of an oral protein-free diet with balanced amino acid (AA) infusion, 36 cirrhotic patients without encephalopathy were randomly divided into four groups. Groups A and B were infused for 5 days with BCAA (valine, leucine, isoleucine) at doses of 0.5 and 1.0 g/kg/day, respectively, as the only nitrogen source. Group C received 0.8 g/kg of essential and nonessential AA solution with a prevalence of BCAA; the last group (D) continued the basic standard diet, as control. Routine chemistry, urinary nitrogen losses, nitrogen balance, and the whole plasma AA pattern were detected before and after the treatment period. BCAA alone led to an impressive and significant improvement in the basic AA pattern in both the A and B groups. The same results were obtained in group C for plasma AA. In particular, the ratio of BCAA to aromatic amino acids in groups A, B, and C was significantly increased (p less than 0.01, less than 0.02, less than 0.02, respectively). In group D the AA pattern and the BCAA/aromatic amino acid ratio remained unchanged. The negative nitrogen balance of the base state remained unchanged after 0.5 g of BCAA (A); it improved significantly and became positive during and after the infusions of a double dose of BCAA (B), as it did in the case of selective solutions (C), although to a lesser extent; the negative nitrogen balance of the control group showed only a slight improvement.(ABSTRACT TRUNCATED AT 250 WORDS)     

Activation of liver branched-chain alpha-keto acid dehydrogenase in rats by excesses of dietary amino acids

As part of an effort to explain the leucine-induced depressions of plasma isoleucine and valine concentrations, and the concomitant stimulation of valine oxidation in vivo, branched-chain alpha-keto acid dehydrogenase (BCKAD) activity was measured in livers from rats that were fed for only 6 h/d large quantities of individual amino acids in a low protein diet. Preincubation of homogenates with buffer containing Mg2+ and Ca2+ allowed estimation of fully active complex. Cytosolic and mitochondrial branched-chain-amino-acid aminotransferase (BCAAT) activities were also measured in livers of rats fed an excess of leucine. The percentage of BCKAD in the active form in livers of rats fed the low protein diet containing an excess of leucine, isoleucine, valine or phenylalanine for 2 d was double that of rats fed the low protein control diet (control, leucine, isoleucine, valine and phenylalanine groups having, respectively, 45 +/- 2, 85 +/- 7, 85 +/- 3, 95 +/- 5, and 81 +/- 4% of hepatic BCKAD in the active form). Consumption of a low protein diet containing an excess of leucine had no significant effect on either cytosolic or mitochondrial BCAAT activities of liver. The response of BCKAD in liver can contribute to the leucine-induced stimulation of valine oxidation in vivo but analysis of the results of this study leads to the conclusion that other mechanisms, probably in nonhepatic tissues, must also be involved.     

Nutritional support in children with end-stage liver disease: a randomized crossover trial of a branched-chain amino acid supplement.

Malnutrition is common in children with end-stage liver disease (ESLD) awaiting orthotopic liver transplantation (OLT), and nutritional support is assuming an important role in preoperative management. To evaluate preoperative nutritional therapy, 19 children (median age 1.25 y) with ESLD awaiting OLT were prospectively studied. Two high-energy, isoenergetic and isonitrogenous nutritional formulations delivered nasogastrically were compared: a branched-chain amino acid (BCAA)-enriched semielemental formulation and a matched standard semielemental formation. Twelve of 19 patients completed a randomized controlled study before OLT and 10 of 19 completed a full crossover study. Improvements in weight and height occurred during the BCAA supplements, with no statistical change on the standard formulation. Significant increases in total body potassium, midupper arm circumference, and subscapular skinfold thickness occurred during the BCAA supplements, whereas no significant changes occurred during the standard formulation period. Significantly fewer albumin infusions were required during the BCAA supplement. These findings suggest that BCAA-enriched formulas have advantages over standard semielemental formulas in improving nutritional status in children with ESLD, and are deserving of wider application and study.     

