Biomedical subjects

Benoît Lamarche

Publications and source records attributed to Benoît Lamarche.

65 records · Page 4Linked to original sources

PubMed2003

Cod protein lowers the hepatic triglyceride secretion rate in rats.

The objective of the present study was to determine the combined effects of cod protein and fish oil on the modulation of triglyceride metabolism in rats, and to evaluate their potential mechanisms of action. Plasma and hepatic lipid concentrations, triglyceride (TG) secretion rates and postheparin plasma lipoprotein lipase (LPL) activity were determined in rats fed for 28 d diets varying in both protein (200 g/kg) and lipid (140 g/kg) sources: 1) casein-menhaden oil, 2) casein-beef tallow, 3) cod protein-menhaden oil or 4) cod protein-beef tallow. Menhaden oil feeding diminished hepatic TG concentrations (P = 0.02), hepatic TG secretion rates (P = 0.003) and triglyceridemia (P = 0.02) compared with beef tallow. Hepatic TG concentrations (P = 0.05) and TG secretion rates (P = 0.04) were reduced in rats fed cod protein compared with those fed casein. The protein source did not exert an independent effect on triglyceridemia, whereas the combination of cod protein and menhaden oil resulted in 50% lower plasma TG compared with the casein-beef tallow mixture, whereas the combination of menhaden oil and casein did not significantly decrease triglyceridemia compared with casein-beef tallow. Menhaden oil (P = 0.005) and cod protein (P = 0.03) also lowered plasma cholesterol concentrations in comparison with beef tallow and casein, respectively. This was associated with a reduction in hepatic cholesterol concentrations when rats fed cod protein were compared with those fed casein (P = 0.006). No diet effect was observed on postheparin plasma LPL activity, but the activity of hepatic triglyceride lipase was reduced in rats fed menhaden oil compared with those fed beef tallow. These findings show that both cod protein and menhaden oil exert independent and beneficial effects on lipid metabolism in rats.

Animal Feed↗

PubMed2003

Consumption of a functional oil rich in phytosterols and medium-chain triglyceride oil improves plasma lipid profiles in men.

Medium-chain triglycerides (MCT) have been proposed as weight-lowering agents, although there is some concern regarding their hyperlipidemic effect. This study evaluates the effects of a combination of MCT oil, phytosterols and flaxseed oil [functional oil (FctO)] on plasma lipid concentrations and LDL particle size. Twenty-four healthy overweight men (body mass index 28.2 +/- 0.4 kg/m(2)) consumed controlled diets designed to maintain weight for two periods of 29 d each. Diets contained 40% of energy as fat, 75% of which was added fat, either FctO or olive oil (OL). Body composition and blood samples were analyzed at the baseline and the endpoint of each period. Total cholesterol concentration decreased 12.5% (-0.68 mmol/L; P < 0.05) when subjects consumed FctO and 4.7% when they consumed OL. Similarly, FctO consumption lowered LDL cholesterol concentrations by 13.9%, whereas OL consumption did not. There was no difference in absolute change in LDL-cholesterol between FctO and OL consumption. Peak LDL particle size was greater in those who consumed FctO than in those who consumed OL (P < 0.05), with no effect of diet on proportion of large, medium or small particles. We conclude that those who consume a diet containing FctO have a better lipid profile than those who consume a diet rich in OL, which also leads to a larger lipoprotein particle size. Functional oil consumption can therefore help reduce the risk of cardiovascular disease.

Adult↗

PubMed2003

Role of isoflavones in the hypocholesterolemic effect of soy.

Epidemiologic data suggest an inverse relationship between the consumption of soy isoflavones and cardiovascular disease risk. The aims of this review are to determine if isoflavones play a role in the hypocholesterolemic effect of soy and whether the studies realized with that scope were adequately designed. In humans, most studies have been performed in postmenopausal women. The results are inconsistent, however; some studies show a decrease in total cholesterol and low-density lipoprotein concentrations, and an increase in high-density lipoprotein levels, and other investigations fail to show any beneficial effect of soy isoflavones on lipid profiles. In most studies, beneficial effects could not be attributed with certainty to soy isoflavones. If these components have any health-protecting effect in humans, it is small in comparison with the effect of soy protein itself. There are currently not enough data to recommend the consumption of isoflavone supplements to lower plasma cholesterol levels.

