Obesity and the metabolic syndrome in Mediterranean countries: A hypothesis related to olive oil

A Possible Therapeutic Application of the Selective Inhibitor of Urate Transporter 1, Dotinurad, for Metabolic Syndrome, Chronic Kidney Disease, and Cardiovascular Disease

The reabsorption of uric acid (UA) is mainly mediated by urate transporter 1 (URAT1) and glucose transporter 9 (GLUT9) in the kidneys. Dotinurad inhibits URAT1 but does not inhibit other UA transporters, such as GLUT9, ATP-binding cassette transporter G2 (ABCG2), and organic anion transporter 1/3 (OAT1/3). We found that dotinurad ameliorated the metabolic parameters and renal function in hyperuricemic patients. We consider the significance of the highly selective inhibition of URAT1 by dotinurad for metabolic syndrome, chronic kidney disease (CKD), and cardiovascular disease (CVD). The selective inhibition of URAT1 by dotinurad increases urinary UA in the proximal tubules, and this un-reabsorbed UA may compete with urinary glucose for GLUT9, reducing glucose reabsorption. The inhibition by dotinurad of UA entry via URAT1 into the liver and adipose tissues increased energy expenditure and decreased lipid synthesis and inflammation in rats. Such effects may improve metabolic parameters. CKD patients accumulate uremic toxins, including indoxyl sulfate (IS), in the body. ABCG2 regulates the renal and intestinal excretion of IS, which strongly affects CKD. OAT1/3 inhibitors suppress IS uptake into the kidneys, thereby increasing plasma IS, which produces oxidative stress and induces vascular endothelial dysfunction in CKD patients. The highly selective inhibition of URAT1 by dotinurad may be beneficial for metabolic syndrome, CKD, and CVD.

The effect of coconut oil and palm oil on anthropometric parameters: a clinical trial

BACKGROUND

During recent years several studies have investigated the impact of different dietary oils on body weight. They have shown differential positive and negative effects on anthropometry. We investigated the effects of palm and coconut oils on body weight and other anthropometric parameters, considering their importance as a primary source of saturated fat, controlling for other confounding variable such as total energy intake.

METHODS

The study was conducted as a sequential feeding clinical trial with 40 healthy men and women divided into two feeding periods of initial palm oil (8 weeks) and subsequent coconut oil (8 weeks), with a 16-week washout period in between. Each participant received a pre-determined volume of each oil, which were integrated into their routine main meals and snacks during the respective study periods. Changes in body weight, body mass index (BMI), waist circumference (WC), hip circumference (HC), and waist-to-hip ratio (WHR) were evaluated. Physical activity levels and dietary intake were also evaluated as potential confounding factors.

RESULTS

Thirty-seven participants completed both oil treatment periods. The mean (± SD) age of the participants was 39 (± 13.1) years. There were no significant differences in any of the anthropometric parameters between the initial point of feeding coconut oil and the initial point of feeding palm oil. Following both oil treatment phases, no significant changes in the subjects' body weight, BMI, or other anthropometric measurements (WC, HC, and WHR) were observed.

CONCLUSION

Neither coconut oil nor palm oil significantly changed anthropometry-related cardiovascular risk factors such as body weight, BMI, WC, HC, and WHR.

TRIAL REGISTRATION

Sri Lankan Clinical Trial Registry: SLCTR/2019/034 on 4th October 2019 ( https://slctr.lk/trials/slctr-2019-034 ).

The Effects of Diets Enriched in Monounsaturated Oleic Acid on the Management and Prevention of Obesity: a Systematic Review of Human Intervention Studies

