Polyunsaturated Fatty Acid Plasma Content in Groups of General Population with lowvitamin B6 or low iron serum levels.

Experimental and human studies describe the adverse effect of iron or vitamin B6 deficiencies on polyunsaturated fatty acid metabolism. Iron is present in end proteins of the delta6-desaturase enzyme complex, and vitamin B6 deficiency can affect the transmethylation reaction of proteins. Plasma polyunsaturated fatty acid content was estimated in apparently healthy subjects of the general population with no consumption of fish and low vitamin B6 serum levels (< 3 microg/l; n = 21) or with low iron serum levels (men: < 12 micromol/l; women: < 10 micromol/l; n = 16) and compared to a control group (n = 22) with normal vitamin B6 and iron serum levels (in reference range). The activities of the delta6-desaturase enzyme complex were calculated as product/precursor (conversion indices). In groups of subjects with low vitamin B6 and low iron levels, delta6-desaturase activity together with delta5-desaturase activity (conversion of alpha-linolenic/18:3,n-3/ into eicosapentaenoic acid/20:5,n-3/) as well as the conversion index of docosahexaenoic acid formation (22:6,n-3) from 22:5,n-3 (second delta6-desaturase activity) were significantly reduced. The inhibition effect on fatty acid synthesis was more pronounced in subjects with low iron levels than in those with low vitamin B6 levels. The conversion indices correlated significantly positively with vitamin B6 or iron levels.

Free radical disease prevention and nutrition.

An improved antioxidant status (overthreshold plasma values of essential antioxidants) minimizes the oxidative damage. The levels of antioxidant vitamins C and E, ,,antioxidant" trace elements selenium, zinc, copper and iron were measured in two groups of adults with different nutritional habits--alternative (vegetarians; n=110) and traditional (mixed diet, control, n=101). The prevalence of iron and zinc deficiencies was found in the alternative group (20% vs 11%--iron, 13% vs 9%--zinc) as a consequence of higher intake of plant trace element absorption inhibitors. As opposed to the latter, the control group had higher findings of iron and copper levels over the optimal range (18% vs 8%--iron, 11% vs 2%--copper). The subjects on mixed diet was showed a significant negative linear correlation between serum zinc and iron levels. This favourable relationship means a decrease in Fenton reaction by indirect zinc effect. Average plasma values of vitamin C, vitamin C/vitamin E, vitamin E/ cholesterol (LDL protection), vitamin E/triacylglycerols (polyunsaturated fatty acid protection) in vegetarians are over the threshold with high number of individual overthreshold values (94% vs 17%--vitamin C, 100% vs 58%--vitamin C/vitamin E, 89% vs 68%--vitamin E/cholesterol, 100% vs 64%--vitamin E/triacylglycerols). Homocysteine levels in vegetarians (36% atherogenic levels) correlate significantly inversely to vitamin C levels, the fact of which means a positive vitamin C effect in free radical remove also in hyperhomocysteinemia. Plant food is a rich source of antioxidants. A correct vegetarian nutrition or optimized mixed diets with regular and frequent consumption of protective food commodities may be an effective contribution to the age-related chronic degenerative disease prevention. (Tab. 2, Fig. 2, Ref. 31.).

Effects of dietary extra virgin olive oil on serum lipid resistance to oxidation and fatty acid composition in elderly lipidemic patients.

