Nutritional value of [15N]-soy protein isolate assessed from ileal digestibility and postprandial protein utilization in humans.

The purpose of this work was to assess the true oro-ileal digestibility, and to concurrently quantify the deamination of absorbed dietary nitrogen to examine the postprandial nutritional value of a soy protein isolate (SPI) in humans. To assess bioavailability and bioutilization of SPI, 10 healthy volunteers ingested 30 g of SPI, intrinsically and uniformly [15N]-labeled, added with 100 g of sucrose and water up to a final volume of 500 mL. True ileal digestibility was assessed by the [15N]-dilution method for 8 h by means of a naso-intestinal intubation technique. To describe and quantify exogenous nitrogen deamination for the same time period, urine and plasma samples were collected. True oro-ileal digestibility of SPI nitrogen was 91%. The amount of absorbed SPI amino acids used for nonoxidative disposal, i.e., postprandial biological value, was 86% 8 h after meal ingestion. Hence, net postprandial protein utilization of SPI was 78%. Compared to previous data that were assessed under the same condition in humans, the nutritional value of SPI is 92% of that in milk protein concentrate.     

Assessment of net postprandial protein utilization of 15N-labelled milk nitrogen in human subjects.

The nutritional quality of milk proteins, evaluated both in terms of digestibility and postprandial oxidation and retention in human subjects, was investigated in this study. Five healthy adult volunteers were given 480 ml 15N-labelled milk (i.e. 190 mmol N). 15N was subsequently determined at the ileal level, using a naso-intestinal intubation technique, as well as at the faecal level. Plasma and urine were sampled for 8 h after meal ingestion. Dietary exogenous N recovered at the terminal ileum after 8 h reached 8.6 (SE 0.8) mmol while the amount collected in the faeces was 6.5 (SE 0.7) mmol after 5 d. The true ileal and faecal digestibilities were 95.5 (SE 0.4)% and 96.6 (SE 0.4)% respectively. The appearance of [15N]amino acids in the plasma was rapid and prolonged. The measurement of 15N in the body urea pool and in the N excreted in the urine allowed us to calculate the deamination occurring after [15N]milk protein absorption. The net postprandial protein utilization (i.e. NPPU = (Nabsorbed-Ndeaminated)/Ningested), calculated as an index of protein quality 8 h after milk ingestion, was 81.0 (SE 1.9)%. Our data confirm that milk protein has a high oro-ileal digestibility in man and demonstrate that milk protein has a high NPPU, an index corresponding to a period in which the dietary protein retention is maximal.     

Increasing habitual protein intake accentuates differences in postprandial dietary nitrogen utilization between protein sources in humans

It is appropriate to characterize the nutritional value of dietary proteins in humans through the specific study of dietary nitrogen metabolism during the postprandial period. However, the influence of the habitual protein intake on this variable has not been studied. We aimed to describe the influence of prior protein intake on the specific metabolic utilization of dietary nitrogen in humans. Healthy men and women were adapted for 7 d to two diets with a normal [NP, 1 g/(kg x d)] and high protein content [HP, 2 g/(kg x d)]. After each period, they were studied for an 8-h postmeal period after ingesting a single (15)N-labeled mixed meal (0.41 g/kg protein) containing either milk (n = 12) or soy protein (n = 8). The HP diet reduced the peak of dietary N incorporation into free serum amino acids in the soy group but had no effect in the milk group. The incorporation of dietary N into plasma protein was higher after soy than after milk protein, but habitual protein level had no effect. The postprandial retention of milk protein was reduced by the HP diet compared with the NP diet by only 5% and that of soy protein was diminished by 13% (protein source: P < 0.0001, protein level: P < 0.0001, interaction: P < 0.001). In conclusion, the efficiency of the meal N postprandial retention was lower after HP adaptation, but this decrease was much more pronounced for soy than for milk protein, indicating that increasing the habitual protein intake accentuates differences in metabolic utilization among dietary proteins.     