Obesity is associated with an increased risk of several major noncommunicable diseases, and is an important public health concern globally. Dietary fat content is a major contributor to the increase in global obesity rates. Changes in dietary habits, such as the quality of fatty acids in the diet, are proposed to prevent obesity and its metabolic complications. In recent years, a number of studies have found that oleic acid (OA), the most common MUFA in daily nutrition, has protective effects against human disease. Importantly, there is emerging evidence indicating the beneficial effects of OA in regulating body weight. Accordingly, the objective of this systematic review was to investigate the effects of diets enriched in monounsaturated OA on the management and prevention of obesity, emphasizing possible mechanisms of action of OA in energy homeostasis. Searches were performed in PubMed/MEDLINE, ScienceDirect, Scopus, ProQuest, and Google Scholar databases for clinical trials that examined the effects of diets rich in OA on obesity. Of 821 full-text articles assessed, 28 clinical trials were included in the present study. According to the studies examined in this review, diets enriched in OA can influence fat balance, body weight, and possibly energy expenditure. Importantly, abdominal fat and central obesity can be reduced following consumption of high-OA-containing meals. Mechanistically, OA-rich diets can be involved in the regulation of food intake, body mass, and energy expenditure by stimulating AMP-activated protein kinase signaling. Other proposed mechanisms include the prevention of the nucleotide-binding oligomerization domain-like receptor 3/caspase-1 inflammasome pathway, the induction of oleoylethanolamide synthesis, and possibly the downregulation of stearoyl-CoA desaturase 1 activity. In summary, current findings lend support to advice not restricting consumption of OA-rich meals so as to maintain a healthy body weight.

Changes in SCD gene DNA methylation after bariatric surgery in morbidly obese patients are associated with free fatty acids

Stearoyl CoA Desaturase-1 (SCD) is considered as playing an important role in the explanation of obesity. The aim of this study was to evaluate whether the DNA methylation SCD gene promoter is associated with the metabolic improvement in morbidly obese patients after bariatric surgery. The study included 120 subjects with morbid obesity who underwent a laparoscopic Roux-en Y gastric by-pass (RYGB) and a control group of 30 obese subjects with a similar body mass index (BMI) to that found in morbidly obese subjects six months after RYGB. Fasting blood samples were obtained before and at six months after RYGB. DNA methylation was measured by pyrosequencing technology. DNA methylation levels of the SCD gene promoter were lower in morbidly obese subjects before bariatric surgery but increased after RYGB to levels similar to those found in the control group. Changes of DNA methylation SCD gene were associated with the changes of free fatty acids levels (r = −0.442, p = 0.006) and HOMA-IR (r = −0.249, p = 0.035) after surgery. RYGB produces an increase in the low SCD methylation promoter levels found in morbidly obese subjects. This change of SCD methylation levels is associated with changes in FFA and HOMA-IR.

Variable patterns of obesity and cardiometabolic phenotypes and their association with lifestyle factors in the Di@bet.es study

BACKGROUND AND AIM

Prevalence rates of "metabolically healthy obese" (MHO) subjects vary depending on the criteria used. This study examined the prevalence and characteristics of MHO subjects and metabolically abnormal normal-weight subjects and compared the findings with the NHANES 1999-2004 study. The aims of the present study were, first, to determine the prevalence rates of MHO and MNHNO subjects using the same criteria as those of the National Health and Nutrition Examination Survey (NHANES) (1999-2004) study, and second to compare the prevalence and correlates of obese subjects who are resistant to the development of adiposity-associated cardiometabolic abnormalities (CA) and normal-weight individuals who display cardiometabolic risk factor clustering between the Spanish and the US populations.

METHODS AND RESULTS

Di@bet.es study is a national, cross-sectional population-based survey of 5728 adults conducted in 2009-2010. Clinical, metabolic, sociodemographic, and anthropometric data and information about lifestyle habits, such as physical activity, smoking habit, alcohol intake and food consumption, were collected. Subjects were classified according to their body mass index (BMI) (normal-weight, <25 kg/m(2); overweight, 25-29.9 kg/m(2); and obese, >30 kg/m(2)). CA included elevated blood pressure; elevated levels of triglycerides, fasting glucose, and high-sensitivity C-reactive protein (hs-CRP); and elevated homeostasis model assessment of insulin resistance (HOMA-IR) value and low high-density lipoprotein cholesterol (HDL-c) level. Two phenotypes were defined: metabolically healthy phenotype (0-1 CA) and metabolically abnormal phenotype (≥2 CA). The prevalence of metabolically abnormal normal-weight phenotype was slightly lower in the Spanish population (6.5% vs. 8.1%). The prevalence of metabolically healthy overweight and MHO subjects was 20.9% and 7.0%, respectively, while in NHANES study it was 17.9% and 9.7%, respectively. Cigarette smoking was associated with CA in each phenotype, while moderate physical activity and moderate alcohol intake were associated with being metabolically healthy. Olive oil intake was negatively associated with the prevalence of CA.

CONCLUSIONS

Smoking, physical activity level, and alcohol intake contribute to the explanation of the prevalence of CA in the Spanish population, as in the US population. However in Spain, olive oil intake contributes significantly to the explanation of the variance in the prevalence of CA.