An inverse relation between high consumption of olive oil and low incidence of coronary heart disease among the people living in Mediterranean countries has been proposed. It has been shown, that an oleic acid-rich diet could increase the resistance of human LDL to in vitro oxidation which is postulated to play an important role in the development of atherosclerotic lesions. The aim of this study was to assess the effect of extra virgin olive oil consumptiom on the resistance of serum lipids to in vitro oxidation and on fatty acid composition in the serum of elderly lipidemic patients. A total of 26 patients (mean age 69 years) with combined hyperlipidemia consumed daily 2 table spoons (approx. 20 g) of extra virgin olive oil for 6 weeks. Plasma lipids, total antioxidant capacity, indices of serum lipid oxidizability (lag time and maximal rate of oxidation) and the content of fatty acids in serum phospholipids were determined before and after dietary supplementation with olive oil. Plasma total cholesterol and LDL cholesterol decreased significantly after 6 weeks of dietary intervention. A significant increase in the lag time of conjugated diene formation (p = 0.026) and the decrease in the rate of lipid oxidation (p = 0.030) were observed after olive oil consumption. The changes in the fatty acid profile were characterized by an increase in oleic acid content (p = 0.005) as well as by a decline in the content of linoleic acid (p = 0.020) and arachidonic acid (p = 0.022). Linear regression analysis revealed some interesting and significant correlations between indices of serum lipid resistance to oxidation and individual fatty acids, suggesting a protective effects of olive oil in lipoprotein oxidation. In conclusion, the daily consumption of extra virgin olive oil in elderly lipidemic patients favourably affected serum lipoprotein spectrum and fatty acid composition that probably contributed to the increased resistance of serum lipids to oxidation. (Tab. 2, Ref. 18).

Selected retinoids: determination by isocratic normal-phase HPLC.

Retinol (ROL), retinal (RAL) and retinoic acid (RA) are physiologically active forms of vitamin A. All-trans retinoic acid (ATRA) can be formed by oxidation from all-trans retinal (ATRAL). Isomerization of RA is considered to be an important metabolic pathway of retinoids. RA isomers transactivate various response pathways via their cognate nuclear receptors that act as ligand inducible transcription factors. The aim of this study was to establish a rapid and simple method for determination of ATRA, 13-cis retinoic acid (13CRA) and ATRAL by HPLC. In our laboratory, we slightly modified the method of Miyagi et al. (2001) and separated ATRA, 13CRA and ATRAL by simple isocratic normal phase HPLC. Both retinoic acid isomers and ATRAL were eluted within 13 min and all components were well resolved. The coefficients of variation (C.V.) for RAs and RAL were from 3.0 to 5.4 %.

Homocysteine and vitamin C.

Homocysteine has a pro-oxidative activity. This amino acid, a lipid-independent vascular disease risk factor, might cause atherosclerosis by damaging the endothellium either directly or by altering the oxidative status. Levels of plasma homocysteine and vitamin C concentrations were determined in the adult majority population of Southern Slovakia (n=146) and in the ethnic Romany minority (n=119) in this region. Average homocysteine and vitamin C values in Romanies are similar to those in the majority group (non-significantly changed) with an equal finding of hyperhomocysteinemia, as well as with similar frequency of deficient, suboptimal and optimal vitamin C values. Under the condition of suboptimal (23-50 micromol/l) and optimal (>50 micromol/l) vitamin C levels, homocysteine values in connected groups are significantly lower with comparison to the value at deficient vitamin C level (<11.5 micromol/l), reduction from 10.74 micromol/l to 9.35 and 9.17 micromol/l. Multiple regression showed a negative linear correlation of homocysteine and folic acid, vitamin B12 (determinants of homocysteine metabolism), vitamin C (antioxidative effect) together (n=265, r=-0.282, p<0.00008). The significance for vitamin B12 alone, was p=0.0199, for folic acid p=0.0046, for vitamin C p=0.0499. The results express a significant effect of vitamin C in prevention of vascular damage. (Tab. 1, Fig. 1, Ref; 19.).

Advanced glycation end products and nutrition.