Effects of restricted diet on protein metabolism measured by [15N]glycine in high-fat-diet-induced obese rats

The effect of restricted diets on protein metabolism was studied in obese rats (obesity had been induced by ad libitum feeding of a diet containing 30% fat and 25% casein). The obese rats were fed on one of three restricted diets, each containing 5% fat, for 2 weeks (restricted feeding groups); a high-protein diet (HPD, 50% casein), a standard-protein diet (SPD, 25% casein), or a low-protein diet (LPD, 5% casein). The food intake was restricted to 5 g per day per rat. On the eleventh day, the rats were given [15N]glycine orally, and 4 days later, they were killed. The restricted feeding groups all showed similar weight losses (about 100 g), 2 weeks after the start of the restricted diet. The 15N distribution in whole body was measured and results were compared with those of control rats given 5%- or 30%-fat diet ad libitum. The whole-body distribution of 15N in the HPD group was similar to that in the rats fed ad libitum although the diet intake was restricted. The results suggested that the amount of protein in a restricted diet is important for maintenance of protein metabolism in obese rats.     

Effects of diet quality on urea fates in sheep as assessed by refined, non-invasive [15N15N]urea kinetics

The effect of diet quality on urea production, entry into the gastrointestinal tract (GIT) and subsequent diversion to anabolic or catabolic fates was examined in four sheep (mean live weight 49.5 kg). The animals received, in a crossover design, each of two rations, hay-grass pellets (1:1 HG) and a mixed concentrate-forage (CF). Measurements were made of N balance and urea kinetics based on a 4 d continuous intravascular infusion of [15N15N]urea. Enrichments of [15N15N]- and [14N15N]urea in the urine, and faecal 15N content were determined each day. After 24 h of infusion, urinary [15N15N]urea enrichments reached constant enrichment but a further 24 h was required before [14N15N]urea enrichment was at plateau. The latter is derived from hydrolysis of urea to 15NH3 in the digestive tract with subsequent absorption and reconversion to urea. The diets were not isonitrogenous (14.3 v. 17.1 g N supplied daily for HG and CF respectively) but showed no difference in N balance. Urea-N production was much greater (16.3 v. 11.1 g/d; P = 0.011) for CF compared with HG and more urea-N entered the GIT (9.9 v. 7.7; P = 0.07). A larger proportion of GIT entry was returned to ureagenesis (51 v. 42%; P = 0.047) for the CF diet but a smaller fraction was lost in the faeces (3.3% v. 7.1%; P = 0.013). In consequence, most of the additional urea-N which entered the GIT on the CF diet was returned to the ornithine cycle (probably as NH3) and the absolute amount available for anabolic purposes was similar between the rations (3.9 v. 4.5 g N/d).     

Rapeseed and milk protein exhibit a similar overall nutritional value but marked difference in postprandial regional nitrogen utilization in rats

Background

Rapeseed is an emerging and promising source of dietary protein for human nutrition and health. We previously found that rapeseed protein displayed atypical nutritional properties in humans, characterized by low bioavailability and a high postprandial biological value. The objective of the present study was to investigate the metabolic fate of rapeseed protein isolate (RPI) and its effect on protein fractional synthesis rates (FSR) in various tissues when compared to a milk protein isolate (MPI).

Methods

Rats (n = 48) were given a RPI or MPI meal, either for the first time or after 2-week adaptation to a MPI or RPI-based diet. They were divided in two groups for measuring the fed-state tissue FSR 2 h after the meal (using a flooding dose of ¹³C-valine) and the dietary N postprandial distribution at 5 h (using ¹⁵N-labeled meals).

Results

RPI and MPI led to similar FSR and dietary nitrogen (N) losses (ileal and deamination losses of 4% and 12% of the meal, respectively). By contrast, the dietary N incorporation was significantly higher in the intestinal mucosa and liver (+36% and +16%, respectively) and lower in skin (-24%) after RPI than MPI.

Conclusions

Although RPI and MPI led to the same overall level of postprandial dietary N retention in rats (in line with our findings in humans), this global response conceals marked qualitative differences at the tissue level regarding dietary N accretion. The fact that FSR did not however differed between groups suggest a differential modulation of proteolysis after RPI or MPI ingestion, or other mechanisms that warrant further study.     

Iron absorption in humans as influenced by bovine milk proteins

The effect of the two major bovine milk protein fractions on the dialyzability of iron in vitro under simulated gastrointestinal conditions and on the absorption of Fe by humans was studied. Liquid-formula meals were prepared from hydrolyzed maize starch, corn oil, and either spray-dried egg white or a milk-protein product. In meals containing egg white, 3.32% of the Fe was dialyzable. The substitution of casein and whey protein products reduced the dialyzable fraction to 0.19-0.56% and 0.86-1.60%, respectively. Percentage Fe absorption was also reduced by the substitution of casein or whey protein for egg white. Mean absorption values fell from 6.67 to 3.65% and 2.53 to 0.98%, respectively. When the intact milk-protein products were replaced by enzyme- or acid-hydrolyzed preparations, the dialyzable fraction increased markedly and in proportion to the extent of hydrolysis. A similar but much smaller effect on absorption was observed. These studies suggest that bovine casein and whey proteins are responsible at least in part for the poor bioavailability of the Fe in some infant formulas.     