Animals↗

PubMed2003

Contribution of visceral adiposity to the exaggerated postprandial lipemia of men with impaired glucose tolerance.

OBJECTIVE: Impaired glucose tolerance (IGT) has been associated with alterations in numerous coronary heart disease risk factors, including postprandial hyperlipidemia. An excess visceral adipose tissue accumulation is also predictive of IGT and of an exaggerated postprandial lipemia. The objective of the present study was therefore to compare the respective contributions of visceral adipose tissue accumulation versus IGT with the variation in postprandial lipemia. RESEARCH DESIGN AND METHODS: Potential differences in postprandial triglyceride (TG)-rich lipoprotein (TRL) levels following a standardized breakfast with a high fat content were examined among men characterized by normal glucose tolerance (NGT) or IGT. Sixty-seven men were classified according to their glucose tolerance status (<7.8 mmol/l [NGT] or between 7.8 and 11.1 mmol/l [IGT] 2 h after a 75-g oral glucose test). RESULTS: Men with IGT showed the highest TRL-TG concentrations (P < 0.05) at the 4-, 6-, and 8-h time points compared with men with NGT. These higher postprandial TRL-TG levels among men with IGT were also accompanied by a greater postprandial TG total area under the incremental curve in all TRL fractions (large, medium, and small) (P < 0.05). Furthermore, subjects characterized by IGT had also the highest visceral adipose tissue accumulation (P < 0.009). When subgroups of IGT and NGT men were individually matched (n = 11) for similar visceral adipose tissue accumulation, no significant difference was found in postprandial responses of all TRL-TG fractions between the two groups. CONCLUSIONS: These results provide evidence that visceral adipose tissue accumulation is an important factor involved in the deterioration of postprandial lipemia noted among men with IGT.

Adipose Tissue↗

PubMed2002

Characterization of LDL particle size among carriers of a defective or a null mutation in the lipoprotein lipase gene: the Québec LIPD Study.

OBJECTIVE: The objective of the present study was to compare the impact of the null P207L and defective D9N mutations in the LPL gene on LDL particle size among heterozygous carriers. METHODS AND RESULTS: LDL particle size was measured on whole plasma by 2% to 16% non-denaturing polyacrylamide gradient gel electrophoresis in a cohort of 206 heterozygous carriers of either the P207L or the D9N mutation. The P207L carriers (N=88) presented with a more atherogenic lipoprotein-lipid profile compared with the D9N carriers (N=118). Accordingly, LDL particle size was smaller in the P207L carriers than in the D9N subjects (248.8+/- 1.0 vs 254.5+/-1.0 A, P< 0.001), and the difference remained significant after adjustment for plasma triglyceride (TG) levels. The difference in LDL diameter between the P207L and the D9N carriers was 3-fold greater in individuals with plasma TG levels >3.5 mmol/L than in subjects with TG < or =3.5 mmol/L. The factors that statistically contributed to LDL particle size variation in multivariate analyses were plasma TG levels (11.6%) and age (6.4%) in subjects with TG levels < or =3.5 mmol/L and HDL cholesterol levels (15.5%) and the LPL gene mutation (null versus defective, 7.0%) in patients with TG levels >3.5 mmol/L. CONCLUSIONS: These results suggest that the null P207L mutation in the LPL gene has a greater impact on LDL particle size than the defective D9N mutation and that this mutation-specific effect is amplified at greater plasma TG concentrations.

Cohort Studies↗

PubMed2002

Association of fibrinogen and lipoprotein(a) as a coronary heart disease risk factor in men (The Quebec Cardiovascular Study).

