Clinical studies on the hypolipidemic and antioxidant effects of selected natural substances.

BACKGROUND: The average blood levels of cholesterol and triacylglycerol in population are generally considered to be indicators of cardiovascular risk. AIM OF THE STUDY: The aim of our study was to present representative data of selected fractions of blood lipids, and the trend of their levels during the last 35 years in the adult population of Slovakia. RESULTS: This study demonstrates the risk of the elevated average cholesterolaemia and triacylglycerolaemia in men aged 35-39 years and above 60 years, as compared to womens' increased blood level that were detected only in the age group above 60 years. Strong gender differences in HDL-cholesterol were found, women having higher values than men, with these differences fading in the age group above 60 years. The results of two clinical studies present the hypolipemic effects of n-3 polyunsaturated fatty acid in individuals with dyslipidaemia, the hypotriacylglycerolemic effect being dominant (p < 0.001). The hypocholesterolemic effect was less significant (p < 0.05) than in cases when lyophilized powder of the Pleurotus ostreatus was applied (p < 0.01). In both cases, a stabilizing effect on serum HDL-cholesterol had been observed. In case of polyunsaturated fatty acid n-3, its increase was borderline with statistical significance (p = 0.05). CONCLUSION: The study emphasises the necessity of improving the average blood level of lipids in the population of Slovakia and the pertinence of using natural substances with a hypolipemic effect in secondary and even primary prevention of atherosclerosis and its serious complications (Tab. 3, Fig. 4, Ref. 27).

Selected prooxidative - antioxidative parameters in blood of adult vegetarians.

Selected prooxidative - antioxidative parameters (conjugated dienes of fatty acids CD, vitamin C, vitamin E, catalase activity CAT, glutathione peroxidase GSH-Px activity) were investigated in blood of 81 vegetarians aged 20-40 years. The average period of consuming vegetarian food was 3.5 years. The results were compared to corresponding values of non-vegetarians of the same age and from the same geographical region (Bratislava). The levels of conjugated dienes of fatty acids were significantly lower in vegetarians. Significantly higher values of molar ratio vitamin E/cholesterol, vitamin E/triacylglycerols and vitamin E/polyunsaturated fatty acids found in vegetarians imply a higher protective effect against lipid peroxidation - antioxidative status in vegetarians is indicated also by significantly higher levels of vitamin C in plasma, significantly increased catalase activity and insignificantly increased activity of glutathione peroxidase in erythrocytes.

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.

Correlation of carnitine levels to methionine and lysine intake.

Plasma carnitine levels were measured in two alternative nutrition groups--strict vegetarians (vegans) and lactoovovegetarians (vegetarians consuming limited amounts of animal products such as milk products and eggs). The results were compared to an average sample of probands on mixed nutrition (omnivores). Carnitine levels were correlated with the intake of essential amino acids, methionine and lysine (as substrates of its endogenous synthesis), since the intake of carnitine in food is negligible in the alternative nutrition groups (the highest carnitine content is in meat, lower is in milk products, while fruit, cereals and vegetables contain low or no carnitine at all). An average carnitine level in vegans was significantly reduced with hypocarnitinemia present in 52.9% of probands. Similarly, the intake of methionine and lysine was significantly lower in this group due to the exclusive consumption of plant proteins with reduced content of these amino acids. Carnitine level in lactoovovegetarians was also significantly reduced, but the incidence of values below 30 micromol/l was lower than in vegans representing 17.8% vs. 3.3% in omnivores. Intake of methionine and lysine was also significantly reduced in this group, but still higher compared to vegans (73% of protein intake covered by plant proteins). Significant positive correlation of carnitine levels with methionine and lysine intake in alternative nutrition groups indicates that a significant portion of carnitine requirement is covered by endogenous synthesis. Approximately two thirds of carnitine requirement in omnivores comes from exogenous sources. The results demonstrate the risks of alternative nutrition with respect to the intake of essential amino acids, methionine and lysine, and with respect to the intake and biosynthesis of carnitine.

The effect of dietary protein and sucrose on the diabetic rat kidney.

