Yeow K Goh

Effect of w3 fatty acid on plasma lipids, cholesterol and lipoprotein fatty acid content in NIDDM patients

Summary This study was conducted to examine the effect of ω3 fatty acid supplementation on plasma lipid, cholesterol and lipoprotein fatty acid content of non-insulin-dependent diabetic individuals consuming a higher (0.65, n = 10) or lower (0.44, n = 18) ratio of dietary polyunsaturated to saturated fatty acid (P/S). The participants were initially given an olive oil supplement (placebo) equivalent to 35 mg of 18:1 · kg body weight–1· day–1 for 3 months. This was followed by two ω3 supplement periods in a randomized crossover. In these 3-month periods, participants were given a linseed oil supplement equivalent to 35 mg of 18:3ω3 · kg body weight–1· day–1 or a fish oil supplement equivalent to 35 mg of 20:5ω3 + 22:6ω3 · kg body weight–1· day–1. At the end of each supplement period, a blood sample was drawn from each participant for lipid, lipoprotein, insulin, glucagon and C-peptide analyses. At the end of each 3-month period a 7-day dietary record was completed to calculate dietary fat intake and P/S ratio. Results indicate that fish oil significantly reduced plasma triacylglycerol level (p < 0.05) and increased 20:5ω3 and 22:6ω3 content of all lipoprotein lipid classes. Linolenic acid supplementation had no effect on plasma triacylglycerol level, but it increased 18:3ω3 content of lipoprotein cholesterol ester fractions (p < 0.05). A slight increase in 20:5ω3, but not 22:6ω3, content was noted in lipoprotein lipid classes as a result of 18:3ω3 supplementation. LDL and HDL cholesterol, insulin, glucagon and C-peptide levels were not affected by either ω3 supplement. It is concluded that a modest intake of ω3 fatty acids, such as could be obtained from consuming fish regularly, will reduce plasma triglyceride level without affecting LDL or HDL cholesterol levels. [Diabetologia (1997) 40: 45–52]

The effect of a controlled manipulation of maternal dietary fat intake on medium and long chain fatty acids in human breast milk in Saskatoon, Canada.

BackgroundFew studies in recent years have demonstrated the effect of maternal diet on fatty acid composition of human milk.MethodsFourteen free-living lactating women participated in a cross-over dietary intervention study, consuming a low fat diet (17.6% of energy as fat, 14.4% of energy as protein, 68.0% of energy as carbohydrate) and a high fat diet (40.3% of energy as fat, 14.4% of energy as protein, 45.3% of energy as carbohydrate) each for periods of 4 days, in randomised order. Each mother was her own control. Mature milk samples were collected during each period and analysed for medium and long chain fatty acids.ResultsThe concentration of medium chain fatty acids (MCFA), was 13.6% in breast milk for the low fat diet compared to 11.4% for the high fat (p < 0.05). Arachidonic acid (C20:4n-6) levels were significantly higher in breast milk when women consumed the low fat diet. Increased dietary intake of stearic acid (C18:0) and alpha-linolenic acid (C18:3n-3) on the high fat diet significantly increased proportions of these fatty acids in breast milk (p < 0.05) in 4 days.ConclusionsChanging maternal dietary fat intake has a rapid response in terms of changes to fatty acids in breast milk.

Omega-3 fatty acid intake results in a relationship between the fatty acid composition of LDL cholesterol ester and LDL cholesterol content in humans

The relationship between the fatty acid composition of the low density lipoprotein (LDL) cholesterol ester and LDL cholesterol content was assessed in 26 free-living, normal subjects. Dietary intakes of 14:0, 16:0, 18:0, 18:1, 18:2omega6, 18:3omega3, 20:4omega6, 20:5omega3, 22:6omega3 were calculated from seven-day food records kept by each subject at baseline and after three months of supplementation with olive, flaxseed or fish oil, respectively. A randomized cross-over design was used. The fatty acid content of specific foods was calculated. Fasting blood samples, taken at the beginning and end of each supplementation period, were analyzed for the fatty acid content present in individual lipoproteins. There was a significant correlation between 20:5omega3 and 22:6omega3 intake and the content of these fatty acids in the LDL cholesterol ester fraction. During the fish oil treatment period the 16:0 and 18:0 content of the LDL cholesterol ester was highly predictive of LDL cholesterol content. This relationship was not observed during the baseline or placebo (olive oil) supplement period.

