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At least 19 recordsLinked to original sources
PubMed1988

A randomized controlled trial of the effect on blood pressure of dietary non-meat protein versus meat protein in normotensive omnivores.

1. A randomized, controlled trial was carried out to examine whether changes in type and amount of dietary protein were responsible for earlier observations of blood-pressure-lowering effects of lacto-ovo-vegetarian diets. 2. Sixty-four subjects were pair-matched for sex, age, weight and sitting systolic blood pressure, and were randomly allocated to receive one of two types of protein supplement: one containing proteins from meat, the other proteins from non-meat sources. The supplements were balanced in terms of other nutrients. Consumption of other meat, poultry or fish was prohibited. 3. Sitting and standing blood pressures, weight, dietary intakes and plasma and urinary electrolytes were measured at regular intervals during the 12 weeks of trial. Urinary 3-methylhistidine was used as a measure of compliance. 4. Fifty subjects completed the trial. There were no statistically significant blood pressure differences between groups either at baseline or at end-of-trial, neither were there any substantive differences in mean blood pressure changes between baseline and end-of-trial. 3-Methyl-histidine excretion was significantly lower in subjects on the non-meat diet. 5. The results suggest that the protein components of the lacto-ovo-vegetarian diet are not responsible for the blood-pressure-lowering effects of that diet.

Adolescent↗
PubMed2004

Controlled substitution of soy protein for meat protein: effects on calcium retention, bone, and cardiovascular health indices in postmenopausal women.

In a controlled feeding study, the effects of substituting 25 g soy protein for meat on calcium retention and bone biomarkers were determined. Postmenopausal women (n = 13) ate two diets that were similar, except that, in one diet, 25 g high-isoflavone soy protein (SOY) was substituted for an equivalent amount of meat protein (control diet), for 7 wk each in a randomized crossover design. After 3 wk of equilibration, calcium retention was measured by labeling the 2-d menu with (47)Ca, followed by whole-body counting for 28 d. Urinary calcium and renal acid excretion were measured at wk 3, 5, and 7. Biomarkers of bone and cardiovascular health were measured at the beginning and end of each diet. Calcium was similarly retained during the control and SOY diets (d 28, percent dose, mean +/- pooled sd: 14.1 and 14.0 +/- 1.6, respectively). Despite a 15-20% lower renal acid excretion during the SOY diet, urinary calcium loss was unaffected by diet. Diet also did not affect any of the indicators of bone or cardiovascular health. Substitution of 25 g high isoflavone soy protein for meat, in the presence of typical calcium intakes, did not improve or impair calcium retention or indicators of bone and cardiovascular health in postmenopausal women.

Aged↗
PubMedDate not supplied

Protein supplementation of human milk for the nutrition of VLBW-infants: human milk protein vs. meat protein hydrolysate.

In 25 very low birth weight infants appropriate for gestational age the influences of different human milk (HM) preparations on weight gain, gross indices of nitrogen metabolism and energy balance were studied during the second month of postnatal life. HM was fortified either by HM-protein (HMP) or by an enzymatic meat protein hydrolysate (PH) to protein concentrations between 1.5 and 1.7 g/100 ml. The caloric densities of both HM preparations were similar between 62 and 68 kcal/100 ml. There were no differences in weight gain (MM + HMP: 18.6 +/- 3.4 g/kg/day; HM + PH: 16.5 +/- 4.1 g/kg/day), nitrogen retention (HM + HMP: 31.5 +/- 3.1 mmol/kg/day; HM + PH: 30.0 +/- 3.2 mmol/kg/day), and the preprandial estimated essential amino acid profiles between the both feeding groups. In contrast the serum concentrations of alpha-amino-nitrogen 60 minutes postprandially were elevated in the infants fed HM + PH in comparison to the infants fed HM + HMP. This high postprandial amino acid concentrations in serum in the group fed HM + PH were accompanied by increased bile acids concentrations in serum, higher renal amino acid excretion and increased fecal fat losses. The results suggest that due to the more rapid intestinal absorption of amino acids from PH than from HMP the concentrations of amino acids increase postprandially which results in a detectable increase of the newborn cholestasis in these infants. Nevertheless, the scale of these metabolic responses to feeding protein hydrolysates is small and without detectable influences on nitrogen retention or weight gain.

Amino Acids, Essential↗
PubMed1994

Reduction of hypercholesterolemia and proteinuria in nephritic rats by low-meat-protein diets.