The effect of 3 months feeding with diets of different protein and sucrose content (9% casein + 70% sucrose vs. 18% casein + 61% sucrose) on the development of diabetic nephropathy and changes in serum lipid spectrum was investigated in rats with insulin-dependent diabetes (streptozotocin 45 mg.kg-1). Metabolism of diabetic animals (before the nutritional regimen) was characterized by hyperglycaemia, moderate hyperlipidemia, lipid accumulation in the liver and elevated creatinine concentration in the blood. Kidney weight and protein content were not significantly changed. Histological picture of kidneys showed initial changes of glomerular structure. After three months hyperlipoproteinaemia was more accentuated in animals given either of the two diets, the kidneys were hypertrophic with a higher protein content and displayed morphological changes of diabetic nephropathy. Animals given the low-protein diet developed smaller morphological changes both in glomeruli and tubuli. The study indicates that dietary protein and not hyperlipoproteinaemia is the major factor, which may significantly influence the progress of diabetic nephropathy.

[Nutrition and Crohn's disease]. / Výziva a Crohnova choroba.

The relationships between non-specific inflammatory bowel disease and nutrition is considered. One of the hypotheses holds that environmental factors, especially those in dietary intake, can be the initiators of intestinal inflammation. In this connection authors examined a group of patients suffering from Crohns disease and ulcerative colitis. Results observed in patients with Crohns disease indicate: preferred consumption of flour products, decreased intake of vegetables and fruit, lowered tolerance to milk and milk products, increased sugar consumption, increased proportion of smokers, no differences in diet regimen between nick and healthy subjects. (Tab. 3, Ref. 16.)

[Is fish oil supplementation (n-3 fatty acids) important for the diabetic?]. / Má suplementácia rybím olejom (n-3 mastnými kyselinami) význam u diabetikov?

Since the 70-ties many investigators have studied the effects of fish oil supplementation in experimental and clinical medicine. Regarding to some perspective results (in healthy subjects, cardiovascular, autoimmune diseases, in disorders of lipid metabolism, in carcinogenesis a.o.), there were also expected favourable consequences in diabetic subjects. Taking into consideration the most controversial information in this field, the authors in this review article try to summarize all relevant questions. (Fig. 1, Tab. 1, Ref. 22.)

[Importance of certain hemostatic indicators as cardiovascular risk factors in type 2 diabetes]. / Význam niektorých hemostatických ukazovatelvov ako kardiovaskulárnych rizík u diabetikov 2. typu.

BACKGROUND: Abnormal levels of some hemostatic factors in patients with type 2 diabetes mellitus are associated with increased risk of severe cardiovascular complications. OBJECTIVES: For the purpose of clinical practice it is necessary to specify most relevant coagulation factor abnormalities pertaining to a particular patient's risk profile (e.g. diabetes duration, his/her lipoprotein profile), since a routine examination to their full extent is in common ambulatory practice hardly manageable. This information is also needed for aiming the efforts to influence them purposefully. METHODS: The investigated group included 42 out-patients with type 2 diabetes mellitus. Selected hemostatic factors and lipoproteins were measured with standard methods. Patients were stratified into terciles based on supposedly causative factors (diabetes duration for vWF and lipoproteins for F VII), these relations being also examined in the whole group using regression analysis. MAIN RESULTS AND CONCLUSIONS: vWF (antigen) plasma concentration mean value in the whole group (in % of reference plasma: 149.917; 95% CI 134.296 to 165.538) was on the upper limit of the normal value reference range (56 to 140), exceeding it distinctly in the tercile III with the longest diabetes duration (vWF mean was 180.115; 95% CI 151.961 to 208.270). The mean in this tercile was also by 42.187 (95% CI of diff. 10.231 to 74.142; sign. level 0.012) higher than in the tercile I with the shortest diabetes duration. These 2 variables significantly correlated (r = 0.345; p = 0.025) also in the whole group. F VII plasma concentration mean values in terciles III with highest triacylglycerol (TAG) or total cholesterol (TCH) serum levels (in %: 129.286, 95% CI 121.117 to 137.455 or 121.071, 95% CI 109.228 to 132.915, respectively; the normal value reference range being 70 to 130) clearly surpassed the analogous values in tercile I by 35.0 (95% CI of diff. 22.793 to 47.207; sign. level < 10(-5)) or by 26.0 (95% CI of diff. 10.815 to 41.185; sign. level 0.002), respectively. There were also positive significant correlations between lipoproteins (TAG, TCH or LDL) and F VII in the whole group (r = 0.697, r = 0.580, r = 0.397; p < 0.0001, p < 0.0001, p = 0.018, respectively). Therefore the estimation of vWF seems to be useful in all diabetic patients and most elevated values are to be expected in long-duration-diabetics. F VII should be cared for especially in patients with concomitantly elevated TAG, TCH or LDL-cholesterol serum levels. (Tab. 6, Fig. 4, Ref. 24.)