Methylation levels of the SCD1 gene promoter and LINE-1 repeat region are associated with weight change: an intervention study

SCOPE

Epigenetic processes may be affected by environmental factors. DNA methylation measured in LINE-1 elements (LINE-1, long interspersed nucleotide element-1) correlates with LINE-1 DNA methylation. Variations in stearoyl CoA desaturase (SCD) activity (a key enzyme in the fatty acid metabolism) may be involved in various processes that can lead to diseases such as obesity. We evaluated whether changes in diet after a nutritional intervention would be associated with changes in LINE-1 DNA methylation and/or specific methylation of SCD1 gene promoter.

METHODS AND RESULTS

DESIGN

Prospective cohort intervention study with a control group. We recorded phenotypic, anthropometric, biochemical, and nutritional information at baseline and 1 year later. DNA methylation was quantified by pyrosequencing. LINE-1 DNA methylation and SCD1 gene promoter methylation levels were similar at the beginning of the study in both populations, whereas after a year these levels were higher in the control group (p < 0.001). In the intervention group, those subjects who lost weight showed higher levels of SCD1 gene promoter methylation after the intervention. Subjects with lower adherence to a Mediterranean diet experienced larger changes in LINE-1 methylation.

CONCLUSION

DNA methylation levels were associated with weight change and with adherence to a Mediterranean diet.

Olive oil has a beneficial effect on impaired glucose regulation and other cardiometabolic risk factors. Di@bet.es study

BACKGROUND

Despite the marked increase in cardiovascular risk factors in Spain in recent years, the prevalence and incidence of cardiovascular diseases have not risen as expected. Our objective is to examine the association between consumption of olive oil and the presence of cardiometabolic risk factors in the context of a large study representative of the Spanish population.

SUBJECTS AND METHODS

A population-based, cross-sectional, cluster sampling study was conducted. The target population was the whole Spanish population. A total of 4572 individuals aged ≥ 18 years in 100 clusters (health centers) were randomly selected with a probability proportional to population size. The main outcome measures were clinical and demographic structured survey, lifestyle survey, physical examination (weight, height, body mass index, waist, hip and blood pressure) and oral glucose tolerance test (OGTT) (75 g).

RESULTS

Around 90% of the Spanish population use olive oil, at least for dressing, and slightly fewer for cooking or frying. The preference for olive oil is related to age, educational level, alcohol intake, body mass index and serum glucose, insulin and lipids. People who consume olive oil (vs sunflower oil) had a lower risk of obesity (odds ratio (OR)=0.62 (95% confidence interval (CI)=0.41-0.93, P=0.02)), impaired glucose regulation (OR=0.49 (95% CI=0.28-0.86, P=0.04)), hypertriglyceridemia (OR=0.53 (95% CI=0.33-0.84, P=0.03)) and low HDL cholesterol levels (OR=0.40 (95% CI=0.26-0.59, P=0.0001)).

CONCLUSIONS

The results show that consumption of olive oil has a beneficial effect on different cardiovascular risk factors, particularly in the presence of obesity, impaired glucose tolerance or a sedentary lifestyle.

Factors determining weight gain in adults and relation with glucose tolerance

OBJECTIVE

Modifications in lifestyle, diet and certain clinical events are major contributors for the high prevalence of obesity. The aim of this study was to assess factors associated with weight gain in a population of Spanish adults.

DESIGN

The study was undertaken in two population-based cohorts from the north and the south of Spain (baseline and after 6 years). The Asturias Study, in the north, included 1034 persons aged 30-75 years, of whom 701 were reassessed. The Pizarra Study, in the south, included 1226 persons aged 18-65 years, of whom 783 were re-evaluated. Both studies involved a nutritional questionnaire, a physical examination and an oral glucose tolerance test (OGTT).

RESULTS

During the follow-up, 32.3% of the participants lost weight, 34.5% gained fewer than 4 kg and 33.2% gained more than 4 kg. Weight gain was greater in persons younger than 50 years and in those with an initial body mass index below 30. Weight gain was associated with a greater incidence of type 2 diabetes mellitus (T2DM) and abnormal glucose tolerance, whereas weight loss in persons with these disorders was associated with a normal OGTT 6 years later. Persons who took less exercise and those who reported a higher daily calorie intake experienced greater weight gain.