Fibrinogen has been prospectively found to correlate with coronary heart disease (CHD) but a similar association has not been well established for lipoprotein (a) (Lp(a)). Plasma lipids, Lp(a), and fibrinogen levels were measured in 2,125 men (aged 47 to 76 years) who were free of clinical CHD. During a 5-year follow-up period, 116 first CHD events were documented. Men with CHD were older, smoked more, had a higher prevalence of diabetes, and higher levels of systolic blood pressure, cholesterol, low-density lipoprotein cholesterol, Lp(a), and fibrinogen, and lower plasma high-density lipoprotein cholesterol levels. Only fibrinogen levels in the upper tertile of the distribution compared with the lower tertiles were associated with a significant risk of CHD (adjusted risk ratio 2.5; 95% confidence interval [CI] 1.4 to 4.2; p = 0.0010). Such an association was not observed with Lp(a). To assess a possible relation between fibrinogen and Lp(a) to the risk of CHD events, men were assigned to 1 of 4 groups according to fibrinogen median levels and a Lp(a) cut-off level of 300 mg/L: group 1: fibrinogen < 4.05 g/L and Lp(a) < 300 mg/L; group 2: fibrinogen < 4.05 g/L and Lp(a) > or =300 mg/L; group 3: fibrinogen > or =4.05 g/L and Lp(a) < 300 mg/L; and group 4: fibrinogen > or =4.05 g/L and Lp(a) > or =300 mg/L. Using group 1 as a reference, a significant risk ratio was only documented in group 4 (2.5; 95% CI 1.2 to 5.1; p = 0.0132). In this population, high fibrinogen levels associated with high Lp(a) levels significantly increased the risk of CHD.

Adult↗

PubMed2002

Interaction between dietary protein and fat in triglyceride metabolism in the rat: effects of soy protein and menhaden oil.

The objective of the present study was to determine the mechanisms by which dietary proteins interact with dietary lipids in the regulation of triglyceridemia in rats. Male Sprague-Dawley rats (n = 56) were subjected to 28-d experimental diets containing different combinations of proteins (20% w/w) and lipid sources (14% w/w): (i) casein-menhaden oil, (ii) casein-beef tallow, (iii) soy protein-menhaden oil, and (iv) soy protein-beef tallow. Significant protein-lipid interactions were observed on triglyceridemia and hepatic cholesterol in fasted rats. The combination of casein and beef tallow was associated with high plasma TG and hepatic cholesterol concentrations, which were reduced by substitution either of soy for casein or of menhaden oil for beef tallow. Therefore, triglyceridemia and liver cholesterol remained low with soy protein feeding, independently of the lipid source, as well as with menhaden oil feeding, regardless of the protein source. The menhaden oil diets reduced plasma cholesterol, hepatic TG, and TG secretion compared with beef tallow diets independently of the dietary protein source. Modifying the source of dietary proteins and lipids had no effect on post-heparin plasma lipoprotein lipase activity. These results demonstrate that soy protein can lower rat triglyceridemia relative to casein when associated with beef tallow consumption, whereas menhaden oil can attenuate hypertriglyceridemia when rats are fed casein. The data further suggest that part of the hypotriglyceridemic effect of soy protein in the rat may be mediated by reduced hepatic lipid synthesis, as is the case for menhaden oil.

Animals↗

PubMed2002

HDL particle size: a marker of the gender difference in the metabolic risk profile.

A low plasma HDL-cholesterol concentration is an important risk factor for coronary heart disease (CHD) and is often accompanied by increased triglyceride concentrations. Women have generally higher HDL-cholesterol and lower triglyceride concentrations and concomitantly are at lower risk of CHD than men. As HDL particle size is a new and potentially important marker of CHD risk, we have examined the potential gender difference in HDL particle size, assessed by nondenaturing 4-30% polyacrylamide gradient gel electrophoresis, in a sample of men (n=231) and women (n=183). Overall, men were characterized by a less favorable lipoprotein--lipid profile, which was accompanied by smaller HDL particle size compared to women. However, when men and women were matched for HDL particle size and compared for their metabolic profile, it was found that both genders were characterized by similar plasma lipoprotein--lipid profile despite the fact that women were characterized by higher levels of total body fat but lower waist girth than men. In summary, HDL particle size is a strong marker of the gender-related difference in the determination of the metabolic risk profile.

Adolescent↗

PubMed2002

Plasma free fatty acid levels and the risk of ischemic heart disease in men: prospective results from the Québec Cardiovascular Study.

