Effect of a high monounsaturated fatty acids diet and a Mediterranean diet on serum lipids and insulin sensitivity in adults with mild abdominal obesity

Evidence-Based Guideline of the German Nutrition Society: Fat Intake and Prevention of Selected Nutrition-Related Diseases

As nutrition-related chronic diseases have become more and more frequent, the importance of dietary prevention has also increased. Dietary fat plays a major role in human nutrition, and modification of fat and/or fatty acid intake could have a preventive potential. The aim of the guideline of the German Nutrition Society (DGE) was to systematically evaluate the evidence for the prevention of the widespread diseases obesity, type 2 diabetes mellitus, dyslipoproteinaemia, hypertension, metabolic syndrome, coronary heart disease (CHD), stroke, and cancer through the intake of fat or fatty acids. The main results can be summarized as follows: it was concluded with convincing evidence that a reduced intake of total and saturated fat as well as a larger intake of polyunsaturated fatty acids (PUFA) at the expense of saturated fatty acids (SFA) reduces the concentration of total and low-density lipoprotein cholesterol in plasma. Furthermore, there is convincing evidence that a high intake of trans fatty acids increases risk of dyslipoproteinaemia and that a high intake of long-chain polyunsaturated n-3 fatty acids reduces the triglyceride concentration in plasma. A high fat intake increases the risk of obesity with probable evidence when total energy intake is not controlled for (ad libitum diet). When energy intake is controlled for, there is probable evidence for no association between fat intake and risk of obesity. A larger intake of PUFA at the expense of SFA reduces risk of CHD with probable evidence. Furthermore, there is probable evidence that a high intake of long-chain polyunsaturated n-3 fatty acids reduces risk of hypertension and CHD. With probable evidence, a high trans fatty acid intake increases risk of CHD. The practical consequences for current dietary recommendations are described at the end of this article.

A Simple and Effective Mass Spectrometric Approach to Identify the Adulteration of the Mediterranean Diet Component Extra-Virgin Olive Oil with Corn Oil

Extra virgin olive oil (EVOO) with its nutraceutical characteristics substantially contributes as a major nutrient to the health benefit of the Mediterranean diet. Unfortunately, the adulteration of EVOO with less expensive oils (e.g., peanut and corn oils), has become one of the biggest source of agricultural fraud in the European Union, with important health implications for consumers, mainly due to the introduction of seed oil-derived allergens causing, especially in children, severe food allergy phenomena. In this regard, revealing adulterations of EVOO is of fundamental importance for health care and prevention reasons, especially in children. To this aim, effective analytical methods to assess EVOO purity are necessary. Here, we propose a simple, rapid, robust and very sensitive method for non-specialized mass spectrometric laboratory, based on the matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS) coupled to unsupervised hierarchical clustering (UHC), principal component (PCA) and Pearson's correlation analyses, to reveal corn oil (CO) adulterations in EVOO at very low levels (down to 0.5%).

The dietary monounsaturated to saturated fatty acid ratio modulates the genetic effects of GCKR on serum lipid levels in children

BACKGROUND

Glucokinase regulator (GCKR) plays important roles in the regulation of glucokinase (GK) activity and the metabolism of glucose and lipids. We investigated whether the association between GCKR genetic variants with serum lipids in Korean adults is replicated in children, and whether these genetic influences might be modulated by dietary monounsaturated fatty acid relative to saturated fatty acid (MUFA:SFA) ratio.

METHODS

We genotyped 711 children for GCKR variants, used 7495 adults in KARE database, and analyzed anthropometric, biochemical, and dietary measurements.