Advanced glycation end products (AGEs) may play an important adverse role in process of atherosclerosis, diabetes, aging and chronic renal failure. Levels of N(epsilon)-carboxymethyllysine and fluorescent AGE values were estimated in two nutritional population groups--alternative group (vegetarians--plant food, milk products, eggs) and traditional group (omnivorous subjects). Vegetarians have a significantly higher carboxymethyllysine content in plasma and fluorescent AGE values. Intake of proteins, lysine and monosaccharides as well as culinary treatment, consumption of food AGEs (mainly from technologically processed products) and the routes of Maillard reaction in organism are the substantial sources of plasma AGEs. Vegetarians consume less proteins and saccharides. Lysine intake is significantly reduced (low content in plant proteins). Subjects on alternative nutrition do not use high temperature for culinary treatment and consume low amount of technologically processed food. Fructation induced AGE fluorescence is greater as compared with that induced by glucose. It is due to higher participation of a more reactive acyclic form of fructose. Intake of vegetables and fruit with predominance of fructose is significantly higher in vegetarians. Comparison of nutrition and plasma AGEs in vegetarian and omnivorous groups shows that the higher intake of fructose in alternative nutrition of healthy subjects may cause an increase of AGE levels.

LDL and HDL oxidation and fatty acid composition in vegetarians.

The oxidation of low-density lipoproteins (LDL) and high-density lipoproteins (HDL) and fatty acid composition, which may affect the resistance of lipoproteins to oxidation, were determined in 24 lacto-ovo vegetarians. Vegetarian diets contain more essential polyunsaturated fatty acids (PUFAs). Therefore, the relationship between LDL and HDL oxidation resistance measured by the kinetics of the formation of fatty acid conjugated dienes (lag time, maximal rate of oxidation and maximal amount of conjugated dienes), LDL and HDL fatty acid composition and vitamin E content were evaluated. All parameters of in vitro oxidation were significantly lower in HDL when compared with LDL. The relative values of arachidonic, dihomo-gamma-linoleic and docosahexaenoic acid were significantly higher in HDL, alpha-linolenic acid content significantly lower, when compared with LDL; the peroxidizability index was significantly higher in HDL. The content of vitamin E was found more than 2-fold lower in HDL particles. The results show the importance of fatty acid composition in the resistance of LDL and HDL to oxidation and from this aspect, the composition of LDL isolated from vegetarians seems to be more favourable compared to HDL.

[Nutritional status in adults on an alternative or traditional diet]. / Nutricný status dospelých na alternatívnom vs tradicnom stravovaní.

BACKGROUND: Plant food lacks vitamin B12, vitamin D and higher n-3 polyunsaturated fatty acids. Essential aminoacids methionine and lysine can be found in significantly lower amounts. On the contrary, the culinary and technologically non-processed plant food and whole-grain products contain essential nutrients in a highly condensed form. The aim of the study was to compare nutritional status of adults on alternative or on traditional diet and sequels of the diet to body metabolism. METHODS AND RESULTS: The group on alternative diet consisted of 89 lacto-ovo-vegetarians (age 38.7 +/- 0.6 years, average duration of vegetarianism 7.8 years). Control group on traditional diet (omnivores, n = 84) was formed as an average sample. Nutritional regime was determined using dietetic questionnaire on the food intake regularity. Vegetarians consume optimal amount of fat (along with recommendations of OVD) with predominance of vegetal lipids. They have low intake of cholesterol (62.8 mg), recommended ratio of saturated fatty acids (SFA), monounsaturated (MUFA), and polyunsaturated (PUFA) 6.5:10.6:8.9 energetic percent. Their ratio of linolic:alpha-linolenic acid (10.4:1) also corresponds with recommendations. In traditional diet, the content of lipids and energy usually exceeds the norm of OVD (by 33% or 19% respectively), cholesterol intake is much higher (512.2 mg, 200 mg is recommended as a maximum). Higher is the amount taken of SFA (11.2 energetic %, recommended 7%), and not sufficient is the intake of alpha-linolenic acid (68% of OVD). People on alternative diet have low plasma levels of risk lipid parameters and significantly higher levels of antisclerotic substances. As a result of significantly higher intake of fruits and vegetables, plant oil, sprouts, seeds, and whole-grain food the plasma levels of antioxidative vitamins are in vegetarians higher then threshold. It reduces the risk of the free-radical disease. On the contrary, vegetarians have deficits in methionine intake, and 15% of them have hypoproteinemia is (0% in omnivores). Low plasma levels of iron and calcium, occurrence of hyposideremia (16% versus 2%) and hypocalcemia (21% versus 8%) corresponds with intake of vegetal absorption inhibitors (fytolic acid, oxalic acid, roughage). Frequently a mild form of hyperhomocysteinemia is found (28% versus 5%), resulting vitamin B12 deficit. CONCLUSIONS: Vegetarian diet is optimal for prevention of free-radical diseases, especially those of the cardiovascular system. It may bring a risk from the point of view of low iron and calcium absorption, low intake of methionine and occurrence of mild forms of hyperhomocysteinemia. In traditional diet, total lipid content should be lowered, amount of vegetable oil with alpha-linolenic acid should be elevated as well as fruit and vegetable consummation. Whole grain food and oily seeds should be included into the daily food.