Supplementation with branched-chain amino acids attenuates hepatic apoptosis in rats with chronic liver disease

Branched-chain amino acids (BCAA) can function as pharmacologic nutrients for patients with decompensated cirrhosis. However, the effects of BCAA at the early stage of chronic liver disease are not clear. We hypothesized that early BCAA supplementation would attenuate the progression of chronic liver disease. The present study examined the effects of BCAA supplementation on the progression of chronic liver disease in rats caused by injected carbon tetrachloride (CCl₄). Sprague-Dawley rats were fed with a casein diet (control group) or the same diet supplemented with BCAA (BCAA group) for 11 weeks, and all rats were repeatedly injected with CCl₄. Food intake did not significantly differ between control and BCAA groups during the experimental period. Plasma alanine aminotransferase activities gradually increased during the experimental period in both groups but peaked later in the BCAA group. Liver fibrosis was more evident in the control group. Levels of connective tissue growth factor messenger RNA were significantly lower in the livers of rats in the BCAA group than in the control group. Terminal deoxynucleotidyl transferase–mediated deoxyuridine 5-triphosphate nick end labeling assays found considerably more hepatic apoptosis in the control group. Liver cytosolic cytochrome c levels and expression of the proapoptotic Bax protein in the mitochondrial fraction were significantly lower in the BCAA group than in the control group. These results suggest that supplementation with BCAA delays the progression of chronic liver disease caused by CCl₄ in rats by attenuating hepatic apoptosis.     

Effect of oral amino acid supplementation on liver disease after jejunoileal bypass for morbid obesity.

Previous work in our laboratory and others suggests that protein malnutrition plays an important role in the pathogenesis of hepatic steatosis and dysfunction which characteristically appears after jejunoileal bypass for morbid obesity. Postoperative protein-calorie malnutrition is at least in part a consequence of diminished intestinal absorption of free amino acids. In an attempt to prevent liver disease, six morbidly obese patients were orally supplemented with essential amino acids for 4 months after surgery. Oral amino acid supplementation only partially influenced protein malnutrition and had no effect on deterioration of hepatic morphology and dysfunction. Although this mode of therapy appears to be ineffective in preventing postoperative liver abnormalities, other studies suggest that oral oligopeptide supplementation and parenteral administration of amino acids are beneficial. In addition to protein deificiency, other factors which may contribute to the development of liver disease are reviewed.     

Branched chain amino acid therapy in liver disease

Patients with hepatic cirrhosis often are malnourished and wasted. If portal-systemic encephalopathy (PSE) develops, restriction of dietary protein in an attempt to treat encephalopathy may further promote negative nitrogen balance. There is considerable interest in providing nutritional supplements to patients with cirrhosis and PSE which would lead to improvement in nitrogen balance while improving or at least not worsening PSE. Amino acid supplements designed to correct the abnormal amino acid pattern characteristically found in patients with cirrhosis and PSE are under investigation as potential therapeutic agents. The levels of the branched chain amino acids (BCAAs) are decreased in almost all patients with cirrhosis and PSE. The exact mechanism for the reductions in BCAA concentrations is unknown. Furthermore, aromatic amino acids (AAA) and methionine (MET) concentrations are usually increased in these patients. It has been suggested that BCAAs and neutral amino acids compete for transport across the blood-brain barrier and that a decrease in BCAA concentrations promotes entrance of neutral amino acids into the brain. Aromatic amino acids, MET, and their derivatives may have a role in the production of PSE. These observations have increased interest in the potential therapeutic benefit of administering BCAAs to patients with cirrhosis and PSE in order to decrease the entrance of putative toxins into the brain. Treatment trials using BCAAs alone or in solutions containing other amino acids in patients with cirrhosis and PSE have given conflicting results. In one trial, there appeared to be less PSE induced by a BCAA-enriched solution when compared to equinitrogenous dietary protein. However, other controlled studies have not demonstrated any advantage to the addition of BCAAs as compared to placebo with regards to reducing mortality or improving cerebral function in patients with acute cirrhosis and PSE. Some of the differences in study outcomes may relate to the patient population evaluated; the type, amount, and duration of treatment; and whether other therapy was administered. BCAA supplements may also be useful in minimizing or reversing the catabolic state characteristic of patients with cirrhosis. A reduction of increased urinary 3-methylhistidine excretion by infusions of BCAAs in cirrhotic patients suggests an anticatabolic effect. These potential anticatabolic effects of BCAAs are most interesting and deserve further study.     

Effects of branched-chain amino acid supplementation on plasma concentrations of free amino acids, insulin, and energy substrates in young men

The present study was conducted to examine alterations in the concentrations of plasma free amino acids, glucose, insulin, free fatty acids (FFAs), and urea nitrogen induced by branched-chain amino acid (BCAA) supplementation in young men. Overnight-fasted subjects ingested drinks containing 1 or 5 g of a BCAA mixture (weight ratio of 1 : 2.3 : 1.2 for isoleucine : leucine : valine), and blood was intermittently collected for 3 h after ingestion. Ingestion of the BCAA mixture resulted in significant increases in the plasma concentrations of individual BCAAs, corresponding to the amounts of amino acids ingested. On the other hand, plasma concentrations of methionine and aromatic amino acids tended to decrease in the trial with 5 g BCAAs, suggesting that BCAA ingestion affects the metabolism of these amino acids. The ingestion of BCAAs temporarily increased plasma insulin levels and affected plasma concentrations of FFAs, but had almost no effect on glucose or urea nitrogen.     