Net protein utilization determined by rat bioassay of a protein hydrolysate and a diet for children with phenylketonuria

In a previous study (Kindt et al. 1983, 1984) it was assumed that a protein hydrolysate, devoid of phenylalanine, together with intact protein as given to children with phenylketonuria (PKU), was equivalent to egg or milk protein. One group of children was given this 'PKU protein' in amounts corresponding to the Joint FAO/WHO ad hoc Expert Committee (1973) recommendations. The results indicated that the Joint FAO/WHO ad hoc Expert Committee (1973) recommended levels of protein intake were marginal. The purpose of the present study was to evaluate whether the quality of the protein hydrolysate, together with intact protein ('PKU protein'), is equivalent to egg or milk protein. This was done using a rat bioassay. Four protein sources were used: (1) egg protein, (2) protein hydrolysate, (3) protein hydrolysate diluted with non-essential amino acids, (4) protein hydrolysate mixed with food proteins ('PKU protein'), comparable with the diet previously used (Kindt et al. 1983, 1984). The results indicated that the 'PKU protein' was of very high quality: net protein utilization (NPU) greater than 90. The protein hydrolysate alone and the protein hydrolysate diluted with non-essential amino acids gave a NPU greater than 80. The conclusion drawn from the present study is that the 'PKU protein', as used in the treatment of children with PKU, is equivalent to egg or milk protein. This supported the view that the Joint FAO/WHO ad hoc Expert Committee (1973) recommended levels of intake were marginal.     

Increasing habitual protein intake results in reduced postprandial efficiency of peripheral, anabolic wheat protein nitrogen use in humans

BACKGROUND: The postprandial retention of dietary protein decreases when the prevailing protein intake increases. OBJECTIVE: We investigated the influence of the prevailing protein intake on the regional utilization and anabolic use of wheat protein during the postprandial non-steady state in humans. DESIGN: Healthy adults (n = 8) were adapted for 7 d, first to a normal-protein diet (NP: 1 g x kg(-1) x d(-1)) and then to a high-protein diet (HP: 2 g x kg(-1) x d(-1)). After each adaptation period, the subjects received the same single, solid mixed meal containing [15N]-labeled wheat protein. The postprandial kinetics of dietary nitrogen were then measured for 8 h in blood and urine. These data were further analyzed by using a multicompartmental model to predict the postprandial kinetics of dietary nitrogen in unsampled pools. RESULTS: The postprandial whole-body retention of wheat protein nitrogen, measured 8 h after meal ingestion, decreased by 10% when the subjects switched from the NP diet to the HP diet. According to modeling results, this resulted from an increased splanchnic utilization of dietary nitrogen for urea production, whereas its incorporation into splanchnic proteins was unchanged, leading to a 20-30% decrease in peripheral availability and anabolic use in HP-adapted compared with NP-adapted subjects having ingested the same protein load. CONCLUSIONS: By combining clinical experimentation with compartmental modeling, we provide a global overview of postprandial dietary protein metabolism. Increasing prior protein intake was shown to reduce the postprandial retention of wheat protein nitrogen, mainly by diminishing the efficiency of its peripheral availability and anabolic use.     