Plasma levels of advanced glycation end products in healthy, long-term vegetarians and subjects on a western mixed diet.

BACKGROUND: Evidence indicates that food-derived Maillard's reaction products are absorbed and yet can be detected in the circulation. AIM OF THE STUDY: We postulated that consumption of the heat-treated food by omnivores could be reflected by higher plasma levels of advanced glycation end products (AGEs) in comparison with vegetarians, who in cooking (by keeping away from meat) use lower temperatures and less time for heating. METHODS: Plasma fluorescent AGEs (350/450 nm) and N(epsilon)-(carboxymethyl)lysine (CML, competitive ELISA) levels were investigated in 3 groups of healthy vegetarians (9 vegans-V, 19 lactoovo-vegetarians--VLO and 14 semi-vegetarians--VS) and compared with those of age-matched omnivores (O, n=19). Mean duration of vegetarian diet was V: 7.2 +/- 1.0,VLO: 8.2 +/- 0.8 and VS: 7.9 +/- 1.1 years. RESULTS: Both fluorescent AGE (O: 9.9 +/- 0.5; V: 10.8 +/- 0.7, LO: 13.1 +/- 0.8* and SV: 11.6 +/- 1.2 x 10(3) AU), and CML levels (O: 427.1 +/- 15.0,V: 514.8 +/- 24.6*, LO: 525.7 +/- 29.5**, SV: 492.6 +/- 18.0* ng/ml) were significantly lower in omnivores than in vegetarians. Plasma glucose, parameters of renal function (plasma concentration of creatinine and cystatin C, calculated glomerular filtration rate--GFR) as well as C-reactive protein levels were within the normal range and did not differ significantly between the groups. Thus, neither decline of kidney function nor inflammatory processes contributed to the rise in plasma AGEs. CONCLUSION: Enhanced plasma AGE levels in vegetarians in comparison to omnivores are herein presented for the first time. Mechanisms of AGE elevation and potential pathophysiological relevance of this finding are to be elucidated in prospective studies.

Supplementation with long-chain n-3 fatty acids in non-insulin-dependent diabetes mellitus (NIDDM) patients leads to the lowering of oleic acid content in serum phospholipids.

