[Comparison of nutrient intake and corresponding biochemical parameters in adolescent vegetarians and non-vegetarians]. / Porovnanie príjmu zivín a odpovedajúcich biochemických parametrov u dospievajúcich vegetariánov a nevegetariánov.

BACKGROUND: In comparison to food habits of non-vegetarians alternative nutrition bears several risks, but it also has beneficial effects. Considering risks represent a significant age aspect. Nutritional risk and protective factors were evaluated in a adolescent group. METHODS AND RESULTS: Food habits of 53 lactoovovegetarians (mean duration of vegetarianism 3.2 y) assessed by analysis of dietary questionnaires were compared to those of 55 nonvegetarians and evaluated with respect to basic biochemical indicators (iron, hemoglobin, calcium, total protein, cholesterol, fatty acids, vitamin A, beta-carotene, vitamin C, vitamin 3). Vegetarians consume less fat, and they have higher intake of plant fat, which is reflected din more favourable lipid levels, i.e. lower risk parameters of atherosclerosis (cholesterol, LDL-cholesterol, atherogenic index, saturated fatty acids) and higher values of factors with antisclerotic effect (32.9% ratio of HDL-cholesterol vs. 30.6% in non-vegetarians, polyunsaturated fatty acids, vitamin E/cholesterol ratio, vitamin C). Total plasma protein levels are balanced in both groups (intake of full value mixture of amino acids from grains, legumes (soya), and mild in vegetarians, similar intake of total proteins with a small difference in plant protein consumption). Iron and calcium absorption is inhibited in vegetarians as a consequence of presence of plant food--physic acid, oxaloacetic acid (20.7% hyposiderinemia vs. 0% in non-vegetarians, high iron intake in both groups, iron from plant sources represented 82% in vegetarian boys and 95% in vegetarian girls, hypocalcemia in 28% of vegetarians vs. 7.3% of non-vegetarians). Vegetarians have significantly higher levels of all antioxidant vitamins. This is result of higher consumption of vegetables, fruit, plant fat and sprouts. Higher intake and higher levels of antioxidants are reflected in significantly lower lipoperoxidation values. CONCLUSIONS: Lactoovovegetarian nutrition represents risk for adolescents if the values of iron and calcium are considered, however it has positive aspects on lipid parameters, protein values, and antioxidant parameters.

[Nutritional risk factors of a vegetarian diet in adult lacto-ovo vegetarians]. / Rizikové nutricné faktory vegetariánskeho stravovania u dospelých laktoovovegetariánov.

Risk nutritional factors of alternative alimentation detected in childhood were evaluated in a group of adult lactoovovegetarians (n = 47). The levels of iron, calcium, zinc, total proteins, gluthatione, plasmatic profile of fatty acids and the lipoperoxidation product in correlation with the values of antioxidative vitamins were studied. The results are compared with mean sample upon mixed nutrition (omnivores n = 42). In both groups were the mean values of iron, calcium and zinc in physiological range, but significantly lower in vegetarians. In the alternative nutrition group was in 21 percent of probands hyposiderinemia detected (vs 5 percent in the omnivores group), in 19 percent of probands hypocalcemia (vs 9 percent) and in 6 percent hypozincemia (vs 0 percent). Full-bodied mixture of milk proteins, egg proteins and vegetable sources in lactoovovegetarians ensured sufficient protein saturation and caused significantly higher level of blood gluthatione (intake also in food). Increased value of fatty acid peroxidation index was not due to increased lipoperoxidation in lactoovovegetarians--significantly lower levels of conjugated fatty acid dienes were determined. This was ensured by sufficient protection by means of essential antioxidants--the levels of vitamins E, C, beta-carotene are in vegetarians significantly higher. These are overtreshold values representing reduced risk of free-radical diseases. Lactoovovegetarians had significantly higher content of linoleic and alpha-linoleic acids in plasma. Values of polyunsaturated fatty acids with C20 and C22 and 3-6 double bonds were similar to values in omnivores. In probands on alternative nutrition with iron deficit was significantly lower activity of delta 6 desaturase determined. (Tab. 3, Ref. 45.)