CONCLUSION

The longitudinal changes in weight affect the development of T2DM and abnormal glucose tolerance. The weight is a dynamic phenomenon affected by several social customs.

Plasma phospholipid fatty acid composition and estimated desaturase activity in heart failure patients with metabolic syndrome

Metabolic syndrome is one of the major factors to increase the incidence of heart failure. In our study, we compared plasma fatty acid compositions among heart failure patients with and without Metabolic syndrome. Fatty acid (FA) composition of plasma phospholipids was analyzed and the activities of desaturase were estimated as the ratio of substrate and product fatty acids in 85 stable heart failure patients. Fatty acid and estimated desaturase activities were further examined for their associations with Metabolic syndrome components. Heart failure patients with Metabolic syndrome showed significant changes in fatty acid composition in comparison to those without Metabolic syndrome, which had a decreased proportion of lauric acid (C12:0) and an increased proportion of dihomo-γ-linolenic acid (C20:3n-6). Also, estimated desaturase activities (D5D and D6D) were closely related to Metabolic syndrome condition among heart failure patients. The content of dihomo-γ-linolenic acid showed positive correlations with BMI, waist circumference, and plasma triglyceride levels. D6D were positively associated with plasma triglyceride levels, whereas D5D showed a negative correlation with plasma triglyceride levels and waist circumferences. The content of dihomo-γ-linolenic acid as well as estimated D6D and D5D were altered in heart failure patients with Metabolic syndrome.

Heart rate is associated with markers of fatty acid desaturation: the GOCADAN study

Objectives

To determine if heart rate (HR) is associated with desaturation indexes as HR is associated with arrhythmia and sudden death.

Study design

A community based cross-sectional study of 1214 Alaskan Inuit.

Methods

Data of FA concentrations from plasma and red blood cell membranes from those ≥35 years of age (n =819) were compared to basal HR at the time of examination. Multiple linear regression with backward stepwise selection was employed to analyze the effect of the desaturase indexes on HR, after adjustment for relevant covariates.

Results

The Δ⁵ desaturase index (Δ⁵-DI) measured in serum has recently been associated with a protective role for cardiovascular disease. This index measured here in plasma and red blood cells showed a negative correlation with HR. The plasma stearoyl-CoA-desaturase (SCD) index, previously determined to be related to cardiovascular disease (CVD) mortality, on the other hand, was positively associated with HR, while the Δ⁶ desaturase index (Δ⁶-DI) had no significant effect on HR.

Conclusion

Endogenous FA desaturation is associated with HR and thereby, in the case of SCD, possibly with arrhythmia and sudden death, which would at least partially explain the previously observed association between cardiovascular mortality and desaturase activity.

Children whose diet contained olive oil had a lower likelihood of increasing their body mass index Z-score over 1 year

OBJECTIVE

Changes in eating habits may be influential in the ever-increasing rate of childhood obesity. Our aim was to determine whether those children who consume olive oil have a lower risk of weight gain compared with children who consume other oils.

DESIGN AND METHODS

The study included 18 girls and 74 boys, all aged 13-166 months. A survey was completed for each subject about eating habits and physical activity. A sample of subcutaneous adipose tissue was also obtained for cellular study. Data were recorded on the mean size of the adipocytes, the number of preadipocytes, and the concentration of particular fatty acids. The weight and height of the children were measured 13 months later.

RESULTS

The likelihood that after 1 year the children would have increased their body mass index (BMI) Z-score above the initial score was less in the children who consumed only olive oil (odds ratio (OR)=0.22; 95% confidence interval (CI): 0.08-0.63; P=0.005). These results remained after adjusting for age, physical activity and BMI (OR=0.19; 95% CI: 0.06-0.61; P=0.005) and after adjusting for age, physical activity and adipocyte volume (OR=0.15; 95% CI: 0.04-0.52; P=0.003).

CONCLUSIONS

Diets with mono unsaturated fatty acid (MUFA)-rich olive oil could reduce the risk of obesity in childhood.