BACKGROUND: The dietary supplementation with EPA (eicosapentaenoic acid; 20:5n3) and DHA (docosahexaenoic acid; 22:6n3) has been recommended because of their favourable effects on the cardiovascular system (including complications of NIDDM). Oleic acid (18:1n9) from olive oil has some analogous and complementary effects. Potential competitive relations between long-chain n-3 fatty acids (FAs) and the oleic acid would therefore mean a problem. AIM OF THE STUDY: We focused primarily on the oleic acid changes in serum phospholipids (SPL) after a supplementation with EPA and DHA. METHODS: Thirty-five patients with type 2 diabetes mellitus (NIDDM) were supplemented for 28 days with 1.7 g of EPA plus 1.15 g of DHA/day (as Maxepa capsules, Seven Seas, U. K.). After that, a 3-month wash-out control period with 21 patients followed. A fatty acid composition of serum phospholipids (SPL) was determined by capillary gas-chromatography. Values were calculated as relative percentages of all FAs. RESULTS: After the supplementation with the Maxepa capsules, there was a very strong increase in EPA, docosapentaenoic acid (22:5n3) and DHA content in SPL. It was followed by a strong decrease after the wash-out (all p < 0.0001). The oleic acid SPL content after the intervention significantly decreased from 10. 105 +/- 0.307% (mean +/- S. E. M.) to 9.082 +/- 0.276 % (p < 0.0003). During the wash-out, the change was in the opposite direction (p < 0.0001). When the intervention and the wash-out periods were taken together, changes in the oleic acid were inversely correlated with changes in EPA, docosapentaenoic acid and DHA (r = -0.729; r = -0.552; r = -0.629, respectively; p < 0.0001; n = 56). On the background of the overall n-6 FA reduction, the decline in the arachidonic acid after the supplementation (p < 0.0001) and its rise after the wash-out (p < 0.0003) were similar. There were no significant changes in the saturated FA spectrum. CONCLUSIONS: Supplementation with long-chain n-3 FAs in NIDDM patients leads to the lowering of oleic acid SPL content. Whereas the reduction of the arachidonic acid may have some desirable aspects (e. g. suppression of thromboxane TxA2 or 4 series leukotriene production), the decline of the former is to be regarded as a potential problem. Therefore, the search for optimally balanced blends of n-3 polyunsaturated fatty acids (PUFAs) and monounsaturated fatty acids (MUFAs) seems to be more promising than a supplementation with only one type of FA.

[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.

Blood levels of natural antioxidants in gastric and colorectal precancerous lesions and cancers in Slovakia.

A long-term sufficient intake of fruits and vegetables reduces significantly the risk of gastric and colorectal carcinoma. It is anticipated that natural antioxidants are involved in this effect in addition to other substances. The aim of this study was to determine levels of vitamins A, C and E, as well as beta-carotene, selenium, zinc and copper in blood of 249 patients with precancerous lesions (atrophic gastritis, gastric hyperplastic polyp, gastric, colonic and rectal adenoma, chronic ulcerative colitis) and in 96 individuals with gastric, colonic or rectal carcinoma and to compare these levels with the values of a control group of 130 healthy individuals. We have found that the frequency of average values of analyzed micronutrients in precancerous groups was decreasing in the order vit C > vit E/vit A > Se > beta-car. The average levels of vitamins and beta-carotene were significantly reduced in all carcinoma groups, while selenium level showed a decrease only in the gastric carcinoma group. Copper level was elevated in the ulcerative colitis group and in all groups with carcinoma. The results indicate a frequent insufficient saturation of organism by natural antioxidants in groups with precancerous lesions and carcinomas of stomach and colorectum. Therefore, it is necessary to increase the general consumption of fruits and vegetables in Slovakia as a part of primary prevention of malignant diseases in these organs. Chemoprevention may be recommended in individuals with precancerous lesions.

[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.)

Traditional and alternative nutrition--levels of homocysteine and lipid parameters in adults.

Values of homocysteine and lipid parameters were measured in groups of adults consuming alternative nutrition (vegetarians/lactoovo/, vegans) and compared with a group consuming traditional diet (omnivores, general population). Frequency of hyperhomocysteinemia was 53% in the vegans group, 28% in vegetarians vs. 5% in omnivores. In conditions of lower methionine intake (reduced content in plant proteins), the remethylation pathway of homocysteine metabolism prevails and it is vitamin B12 and folate-dependent. The intake of vitamin B12 is equal to zero in vegans; vegetarians consume 124% of the RDA vs. 383% in omnivores. Serum vitamin levels are significantly lower in subjects consuming alternative nutrition with deficiency observed in 24% of vegetarians, 78% of vegans vs. 0% in omnivores. Serum folate levels are within the reference range in all groups. Mild hyperhomocysteinemia in the groups consuming alternative diet is a consequence of vitamin B12 deficiency. Vegetarians and vegans meet the RDA for energy and fat, and have a favourable proportion of saturated, mono- and polyunsaturated fatty acids on total energy intake; the ratio of linoleic/alpha-linolenic acid in their diet corresponds with the recommendations. They have low cholesterol consumption and higher vitamin E and C intake. Optimal fat intake of correct composition is reflected in lower values of atherosclerosis risk factors (cholesterol, LDL-cholesterol, atherogenic index, saturated fatty acids, triacylglycerols), and significantly higher levels of protective substances (linoleic acid, alpha-linolenic acid, HDL-cholesterol, vitamin E, vitamin E/cholesterol, vitamin C). Low lipid risk factors but higher findings of mild hyperhomocysteinemia in vegetarians mean a diminished protective effect of alternative nutrition in cardiovascular disease prevention.