RESULTS

The major allele carriers of rs780094 and rs780092 in adults had significantly higher serum total cholesterol and triglycerides levels compared to noncarriers. Five variants in children, including rs780094 and rs780092, correlated similarly with high total and low-density lipoprotein (LDL) cholesterol. When the dietary MUFA:SFA ratio was dichotomized (MUFA:SFA≥1 or <1), the aggravating effects of the major allele on total cholesterol, LDL cholesterol, and triglycerides were only evident in the group in which MUFA:SFA ratio was <1. Additionally, we observed that the GCKR haplotype with a functional variant, rs1260326, influenced lower total and LDL cholesterol in children whose MUFA:SFA ratio was <1.

CONCLUSION

We replicated the genetic association effect of GCKR on total cholesterol in children, and found that the interaction effects between GCKR genetic variants and the dietary MUFA:SFA ratio on lipid levels, were commonly observed in Korean adults and children.

Combined effect of unsaturated fatty acids and saturated fatty acids on the metabolic syndrome: Tehran lipid and glucose study

AIMS

The aim of this study was to investigate whether the background intakes of total dietary fat, monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA) modulate the effects of dietary saturated fatty acids (SFA) on metabolic syndrome (MetS).

MATERIAL AND METHODS

This population-based cross-sectional study was conducted on a representative sample of 4,677 adults, aged 19 to 84 years. MetS was defined according to the ATP III criteria.

RESULTS

Median intakes of SFA, MUFA and PUFA were 9.5, 9.6 and 5.6% of total energy. High SFA intakes were associated with higher prevalence of MetS, in both individuals with higher and lower median intakes of total fat, MUFA and PUFA.

CONCLUSIONS

Our findings indicate that SFA intakes were positively associated with the prevalence of MetS, independent of total dietary fat, MUFA and PUFA intake.

The Mediterranean diet: health, science and society

The Mediterranean diet (MD) emerged as a healthy food regimen long before it could be recognised which nutrients or foods were responsible for its observed benefits, and it was only in the middle of the last century that the first scientific approach ‘The Seven Countries Study’ appeared. Epidemiological and anthropological studies of the MD converged, first by investigating at single nutrients or foods, then by adopting the more holistic approach of dietary patterns (DP), and now with a molecular approach. These studies resulted in convincing evidence that a MD decreases the risk of all-cause mortality and cardiovascular mortality and incidence. A risk reduction of developing type 2 diabetes is probable. Evidence is less stringent for other metabolic diseases and all cancers but from possible to probable for some cancer sites. Although DP showed that the MD has to be considered in its totality, olive oil could have a specific role. Lifestyle factors such as physical activity for energy balance, outdoor life for vitamin D synthesis and conviviality are also probably partly responsible for the health benefits. The MD is a lifestyle well suited for coping not only with personal health but also with wider societal concerns in relation to environment, public health and economy.

Energy Intake, Profile, and Dietary Sources in the Spanish Population: Findings of the ANIBES Study

Energy intake, and the foods and beverages contributing to that, are considered key to understanding the high obesity prevalence worldwide. The relative contributions of energy intake and expenditure to the obesity epidemic, however, remain poorly defined in Spain. The purpose of this study was to contribute to updating data of dietary energy intake and its main sources from food and beverages, according to gender and age. These data were derived from the ANIBES ("Anthropometry, Intake, and Energy Balance in Spain") study, a cross-sectional study of a nationally representative sample of the Spanish population (from 9-75 years old). A three-day dietary record, collected by means of a tablet device, was used to obtain information about food and beverage consumption and leftovers. The final sample comprised 2009 individuals (1,013 men, 996 women). The observed mean dietary energy intake was 7.6 ± 2.11 MJ/day (8.2 ± 2.22 MJ/day for men and 6.9 ± 1.79 MJ/day for women). The highest intakes were observed among adolescents aged 13-17 years (8.4 MJ/day), followed by children 9-12 years (8.2 ± 1.80 MJ/day), adults aged 18-64 (7.6 ± 2.14 MJ/day) and older adults aged 65-75 years (6.8 ± 1.88 MJ/day). Cereals or grains (27.4%), meats and derivatives (15.2%), oils and fats (12.3%), and milk and dairy products (11.8%) contributed most to daily energy intake. Energy contributions from non-alcoholic beverages (3.9%), fish and shellfish (3.6%), sugars and sweets (3.3%) and alcoholic beverages (2.6%) were moderate to minor. Contributions to caloric profile were 16.8%E from proteins; 41.1%E from carbohydrates, including 1.4%E from fiber; 38.5%E from fats; and 1.9%E from alcohol intake. We can conclude that energy intake is decreasing in the Spanish population. A variety of food and beverage groups contribute to energy intake; however, it is necessary to reinforce efforts for better adherence to the traditional Mediterranean diet.