The effects of low-meat-protein diets on hypercholesterolemia and proteinuria were studied in rats with nephrotoxic serum nephritis. After an injection of nephrotoxic serum, rats were given either a 20% meat-protein diet (20M), an 8.5%-meat-protein diet (8.5M), or a valine-(0.05%)-supplemented 8.5%-meat-protein diet (8.5MV) for 12 days. Urinary protein excreted from the 20M-fed, nephritic control rats increased rapidly and linearly during the initial 3 days, and thereafter the high excretion rate was maintained for up to 12 days. Two low-meat-protein diets (8.5M, 8.5MV) commenced to suppress proteinuria 3 days after feeding and the suppression was preserved during the rest of the experimental periods. Compared with the 20M, both low-meat-protein diets significantly improved hypercholesterolemia induced in this nephritic model. These two diets significantly enhanced the fecal excretion of neutral sterols. They caused neither fatty liver nor severe growth retardation. These effects of 8.5MV were identical to those of 8.5M. The results suggest that low-meat-protein feeding, without amino acid supplementation, improves hypercholesterolemia and proteinuria in nephritis without severe protein malnutrition. The results also suggest that the hypocholesterolemic effect of the low-meat-protein diets may be, at least in part, attributed to increased fecal excretion of steroids.

Animals↗
PubMed1983

Nitrogen balance studies in young men to assess the protein quality of an isolated soy protein in relation to meat proteins.

The protein nutritional value of an isolated soy protein was examined in healthy young men during 10-day N-balance periods. In the first study (expt 1), 10 young men received a diet providing a test protein (N X 6.25) intake of 0.6 g protein per kilogram per day with nitrogen from either lean beef, isolated soy protein or various combinations of the two sources. No differences in N balance, digestibility or net protein utilization were observed when the soy protein replaced beef. In the second study (expt 2), three separate groups of seven young men each received graded intakes of either beef or an isonitrogenous mixture of beef and the isolated soy protein or dried skim milk. An estimate was made of the N intake from each source required for N equilibrium. These values were 116, 106 and 103 mg N/kg per day, respectively. No statistically significant differences were found among the three dietary groups. Thus, the protein quality of the isolated soy protein appears to be comparable to that of animal protein sources such as milk and beef.

Adolescent↗
PubMed2001

Sensitivity to meat protein intake and hyperoxaluria in idiopathic calcium stone formers.

BACKGROUND: High protein intake is an accepted risk factor for renal stone disease. Whether meat protein intake affects oxaluria, however, remains controversial in healthy subjects and in stone formers. This study was designed (1) to test the oxaluric response to a meat protein load in male recurrent idiopathic calcium stone formers (ICSFs) with and without mild metabolic hyperoxaluria (MMH and non-MMH, respectively), as well as in healthy controls, and (2) to seek for possible disturbed vitamin B(6) metabolism in MMH, in analogy with primary hyperoxaluria. METHODS: Twelve MMH, 8 non-MMH, and 13 healthy males were studied after five days on a high meat protein diet (HPD; 700 g meat/fish daily) following a run-in phase of five days on a moderate protein diet (MPD; 160 g meat/fish daily). In both diets, oxalate-rich nutrients were avoided, as well as sweeteners and vitamin C-containing medicines. Twenty-four-hour urinary excretion of oxalate was measured on the last day of each period, along with 4-pyridoxic acid (U(4PA)) and markers of protein intake, that is, urea, phosphate, uric acid, and sulfate. Serum pyridoxal 5' phosphate (S(P5P)) was measured after protein loading. RESULTS: Switching from MPD (0.97 +/- 0.18 g protein/kg/day) to HPD (2.26 +/- 0.38 g protein/kg/day) led to the expected rise in the urinary excretion rates of all markers of protein intake in all subjects. Concurrently, the mean urinary excretion of oxalate increased in ICSFs taken as a whole (+73 +/- 134 micromol/24 h, P = 0.024) as well as in the MMH subgroup (+100 +/- 144 micromol/24 h, P = 0.034) but not in controls (-17 +/- 63 micromol/24 h). In seven ICSFs (4 MMH and 3 non-MMH) but in none of the healthy controls (P = 0.016, chi square), an increment in oxaluria was observed and considered as significant based on the intra-assay coefficient of variation at our laboratory (8.5%). There was no difference in S(P5P)nd U(4PA)etween the groups after protein loading. CONCLUSION: Approximately one third of ICSFs with or without so-called MMH are sensitive to meat protein in terms of oxalate excretion, as opposed to healthy subjects. Mechanisms underlying this sensitivity to meat protein remain to be elucidated and do not seem to involve vitamin B(6) deficiency.