Oleic acid serum phospholipid content is linked with the serum total- and LDL-cholesterol in elderly subjects.

INTRODUCTION: Increased dietary intake of the olive oil has been found to lower several cardiovascular risk factors. Aim of our study was to check if there is any link between the oleic acid (OL-18:1n9) serum phospholipid (SPL) content and some of these factors in subjects living relatively far from the Mediterranean region and in habitual conditions, i.e. without any dietary intervention. MATERIAL AND METHODS: The investigated group included 62 out-patients older than 51 yr. Serum lipids were measured using standard hospital laboratory methods, the LDL-cholesterol was calculated using Friedewald's formula. Gas chromatography was used for estimation of fatty acids (FA) in SPL, their values were calculated as relative percentages of all FA. RESULTS: There was a statistically significant inverse correlation between the OL SPL content and the serum total cholesterol (TCHOL) in all 62 patients (r = -0.294; p = 0.020). Analogous correlation was marginally significant for the LDL (r = -0.245; p = 0.055). After a division into 2 groups based on the median of the OL, the group with OL higher than median had significantly lower both TCHOL and LDL (p = 0.014; p = 0.033, respectively). OL correlated positively with the alpha-linolenic acid (18:3n3; r = 0.281; p = 0.027) but inversely with the stearic acid (18:0; r = -0.303; p = 0.017). CONCLUSION: The subjects with less OL in their SPL had higher TCHOL and LDL serum levels and also their fatty acid SPL spectrum showed some other features which may be characterized as undesirable. This is an independent argument emphasizing the need for enhancing OL dietary intake.

[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.)

[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.)

Plasma fatty acid profile and alternative nutrition.

Plasma profile of fatty acids was examined in a group of children consisting of 7 vegans, 15 lactoovovegetarians and 10 semivegetarians. The children were 11-15 years old and the average period of alternative nutrition was 3.4 years. The results were compared with a group of 19 omnivores that constituted an average sample with respect to biochemical and hematological parameters from a larger study of health and nutritional status of children in Slovakia. Alternative nutrition groups had significantly lower values of saturated fatty acids. The content of oleic acid was identical to omnivores. A significant increase was observed for linoleic and alpha-linolenic (n-3) acids. The dihomo-gamma-linolenic (n-6) acid and arachidonic (n-6) acid values were comparable to omnivores for all alternative nutrition groups. Values of n-3 polyunsaturated fatty acids in lactoovovegetarians were identical to those of omnivores whereas they were significantly increased in semivegetarians consuming fish twice a week. Due to the total exclusion of animal fats from the diet, vegans had significantly reduced values of palmitoleic acid as well as eicosapentaenoic (n-3) acid and docosahexaenoic (n-3) acid resulting in an increased n-6/n-3 ratio. Values of plasma fatty acids found in alternative nutrition groups can be explained by the higher intake of common vegetable oils (high content of linoleic acid), oils rich in alpha-linolenic acid (cereal germs, soybean oil, walnuts), as well as in n-3 polyunsaturated fatty acids (fish). The results of fatty acids (except n-3 in vegans) and other lipid parameters confirm the beneficial effect of vegetarian nutrition in the prevention of cardiovascular diseases.

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.