Effect of dietary protein on vitamin A levels in plasma and liver of hypervitaminotic-A rats

Level of vitamin A increased in plasma and liver in hypervitaminotic A albino rats fed normal quantity of protein in diet. In low protein fed state vitamin A level in liver increased due to accumulation of vitamin A and lack of carrier protein with an associated decrease of plasma vitamin A. In high protein fed rats the level of vitamin A in plasma increased due to enhanced transport while in liver it decreased. The results indicate that for normal transport of vitamin A adequate plasma protein level is essential.     

Effect of different levels of dietary fats upon the positional distribution of fatty acids in rat body triacylglycerols

• 1.1. The main purpose of the study was to describe and to compare the effect of different dietary fatty acids introduced at different levels into the diet on the positional distribution of fatty acids in rat body triacylglycerols. Only distribution between sn-2 (internal) and sn-1 + sn-3 (external) positions was considered in this study.
• 2.2. The positional distribution of fatty acids was first determined for controls fed on a low fat diet (1% D.M.). The same study was then carried out with 11 different dietary treatments and results were systematically compared with controls. The effects of four main molecules were tested: linoleic acid, oleic acid, lauric acid and capric acid.
• 3.3. Different alterations of the positional distribution of fatty acids in body triacylglycerols were obtained. They are graphically described and discussed.

     

Crosstalk between zinc and free fatty acids in plasma

In mammalian blood plasma, serum albumin acts as a transport protein for free fatty acids, other lipids and hydrophobic molecules including neurodegenerative peptides, and essential metal ions such as zinc to allow their systemic distribution. Importantly, binding of these chemically extremely diverse entities is not independent, but linked allosterically. One particularly intriguing allosteric link exists between free fatty acid and zinc binding. Albumin thus mediates crosstalk between energy status/metabolism and organismal zinc handling. In recognition of the fact that even small changes in extracellular zinc concentration and speciation modulate the function of many cell types, the albumin-mediated impact of free fatty acid concentration on zinc distribution may be significant for both normal physiological processes including energy metabolism, insulin activity, heparin neutralisation, blood coagulation, and zinc signalling, and a range of disease states, including metabolic syndrome, cardiovascular disease, myocardial ischemia, diabetes, and thrombosis.     

Influence of dietary selenium and vitamin E on the levels of fatty acids in brain and liver tissues of lambs

In this study, the effects of dietary vitamin E, selenium, and their combination on the levels of fatty acid composition of the brain and liver tissues were examined. In brain tissue, the amounts of most fatty acids increased in vitamin E, combination and selenium groups compared with control group values. While the proportions of myristic, pentadecanoic, palmitic, linoleic, and total saturated fatty acids were decreased in vitamin E, Se and combination groups, eicosapentaenoic, total unsaturated and MUFA were increased in the same groups. In addition, the proportions arachidonic, eicosapentaenoic, total unsaturated, ω6 and MUFA in the combination group were higher than in the control group. In liver tissue, the amounts of myristic, pentadecanoic, palmitic, eicosedienoic, eicosapentaenoic, docosahexaenoic, ω3 and PUFA were higher in the combination group than in the control group. Also the proportions of eicosapentaenoic, docosahexaenoic acids in supplemented groups were higher than those in the control group. We conclude that dietary vitamin E and selenium have an influence on the levels of fatty acids in the brain and liver. Copyright © 1999 John Wiley & Sons, Ltd.     

Effects of dietary monounsaturated fatty acids on plasma lipids in humans

In order to test whether monounsaturated fatty acids (MUFA, M) would lower plasma cholesterol and/or triglycerides (TG), 14 young men were studied in a metabolism ward. They were given two experimental diets with the same P/S ratio (P: polyunsaturated; S:saturated fatty acids) but different P + M/S ratios in composition of dietary fatty acids. Six men were in experiment I. In two groups of three, each group was given either the high or the low P + M/S ratio diet for 6 weeks. In experiment II, two groups of four men were subjected to a 3-week cross-over feeding trial (total of 6 weeks). We found in the crossover study that when the dietary P/S ratio was fixed at 1.0, those subjects given a diet with the higher P + M/S ratio of 4.5 showed significantly higher plasma total TG, very low density lipoprotein (VLDL)-TG, low density lipoprotein (LDL)-TG, and LDL-cholesterol than when given a diet with a lower P + M/S ratio of 1.5. Plasma total cholesterol, apoprotein A-I, and apoprotein B-100 were not significantly different between the two dietary periods. Plasma fatty acid patterns showed a significantly higher plasma MUFA level during the period of a higher P + M/S diet. In contrast to some recent reports, our studies indicate that a large amount of dietary MUFA may raise some fractions of plasma lipids in humans.     

Effect of dietary protein levels on the amount of blood free amino acids in lambs]

Growing lambs were fed increasing amounts of nitrogenous matter (12 to 20 per 100 on dry matter basis). Free amino acid and urea levels were measured in blood of 37 kg lambs. When crude protein content of diets exceeded 16 per 100, the catabolism of several essential amino acids increased. Methionine, lysine and histidine seemed to be limiting for growing lambs.     