Insulin resistance, through numerous related disturbances in glucose and lipoprotein-lipid metabolism, is associated with an increased risk of ischemic heart disease (IHD). The purpose of the present study was to examine the relationship between increased plasma free fatty acid (FFA) concentrations, as a feature of the insulin resistance syndrome, and the risk of IHD in men. Analyses were carried out in a nested, case-control sample of men selected from a population of 2103 individuals without IHD at baseline among whom 114 developed IHD during a 5-year follow-up period. Incident IHD cases were matched with controls for age, body mass index, smoking habits and alcohol intake. Analyses were performed while excluding (88 cases and 98 controls) and including (103 cases and 99 controls) patients with type 2 diabetes. Among non-diabetic individuals, elevated plasma FFA concentrations (3rd tertile of the distribution) yielded a twofold increase in the risk of IHD (odds ratio [OR] 2.1, P=0.05) compared with lower plasma FFA levels (lowest tertile) after adjusting for non-lipid risk factors. Further adjustment for insulin, triglycerides, apolipoprotein B, HDL cholesterol and small dense LDL attenuated significantly the relationship between plasma FFA concentrations and the risk of IHD. High plasma FFA levels showed no synergism with selected features of the insulin resistance syndrome in determining the risk of IHD. Inclusion of diabetic subjects in the study did not improve FFA independent prognostic value to the risk of IHD. These results suggest that elevated plasma FFA concentrations are associated with an increased risk of IHD. However, a single fasting measurement of plasma FFA levels does not appear to improve our ability to predict IHD onset in men when information on other risk factors is considered.

Adult↗

PubMed2002

Determinants of HDL particle size in patients with the null (P207L) or defective (D9N) mutation in the lipoprotein lipase gene: the Québec LipD Study.

The aim of the present study was to examine the impact of the defective D9N and the null P207L mutations in the lipoprotein lipase (LPL) gene on high density lipoprotein (HDL) particle size in relation to specific environmental factors such as obesity, gender and menopausal status. Analyses were carried out in 118 heterozygous carriers of the D9N mutation and 88 heterozygous for the P207L mutation. HDL particle size was measured on whole plasma by non-denaturing 4-30% polyacrylamide gradient gel electrophoresis. Although carriers of the P207L mutation presented a more deteriorated lipoprotein-lipid profile compared with carriers of the D9N mutation, there was no difference in HDL particle size between the P207L and D9N carriers (81.9+/-4.5 vs. 82.7+/-4.4 A, respectively, P=0.2). Multivariate analyses indicated that waist circumference (P=0.001) and HDL cholesterol levels (P<0.001) were independent predictors of HDL particle size among carriers of the defective D9N mutation. On the other hand, gender (P=0.03), plasma cholesterol (P=0.01) and TG (P=0.04) levels were significant predictors of HDL particle size among carriers of the null P207L mutation in multivariate analyses. These results suggest that the nature of the mutation in the LPL gene modifies the relationship of HDL particle size to other metabolic variables and secondary factors such as abdominal obesity and gender.

Adult↗

PubMed2002

Does correction of the friedewald formula using lipoprotein(a) change our estimation of ischemic heart disease risk? The Quebec Cardiovascular Study.

BACKGROUND: LDL-cholesterol is usually calculated using the Friedewald formula. This calculation method does not take into account the presence of Lp(a), which is associated with LDL-cholesterol. Dahlen has suggested that the Friedewald formula should be modified to account for Lp(a) associated cholesterol. This study was undertaken to determine if correction of the Friedewald formula would result in a better evaluation of ischemic heart disease (IHD) risk. METHODS: 2222 men free from IHD were prospectively followed for 5 years for the appearance of myocardial infarction, coronary insufficiency or coronary death. At the baseline evaluation all had a complete fasting lipid profile which included Lp(a) determinations. LDL-cholesterol levels were calculated from total cholesterol, total triglycerides and HDL-cholesterol using the Friedewald formula and also using the Dahlen modification of the Friedewald formula. RESULTS: During the follow-up there were 89 first IHD events. Both types of LDL-cholesterol calculations showed that the last tertile of the LDL-cholesterol distribution in comparison to the first tertile, doubles the relative risk (RR: 2.15; 95% confidence limits: 1.23-3.75) using the Friedewald formula (RR: 2.18; 95% confidence limits: 1.25-3.81) using the Dahlen modification. Lp(a) levels were not an independent predictor of IHD risk. CONCLUSION: Modification of the Friedewald formula to account for Lp(a) levels does not improve our evaluation of IHD risk.

Adult↗