During neuronal and glial cell development diet n-6 to n-3 fatty acid ratio alters the fatty acid composition of phosphatidylinositol and phosphatidylserine.

Brain development was examined in the neonatal rat in response to feeding increased levels of 18:3n - 3, 20:4n - 6 or 22:6n - 3 at levels proposed for infant formula. Diets varying in n - 6 to n - 3 fatty acid ratio, with or without 20:4n - 6 and 22:6n - 3 alone or in combination, were fed to nursing dams at parturition and subsequently to weaned pups until six weeks of age. Neuronal and glial cells were isolated from the frontal, cerebellar and hippocampal brain regions of rat pups at birth, one, two, three and six weeks of age. Fatty acid analysis of inositol- and serine- phosphoglycerides indicated that small changes in dietary n - 6 to n - 3 fatty acid ratio significantly affect neuronal and glial cell membrane composition. Fatty acid composition of phosphatidylinositol and phosphatidylserine was distinct and exhibited change with age. Individual brain regions and cell types varied in amount and rate of 20:4n - 6 and 22:6n - 3 accretion. Alteration of brain fatty acid composition reflected the fatty acid composition of the diet fed. If analogous changes occur during human brain development, feeding infants 20:4n - 6 and 22:6n - 3 or a reduced 18:2n - 6 to 18:3n - 3 ratio may alter fatty acid profiles of brain cells.

Use of deuterium oxide to measure de novo fatty acid synthesis in normal subjects consuming different dietary fatty acid composition

The effect of dietary linoleic (C18:2n-6) and palmitic acids (C16:0) on rate of hepatic de novo fatty acid synthesis was assessed in normal subjects. The diet was formulated to provide combinations of high and low levels of C18:2n-6 and C16:0. After 21 days of diet treatment, plasma triacylglycerol level and incorporation of deuterium into the plasma very low density lipoprotein triacylglycerol (VLDL-TG) pool over 24 hours was measured. Plasma triacylglycerol levels were within the normal range. Increasing dietary intake of linoleic acid decreased plasma triacylglycerol level when subjects consumed a low level of dietary palmitic acid. The relative and net amount of de novo synthesized fatty acid in the plasma VLDL-TG pool was not influenced by the diet treatments. A relationship between plasma triacylglycerol level and rate of hepatic de novo fatty acid synthesis was observed.

The effect of palmitic acid on lipoprotein cholesterol levels and endogenous cholesterol synthesis in normal and hypercholesterolemic subjects

The present study assessed the effect of high versus low palmitic acid intakes of plasma lipoprotein cholesterol levels and on rates for endogenous synthesis of cholesterol in normal and hypercholesterolemic subjects. On day 21 of each diet treatment, a fasting blood sample was drawn for lipoprotein determination and to provide a measure of the background level of deuterium. A priming dose of deuterium was consumed and a second blood sample obtained 24 hours after the first sample. Isotope ratio mass spectrometry was used to determine the incorporation of deuterium into the newly synthesized cholesterol molecule and fractional synthetic rates were calculated. Four diets were formulated to provide combinations of two levels of 16:0 at two levels of 18:2n-6. Subjects received each of the four diet treatments for 21 days, followed by washout periods of 21 days. Serum total cholesterol and LDL-cholesterol was not significantly affected by the high level of 16:0 when diets also contained a high level of 18:2n-6. Fractional synthesis rates of cholesterol observed for each diet treatment did not differ significantly, suggesting no relationship between the endogenous synthesis of cholesterol and dietary 16:0 content. The results indicate that 16:0 has no effect on serum lipoprotein profiles in the presence of recommended intakes for 18:2n-6.