[Relation between fatty acid composition, vitamin e and malondialdehyde levels, and activity of antioxidant enzymes in the blood]. / Vzájomný vztah zlozenia mastných kyselín ku koncentrácii vitamínu E, k hladine malóndialdehydu a k aktivitám antioxidacných enzýmov v krvi.

The aim of our study was to determine the composition of saturated fatty acids (SFA), monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA) in erythrocytes and to investigate their relation to the concentration of vitamin E (Vit E) in the plasma, level of malondialdehyde (MDA) in the serum and activities of antioxidant enzymes (AE) in erythrocytes. We examined 128 healthy volunteers (57 men and 71 women) at the ages ranging between 20 and 72. Fatty acids were assessed by gas chromatography, vitamin E by the HPLC method, MDA by the spectrophotometric method, GSH-Px by the kinetic method, CU, Zn-SOD by the Randox test. We have detected the following order in the proportion of fatty acids: SFA > PUFA > MUFA. The increase in PUFA and MUFA was in direct correlation with the concentration of MDA and AE activity, however in reverse correlation with Vit E. A reverse correlation was observed in the increase in SFA. We have found an increase in lipoperoxidation due to the increase in PUFA in erythrocytes in the group of healthy people. This state is concommited by an increase in the activity of antioxidant protection for the maintenance of the balance state. The authors assume that a decrease in Vit E can be caused by its increased "consumption" as the most effective antioxidant in lipid environment. (Tab. 2, Fig. 1, Ref. 27.)

[Relation between levels of vitamins C, E, A and beta-carotene and activity of antioxidant enzymes in the blood]. / Vztah hladín vitamínov C, E, A a beta-karoténu k aktivite antioxidacných enzýmov v krvi.

UNLABELLED: Antioxidant protection is procured by many enzymatic and non-enzymatic factors which maintain the physiological level of reactive forms of oxygen. The aim of this study was to determine the levels and relationship between concentrations of the selected non-enzymatic antioxidants in healthy people (vitamin C--Vit C, vitamin E--Vit E, beta-carotene-beta-Car and vitamin A--Vit A) in the serum, antioxidant enzymes, CuZn-superoxide dismutase--SOD, catalase CAT, glutathione peroxidase--GPx) in erythrocytes and malondialdehyde (MDA) in the serum. We have examined 128 volunteers (57 men and 71 women) at the age ranging between 20 and 72. The average levels of vitamins and beta-Carotene were detected near the lower level of normal values or below it, whilst the highest interindividual differences were detected in Vit C and Vit E. The level of Vit E indirectly correlated with SOD, GPx, MDA, but directly with CAT. On the contrary, the levels of Vit A directly correlated with SOD, GPx, MDA and indirectly with CAT. The levels of Vit C and beta-Carotene had no relation with the activities of antioxidant enzymes and the level of MDA. The direct correlation was between the levels of Vit C and Vit E, and Vit C and beta-Carotene. CONCLUSIONS: 1. A decrease in average levels of Vit A, C, E and beta-Carotene in the blood of the investigated group of healthy persons indicates their lower antioxidant protection. 2. The relation between Vit E, MDA, activities of GPx and SOD indicates the presumed mutually supplementing effect of these antioxidants in liquidation of products of lipoperoxidations. (Tab. 2, Fig. 3, Ref. 17.)

LDL oxidizability and antioxidative status of plasma in vegetarians.