[Lipid and pro-oxidative and antioxidative parameters in the blood of vegetarians]. / Lipidové a prooxidacno-antioxidacné parametre v krvi vegetariánov.

The authors subdued 183 vegetarians to examination, the aim of which was to judge the state of health and nutrition of the vegetarian population. The examined group was composed of people with their age ranging from 19-60 years, out of which 102 were of younger (19-39 years) and 81 were of older age. Their average period of vegetarian food consumption was 4.2 years. One third of men and a half of women were lacto-vegetarians, the rest were lacto-ovo-vegetarians. The results were compared with 160 nonvegetarians (64 of younger and 96 of older age). The detected values of lipid parameters were evaluated as favourable for vegetarians (low values of cholesterol, triacylglycerols, atherogenic index, LDL-cholesterol, the share of HDL-cholesterol was 28-33% (vs 24-26% in nonvegetarians) with values converging to 1.4 mmol.l-1--i.e. reduced risk). Additional favourable factors in prevention of atherosclerosis include the absence of obesity in vegetarians and values of antisclerotic active substances in blood (high values of vitamin C, in comparison with nonvegetarians a significantly higher molar ratio of vitamin E/cholesterol and vitamin E/triacylglycerols--more effective protection against peroxidation of lipids). Vegetarian mode of food consumption may be favourably evaluated regarding prooxidative-antioxidative parameters which play an important role in the process of atherogenesis, and carcinogenesis. Significantly lower values of conjugated dienes in plasma of vegetarians and vice versa high values of antioxidant substances (vitamin C, vitamin E/lipid components, catalase activity) were detected. A more pronounced system of detoxication in vegetarians is important due to a possible risk of an increased intake of xenogenous substances. (Tab. 3, Ref. 27.)

[The effect of n-3 fatty acid administration on selected indicators of cardiovascular disease risk in patients with type 2 diabetes mellitus]. / Vplyv podávania n-3 mastných kyselín na vybrané ukazovatele kardiovaskulárnych rizík u pacientov s diabetom mellitus II. typu.

BACKGROUND: Serum triacylglycerols (TG), VLDL, HDL, fatty acid and eicosanoid spectrum are among the factors determining the risk of cardiovascular complications in NIDDM. N-3 polyunsaturated fatty acids (PUFA) are expected to have beneficial effects on these factors. In NIDDM patients there have however been previously reported (late 1980s) some adverse effects. OBJECTIVES: Our aim was to verify the effects of n-3 PUFA in NIDDM patients using relatively low dosage. METHODS: The investigated group included 21 NIDDM patients with dyslipoproteinemia type IV. The patients were treated for 28 days with 1.7 g EPA (eicosapentaenoic acid) + 1.15 g DHA (docosahexaenoic acid)/day (10 capsules/day of MAXEPA, Seven Seas U.K.). The lipoproteins were measured using the BIO-LACHEMA kits, the fatty acid spectrum in phospholipids was determined by gas chromatography and prostanoids (after their separation) were measured by RIA methods. MAIN RESULTS AND CONCLUSIONS: After the MAXEPA treatment there has been a strong decrease in TG (p < 0.005) and VLDL (p < 0.002) serum levels, accompanied by a significant increase in HDL (p < 0.02). The final-to-baseline TG ratio in individual patients negatively correlated with the relative percentage of EPA in phospholipids after the treatment (p < 0.03; r = -0.474). There was no significant change in serum total cholesterol, fasting glycaemia and glycosylated hemoglobin. There was a slight, but statistically already significant (p < 0.05), rise in LDL. The relative percentage of EPA, docosapentaenoic acid and DHA in serum phospholipids increased sharply (p < 0.001, p < 0.001, p < 0.001). The increase of n-3 PUFA in individual patients was linked with the decrease in n-6 PUFA (p < 0.001; r = -0.686). The spectrum of the latter has changed also very markedly. The prostacyclin PGI2-to-thromboxane TxA2 ratio increased significantly (p < 0.001). Beneficial effects of n-3 fatty acids have prevailed and this kind of treatment seems very encouraging also in NIDDM patients. The results are logically compatible with other authors' results pattern formed in 1990s. A slight rise in serum LDL needs a more detailed discussion since only its phenotype B ("small dense LDL particles") has been recently found to be atherogenic. (Tab. 2, Fig. 5, Ref. 15.)

[Biochemical and hematologic indicators in the blood of young vegetarians]. / Niektoré biochemické a hematologické ukazovatele v krvi mladých vegetariánov.

