Estimated Protein Intake Research Articles

A crossover comparison of progression of chronic renal failure: Ketoacids versus amino acids

Rates of progression of chronic renal failure were compared in patients receiving alternately an amino acid supplement (AA) and a ketoacid supplement (KA) to a very low protein (0.3 g/kg), low phosphorus (7 to 9 mg/kg) diet. The first supplement was randomly chosen. Bias due to carryover effects was minimized by delaying the regression analysis until one month after starting or changing supplements. In order to minimize possible bias caused by initiating the two supplements at differing levels of severity, a multiple crossover design was used (ABA, BAB, ABAB, or BABA) with at least four GFR's in each treatment period (except for three GFR's in one instance). Sixteen patients completed the protocol; five dropped out. Average starting GFR's were nearly identical for the two supplements (15.4 and 15.9 ml/min). For each patient, mean progression on KA was compared with mean progression on AA. Thirteen out of 16 patients progressed more slowly on KA than AA. On the average, progression on KA was significantly slower (95% confidence limits = -0.36 to 0.09 ml/min/month) than on AA (-0.91 to -0.41 ml/min/month; P = 0.024). There was no significant difference in estimated protein intake, phosphate excretion, or mean arterial pressure between KA and AA periods. Serum triglyceride concentration was significantly lower on KA (P = 0.0026). 17-hydroxycorticosteroid excretion was also lower (P = 0.031). We conclude that KA slow progression, relative to AA, independently of protein or phosphorus intake, in patients on this regimen.

The Modification of Diet in Renal Disease Study: Design, Methods, and Results From the Feasibility Study

The Modification of Diet in Renal Disease (MDRD) Study is a multicenter clinical trial designed to assess acceptance, safety, and efficacy of restricted protein and phosphorus diets in patients with progressive renal disease. The Feasibility Study was designed to test procedures and recruitment strategies and to estimate sample size for the Full-Scale Trial. The Feasibility Study was not designed to compare rates of progression of renal disease among diet groups. Patients aged 18 to 75 years, with a glomerular filtration rate (GFR; measured by 125I-iothalamate clearance) between 7.5 and 80 mL/min/1.73 m2, and a previous progressive increase in serum creatinine, were eligible for enrollment. Compliance with prescribed dietary protein intake was calculated from urea nitrogen appearance (UNA). Nutritional status was monitored by anthropometry and serum proteins. Progression of renal disease was calculated as the rate of decline of GFR. Ninety-six patients met all of the eligibility requirements and were randomized to study diets. Follow-up was conducted for a mean duration of 14 months (range, 2 to 22 months). Although most patients did not achieve the prescribed protein intake, marked changes in intake were observed among patients assigned to the low-protein diets, and mean estimated protein intake differed significantly among diet groups. No patients became malnourished. Mean rates of decline in GFR were relatively slow, and variability among individuals was high. As expected, the number of patients enrolled was too small to determine if the rate of decline in GFR was significantly slower among patients assigned to the restricted protein and phosphorus diets. The rate of decline in GFR was significantly inversely correlated with long-term average mean arterial blood pressure (MAP), even among patients whose blood pressure was controlled to levels within the normal range. However, because patients were not randomly assigned blood pressure goals, it was not possible to determine whether a causal relationship exists. Based on the experience gained during the Feasibility Study, the design for the Full-Scale Study includes two studies of defined by patients' baseline levels of renal function. Within each study, patients will be assigned randomly to one of two diets, and within each diet group, to one of two levels of blood pressure control. Based on variability of rates of decline in GFR slopes observed during the Feasibility Study, 800 patients with follow-up periods of up to 4 years will be required for the Full-Scale Trial.