Vegetarian food with a higher content of natural antioxidants may decrease the risk of developing cardiovascular diseases. The oxidative modification of low-density lipoprotein (LDL) has been implicated in the pathogenesis of atherosclerosis. The objectives of this study were to investigate in vitro resistance of LDL against oxidation and antioxidative status of plasma in 19 lactoovovegetarians and nonvegetarians (n = 19). The kinetics of conjugated diene formation (lag time and maximal rate of oxidation, Vmax) and thiobarbituric acid reacting substances (TBARS) were determined as indices of LDL oxidation. No significant differences in lag time and Vmax were observed between vegetarians and nonvegetarians, while TBARS in native and oxidatively modified LDL were significantly lower in vegetarians. Plasma vitamin (C, E, beta-carotene) levels were increased in vegetarians, but only the vitamin C increase was statistically significant. Vegetarians also had a significantly increased plasma total antioxidant status (TAS) and molar ratio vitamin E/cholesterol which indicates a more effective protection of lipoproteins against oxidation. A significant positive correlation was observed between lag time and plasma TAS in both vegetarians and nonvegetarians. We conclude that although the resistance of LDL to in vitro oxidation, as measured by the kinetics of conjugated diene formation was not altered in vegetarians, the effect of vegetarian nutritional habits favorably affected TBARS levels in LDL and total plasma antioxidant capacity.

Influence of vegetarian and mixed nutrition on selected haematological and biochemical parameters in children.

To evaluate the health and nutritional status of children with two different nutritional habits, the authors examined 26 vegetarians (lacto- and lacto-ovo; an average period of vegetarianism 2.8 years) and 32 individuals on mixed diet (omnivores) in the age range 11-14 years. Vegetarian children had significantly lower erythrocyte number as well as reduced levels of haemoglobin and iron compared to omnivores. The average level of iron did not reach the lower limit of the physiological range and hyposiderinemia was found in 58% of vegetarians vs 9% of omnivores. Reduced iron levels were observed in spite of increased intake of vegetable iron sources and vitamin C (which facilitates the conversion to ferro-form). This reduction can be attributed to the absence of animal iron sources with high utilizability and to lower iron utilization in the presence of phytic acid (higher intake of grains compared to omnivores). The incidence of hypoalbuminemia and hypoproteinemia in vegetarian children was 38 and 12%, respectively, compared to 0% in omnivores. The protein mixture from milk, eggs and vegetable sources is complete, but vegetarian children had significantly reduced intake of milk and dairy products. Favourable lipid and antioxidant parameters in vegetarian children reflect the optimal nutrition composition with respect to the prevention of free radical diseases. Such a nutrition results in significantly lower levels of cholesterol and LDL-cholesterol compared to omnivores and significantly higher and over threshold values of essential antioxidants--vitamin C, vitamin E/cholesterol (more effective protection against LDL oxidation), beta-carotene, vitamin A.

[The plasma profile of fatty acids in vegetarians]. / Plazmatický profil mastných kyselín u vegetariánov.

The plasma profile of fatty acids has been observed in 27 vegetarian adults, their age ranging from 20 to 63 years (13 men, 14 women) with the average period of vegetarian dietary pattern being 8.8 years. A third of the men and a half of the women were lacto-vegetarians, the rest of them were lacto-ovo-vegetarians. The contents of saturated and monounsaturated fatty acids insignificantly decreased in vegetarians when compared with non-vegetarians (n = 26, 12 men, 14 women, average group of non-smokers with mixed nutrition). The results of parameters regarded as positive factors in vegetarian diet and effective in prevention of atherosclerosis are as follows: significantly higher values of linoliec acid C 18:2, a significantly higher ratio of linoliec/leic acids C 18:2/C18:1 and insignificantly higher value of linolenic acid C 18:3, together with an unchanged, or moderately decreased contents of poly-unsaturated fatty acids C 20:4 (arachidonic acid) and C 22:6 (n3; docosahexaenoic acid). Further prooxidative-antioxidative parameters were selected in regard to the theoretical anticipation of risk brought about by increased lipoperoxidation in vegetarians (poly-unsaturated fatty acids-substrate of the process) which is significant in the etiology of cardio-vascular and oncologic diseases. Their favourable values (significantly lower plasma contents of conjugated dienes of fatty acids, significantly higher plasma value of vitamin C, Beta-carotene, vitamin E/cholesterol-protection of LDL, vitamin E/triacylglycerols-protection of fatty acids, 3.5 times more significant positive linear correlation of vitamin E/triacylglycerol versus plasma contents of C 18:2) eliminate the risk of increased lipoperoxidation in vegetarians. (Tab. 3, Fig. 1, Ref. 29.)