Cholesterol metabolism in adult baboons is influenced by infant diet

We tested the hypothesis that preweaning diet alters cholesterol metabolism in adult baboons. Eighty baboons, progeny of 6 sires and 80 dams, were either breast-fed or fed one of three infant formulas containing 2, 30 or 60 mg cholesterol/100 mL. At 16 wk of age the baboons were weaned to one of four diets containing 1.0 or 0.01 mg cholesterol/kcal with 40% of energy from saturated [polyunsaturated fat/saturated fat [P/S) = 0.37] or unsaturated fat [P/S = 2.1] and maintained on these diets until they were necropsied as young adults at 7-8 yr of age. We observed no significant effects of formula cholesterol content on serum lipid or lipoprotein concentrations measured at 6-8 yr of age, but formula cholesterol intake influenced the cholesterol turnover rate and several variables of cholesterol metabolism in the adult. At 6-8 yr, baboons that were breast-fed during infancy, compared with those that were formula-fed, had lower high-density lipoprotein cholesterol (HDL-C) concentrations and higher ratios of very-low-density plus low-density lipoprotein cholesterol (VLDL + LDL-C) to HDL-C. Breast-fed baboons, as adults, had lower cholesterol production rates, masses of the rapidly exchanging cholesterol compartment (pool A) and neutral steroid excretion rates than did those fed formula as infants. Breast and formula feeding differentially influenced the adult metabolic responses to dietary cholesterol or fat saturation. These results demonstrate that breast vs. formula feeding in infancy alters cholesterol metabolism and serum lipoprotein concentrations in adult baboons.     

Postprandial modulation of dietary and whole-body nitrogen utilization by carbohydrates in humans

BACKGROUND: Sucrose exerts a sparing effect on whole-body protein metabolism, mainly during the absorptive phase. OBJECTIVE: We aimed to characterize the acute postprandial effect of addition of sucrose on deamination of dietary and endogenous nitrogen, with particular consideration being given to the effects of bioavailability. DESIGN: Twenty-one subjects equipped with ileal tubes ingested (15)N-labeled soy protein combined with [(13)C]glycine, with (n = 10) or without (n = 11) sucrose. Dietary and endogenous ileal flow of nitrogen were determined from the ileal effluents. The kinetics of dietary amino acid transfer to the blood were characterized by (13)CO(2) enrichment in breath and (15)N enrichment in plasma amino acids. Deamination of dietary and endogenous amino acid was determined from body urea, urinary nitrogen, and (15)N enrichment. RESULTS: (13)CO(2) recovery in breath and (15)N plasma amino acid enrichments were highly correlated (R:(2) >/= 0.95, P: < 0.001, for both meals) and markedly delayed by sucrose (half-(13)CO(2) recovery: 274 min compared with 167 min), whereas exogenous and endogenous ileal nitrogen kinetics and balances remained unchanged. Addition of sucrose halved the early (0-2 h) deamination peak of dietary nitrogen and reduced endogenous nitrogen oxidation over the first 4 h. Both were reduced by 18-24% over the 8-h period after the meal. CONCLUSIONS: Without changing the nitrogen absorptive balance, sucrose markedly affected the bioavailability profile, which is governed by gastric emptying. Endogenous and dietary nitrogen were not spared in the same way and over the same periods, showing that the metabolism of endogenous and dietary nitrogen may be affected differently by nutritional modulation, even if the effects are of a similar magnitude over the entire postprandial period.     

The poor digestibility of rapeseed protein is balanced by its very high metabolic utilization in humans

Rapeseed protein (RP, Brassica napus) is used in only animal feed despite its high nutritional potential for human nutrition. We sought to assess the nutritional quality of rapeseed by measuring its real ileal digestibility (RID) and net postprandial protein utilization (NPPU) in humans fed (15)N-RP. Volunteers equipped with an intestinal tube at the jejunal (n = 5) or ileal level (n = 7) ingested a mixed meal containing 27.3 g (15)N-RP and a total energy content of 700 kcal (2.93 MJ). Dietary N kinetics was quantified in intestinal fluid, urine, and blood sampled at regular intervals during the postprandial period. The RID of RP was 84.0 +/- 8.8%. Dietary N at the ileal level was mostly in the form of undigested protein from both 12S and 2S rapeseed fractions. Aminoacidemia was not significantly increased by meal ingestion. The postprandial distribution of dietary N was 5.4 +/- 1.8% in urinary urea and ammonia, 8.2 +/- 3.4% in body urea, and 7.7 +/- 2.0% in plasma protein 8 h after the meal. The NPPU of RP amounted to 70.5 +/- 9.6% and the postprandial biological value (PBV) was high at 83.8 +/- 4.6%. RP has a low RID in humans compared with other plant proteins but also exhibits a very low deamination rate. Thus, the PBV of RP is excellent in humans, being as high as that of milk protein. We conclude that RP has a high nutritional potential for human nutrition.     