Dietary rapeseed/canola-oil supplementation reduces serum lipids and liver enzymes and alters postprandial inflammatory responses in adipose tissue compared to olive-oil supplementation in obese men

SCOPE

Obesity is associated with hyperlipidemia, hepatic steatosis, and low-grade inflammation. Studies have shown that MUFA as well as PUFA have beneficial effects on blood lipids and the inflammatory state.

METHODS AND RESULTS

This study investigates the effects of a daily supplementation of either 50 g of rapeseed/canola (RA) or olive (OL) oil over 4 wk on serum lipids, serum liver enzymes, and inflammatory gene expression in subcutaneous (s. c.) adipose tissue in obese men. Consuming RA resulted in increased serum n-3 fatty acids and a reduction in total cholesterol, LDL cholesterol, and serum aspartate aminotransferase compared to OL. In s. c. adipose tissue, gene expression of the pro-inflammatory cytokine IL6 was reduced in RA compared to OL. However, after 4 h after a test meal, containing the appropriate oil, white bread, and 400 mL of liquid diet drink (835 kcal in total), gene expression of IL6, IL1B, and EMR1 (egf-like module containing Mucin-like hormone receptor-like 1) was increased in RA and of monocyte chemoattractant protein-1 (CCL2) in both RA and OL.

CONCLUSION

This demonstrates that consuming RA for 4 wk improves serum lipids, liver enzymes, and basal inflammation in s. c. adipose tissue, but it mediates an acute pro-inflammatory response in adipose tissue upon consuming a meal.

Effect of the amount and type of dietary fat on cardiometabolic risk factors and risk of developing type 2 diabetes, cardiovascular diseases, and cancer: a systematic review