[Precancerous conditions and carcinomas of the stomach and colorectum--blood levels of selected micronutrients]. / Prekancerózy a karcinómy zalúdka a kolorekta--hladiny vybraných mikronutrientov v krvi.

BACKGROUND: Optimal saturation of organism by micronutrients--vitamins and trace elements--has a significant inhibitory effect on the origin and development of malign diseases. OBJECTIVES: The aim of the study was to investigate the blood levels of A, C and E vitamins, Beta-carotene, zinc, and selenium in 249 patients with precanceroses (atrophic gastritis, hyperplastic polyp of the stomach, adenomas of the stomach and colorectum, ulcerative colitis), 96 patients with carcinoma of the stomach or colorectum, and to compare them with a control group of 130 people. RESULTS: We have discovered the frequency of decreased average levels of micronutrients in patients with precanceroses as follows: vitamin C > vitamins E and A > selenium > beta carotene. In all groups of patients with carcinoma the average levels of vitamins and Beta-carotene were significantly decreased, the level of selenium has decreased only in the group of gastric carcinoma. The copper level was increased in the group of ulcerative colitis and in all groups with carcinoma. CONCLUSION: The results indicate that in the primary prevention of these malign diseases it is necessary to improve the levels of the presented micronutrients in the population of the Slovak Republic by increasing the intake of fruit, vegetables and other sources of nutrition, the secondary prevention in persons with precanceroses requires an appropriate intermittent supplementation of micronutrients (chemoprevention). (Tab. 3, Ref. 24.)

Lipid and antioxidant blood levels in vegetarians.

Parameters of lipid metabolism (triacylglycerols TG, cholesterol CH, HDL-CH, LDL-CH, atherogenic index AI, profile of fatty acids) were measured in blood samples of 81 healthy lacto and lacto-ovo vegetarians (42 males, 39 females; age range 19-39 years). The average period of being on a vegetarian diet was 6.2 years. Low levels of TG, CH, LDL-CH, AI and HDL-CH values on the borderline between standard and reduced risk (1.4 mmol.l-1) can be considered as favourable from the atherosclerosis prevention aspect. Compared with non-vegetarians (n = 62), the levels of TG, CH, LDL-CH, and AI are significantly reduced in the vegetarian group. As opposed to non-vegetarians, vegetarians showed a higher total sum of polyunsaturated fatty acids, a significantly higher content of linoleic acid (C 18:2) and linolenic acid (C 18:3), unchanged content of oleic acid (C 18:1), stearic acid (C 18:0) and other polyunsaturated fatty acids. The process of lipoperoxidation (with polyunsaturated fatty acids as substrate) is involved in the etiology of cardiovascular and oncological diseases. Favourable values of prooxidative-antioxidative parameters demonstrated a reduced risk of lipoperoxidation in vegetarians, compared to non-vegetarians (significantly reduced content of conjugated dienes of fatty acids in plasma, significantly higher plasma levels of vitamin C, beta-carotene, vitamin E/cholesterol ratio--and indicator of LDL protection, vitamin E/triacylglycerols ratio--an indicator of fatty acid protection--, selenium and glutathione-peroxidase activity).

Antioxidative levels in two nutritional population groups.

