Effect of trans-fatty acid intake on insulin sensitivity and intramuscular lipids--a randomized trial in overweight postmenopausal women

Effects of Repeated Heating on Fatty Acid Composition of Plant-Based Cooking Oils

Several polyunsaturated fatty acids are considered to have beneficial health effects, while saturated fatty acids and industrial trans fatty acids (TFAs) are linked to negative health consequences. Given the increased formation of TFAs during heating, many studies already investigated compositional changes in oils after prolonged heating or at extremely high temperatures. In contrast, our aim was to measure changes in fatty acid composition and in some health-related indices in edible oils after short-time heating that resembles the conventional household use. Potatoes were fried in palm, rapeseed, soybean, sunflower and extra virgin olive oils at 180 °C for 5 min, and samples were collected from fresh oils and after 1, 5 and 10 consecutive heating sequences. Regardless of the type of oil, the highest linoleic acid and alpha-linolenic acid values were measured in the fresh samples, whereas significantly lower values were detected in almost all samples following the heating sequences. In contrast, the lowest levels of TFAs were detected in the fresh oils, while their values significantly increased in almost all samples during heating. Indices of atherogenicity and thrombogenicity were also significantly higher in these oils after heating. The present data indicate that prolonged or repeated heating of vegetable oils should be avoided; however, the type of oil has a greater effect on the changes of health-related indices than the number of heating sequences.

Whole-diet interventions and cardiovascular risk factors in postmenopausal women: A systematic review of controlled clinical trials

OBJECTIVES

Menopause is accompanied by many metabolic changes, increasing the risk of cardiometabolic diseases. The impact of diet, as a modifiable lifestyle factor, on cardiovascular health in general populations has been well established. The purpose of this systematic review is to summarize the evidence on the effects of whole diet on lipid profile, glycemic indices, and blood pressure in postmenopausal women.

METHODS

Embase, Medline, Cochrane Central Register of Controlled Trials, and Google Scholar were searched from inception to February 2021. We included controlled clinical trials in postmenopausal women that assessed the effect of a whole-diet intervention on lipid profile, glycemic indices, and/or blood pressure. The risk of bias in individual studies was assessed using RoB 2 and ROBINS-I tools.

SUMMARY OF EVIDENCE

Among 2,134 references, 21 trials met all eligibility criteria. Overall, results were heterogenuous and inconsistent. Compared to control diets, some studies showed that participants experienced improvements in total cholesterol (TC), low-density lipoprotein cholesterol (LDL), systolic blood pressure (SBP), fasting blood sugar (FBS), and apolipoprotein A (Apo-A) after following fat-modified diets, but some adverse effects on triglycerides (TG), very low-density lipoprotein cholesterol (VLDL), lipoprotein(a) (Lp(a)), and high-density lipoprotein cholesterol (HDL) concentrations were also observed. A limited number of trials found some effects of the Paleolithic, weight-loss, plant-based, or energy-restricted diets, or of following American Heart Association recommendations on TG, TC, HDL, insulin, FBS, or insulin resistance.

CONCLUSION

Current evidence suggests that diet may affect levels of some lipid profile markers, glycemic indices, and blood pressure among postmenopausal women. However, due to the large heterogeneity in intervention diets, comparison groups, intervention durations, and population characteristics, findings are inconclusive. Further well-designed clinical trials are needed on dietary interventions to reduce cardiovascular risk in postmenopausal women.

Fatty acids and cardiometabolic health: a review of studies in Chinese populations

Rapid nutrition transition from plant-based traditional diet to westernized diet has led to dramatically heightening burdens of cardiometabolic diseases in China in past decades. Recently, national surveys reported that poor dietary quality including low marine n-3 fatty acids and high intakes of red meat and processed meat was associated with considerably elevated cardiometabolic deaths. Previous studies mainly from Western population-based cohorts have indicated that not only fat quantity but also quality linked with different cardiometabolic outcomes. Compared with Western peoples, Asian peoples, including Chinese, are known to have different dietary patterns and lifestyle, as well as genetic heterogeneities, which may modify fatty acid metabolism and disease susceptibility in certain degree. To date, there were limited prospective studies investigating the relationships between fatty acids and cardiometabolic disease outcomes in Chinese, and most existing studies were cross-sectional nature and within one or two region(s). Notably, shifting dietary patterns could change not only amount, types, and ratio of fatty acids accounting for overall energy intake, but also their food sources and ratio to other macronutrients. Moreover, large geographic and urban-rural variations in prevalence of cardiometabolic diseases among Chinese may also reflect the effects of socioeconomic development and local diets on health status. Therefore, current review will summarize available literatures with more focus on the Chinese-based studies which may extend current knowledge about the roles of fatty acids in pathogenesis of cardiometabolic diseases for Asian populations and also provide useful information for trans-ethnic comparisons with other populations.