For the purpose of judgement of the vegetarian population state of health and nutrition 41 vegetarians were examined, namely university students in the age of 18-24 years, 36% of which were lacto-vegetarians and 64% lacto-ovo-vegetarians, 22 men and 19 women. Low values of cholesterol and triacylglycerols, content of HDL-cholesterol to 32% (close to the value 1.4 mmol per litre), low atherogenic index, low values of blood pressure and no case of obesity are favourable factors in the prevention of atherosclerosis. The only exception is represented by low values of vitamin C which neither in autumn period achieved the bottom value of the physiological range (low intake of fruit and vegetables). Saturation of organism with proteins is good (intake of full-value mixture of aminoacids in the form of plant and milk proteins), the values of glycemia were on the level of the bottom border of the physiological range. Low values of hematological parameters were detected. The erythrocyte count and levels of hemoglobin and hematocrit were on the bottom border of the physiological range; the values of serum iron in the bottom half of the physiological standard. The vegetarians consumed less fruit and vegetables (vitamin C facilities the conversion of the ferri-form into ferro-form), more cerials (linkage of iron with the phytic acid), and only scarcely the foliage vegetables. The incidence of anemias was equal with that in non-vegetarians in the age of 17-18 years (epidemiologic study of the institute). The supply of organism by vitamins B1,B2 and B6 were within the physiological standard.(ABSTRACT TRUNCATED AT 250 WORDS)

[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.)

[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.)

[Risks and advantages of the vegetarian diet]. / Riziká a prednosti vegetariánskej výzivy.

The authors summarize the health risks and advantages of alternative nutrition-lactovegetarian, lactoovovegetarian and vegan. These dietary patterns involve risk in particular during pregnancy, lactation and for the growing organism. Veganism excluding all foods of animal origin involves the greatest risk. General nutritional principles for the prevention of cardiovascular diseases, oncological diseases and diabetes are fully met by the vegetarian diet. Vegetarians and vegans have low risk factors of atherosclerosis and conversely higher levels of antisclerotic substances. Overthreshold values of essential antioxidants in vegetarians imply a protective action against reactive metabolic oxygen products and toxic products of lipid peroxidation and may reduce the incidence of free radical diseases. The authors also draw attention to some still open problems of vegetarianism (higher n-3 fatty acids, taurine, carnitine). In the conclusion semivegetarianism is evaluated.

[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.

[Alternative nutrition and glutathione levels]. / Alternatívne stravovanie a hladiny glutatiónu.

BACKGROUND: Low protein quality and quantity is reported to be a possible risk of alternative nutrition. Pulses contain 18-41% of methionine in relation to reference protein, moreover, its content in cereals is by one half lower. Therefore vegetarians and vegans may have an insufficient intake of sulphur-containing amino acids that may subsequently affect glutathione values (precursors of its synthesis). METHODS AND RESULTS: In groups of adults on an alternative diet--lactoovovegetarians (n = 47) and vegans (n = 44) aged 19-62 years with average duration on a vegetarian or vegan diet of 7.6 and 4.9 years, respectively, glutathione levels (GSH) were measured in erythrocytes (spectrophotometrically), as well as the activity of GSH-dependent enzymes. As nutritional control (n = 42) served an average sample of omnivores selected from a group of 489 examined, apparently healthy subjects of the same age range living in the same region. One to low protein intake (56% of RDA) exclusively of plant origin significantly lower levels of total proteins were observed in vegans with a 16% frequency of hypoproteinaemia (vs 0% in omnivores). In comparison to omnivores a significantly lower glutathione level was found (4.28 +/- 0.12 vs 4.84 +/- 0.14 mumol/g Hb, P < 0.01). Lactoovovegetarians because of their protein intake in adequate amounts with a 27% proportion of animal proteins (dairy products, eggs) consume a balanced mixture of amino acids, which is reflected in total protein levels similar to omnivores and significantly higher values of glutathione -5.26 +/- 0.12 mumol/g Hb, P < 0.05 (intake of glutathione in diet, higher consumption of fruit and vegetable in comparison to omnivores). A sufficient supply of glutathione as the substrate for enzymatic reactions of hydrogen peroxide or lipid hydroperoxide catabolism, as well as for detoxication of xenobiotics, was reflected in lactoovovegetarians in a significantly higher activity of glutathione-peroxidase and glutathione-S-transferase in erythrocytes. CONCLUSIONS: Low protein intake exclusively of plant origin, significantly lower protein levels with 16% frequency of hypoproteinaemia, significantly lower glutathione values in blood in comparison to omnivores and lactoovovegetarians confirm the risk of a vegan diet also in adult age.