Estimated protein intakes of toddlers: predicted prevalence of inadequate intakes in village populations in Egypt, Kenya, and Mexico

This paper presents a probability assessment of the adequacy of protein intakes of toddlers (aged 18-30 mo) in study communities in Egypt, Kenya, and Mexico judged in relation to FAO/WHO/UNU estimates of requirements. Effects of supplementing amino acid intakes, or of assuming lower bioavailability for lysine are also considered. In Egypt and Mexico existing protein intakes of toddlers were adequate. In Kenya existing intakes were marginal. Total protein intake was low and often lysine or tryptophan concentration was low. If Kenyan intakes met estimated energy requirements, protein intakes would be adequate. We conclude that protein intake is unlikely to be a primary limiting factor for toddler growth and development, and the benefit to be expected from increasing the intake of limiting amino acids is marginal. Reported associations of animal-source protein and energy with growth, size, and psychologic function of these toddlers are unlikely to be causally attributable to inadequacy of protein intakes.

Kidney transplantation in Type 1 (insulin-dependent) diabetic patients

The development of diabetic glomerulopathy in kidneys transplanted to diabetic patients was estimated in transplant biopsies and evaluated in relation to suspected clinical risk factors for diabetic nephropathy. Surgical biopsies were taken at baseline and at 24-36 months post-transplantation in 16 Type 1 (insulin-dependent) diabetic patients and 8 non-diabetic control subjects with a glomerular filtration rate more than 30 ml.min-1 at follow-up. Immunosuppressive therapy included cyclosporine in all but one case. Stereological methods were used to assess basement membrane thickness, volume fraction of mesangium per glomerulus, and volume fraction of matrix per mesangium. The volume fraction of interstitial tissue per cortex was estimated by light microscopy. After 2 years the basement membrane thickness had increased by 55 nm (SD 58 nm) in the diabetic group. This change was significantly different from that of 2 nm (SD 37 nm) in control subjects (p = 0.02). Mesangial volume fraction increased significantly by 0.04 (SD 0.03) in diabetic patients, and this change was significantly different from that of -0.01 (SD 0.04) in non-diabetic patients (p = 0.009). No change was detectable in the matrix expressed as fraction of mesangial volume. An increase in interstitial volume fraction from baseline to 2 years was observed, but was significant only in the diabetic group (p = 0.04). The changes in structural parameters did not correlate with mean values during follow-up of glycated haemoglobin or estimated protein intake, nor was any pattern discernible in the relationship to graft tissue types.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of two Methods for the Estimation of Urea Kinetics and Introduction of a Third Simplified Method

It has been claimed that computed urea kinetic (UK) modelling in hemodialysed patients, for the estimation of protein intake, leads to an overestimation of protein catabolic rate (PCR). In the present study, three different methods of kinetic modelling for the determination of PCR and Kt/V are compared in 24 patients. The first method was the direct quantification method (DDQ) based on the collection of all urea eliminated from the body. The first computed method (ICMI) was the urea kinetic modelling method as described by Sargent. Dialyzer clearances were measured directly and not estimated by theoretical extrapolation. The second computed method (ICMII) is based on the indirect calculation of urea distribution volume (Vu), according to Watson, and of dialyzer clearances from this Vu and from pre- and post-dialysis urea concentrations. All three methods resulted in PCR's that were not significantly different (DDQ: 1.03 +/- 0.19; ICMI: 1.04 +/- 0.22; ICMII: 1.08 +/- 0.25 mg/Kg BW.24 hrs; p greater than 0.05). When the results were correlated, the following results were obtained: ICMI vs ICMII: r = 0.89, p less than 0.001; ICMI vs DDQ: r = 0.68, p less than 0.01; DDQ vs ICMII: r = 0.78, p less than 0.001. Intermutual comparison of Kt/V values resulted in virtually identical results, especially when comparing ICMI and ICMII, where the regression line equalled the identity line. In conclusion, all methods seem equally reliable in determining mean PCR and Kt/V. Our data, obtained with directly measured dialyzer urea clearances, do not confirm the earlier held opinion that computed modelling results in an overestimation of PCR.(ABSTRACT TRUNCATED AT 250 WORDS)

A step towards using urinary nitrogen as a tool for validating 24-hour dietary recall interviews.