Cimicifuga heracleifolia is therapeutically similar to black cohosh in relieving menopausal symptoms: evidence from pharmacological and metabolomics studies

In the market of botanical dietary supplements, Cimicifuga heracleifolia (CH) has always been considered as an adulterated species of Cimicifuga racemosa (CR), a conventional American herb with promising benefits to counteract troubles arising from the menopause. However, the detailed comparison of their therapeutic effects is lacking. In present study, the pharmacological and metabolomics studies were comparatively conducted between CH and CR in ovariectomized (OVX) female rats. Specifically, estrogen-like, anti-hyperlipidemia and anti-osteoporosis effects were evaluated through measuring serum biochemical parameters, histopathological examination and micro computed tomography (Micro-CT) scanning. At the same time, a gas chromatography-mass spectrometry (GC-MS)-based serum metabolomics method was employed to profile the metabolite compositional changes. As a result, both CR and CH displayed anti-osteoporosis and anti-hyperlipemia on menopause syndrome. Meanwhile, their potentials in improving the OVX-induced metabolic disorders were discovered. In conclusion, these results demonstrated that CH is therapeutically similar to CR in relieving menopausal symptoms and CH could be considered as a promising alternative to CR instead of an adulterant in the market of botanical dietary supplements.

Metabolic Syndrome-Role of Dietary Fat Type and Quantity

Background: Metabolic syndrome increases the risk of cardiovascular disease (CVD) over and above that related to type 2 diabetes. The optimal diet for the treatment of metabolic syndrome is not clear. Materials and Methods: A review of dietary interventions in volunteers with metabolic syndrome as well as studies examining the impact of dietary fat on the separate components of metabolic syndrome was undertaken using only recent meta-analyses, if available. Results: Most of the data suggest that replacing carbohydrates with any fat, but particularly polyunsaturated fat, will lower triglyceride(TG), increase high density lipoprotein (HDL) cholesterol, and lower blood pressure, but have no effects on fasting glucose in normal volunteers or insulin sensitivity, as assessed by euglycemic hyperinsulinemic clamps. Fasting insulin may be lowered by fat. Monounsaturated fat (MUFA) is preferable to polyunsaturated fat (PUFA) for fasting insulin and glucose lowering. The addition of 3–4 g of N3 fats will lower TG and blood pressure (BP) and reduce the proportion of subjects with metabolic syndrome. Dairy fat (50% saturated fat) is also related to a lower incidence of metabolic syndrome in cohort studies.

Dietary fat composition, total body fat and regional body fat distribution in two Caucasian populations of middle-aged and older adult women

OBJECTIVE

We aimed to study whether dietary fat composition (n-3 and n-6 polyunsaturated fatty acids ratio (PUFAs) and PUFAs and saturated fatty acids (SFAs) ratio) is associated with total body fat (TF) and body fat distribution and whether this association was modified by the presence of chronic disease in middle-aged and elderly women in two population-based cohorts in the Netherlands and Australia.

METHODS

The study was performed in the Rotterdam Study (RS), a prospective cohort study among subjects aged 55 years and older (N = 1182 women) and the Calcium Intake Fracture Outcome Study (CAIFOS), a 5-year randomized controlled trial among women age 70+ (N = 891). At baseline, diet (i.e. PUFAs and SFAs) was measured by validated food frequency questionnaires. TF was assessed using Dual-energy X-ray absorptiometry in both studies and android abdominal fat (AF), gynoid fat (GF) and the android/gynoid ratio (A/G ratio) in the RS but not the CAIFOS. Chronic disease was defined as the presence of cardiovascular disease, diabetes mellitus and cancer.

RESULTS

No association was found between dietary n-3/n-6 PUFAs ratio or SFA/PUFAs ratio with TF in both cohorts. In the RS, a high n-3/n-6 PUFAs ratio was associated with a higher AF (3rd vs. 2nd tertile (reference): β: 0.15; 95% CI: 0.05, 0.24) but not with the A/G ratio. A low SFA/PUFA ratio was associated with a lower AF (1st vs. 2nd tertile (reference): β: -0.12; 95% CI: -0.22, -0.06) but not with the A/G ratio. Presence of chronic disease was found to be a significant effect modifier in both cohorts with regard to n-3/n-6 PUFAs and TF (P < 0.05). In participants without chronic disease, a higher n-3/n-6 PUFAs ratio was associated with a higher TF in the RS cohort (3rd vs. 2nd tertile (reference): β: 0.94; 95% CI: 0.12, 1.76), but this was not replicated in CAIFOS.

CONCLUSION

These findings do not support the hypothesis that dietary fat composition is consistently associated with TF and body fat distribution in women. Future studies should clarify to what extent these findings may be influenced by the presence of chronic disease.