Plasma profile of polyunsaturated fatty acids, conjugated dienes of fatty acids (CD) in plasma, levels of vitamins C, E, A and beta-carotene, as well as plasma levels of trace elements (selenium, zinc, copper) were estimated in a group of 162 healthy lacto-vegetarians and lacto-ovo-vegetarians (non-smokers, aged 30-63 years, average period of vegetarianism was 5 years). When compared to omnivores (n = 159, average sample of non-smokers of the same age range from the same geographic region as the vegetarians), a significantly higher content of linoleic acid C 18:2 and linolenic acid C 18:3 was found in vegetarians. Plasma level of the first product of lipoperoxidation (CD) was significantly reduced in vegetarians compared to omnivores. Levels of essential antioxidative vitamins in plasma were significantly higher in vegetarians (vitamin C, beta-carotene, vitamin A, vitamin E/cholesterol-indicating more effective protection of LDL against oxidation, vitamin E/triacylglycerols and 2.27-fold pronounced the positive linear correlation between vitamin E/triacylglycerols and plasma C 18:2 content-indicating higher protective effect against peroxidation of polyunsaturated fatty acids). Beneficial antioxidative values were complemented by elevated level of selenium as well as copper and zinc values equivalent to omnivores. These results support the positive effect of vegetarianism on the regulation of prooxidative processes. This nutritional habit can thus contribute to reduced risk of free radical diseases such as cancer or cardiovascular diseases.

[Serum levels of vitamins A, C and E in the population of Slovakia]. / Sérové hladiny vitamínov A, C a E u obyvatel'ov Slovenska.

BACKGROUND: Significant forms of vitamin deficiencies are rare in Slovak Republic, however mild hypovitaminoses are still relatively frequent and they have negative consequences on the functional status. Vitamins A, C and E represent an important part of the antioxidant defense system acting against free-radical damage. Imbalance between oxidative stress and antioxidant capacity which leads to free radical damage is considered to be an aetiological factor of ischaemic heart disease and cancer. OBJECTIVES: The study was focused on assessment of serum levels of vitamins A, C and E in the Slovak population older than 35 y and frequency of decreased levels. Relationship between high prevalence of chronic non-communicable diseases and high frequency of suboptimal levels of antioxidant vitamins is discussed. METHODS: Serum levels of vitamin A and E were assessed by the HPLC method, the levels of vitamin C by the colorimetric method. RESULTS: Mean levels of vitamin A were 1.85 mumol/l in both sexes (95% c.i. 1.75-1.89 in males, 1.77-1.92 in females). Mean level of vitamin C was 31.36 mumol/l in males (95% c.i. 30.06-32.72), the value observed in females was significantly higher (43.05 mumol/l, 95% c.i. 41.75-44.40). Mean level of vitamin E observed in males (29.2 mumol/l, 95% c.i. 27.62-30.87) was only slightly, not significantly higher than in females (28.11 mumol/l, 95% c.i. 26.45-29.87). Decreased levels of vitamin E were observed only in a small proportion of the sample, however almost one third of males had decreased level of vitamin C and more than 20% had low level of vitamin A. We observed high prevalence of serum levels of vitamins A, C and E suboptimal from the aspect of risk of coronary heart disease and cancer (vitamin A: males 78%, females 75.5%, vitamin E: 41.9 and 49.6%, respectively, vitamin C: 61.8% and 41.1%). CONCLUSION: Results indicate that sizeable proportion of population has decreased serum levels of vitamins, males especially of vitamin C and females of vitamin A. According to serum levels of vitamin A, C and E high percentage of population can be ranked into the group with increased risk of CHD and cancer. (Tab. 6, Ref. 29.)

Plasma fatty acid profile and prooxidative-antioxidative parameters in vegetarians.