Total-body protein turnover in parenterally fed neonates: effects of energy source studied by using [15N]glycine and [1-13C]leucine

The effects of nonprotein energy source (ie, glucose only vs glucose and lipid) on nitrogen retention and total-body protein turnover were studied in 20 parenterally fed newborn infants. All infants received approximately 3 g amino acids and 80-90 kcal.kg body wt.d. Total-body protein synthesis was estimated by using three constant-infusion, end-product methods: enrichment of urinary urea and ammonia in response to a [15N]glycine label and exhaled carbon dioxide enrichment in response to a [1-13C]leucine label. No differences were seen in nitrogen retention between the two energy sources. The estimate of total-body protein turnover obtained from the 13C label was similar to that obtained with the [15N]urea label. No differences in turnover rates were observed between the two diet groups. Use of the glucose-plus-lipid fuel system enhanced energy storage and the reutilization of amino acid for protein synthesis.     

Fate and metabolism of [15N]2,4,6-trinitrotoluene in soil

The fates of the labels from [14C] and [15N] trinitrotoluene were analyzed in bioreactors under aerobic conditions in soil treated by a fungal bioremediation process with Stropharia rugosoannulata and in control soil. Up to 17.5% of the 15N label had a different fate than the 14C label. Three N-mineralization processes were identified in detailed experiments with [15N]TNT. About 2% of the 15N label was found as NO3- and NH4+, showing simultaneous processes of direct TNT denitration (I) and reduction with cleavage of the amino groups (II). The enrichment of NO2-/NO3- (up to 7.5 atom% 15N abundance) indicates the formation of Meisenheimer complexes with a denitration of [15N]TNT. A 1.4% of the label was found distributed between N2O and N2. However, the 15N enrichment of the N2O (up to 38 atom%) demonstrated that both N atoms were generated from the labeled TNT and clearly indicates a novel formation process (III). We propose, as an explanation, the generation of N2O by cleavage from condensed azoxy metabolites. In addition, 1.7% of the 15N label was detected as biogenic amino acids in the wheat straw containing the fungus. Overall, 60 to 85% of the applied [15N]TNT was degraded and 52 to 64% was found as nonextractable residues in the soil matrix. Three percent was detected as 2-amino-4,6-dinitrotoluene and 4-amino-2,6-dinitrotoluene.     

Nutrient balance in humans: effects of diet composition

The purpose of this study was to examine the effect of alterations in diet composition on energy expenditure and nutrient balance in humans. Eight adults (three men, five women) ate a high-carbohydrate (60% of calories from carbohydrate) and a high-fat (60% of calories from fat) diet for 7 d each according to a randomized, crossover design. Six subjects were studied for an additional week on a mixed diet (45% of calories from fat). For each subject, total caloric intake was identical on all diets and was intended to provide the subject's maintenance energy requirements. All subjects spent days 3 and 7 of each week in a whole-room indirect calorimeter. Diet composition did not affect total daily energy expenditure but did affect daily nutrient oxidation by rapidly shifting substrate oxidation to more closely reflect the composition of the diet. These results show that diet composition can affect substrate oxidation without producing measurable effects on total energy expenditure.     

Effects of low energy diets on protein metabolism studies with [15N]glycine in obese patients

The effects of low energy diets on protein metabolism in terms of the metabolic pool, active protein pool, and active and inactive protein synthesis rates were studied using [15N]glycine in five obese patients (percentage of ideal body weight, 120-190%). For 10 days, the patients were given a control diet containing 2,000 kcal of energy and 80 g of protein. For the next 2 weeks, they were given Diet A with 1,100 kcal of energy and 70 g of protein, and for the last 2 weeks given Diet B with 1,100 kcal of energy and 50 g of protein. During the Diet A period, the active protein pool and the active and inactive protein synthesis rates were about the same as during the control diet period, although the metabolic pool tended to be slightly smaller than during the control diet period. During the Diet B period, the metabolic pool, active protein pool, and active protein synthesis rate were all significantly different from the values during the control diet period. The results suggest that protein metabolism in obese patients is not maintained with less than 70 g of protein daily when energy intake was restricted to 1,100 kcal/day.     