In an active population, can urinary nitrogen output provide a satisfactory basis for estimating protein intake without preliminary screening to rule out metabolic disease? A successful demonstration would justify comparing average protein intake for active groups derived from 24-hour recall interviews with that obtained from 24-hour urine specimens. This could then be a practical test of the hypothesis that 24-hour recall data provide valid estimates for groups. Volunteers (45) from a university population limited their diet for four days to a commercially prepared liquid diet and provided a 24-hour urine specimen beginning on the morning of the fourth day. For men, average daily intake of protein was 112.8 grams and the estimated intake based on urinary nitrogen was 114.5. Corresponding data for women were 84.6 and 83.9. Screening for metabolic disease seems unnecessary but persons restricting their intake to less than their caloric needs will have their protein intake overestimated on the basis of urinary nitrogen measurement.

Comparison of calculated estimates and laboratory analysis of food offered to hospitalized eating disorder patients

Estimation of caloric intake is an integral part of a comprehensive research/treatment program for patients with eating disorders at the National Institute of Mental Health. Caloric intakes are estimated by recording daily food intake and calculating calories using food exchange lists and food composition tables. To evaluate the validity of that method, caloric intake estimates were compared with laboratory analysis data over a 15-day period. The estimations for daily caloric intake in comparison with the laboratory analysis data were underestimated by a mean percent difference of 2.4%. The estimated carbohydrate and fat intakes were overestimated by 4.5% and 5.4%, respectively. The estimated protein intake was underestimated by 1.1%. The data suggest that estimates of caloric intake based on food exchange lists and food composition tables are within an acceptable range of error and, therefore, represent a practical approach to estimating caloric intake for patients hospitalized with an eating disorder.

Path Analysis of Dry Period Nutrition, Postpartum Metabolic and Reproductive Disorders, and Mastitis in Holstein Cows

Path analysis and logistic regression were used to model direct and indirect relationships among clinical periparturient (within 30 d after calving) retained placenta, metritis, veterinary-assisted dystocia, uncomplicated and complicated ketosis, left displaced abomasum, parturient paresis, mastitis, and estimated nutrient intakes (protein, calcium, phosphorus, energy; coded into terciles) in the last 3 wk of the dry period. Data were from 1,374 multiparous Holstein lactations for calvings from March 1981 through February 1982 in 31 commercial herds in central New York.Periparturient disorders occurred as a complex. Odds ratios for the multiplicative effects of parturient paresis on incidence of veterinary-assisted dystocia, retained placenta, complicated ketosis, and clinical mastitis were 7.2, 4.0, 23.6, and 5.4, respectively. Reproductive disorders were interrelated. Retained placenta, left displaced abomasum, and parturient paresis directly increased risk of complicated ketosis (odds ratios were 16.4, 53.5, and 23.6, respectively).Higher terciles of estimated energy intake in the last 3 wk of the dry period decreased risk of veterinary-assisted dystocia and left displaced abomasum, while higher terciles of estimated protein intake decreased risk of retained placenta and uncomplicated ketosis. Estimated nutrient intakes were directly related to subsequent metabolic disorders and directly and indirectly related (mediated by metabolic disorders) to reproductive disorders.The study suggests that feeding higher intakes (relative to National Research Council recommendations) of protein and energy in the last 3 week of the dry period may reduce the incidence of metabolic and reproductive disorders. Exact recommendations as to the amounts and types of feed cannot be made from our results.

Low protein diet and chronic renal failure in Buddhist monks.