Is the metabolic syndrome inversely associates with butter, non-hydrogenated- and hydrogenated-vegetable oils consumption: Tehran lipid and glucose study

AIM

The aim of this study was to investigate the association between hydrogenated- (HVOs) and non-hydrogenated vegetable oils (non-HVOs) and butter and the metabolic syndrome (MetS) after 3-years of follow-up in adults.

METHODS

This study was conducted between 2006-2008 and 2009-2011 within the framework of the Tehran Lipid and Glucose Study, on 1582 adults, aged 19-84 years. Intakes of HVOs, non-HVOs and butter were assessed by a validated semi-quantitative food frequency questionnaire. Based on the consumption of food rich in fat including HVOs, non-HVOs and butter, participants were categorized to consumers and non-consumers.

RESULTS

Of 1582 participants during a 3-year follow-up, 15.2% developed MetS. Non-consumption of butter was associated with lower MetS risk compared with its consumption. Among consumers of food rich in fat, intake of HVOs and butter were associated with an increased risk of MetS; ORs in the final multivariate model were 2.70 (95% CI: 1.52-4.78) for HVOs and 2.03 (95% CI: 1.20-3.41) for butter, in the highest, compared to the lowest category of dietary intakes. Intake of non-HVOs was not associated with risk of MetS.

CONCLUSIONS

Consumption of HVOs and butter were positively associated with an increase risk of MetS.

Effects of trans fatty acids on glucose homeostasis: a meta-analysis of randomized, placebo-controlled clinical trials

BACKGROUND

Although evidence from cohort studies has suggested that trans fatty acid (TFA) consumption may be associated with insulin resistance and diabetes, randomized placebo-controlled trials (RCTs) have yielded conflicting results.

OBJECTIVE

In a meta-analysis, we combined all available RCTs that examined the role of TFA intake on glucose homeostasis.

DESIGN

A systematic review of PubMed was performed, and a total of 7 RCTs were included in the meta-analysis. Primary outcomes were glucose and insulin concentrations. Secondary outcomes were total, LDL-, and HDL-cholesterol and triglyceride concentrations. The pooled effect size (ES) was calculated through fixed- and random-effects meta-analyses. The potential existence of publication bias was evaluated by using funnel-plot analysis. Metaregression analysis was performed to evaluate for potential dose-response relations between the ES of outcomes and TFA intake.

RESULTS

Increased TFA intake did not result in significant changes in glucose or insulin concentrations. Increased TFA intake led to a significant increase in total and LDL-cholesterol [ES (95% CI): 0.28 (0.04, 0.51) and 0.36 (0.13, 0.60), respectively] and a significant decrease in HDL-cholesterol concentrations [ES (95% CI): -0.25 (-0.48, -0.01)]. Our analysis also showed the absence of publication bias and any dose-response relations between the ES and TFA intake.

CONCLUSIONS

Increased TFA intake does not result in changes in glucose, insulin, or triglyceride concentrations but leads to an increase in total and LDL-cholesterol and a decrease in HDL-cholesterol concentrations. There is no evidence to support a potential benefit of the reduction of dietary TFA intake on glucose homeostasis.

A cross-sectional study ontrans-fatty acids and risk markers of CHD among middle-aged men representing a broad range of BMI

Intake oftrans-fatty acids (TFA), especially industrially produced TFA (I-TFA), has been associated with the risk of CHD through influence on serum lipid levels. Other causal pathways remain less investigated. In the present cross-sectional study of middle-aged men representing a broad range of BMI, the association between intake of TFA, I-TFA and ruminant TFA (R-TFA) and obesity-associated risk markers of CHD was assessed. The study comprised 393 Danish men (median age 49 years) with a median BMI of 28·4 kg/m2. Intake of TFA was estimated based on 7 d dietary records, whereas outcomes of interest (waist circumference, sagittal abdominal diameter, percentage of truncal fat, C-reactive protein, IL-6, blood lipids, blood pressure, HbA1c and insulin sensitivity index) were obtained through clinical examination. The associations were assessed by linear regression analysis. The median intake of total TFA among the 393 men was 1·3 g/d, covering a daily I-TFA intake of 0·4 g (10–90th percentile 0·0–1·0) and R-TFA intake of 0·9 g (10–90th percentile 0·4–1·8). Intake of these amounts of TFA showed no significant associations with abdominal fatness, inflammatory markers, blood lipids, blood pressure and insulin homeostasis. Among middle-aged men with a generally low intake of TFA, neither I-TFA nor R-TFA was significantly related to obesity-associated risk markers of CHD. The decreased average intake of I-TFA in Denmark since 1995 is suggested to effectively prevent occurrence of the adverse metabolic changes and health consequences, which have formerly been observed in relation to, especially, I-TFA intake.