Fatty acid profile in plasma was examined in 12 adult vegetarians (lacto and lacto-ovo) aged 41-63 years with an average period of vegetarian nutrition of 9.8 years. Difference in the content of saturated and monounsaturated fatty acids in vegetarians was insignificant (compared to non-vegetarians). Positive factor of vegetarian nutritional habit with respect to atherosclerosis included significantly elevated content of linoleic acid (C 18:2) and linolenic acid (C 18:3), as well as unchanged or only slightly reduced content of polyunsaturated fatty acids--arachidonic acid (C 20:4) and docosahexaenoic acid (C 22:6, n = 3). Favourable values of prooxidative-antioxidative parameters (significantly reduced content of conjugated dienes of fatty acids in plasma, significantly higher plasma levels of vitamin C, beta-carotene, vitamin E/cholesterol--indicator of LDL protection and vitamin E/triacylglycerols--indicator of fatty acid protection) demonstrated a reduced risk of lipoperoxidation in vegetarians.

Selected vitamins and trace elements in blood of vegetarians.

Selected vitamin (A, C, E, beta-carotene) and trace element (selenium, zinc, copper) levels were estimated in the blood of 67 vegetarian nonsmokers aged 34-60 years. The average period of lacto- or lacto-ovovegetarianism was 6.2 years. The results were compared with those of 75 nonvegetarians of the same age and living in the same region. Vegetarians had significantly higher plasma levels of essential antioxidants: vitamin C, beta-carotene, and vitamin A. A significantly higher molar ratio vitamin E/cholesterol indicates a more effective protection especially of low-density lipoproteins against peroxidation. Oxidation of low-density lipoproteins represents one of the key factors in the pathogenesis of atherosclerosis. The molar ratio vitamin E/total lipids was significantly higher in plasma of vegetarians, demonstrating a more effective protection of polyunsaturated fatty acids against peroxidation. Vegetarians had significantly higher plasma levels of selenium and similar levels of zinc and copper when compared to nonvegetarians. These trace elements are important for the activity of antioxidant enzymes. The results document a beneficial effect of vegetarian nutritional habits on antioxidative parameters and thus on the reduction of cardiovascular diseases and cancer risk. Reactive products of oxygen metabolism and subsequent toxic products of lipid peroxidation play an important role in the etiology of these diseases.

Effect of intake of exogenous vitamins C, E and beta-carotene on the antioxidative status in kidneys of rats with streptozotocin-induced diabetes.

We studied the effect of supplementation with vitamins C, E and beta-carotene (PARABION, produced by Syndipharma) on antioxidative status in kidneys of male Wistar rats with diabetes induced by intravenous application of streptozotocin (45 mg.kg-1 of body weight). The animals received subtherapeutic doses of Insulin Interdep (6 U.kg-1 of body weight). A significant decrease of malondialdehyde (MDA), reduced (GSH) and oxidized (GSSG) glutathione and reduction of the activities of Se-glutathione peroxidase (Se-GSH-PX, EC. 1.11.1.9.) and glutathione S-transferase (GST, EC. 2.5.1.18.) were observed in kidneys of diabetic rats treated with these vitamins. On the contrary, the activity of CuZn-superoxide dismutase (CuZn-SOD, EC. 1.15.1.1) and the level of vitamin C (vit. C) increased significantly. No changes were observed for vitamin E (vit. E), beta-carotene and catalase (CAT, EC. 1.11.1.6). Supplementation with vitamins C, E and beta-carotene resulted in an improvement of antioxidative status of kidneys of rats with streptozotocin-induced diabetes.

Influence of casein and soy flour proteins on aminoacid content in the liver of experimental animals.