Factors affecting the capture of dietary nitrogen by micro-organisms in the forestomachs of the young steer. Experiments with [15N]urea

For a period of at least 2 weeks before an experimental collection each of four young steers received total daily intakes consisting of approximately (g/kg) 600 straw and 400 concentrates with the nitrogen provided mainly as urea and in which the main energy source was starch (tapioca) for diet 1 and glucose for diet 2. Concentrates were given twice daily at about 09.00 and 17.00 hours, straw at 17.00 hours only. The value for the ratio, rumen-degradable N: metabolisable energy (g/MJ) in the daily intake was estimated to be approximately 1.2. On the day that an experimental collection was to be made the urea normally given in the feed at 09.00 hours was labelled with 15N. This urea and sometimes the appropriate energy source were added either as a single dose (SD) at 09.00 hours or in three equally-divided doses (DD) at 09.00, 11.00 and 13.00 hours. Treatments, given in a Latin-square design, were: (A), starch (SD) + urea (SD); (B), starch (SD) + urea (DD); (C), glucose (SD) + urea (DD); (D), glucose (DD) + urea (DD). Doses of polyethylene glycol (PEG) and 144Ce (as cerous chloride) were given as markers with the urea. After these doses were given, samples of abomasal and duodenal digesta were taken periodically for 72 h. It appeared that virtually all the PEG had left the rumen by this time and mean recovery of 144Ce relative to PEG was approximately 90%. From recoveries of non-ammonia-15N (microbial 15N) at the abomasum, estimated relative to PEG, values for mean fractional efficiencies of conversion of urea-N to microbial-N were calculated to be 0.59, 0.59, 0.40 and 0.41 for treatments A, B, C and D respectively.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of low protein intake on protein metabolism of Papua New Guinea highlanders studied with [15N]glycine

The effects of low protein intake on protein metabolism, including the size of pools and the protein synthesis rates, were studied by use of [15N]glycine in Papua New Guinea highlanders. Studies were made on 9 men between October and December in 1982. In experiment 1, two subjects were given a protein-free diet (PFD) containing 49.1 kcal/kg of energy. In experiment 2, subjects were given a sweet-potato diet (SPD) containing 45.4 kcal/kg of energy and 0.507 g/kg of protein for 8 days, and then were given a low-protein sweet-potato diet (LPSPD) containing 50.0 kcal/kg of energy and 0.265 g/kg of protein. During the SPD period, the sizes of the metabolic and active protein pools (mean +/- SD) were 270 +/- 134 mgN/kg and 362 +/- 107 mgN/kg, respectively, and the rates of active and inactive protein synthesis were 463 +/- 161 mgN/kg/day and 299 +/- 38 mgN/kg/day, respectively. During the LPSPD period, the sizes of the metabolic pool and active protein pool were 131 +/- 64 mgN/kg and 378 +/- 106 mgN/kg, respectively, and the rates of active and inactive protein synthesis were 490 +/- 206 mgN/kg/day and 280 +/- 26 mgN/kg/day, respectively. The protein metabolism in the LPSPD showed no significant difference from the SPD. The results suggest that, when the energy levels were approximately the same, protein metabolism in Papua New Guinea highlanders was maintained in spite of the decrease in protein intake.     

The influence of the albumin fraction on the bioavailability and postprandial utilization of pea protein given selectively to humans

Pulse seed proteins such as those found in peas (Pisum sativum) contain fractions of very dissimilar composition and properties, which may therefore be differently utilized by the human body. To analyze the nutritional value of the soluble protein fractions of pea seed, human volunteers ingested a mixed meal of 30 g of raw purified pea protein either as [15N]-globulins (G, n = 9) or as a mix of [15N]-globulins and [15N]-albumins (GA, n = 7) in their natural proportions (22:8). Dietary and endogenous nitrogen fluxes at the terminal ileum were assessed using a tube perfusion technique with an isotopic dilution method. Systemic dietary amino acid availability and the retention of dietary amino acids were determined using 15N enrichment in plasma amino acids and deamination products in blood and urine for 8 h postprandially. The results showed that the pea albumin fraction had the following effects: 1) significantly lowered the real ileal digestibility of pea protein (94 +/- 2.5% for G vs. 89.9 +/- 4% for GA), probably because of a direct effect of trypsin inhibitors; 2) did not promote acute intestinal losses of endogenous nitrogen; and 3) did not significantly improve the postprandial biological value of pea protein (76.5 +/- 3.9% for G vs. 78.7 +/- 3.6% for GA), despite the fact that it corrected the globulin deficiency in sulfur amino acids. We conclude that both G and GA are of good nutritional value for humans and show that cysteine-rich albumins have a far more modest effect on the efficiency of postprandial dietary protein utilization than would be expected from the amino acid scores.