The effects of both the amount and quality of dietary fat have been studied intensively during the past decades. Previously, low-fat diets were recommended without much attention to the quality of fat, whereas there is general emphasis on the quality of fat in current guidelines. The objective of this systematic review (SR) was to assess the evidence of an effect of the amount and type of dietary fat on body weight (BW), risk factors, and risk of non-communicable diseases, that is, type 2 diabetes (T2DM), cardiovascular diseases (CVD), and cancer in healthy subjects or subjects at risk for these diseases. This work was performed in the process of updating the fourth edition of the Nordic Nutrition Recommendations from 2004. The literature search was performed in October 2010 covering articles published since January 2000. A complementary search was done in February 2012 covering literature until December 2011. Two authors independently selected articles for inclusion from a total of about 16,000 abstracts according to predefined criteria. Randomized controlled trials (RCT) and prospective cohort studies (PCS) were included as well as nested case-control studies. A few retrospective case-control studies were also included when limited or no data were available from other study types. Altogether 607 articles were quality graded and the observed effects in these papers were summarized. Convincing evidence was found that partial replacement of saturated fat (SFA) with polyunsaturated fat (PUFA) or monounsaturated fat (MUFA) lowers fasting serum/plasma total and LDL cholesterol concentrations. The evidence was probable for a decreasing effect of fish oil on concentration of serum/plasma total triglycerides as compared with MUFA. Beneficial effect of MUFA both on insulin sensitivity and fasting plasma/serum insulin concentration was considered as probable in comparisons of MUFA and carbohydrates versus SFA, whereas no effect was found on fasting glucose concentration in these comparisons. There was probable evidence for a moderate direct association between total fat intake and BW. Furthermore, there was convincing evidence that partial replacement of SFA with PUFA decreases the risk of CVD, especially in men. This finding was supported by an association with biomarkers of PUFA intake; the evidence of a beneficial effect of dietary total PUFA, n-6 PUFA, and linoleic acid (LA) on CVD mortality was limited suggestive. Evidence for a direct association between total fat intake and risk of T2DM was inconclusive, whereas there was limited-suggestive evidence from biomarker studies that LA is inversely associated with the risk of T2DM. However, there was limited-suggestive evidence in biomarker studies that odd-chain SFA found in milk fat and fish may be inversely related to T2DM, but these associations have not been supported by controlled studies. The evidence for an association between dietary n-3 PUFA and T2DM was inconclusive. Evidence for effects of fat on major types of cancer was inconclusive regarding both the amount and quality of dietary fat, except for prostate cancer where there was limited-suggestive evidence for an inverse association with intake of ALA and for ovarian cancer for which there was limited-suggestive evidence for a positive association with intake of SFA. This SR reviewed a large number of studies focusing on several different health outcomes. The time period covered by the search may not have allowed obtaining the full picture of the evidence in all areas covered by this SR. However, several SRs and meta-analyses that covered studies published before year 2000 were evaluated, which adds confidence to the results. Many of the investigated questions remain unresolved, mainly because of few studies on certain outcomes, conflicting results from studies, and lack of high quality-controlled studies. There is thus an evident need of highly controlled RCT and PCS with sufficient number of subjects and long enough duration, specifically regarding the effects of the amount and quality of dietary fat on insulin sensitivity, T2DM, low-grade inflammation, and blood pressure. New metabolic and other potential risk markers and utilization of new methodology in the area of lipid metabolism may provide new insight.

Mediterranean diet and health: food effects on gut microbiota and disease control

The Mediterranean diet (MD) is considered one of the healthiest dietary models. Many of the characteristic components of the MD have functional features with positive effects on health and wellness. The MD adherence, calculated through various computational scores, can lead to a reduction of the incidence of major diseases (e.g., cancers, metabolic and cardiovascular syndromes, neurodegenerative diseases, type 2 diabetes and allergy). Furthermore, eating habits are the main significant determinants of the microbial multiplicity of the gut, and dietary components influence both microbial populations and their metabolic activities from the early stages of life. For this purpose, we present a study proposal relying on the generation of individual gut microbiota maps from MD-aware children/adolescents. The maps, based on meta-omics approaches, may be considered as new tools, acting as a systems biology-based proof of evidence to evaluate MD effects on gut microbiota homeostasis. Data integration of food metabotypes and gut microbiota “enterotypes” may allow one to interpret MD adherence and its effects on health in a new way, employable for the design of targeted diets and nutraceutical interventions in childcare and clinical management of food-related diseases, whose onset has been significantly shifted early in life.

High-density lipoprotein cholesterol raising: does it matter?

PURPOSE OF REVIEW

Cardiovascular disease (CVD) is the leading cause of morbidity and premature mortality in Europe and the United States, and is increasingly common in developing countries. High-density lipoprotein cholesterol (HDL-C) is an independent risk factor for CVD and is superior to low-density lipoprotein cholesterol (LDL-C) as a predictor of cardiovascular events. The residual risk conferred by low HDL-C in patients with a satisfactory LDL-C was recently highlighted by the European Atherosclerosis Society. Despite the lack of randomized controlled trials, it has been suggested that raising the level of HDL-C should be considered as a therapeutic strategy in high-risk patients because of the strong epidemiological evidence, compelling biological plausibility, and both experimental and clinical research supporting its cardioprotective effects.

RECENT FINDINGS

Three recent large randomized clinical trials investigating the effect of HDL-C raising with niacin and dalcetrapib in statin-treated patients failed to demonstrate an improvement in cardiovascular outcomes.