Estrogen controls branched-chain amino acid catabolism in female rats

A diurnal rhythm occurs in the activity state of branched-chain alpha-keto acid dehydrogenase complex (BCKDC) in female but not male rats. We attempted to determine the role played by ovarian hormones in this difference in enzyme regulation. A series of experiments examined the effects of the 4-d estrous cycle, ovariectomy, and replacement of female sex steroids on the catabolism of BCAAs. A proestrous decrease in the activity state of the complex corresponded to an increase in the plasma 17beta-estradiol level. Withdrawal of gonadal steroids by ovariectomy resulted in an increase in the activity state of BCKDC and a decrease in the activity of the branched-chain alpha-keto acid dehydrogenase kinase (BDK). However, 17beta-estradiol reversed these effects, resulting in an increase in the BDK activity, thereby decreasing the activity of the complex. Progesterone administration was ineffective. The changes in the percentage of active BCKDC caused by 17beta-estradiol withdrawal and replacement resulted from changes in the amount of BDK protein associated with the complex and therefore its activity. Thus, the marked diurnal variation in the activity state of BCKDC exhibited by female rats involves estrogenic control of BDK activity. We hypothesize that the 17beta-estradiol-controlled feeding pattern produces these variations in BCKDC activity. This may function in female rats to conserve essential amino acids for protein synthesis.     

Branched chain amino acid therapy in liver disease.

Patients with hepatic cirrhosis often are malnourished and wasted. If portal-systemic encephalopathy (PSE) develops, restriction of dietary protein in an attempt to treat encephalopathy may further promote negative nitrogen balance. There is considerable interest in providing nutritional supplements to patients with cirrhosis and PSE which would lead to improvement in nitrogen balance while improving or at least not worsening PSE. Amino acid supplements designed to correct the abnormal amino acid pattern characteristically found in patients with cirrhosis and PSE are under investigation as potential therapeutic agents. The levels of the branched chain amino acids (BCAAs) are decreased in almost all patients with cirrhosis and PSE. The exact mechanism for the reductions in BCAA concentrations is unknown. Furthermore, aromatic amino acids (AAA) and methionine (MET) concentrations are usually increased in these patients. It has been suggested that BCAAs and neutral amino acids compete for transport across the blood-brain barrier and that a decrease in BCAA concentrations promotes entrance of neutral amino acids into the brain. Aromatic amino acids, MET, and their derivatives may have a role in the production of PSE. These observations have increased interest in the potential therapeutic benefit of administering BCAAs to patients with cirrhosis and PSE in order to decrease the entrance of putative toxins into the brain. Treatment trials using BCAAs alone or in solutions containing other amino acids in patients with cirrhosis and PSE have given conflicting results. In one trial, there appeared to be less PSE induced by a BCAA-enriched solution when compared to equinitrogenous dietary protein. However, other controlled studies have not demonstrated any advantage to the addition of BCAAs as compared to placebo with regards to reducing mortality or improving cerebral function in patients with acute cirrhosis and PSE. Some of the differences in study outcomes may relate to the patient population evaluated; the type, amount, and duration of treatment; and whether other therapy was administered. BCAA supplements may also be useful in minimizing or reversing the catabolic state characteristic of patients with cirrhosis. A reduction of increased urinary 3-methylhistidine excretion by infusions of BCAAs in cirrhotic patients suggests an anticatabolic effect. These potential anticatabolic effects of BCAAs are most interesting and deserve further study.     

Effect of branched-chain keto-acids and dietary protein content on the activity of branched-chain amino acid transferase in rat tissues

Rats fed branched-chain keto-acids in place of branched-chain amino acids exhibited increased specific activity of branched-chain amino acid transferase (BATase) in muscle, intestine, brain and liver as compared with controls fed sufficient diet to achieve comparable weight gain. This increase was observed whether or not methionine and phenylalanine were also replaced by their N-free analogues. Kidney BATase was unaffected. Rats fed a protein-free diet exhibited higher BATase specific activity in kidney, brain, liver and intestine than rats fed diets containing 6% casein; but little change in specific activity in these organs was seen as casein intake was progressively increased from 6% to 18%. Muscle BATase specific activity was the same between 0 and 18% dietary casein. The results show that branched-chain keto-analogues augment BATase in several tissues, including muscle. In contrast, varying casein intake from 6% to 18% had little effect, although protein-feeding augments BATase in some organs.