Effect of vagotomy on plasma levels of growth hormone, free fatty acids and glucose in the pigeon

Plasma levels of growth hormone (GH), free fatty acids (FFA) and glucose were measured in vagotomized (VgX) and sham-operated (VgS) control pigeons. In VgX pigeons, GH level was significantly lower whereas FFA and glucose levels were higher than in VgS pigeons. The depression in GH level in VgX pigeons has been attributed to the significantly high levels of norepinephrine (NE) and corticosterone in these Birds. The higher plasma FFA concentration in VgX pigeons was therefore due to adipokinetic hormonal action other than of GH. It has been suggested that the adrenocorticotrophic hormone (ACTH) and/or NE could have produced the increase in plasma FFA in VgX pigeons. The pronounced hyperglycemia seen in VgX pigeons has been attributed to catecholamine action in the absence of the vagal tone.     

Effect of dietary cis and trans fatty acids on serum lipoprotein[a] levels in humans.

Serum lipoprotein[a] (Lp[a]) is a strong risk factor for coronary heart disease. We therefore examined the effect of dietary fatty acid composition on serum Lp[a] levels in three strictly controlled experiments with healthy normocholesterolemic men and women. In Expt. I, 58 subjects consumed a control diet high in saturated fatty acids for 17 days. For the next 36 days, 6.5% of total energy intake from saturated fatty acids was replaced by monounsaturates plus polyunsaturates (monounsaturated fatty acid diet; n = 29) or by polyunsaturates alone (polyunsaturated fatty acid diet; n = 29). Both diets caused a slight, nonsignificant, increase in median Lp[a] levels, with no difference between diets. In Expt. II, 10% of energy from the cholesterol-raising saturated fatty acids (lauric, myristic, and palmitic acid) was replaced by oleic acid or by trans-monounsaturated fatty acids. Each of the 59 participants received each diet for 3 weeks in random order. The median level of Lp[a] was 26 mg/l on the saturated fatty acid diet; it increased to 32 mg/l (P less than 0.020) on the oleic acid diet and to 45 mg/l (P less than 0.001) on the trans-fatty acid diet. The difference in Lp[a] between the trans-fatty acid and the oleic acid diets was also highly significant (P less than 0.001). Expt. III involved 56 subjects; all received 8% of energy from stearic acid, from linoleic acid, or from trans-monounsaturates, for 3 weeks each. All other nutrients were equal.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of dietary omega-6 and omega-3 fatty acids on levels of long chain polyunsaturated fatty acids in erythrocytes]

C18:2 omega 6/C18:3 omega 3 ratio was lowered in the diet of Elderly subjects. This was done by the replacement of usual sunflower oil by rapeseed oil or by supplementing soybean oil. This diet modification induced an increase of EPA (C20:5 omega 3) and DHA (C22:6 omega 3) in red cell phospholipids. The omega 6 fatty acids (C18:2 and C20:4) were slightly modified. Therefore, dietary C18:2 omega 6/C18:3 omega 3 ratio, seems to play an important role in the determination of membrane highly unsaturated fatty acid levels.     

Effect of sex,dietary glycerol or dietary fat during late fattening,on fatty acid composition and positional distribution of fatty acids within the triglyceride in pigs

The effect of sex, source of saturated fat (lard v. palm oil) and glycerol inclusion in the fattening diet on composition and fatty acid positional distribution in the triglyceride molecule was studied in pigs from 78 to 110 kg BW. Average daily gain and carcass characteristics, including ham and loin weight, were not affected by dietary treatment but sex affected backfat depth (P<0.01). A significant interaction between sex and glycerol inclusion was observed; dietary glycerol increased lean content in gilts but not in barrows (P<0.05 for the interaction). Individual and total saturated fatty acid (SFA) concentrations were greater in barrows than in gilts. In contrast, the concentration of total polyunsaturated fatty acids (PUFA) and of C18:2n-6, C18:3n-3, C20:3n-9 and C20:4n-6 in the intramuscular fat (IMF) was higher (P<0.05) in gilts than in barrows. Sex did not affect total monounsaturated fatty acids (MUFA) concentration in the IMF. The proportion of SFA in the subcutaneous fat (SF) was higher in barrows than in gilts (P<0.001). Within the individual SFA, sex affected only the concentrations of C14:0 and C16:0 (P<0.001). Dietary fat did not affect total SFA or PUFA concentrations of the IMF but the subcutaneous total MUFA concentration tended to be higher (P=0.079) in pigs fed lard than in pigs fed palm oil. Dietary glycerol increased total MUFA and C18:1n-9 concentration in the IMF and increased total MUFA and decreased C18:2n-6, C18:3n-3 and total PUFA concentrations in the SF. The data indicate that altering the fatty acid composition of the triglyceride molecule at the 2-position, by dietary intervention during the fattening phase, is very limited.