SUMMARY

There is evidence to support the view that HDL functionality and the mechanism by which a therapeutic agent raises HDL-C are more important than plasma HDL-C levels. Future therapeutic agents will be required to improve this functionality rather than simply raising the cholesterol cargo.

The Mediterranean diet and nutritional adequacy: a review

The Mediterranean dietary pattern, through a healthy profile of fat intake, low proportion of carbohydrate, low glycemic index, high content of dietary fiber, antioxidant compounds, and anti-inflammatory effects, reduces the risk of certain pathologies, such as cancer or Cardiovascular Disease (CVD). Nutritional adequacy is the comparison between the nutrient requirement and the intake of a certain individual or population. In population groups, the prevalence of nutrient inadequacy can be assessed by the probability approach or using the Estimated Average Requirement (EAR) cut-point method. However, dietary patterns can also be used as they have moderate to good validity to assess adequate intakes of some nutrients. The objective of this study was to review the available evidence on the Nutritional Adequacy of the Mediterranean Diet. The inclusion of foods typical of the Mediterranean diet and greater adherence to this healthy pattern was related to a better nutrient profile, both in children and adults, with a lower prevalence of individuals showing inadequate intakes of micronutrients. Therefore, the Mediterranean diet could be used in public health nutrition policies in order to prevent micronutrient deficiencies in the most vulnerable population groups.

Interactions between ADIPOQ gene variants and dietary monounsaturated: saturated fatty acid ratio on serum lipid levels in Korean children

BACKGROUND AND AIMS

Adiponectin plays important roles in the regulation of insulin action and metabolism of glucose and lipids. We investigated whether ADIPOQ genetic variants are associated with serum lipid levels in Korean children and whether those influences might be modulated by dietary factors such as dietary monounsaturated fatty acid to saturated fatty acid ratio (MUFA:SFA).

METHOD AND RESULTS

The study included a population-based sample of 687 children aged 7-11 years in Gwacheon city, Kyunggi Province, Korea. Anthropometric and biochemical measurements and ADIPOQ genotype (-11377 C/G, +45 T/G, and +276 G/T) were determined. Dietary intake was estimated with a self reported 3-day food diary. The -11377 G allele carriers had significantly higher serum total cholesterol and LDL cholesterol compared to non-carriers. When dietary MUFA:SFA ratio was dichotomized (MUFA:SFA ≥ 1 or <1), the aggravating effects of the minor allele on serum total and LDL cholesterol were only present when the MUFA:SFA ratio was <1. Additionally, we observed that the ADIPOQ haplotype influenced serum total and LDL cholesterol levels. G-T-G haplotype carriers had higher total and LDL cholesterol levels than non-G-T-G carriers. The deleterious effect of ADIPOQ G-T-G haplotype to increase serum total and LDL cholesterol could be seen only when the MUFA:SFA ratio was <1.

CONCLUSION

In this present study, we found interaction effects between ADIPOQ genetic variants and dietary MUFA:SFA ratio on serum lipid levels in Korean children. These results suggest that individual genetic information and dietary fatty acid intake information should be assessed together to achieve an effective outcome for reducing the atherogenic lipid profile.