Stearoyl-CoA desaturase-1 is associated with insulin resistance in morbidly obese subjects

Animal studies have revealed the association between stearoyl-CoA desaturase 1 (SCD1) and obesity and insulin resistance. However, only a few studies have been undertaken in humans. We studied SCD1 in visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) from morbidly obese patients and their association with insulin resistance, sterol regulatory element binding protein-1 (SREBP-1) and ATPase p97, proteins involved in SCD1 synthesis and degradation. The insulin resistance was calculated in 40 morbidly obese patients and 11 overweight controls. Measurements were made of VAT and SAT SCD1, SREBP-1 and ATPase p97 mRNA expression and protein levels. VAT and SAT SCD1 mRNA expression levels in the morbidly obese patients were significantly lower than in the controls (P = 0.006), whereas SCD1 protein levels were significantly higher (P < 0.001). In the morbidly obese patients, the VAT SCD1 protein levels were decreased in patients with higher insulin resistance (P = 0.007). However, SAT SCD1 protein levels were increased in morbidly obese patients with higher insulin resistance (P < 0.05). Multiple linear regressions in the morbidly obese patients showed that the variable associated with the SCD1 protein levels in VAT was insulin resistance, and the variables associated with SCD1 protein levels in SAT were body mass index (BMI) and ATPase p97. In conclusion, these data suggest that the regulation of SCD1 is altered in individuals with morbid obesity and that the SCD1 protein has a different regulation in the two adipose tissues, as well as being closely linked to the degree of insulin resistance.

Intake and home use of olive oil or mixed oils in relation to healthy lifestyles in a Mediterranean population. Findings from the prospective Pizarra study

Discordances exist in epidemiological studies regarding the association between the intake of nutrients and death and disease. We evaluated the social and health profile of persons who consumed olive oil in a prospective population cohort investigation (Pizarra study) with a 6-year follow-up. A food frequency questionnaire and a 7 d quantitative questionnaire were administered to 538 persons. The type of oil used in food preparation was determined by direct measurement of the fatty acids in samples obtained from the kitchens of the participants at baseline and after follow-up for 6 years. The fatty acid composition of the serum phospholipids was used as an endogenous marker of the type of oil consumed. Total fat intake accounted for a mean 40 % of the energy (at baseline and after follow-up). The concordance in intake of MUFA over the study period was high. The fatty acid composition of the serum phospholipids was significantly associated with the type of oil consumed and with fish intake. The concentration of polar compounds and polymers, indicative of degradation, was greater in oils from the kitchens where sunflower oil or refined olive oil was used, in oils used for deep frying and in oils that had been reused for frying five times or more. Consumption of olive oil was directly associated with educational level. Part of the discordance found in epidemiological studies between diet and health may be due to the handling of oils during food preparation. The intake of olive oil is associated with other healthy habits.

Markers of dietary fat quality and fatty acid desaturation as predictors of total and cardiovascular mortality: a population-based prospective study

BACKGROUND

Desaturase indexes, as markers of endogenous fatty acid desaturation, and a characteristic serum fatty acid (FA) composition are related to cardiovascular and metabolic diseases, but the relation to mortality is poorly investigated.

OBJECTIVE

The objective was to evaluate the relation between dietary fat biomarkers, desaturase indexes, and mortality.

DESIGN

In this community-based prospective sample, 50-y-old men were followed for a maximum of 33.7 y. Cox proportional hazard analysis was conducted to investigate desaturase indexes (stearoyl-CoA-desaturase and Delta(6)- and Delta(5)-desaturase) and the relation of individual serum esterified fatty acids (FAs) in relation to total and cardiovascular mortality in the total study sample (n = 2009) and in a healthy subsample (n = 1885). Desaturase indexes were estimated as product-to-precursor FA ratios.

RESULTS

During follow-up, 1012 men in the total sample died and 931 men in the healthy subsample died. Desaturase indexes predicted both total and cardiovascular mortality. The relations were independent of smoking status, physical activity, BMI, total cholesterol, and hypertension. The adjusted and standardized (per SD) hazard ratios (HRs) and 95% CIs for cardiovascular mortality were 1.15 (1.04, 1.27) for stearoyl-CoA-desaturase, 1.12 (1.0, 1.24) for Delta(6)-desaturase, and 0.88 (0.80, 0.98) for Delta(5)-desaturase, respectively. The proportion of serum linoleic acid was inversely related, whereas serum FAs associated with saturated fat intake (palmitic, palmitoleic, and dihomo-gamma-linolenic acids) were directly related to total and cardiovascular mortality.

CONCLUSIONS

Altered endogenous FA desaturation might contribute to mortality risk because we observed independent associations between desaturase activity indexes and mortality. The proportion of linoleic acid was inversely related, and FAs reflecting saturated fat intake were directly related to mortality.