Adult↗
PubMed1999

IgE antibody response to vertebrate meat proteins including tropomyosin.

BACKGROUND: Although meat is a main source of proteins in western diets, little information is available regarding allergy to vertebrate meats or the allergens implicated in these reactions. OBJECTIVE: To evaluate the in vitro IgE antibody response to different vertebrate meats in suspected meat-allergic subjects, as well as the possible role of tropomyosin in meat allergy and to analyze the cross-reactivity between vertebrate meats and the effect of heating on the IgE-binding to meat proteins. METHODS: Fifty-seven sera from suspected meat-allergic subjects were tested by grid blot to extracts of beef, lamb, pork, venison, chicken, and turkey and to four mammalian tropomyosins of different origins. RESULTS: Meat-allergic subjects have IgE antibodies to proteins in different mammalian meats (43/57 subjects); cross-reactivity with avian meat was limited: less than 50% (19/43) of meat positive sera reacted to chicken. In contrast, most of the poultry-positive sera also reacted to different mammalian meats. In general, there was stronger IgE reactivity to raw meats in comparison to cooked meats; an exception was six cases in which IgE reactivity to cooked poultry was stronger. Weak IgE reactivity to tropomyosin was detected in only 2/57 sera tested. CONCLUSIONS: Suspected meat-allergic subjects have serum IgE directed to meat proteins. In vitro cross-reactivity among mammalian meats appears to be important, while cross-reactivity to poultry is limited indicating mammalian-specific proteins. Although cooking in general denatures meat proteins rendering them less allergenic, in some cases the process of cooking may result in the formation of new allergenic moieties. The muscle protein tropomyosin is not an important vertebrate meat allergen.

Adolescent↗
PubMed1969

Effect of meat and isolated meat proteins on the thermal inactivation of staphylococcal enterotoxin B.

The thermal inactivation of staphylococcal enterotoxin B was studied in a phosphate-saline buffer, in the presence of two meat proteins, myosin and metmyoglobin (MetMb), and in a ground-beef slurry. When enterotoxin B was incubated at temperatures from 60 to 110 C, it was shown that the initial thermal inactivation at 80 C was faster than at 100 or 110C. The heating of enterotoxin B at 60, 80, and 100 C in the presence of either myosin or MetMb resulted in a rapid loss of the enterotoxin. Thermal loss of the enterotoxin B molecule in the presence of meat proteins was more pronounced at 80 C than at either 60 or 100 C. Thermal loss of enterotoxin B molecule in the presence of meat proteins was more pronounced at 80 C than at either 60 or 100 C. Thermal loss of enterotoxin B in a ground round slurry was rapid when compared to inactivation in a phosphate-saline buffer. The rapid loss of enterotoxin B in the slurry may be due to a combination of thermal inactivation and the binding of enterotoxin molecules to meat proteins.

Buffers↗
PubMed1978

Effect of a high protein (meat) intake on calcium metabolism in man.

The effect of a high protein (meat) intake of 2 g/kg on the calcium excretions and retention and on the intestinal calcium absorption was studied in man. In the control study the protein intake averaged 1 g/kg. The studies were carried out during a low calcium intake of 200 mg/day and a normal calcium intake of 800 mg/day. Two additional studies were carried out during a calcium intake of 1100 mg/day and one during a 2000 mg calcium intake. During the high protein-low calcium intake and during the 800 mg calcium intake the urinary calcium did not significantly increase. It increased moderately in two studies during the higher calcium intakes, however, these excretions decreased with time to control levels. The lack of a significant increase of the urinary calcium in the majority of the studies is probably due to the higher phosphorus content of the high protein intake. The calcium absorption, determined with 47Ca, the fecal calcium and calcium balances did not differ significantly during the high protein intake. In studies carried out during a low protein (meat) intake of 0.5 g/kg the urinary calcium changed little and the fecal calcium, the 47Ca absorption, and the calcium balance remained unchanged.

Adult↗
PubMedDate not supplied

[The relation of the biological value of meat proteins to their content of connective tissue].

The influence of connective tissue on the biological value of meat products, manufactured from hashed meat, was studied in experiments on growing rats. It was shown that collagen level increase from 6.1 to 14.5% of the total amount of meat proteins improved the growth-mass characteristics of the animals. The actual biological value and the absolute protein utilization had a tendency to lowering, although the difference was not statistically significant. At the same time the effectiveness of tissue protein biosynthesis was not lowered. A conclusion has been made that the results of animal experiments correlate with the clinical data on the positive effect of the increase up to 15% (by protein) of collagen content on the anabolic action of hashed meat protein in humans. A further increase of the connective tissue amount leads to its diminished biological value.