Reappraisal of SFA and cardiovascular risk

This review reappraises dietary advice to reduce and replace SFA for the prevention of CVD. In the 1970s, SFA accounted for about 18% UK food energy, by 2001 it had fallen to 13% and continues to be above the <11% target. Compared with carbohydrates, C12–C16 SFA raise serum total cholesterol (TC), LDL-cholesterol (LDL-C) and HDL-cholesterol (HDL-C) without affecting the TC:HDL-C ratio; other SFA have neutral effects on the fasting lipid profile. Replacing 3% dietary SFA with MUFA or PUFA lowers LDL-C by 2% and TC:HDL-C ratio by 0·03. No other specific adverse effects of SFA compared with MUFA on risk CVD factors have been proven. Meta-analyses of prospective cohort studies report the relative risks (95% CI) of high v. low intakes of SFA to be 1·07 (0·96, 1·19) for CHD, 0·81 (0·62, 1·05) for stroke and 1·00 (0·89, 1·11) for CVD mortality and were not statistically significant. Exchanging 5% energy SFA for PUFA or carbohydrates found hazard ratios (95% CI) for CHD death to be 26% (−23, −3) and 4% (−18, 12; NS) lower, respectively. Meta-analysis of randomised controlled trials with clinical endpoints reports mean reductions (95% CI) of 14% (4, 23) in CHD incidence and 6% (−25, 4; NS) in mortality in trials, where SFA was lowered by decreasing and/or modifying dietary fat. In conclusion, SFA intakes are now close to guideline amounts and further reductions may only have a minor impact on CVD.

The relationships between body composition and cardiovascular risk factors in young Australian men

INTRODUCTION

Cardiovascular (CV) disease is a leading cause of global mortality. Despite clear evidence of the coexistence of several risk factors in young people as children and an understanding of the importance of the health behaviors in controlling CV disease, there are limited data on the relationships between risk factors and CV disease in young people. Therefore further study is required.

OBJECTIVE

This study aimed to investigate associations among body composition, health behaviors and CV risk factors in young Australian men.

METHODS

Thirty five healthy men aged 18-25 years had their blood pressure (BP), blood lipids, body composition, resting metabolic rate (RMR), physical activity, dietary intake and cardiorespiratory fitness assessed.

RESULTS

Participants were categorised according to the percentage of body fat into two groups: lean and overweight men. There were no between-group differences in the biochemical indicators except that overweight men had lower HDL-C compared to lean men. Both groups had similar mean energy, protein, fat, carbohydrate and alcohol intake, RMR, physical activity level (PAL) and energy expenditure (EE). Most of the participants (65.7%) had LDL≥2.5 mmol/L. Other common individual risk factors were body fat≥20% (42.9%), waist circumference≥88 cm (28.6%), PAL<1.8 (22.9%) and systolic BP≥130 mmHg (20%). The mean number of CV risk factors was lower among men having a high intake of monounsaturated fatty acids (MUFA, >12% of the energy intake) regardless of whether they were overweight or lean and did not seem to differ according to the source of MUFA consumed.

CONCLUSIONS

It is a serious concern to observe such a high percentage of CV risk factors in a group of apparently healthy young men. The likelihood of multiple CV risk factors is greater among those with high body fatness and low MUFA intake. Intake of MUFA favorably affects CV risk factors regardless of the source.

Lipoprotein subfractions in metabolic syndrome and obesity: clinical significance and therapeutic approaches

Small, dense low density lipoprotein (sdLDL) represents an emerging cardiovascular risk factor, since these particles can be associated with cardiovascular disease (CVD) independently of established risk factors, including plasma lipids. Obese subjects frequently have atherogenic dyslipidaemia, including elevated sdLDL levels, in addition to elevated triglycerides (TG), very low density lipoprotein (VLDL) and apolipoprotein-B, as well as decreased high density lipoprotein cholesterol (HDL-C) levels. Obesity-related co-morbidities, such as metabolic syndrome (MetS) are also characterized by dyslipidaemia. Therefore, agents that favourably modulate LDL subclasses may be of clinical value in these subjects. Statins are the lipid-lowering drug of choice. Also, anti-obesity and lipid lowering drugs other than statins could be useful in these patients. However, the effects of anti-obesity drugs on CVD risk factors remain unclear. We review the clinical significance of sdLDL in being overweight and obesity, as well as the efficacy of anti-obesity drugs on LDL subfractions in these individuals; a short comment on HDL subclasses is also included. Our literature search was based on PubMed and Scopus listings. Further research is required to fully explore both the significance of sdLDL and the efficacy of anti-obesity drugs on LDL subfractions in being overweight, obesity and MetS. Improving the lipoprotein profile in these patients may represent an efficient approach for reducing cardiovascular risk.