We have observed a significantly increased content of fats and decreased content of proteins in the liver of experimental rats fed a diet supplemented with 25% casein proteins in comparison with the application of de-fatted soy flour. Casein proteins have a higher content of methionine in relation to cystine than baked soy flour. But the soy diet in contrast to the casein diet has a high content of free aminoacids which are not present in casein at all: aspartic acid, asparagine, alpha-aminoadipic acid, methionine, norleucine, lysine, phenylalanine, beta-alanine, ethanolamine, histidine, proline, gamma-aminobutyric acid, taurine. Differences in free valine, alanine, arginine, glycine, ornithine and cysteic acid are also significant. The content of free aminoacids in the liver of experimental animals fed a soy diet is high in the content of cystine, cystathionine, ornithine, beta-aminoisobutyric acid, beta-alanine, gamma-aminobutyric acid, leucine. We have also found accumulation of methionine, glycine, alpha-aminobutyric acid, taurine and citrulline in free aminoacids from the liver of animals fed a casein diet. Citrulline and glycine in free aminoacids from the liver of animals fed a soy protein supplement were not recorded. Our investigations have shown that the application of a soy diet enriched with cystine acts protectively on methionine and that methionine is preferentially utilized for protein synthesis. The catabolic pathway of methionine prevails in animals on a casein diet.

Body composition and physiological casein and wheat gluten protein requirements of 180-day-old rats.

Six-month-old male rats were given diets with mounting casein and wheat gluten protein concentrations from 0% to 40% and after 14 days the optimum and minimum physiological doses were determined from changes in body nitrogen, body water, body weight and protein intake. The optimum dose for casein protein was 1.54 g/d (5% protein in the diet) and for wheat gluten protein 2.10 g/d (7.5% protein in the diet). The minimum casein and wheat gluten protein doses for 180- to 194-day-old rats, determined from body nitrogen changes, were 1499 mg/d (4.86%) and 1995 mg/d (7.12%) respectively, from body water changes 1561 mg/d (5.06%) and 2027 mg/d (7.23%) and from body weight changes 1333 mg/d (4.32%) and 1951 mg/d (6.06%). It should be noted that, unlike younger animals aged 35-49, 75-89 and 120-134 days, the optimum and minimum doses for six-month-old rats were approximately the same.

Determination of physiological casein and wheat gluten protein requirements of adult rats aged 75-89 days.

Mounting doses of casein and wheat gluten protein (from 0% to 40% in the diet) were given to adult male rats aged 75-89 days for 14 days. The optimum physiological daily dose, determined from changes in body nitrogen, body water and body weight, was 2.76 g/d for casein protein (corresponding to a 10% casein protein diet) and 3.67 g/d for wheat gluten protein (corresponding to a 15% gluten protein diet). Determined from body weight changes, the daily maintaining dose of casein or wheat gluten protein was 1.054 and 1.511 mg/d respectively, from body nitrogen changes 970 and 1.514 mg/d and from body water changes 1.124 and 1.637 mg/d. Compared with newly weaned animals aged 35-49 days, the optimum physiological daily dietary protein doses for adult animals fall, while the maintaining doses rise.

Physiological casein and gluten protein requirements of growing rats.

Using mounting casein and wheat gluten protein values (0-40%) in the animals' diet, the optimum and minimum physiological daily doses were determined in 49-day-old growing rats from changes in their body water, body nitrogen and protein intake. The optimum physiological doses were identical with the peak of linearity of the given parameters, which coincided with a 15% casein protein and a 20% gluten protein concentration in the diet. This was also confirmed by the maximum body amino acid values, which were found in animals given a 15% casein or 20% gluten protein diet. It was further confirmed by the finding of significantly elevated alanine aminotransferase and aspartate aminotransferase activity in the liver of animals with a higher intake of the above protein sources. The minimum physiological dose of the given protein was determined from the equations of the regression curves in the presence of zero changes in the body nitrogen or body water content. The optimum physiological daily doses of casein and wheat gluten protein were 3.25 g and 4.05 g respectively. The minimum physiological daily doses of casein protein were 268 mg (from body nitrogen changes) and 371 mg (from body water changes) and the minimum physiological daily doses of gluten protein were 892 mg (from body nitrogen changes) and 1,000 mg (from body water changes). The above indicators demonstrate, in the presence of higher and high dietary concentrations, that an intake of the given proteins over and above the optimum physiological daily dose is at the very least uneconomical (gluten), if not harmful (casein), making this a highly topical problem for further study.