Animals↗
PubMed1981

Acute effects of increased meat protein on urinary electrolytes and cyclic adenosine monophosphate and serum parathyroid hormone.

The effect of a high meat protein diet on urinary electrolytes, cyclic AMP, and serum immunoassayable parathyroid hormone was studied in six subjects fed a high meat protein diet (1.5 to 2.9 g/kg) for 7 days. The diet produced minor decreases in serum calcium and phosphorus but increased endogenous creatinine clearance by about 20% (p less than 0.02) and urinary calcium by about 80% (p less than 0.01) without changing urinary sodium. Urinary calcium correlated (p less than 0.01) with urinary sulfate (r = 0.60), ammonia (r = 0.72), and nitrogen (r = 0.60). Urinary cyclic AMP increased (p less than 0.01) 14% while serum parathyroid hormone (measured by C-terminal assays) decreased (p less than 0.05) by more than 30%. It was concluded 1) that this diet acutely altered renal handling of calcium at a site different from that of sodium, 2) that the excretion of acidic products of protein metabolism contributed to these changes, and 3) that parathyroid hormone secretion was not changed acutely.

Adult↗
PubMed1977

The effect of sex, dietary energy, meat protein, ascorbic acid and iron on broiler skin collagen.

Two studies were conducted to determine if variation of sex, dietary energy, meat protein, ascorbic acid or iron had any effect on collagen metabolism in broilers. In the first experiment day-old broiler type chicks were fed diets which contained 3190 or 3410 kcal. M.E./kg. of diet, 0 or 15% meat and bone meal and 0 or 1 g./kg. ascorbic acid. In the second experiment the day-old broiler chicks were fed diets which had 3190 or 3410 kcal. M.E./kg. of diet and 60 or 260 p.p.m. of iron. At 56 days of age the broilers were weighed, a representative number of birds killed from each group and skin samples collected. The skin samples were analyzed for the degree of collagen cross-linking and the total and insoluble collagen contents. An alteration of energy, meat protein, ascorbic acid or iron in the diet had no effect on collagen formation in the skin of broilers reared in cool environmental temperatures. Female broilers had a significantly higher percentage of insoluble collagen in the skin tissue but the level of total collagen and insoluble collagen was higher in the male birds.

Animals↗
PubMed1988

Bile acid and cholesterol excretion in human beings given soya-bean- and meat-protein-based diets: a study in ileostomy subjects.

1. The effect of partial replacement of meat protein with three different soya-bean-protein products on bile acid and cholesterol excretion was studied in seven ileostomy subjects. Four different tests diets containing 60 g meat, rice and bread protein, or a replacement of 250 g protein/kg total dietary protein by soya-bean protein from soya-bean flour, soya-bean concentrate or soya-bean isolate, were randomly assigned to the subjects in 2-d periods. 2. Ileostomy contents were collected at 2-h intervals during the day and in one portion during the night, and immediately deep-frozen to avoid bacteriological degradation. Bile acids and cholesterol were quantified by gas-liquid chromatography. 3. No difference in daily excretion of bile acids and cholesterol was noted between test diets. Ileostomy sterol concentrations were lower when soya-bean products were fed. 4. Incorporation of moderate amounts of soya-bean products in solid diets does not seem to affect short-term sterol balance in man.

Adult↗
PubMed1987

[Interaction of lipids and meat proteins. 2. Digestibility of proteins in vitro, thermohydrolysis of collagen, changes in the content of essential amino acids and coefficients of the relative nutritive value of proteins].

Changes in the nutritive value of meat under the influence of an interaction between oxidized fats and proteins were studied in model experiments. Parameters were the digestibility of protein, sensitivity of tissue against thermohydrolysis, changes in the content of essential amino acids and in the RNV coefficient of the protein. Muscle gel and tissue served as meat substrates, methyl ester of linoleic acid and its oxidation products were used as fat substrates. It has been found that reactions of the oxidation products of methyl linoleate with meat proteins lead to a crosslinking of proteins. Hexanal and hydroperoxide of the oxidized methyl linoleate influence the decrease in digestibility of muscle protein and the thermohydrolysis of the collagen. Proteins of pasteurized gels showed losses in essential amino acids, which corresponded to a lower nutritive value (determined in the RNV coefficient).

Amino Acids, Essential↗