Lipoprotein subfractions in metabolic syndrome and obesity: clinical significance and therapeutic approaches

Small, dense low density lipoprotein (sdLDL) represents an emerging cardiovascular risk factor, since these particles can be associated with cardiovascular disease (CVD) independently of established risk factors, including plasma lipids. Obese subjects frequently have atherogenic dyslipidaemia, including elevated sdLDL levels, in addition to elevated triglycerides (TG), very low density lipoprotein (VLDL) and apolipoprotein-B, as well as decreased high density lipoprotein cholesterol (HDL-C) levels. Obesity-related co-morbidities, such as metabolic syndrome (MetS) are also characterized by dyslipidaemia. Therefore, agents that favourably modulate LDL subclasses may be of clinical value in these subjects. Statins are the lipid-lowering drug of choice. Also, anti-obesity and lipid lowering drugs other than statins could be useful in these patients. However, the effects of anti-obesity drugs on CVD risk factors remain unclear. We review the clinical significance of sdLDL in being overweight and obesity, as well as the efficacy of anti-obesity drugs on LDL subfractions in these individuals; a short comment on HDL subclasses is also included. Our literature search was based on PubMed and Scopus listings. Further research is required to fully explore both the significance of sdLDL and the efficacy of anti-obesity drugs on LDL subfractions in being overweight, obesity and MetS. Improving the lipoprotein profile in these patients may represent an efficient approach for reducing cardiovascular risk.

Effect of substituting saturated with monounsaturated fatty acids on serum visfatin levels and insulin resistance in overweight women: a randomized cross-over clinical trial

OBJECTIVE

This study aimed to determine the effects of a monounsaturated fatty acids (MUFA)-rich diet on serum visfatin, interleukin-6 and insulin levels among overweight women.

DESIGN

In this randomized cross-over clinical trial, 17 premenopausal overweight women were included. Participants were randomly assigned to consume either a hypocaloric, saturated fatty acids (SFA)-rich diet (16% SFA and 8% MUFA) or a hypocaloric, MUFA-rich diet (16% MUFA and 8% SFA) for 12 weeks crossing over after a 2-week washout period. Percentages of energy from other macronutrients were similar between the two diets. Biochemical and anthropometric assessments were done at the first and at the end of each period. Statistical analyses were done using paired t-test. In all statistical analysis, p < 0.05 was considered as significant.

RESULTS

The participant's mean body mass index was 27.6 kg/m². Mean percentages of MUFA intake were 13% during MUFA-rich diet and 7% during SFA-rich diet. The corresponding values for SFA intake were 8.5% and 14%, respectively. We failed to find any significant differences between two intervention diets in terms of their effect on the serum levels of IL-6, visfatin and insulin. However, serum visfatin and IL-6 levels increased during the SFA-rich diet (0.4 ± 0.4 ng/ml and 0.19 ± 0.3 pg/ml, respectively) and decreased during the MUFA-rich diet (-0.7 ± 0.5 ng/ml and -0.17 ± 0.3 pg/ml, respectively). In spite of a slight reduction in both periods, changes in serum insulin levels did not reach significant levels comparing the two periods.

CONCLUSIONS

Our findings did not support any significant effect of a MUFA-rich intake on serum IL-6 and insulin levels as compared with a SFA-rich diet; however, it has the potential to favourably affect serum visfatin levels.