Clinical observations were made in five Buddhist monks with chronic renal failure on a low protein diet. These monks consumed only one meal and meditated three to four times a day. The estimated protein intake was from 15 to 19 g a day. Renal function remained stable over three years of observation. The general condition was satisfactory without any evidence of protein energy malnutrition. The data were compared with those of another group of patients who had a comparable degree of impairment of renal function but who consumed three meals a day of low protein diet. Protein intake was estimated to be from 25 to 30 g a day. These patients developed uraemia with severe renal failure and protein deficiency within three years. The findings support the role of protein restriction in maintenance of renal function in chronic renal failure and perhaps suggest a beneficial role for meditation.

Relationship between nonprotein nitrogen and total nitrogen in chickpea (Cicer arietinum L.) seed

Chickpea (Cicer arietinum L.) is a crop of economic importance and also an important source of protein in the diet of people in India as well as in other countries. Total protein content in the diet of people in the developing countries deserves special attention as large segments of people in these areas are reported to suffer from protein-calorie malnutrition. In the normal procedure for estimating protein intake, nitrogen content is obtained by the standard micro-Kjeldahl method and a factor is used to convert the figure into protein percentage. In this process, it is tactitly assumed that all the nitrogen is associated with the protein. But, in fact, this is not true. Therefore, any large variation in NPN content would affect the estimated protein of the sample and would consequently affect the estimated protein intake'in the diet. However, some of the NPN probably consists of amino acids and peptides which would be utilized. Attempts have been made to determine NPN in various crops (Bell, 1963; Boulter and Davis, 1968: Bhatty, 1972; Millerd, 1972). This study was conducted to determine the variation, if any, that might exist in chickpea samples and to identify the relationship between NPN and crude protein nitrogen in chickpea.

Optimal enteral nutritional support as an adjunct to breast cancer chemotherapy: preliminary report.

Malnutrition is a recognized problem in cancer patients. It remains to be determined whether nutritional support can prevent or delay the onset of nutritional deterioration which is usually associated with an increased susceptibility to infectious disease and poor response to therapy. In the present study, well‐nourished breast cancer patients undergoing chemotherapy have been followed for 3 to 12 months to determine the effects of nutritional support on their nutrient intake, nutritional status, immune function and disease state. For the present, eight patients have been given a nutritional supplement (S–‐Isocal or Sustacal) to be taken along with self‐selected regular foods and nine patients were maintained on self‐selected regular foods only (US). Information was obtained on a regular basis concerning dietary intakes. Records of taste and appetite changes and GI complaints were kept along with weights and estimates of protein intake. The differences between the S and the US groups have been: 1. The S group met their protein allowance according to the RDA and the US group did not; 2. The S group reported fewer taste abnormalities and the US group reported strong tastes and desires for cold, sweet, protein free drinks; 3. Immune competency improved in one S patient and deteriorated in one US patient; and 4. Mid‐arm muscle circumferences increased or remained the same in six S patients and decreased in 7 US. One might reasonably expect that this continued course of dietary pattern in the US group, deficient protein intake, would lead to nutritional deterioration.

Zen Macrobiotic Dietary Problems in Infancy

Two infants fed Kokoh, a Zen macrobiotic food mixture comprising cereal grains, legumes, and oil seeds, for a period of several months weighed 4.96 kg and 5.81 kg at 7 and 13 months of age, respectively. Kokoh formulas were evaluated by computation using food composition tables and chemical analysis. The computed energy value of Kokoh was within 3% of that measured by calorimetry. The daily intake of energy by the infants from Kokoh and other supplementary foods was about 400 Calories. This represents only 40% of the Recommended Dietary Allowances (R.D.A.) for the United States. The estimated protein intake was 11 gm for one child, and 13 gm for the other. The quality of the Kokoh protein as determined by computation was adequate for growth, but the analytical data suggested that the amino acid pattern was poor. The unsatisfactory nature of the formulas given to the infants was due to excessive dilution. There is a need for more definitive data on the feasibility of feeding infants Kokoh and similar foods, at a concentration that will meet energy needs. Further information is required on the amino acid content of plant foods used for infant feeding. Until more is known about feeding infants on plant food proteins, infants and children fed Kokoh should be kept under strict surveillance.