The impact of abdominal obesity status on cardiovascular response to the mediterranean diet

We investigated the impact of abdominal obesity status on the cardiovascular response to a fully controlled 4-week isoenergetic Mediterranean diet (MedDiet). Thirty-eight abdominally obese individuals (waist circumference >102 cm in men and >88 cm in women) and thirty-one nonabdominally obese individuals were recruited and studied before and after the MedDiet. All analyses were adjusted for the slight decrease in body weight, which occurred during the MedDiet (mean: 0.9 ± 1.2 kg). A group by time interaction was noted for waist circumference (P = 0.02), abdominally obese subjects showing a significant decrease and nonabdominally obese subjects a nonsignificant increase (resp., -1.1 and +0.3%). The MedDiet resulted in decreases in total cholesterol, LDL-C, HDL-C, apolipoprotein B, A-1, and A-2, total cholesterol/HDL-C ratio, LDL-C/HDL-C ratio, and systolic and diastolic blood pressure (time effect: P < 0.05). For all variables related to glucose/insulin homeostasis, no change was observed except for a decrease in 2 h glucose concentrations (time effect: P = 0.03). No group by time interaction was observed in any of the metabolic variables studied. Results from our study suggest that the adoption of the MedDiet leads to beneficial metabolic effects, irrespective of the abdominal obesity status.

High-density lipoprotein therapy: is there hope?

OPINION STATEMENT

The treatment of lipid abnormalities generally has focused on low-density lipoprotein cholesterol (LDL-C) reduction based on extensive clinical trials and the National Cholesterol Education Program Adult Treatment Panel III guidelines. Unfortunately, it has become increasingly clear that a significant percentage of patients continue to have cardiovascular events despite being on LDL-C-lowering medications and having LDL-C levels below 100 mg/dL. Numerous epidemiologic studies have associated low high-density lipoprotein cholesterol (HDL-C) levels with increased risk of cardiovascular disease (CVD). Furthermore, recent data show that up to 55% of patients hospitalized for CVD have low HDL-C levels (<40 mg/dL) on admission, suggesting a possible target for further reducing CVD. Low HDL-C also is part of the atherogenic phenotype associated with obesity, glucose intolerance, and hypertension, termed the metabolic syndrome, and often is seen in patients with insulin resistance states. In general, the first line of therapy for increasing HDL-C in patients with levels below 40 mg/dL is lifestyle modification with smoking cessation, exercise, weight loss, and diet modifications. The pharmacologic treatment of isolated low HDL-C in patients without coronary disease is controversial but should be considered in those with a strong family history of CVD. In patients with coronary artery disease and isolated low HDL-C, statins remain the first-line therapy and should be instituted after lifestyle modifications, with the goal of increasing HDL-C above 40 mg/dL. If concomitant hypertriglyceridemia is present, a fibrate or niacin should be considered. Although statins do offer some HDL-C-raising properties, they tend to have modest effects. If treatment goals have not been achieved with either lifestyle changes or statin therapy, then the next agent of choice is niacin. Among the various HDL-C-raising therapies, niacin continues to be the most potent therapeutic option available. There are several novel HDL-C therapies in the research pipeline; however, only one class of medications is relatively close to clinical use, the cholesteryl ester transferase protein (CETP) inhibitors. Although one of the CETP inhibitors, torcetrapib, has received much negative attention from a large randomized trial showing increased mortality associated with its use, the overall class of therapeutic agents may still hold some benefit. Currently, two new CETP inhibitors without the off-target effects of torcetrapib are undergoing clinical research. Overall, the use of HDL-C-modifying agents likely will increase over the next decade.

Effects of Panicum miliaceum L. extract on adipogenic transcription factors and fatty acid accumulation in 3T3-L1 adipocytes

The dietary intake of whole grains is known to reduce the incidence of chronic diseases such as obesity, diabetes, cardiovascular disease, and cancer. To investigate whether there are anti-adipogenic activities in various Korean cereals, we assessed water extracts of nine cereals. The results showed that treatment of 3T3-L1 adipocytes with Sorghum bicolor L. Moench, Setaria italica Beauvois, or Panicum miliaceum L. extract significantly inhibited adipocyte differentiation, as determined by measuring oil red-O staining, triglyceride accumulation, and glycerol 3-phosphate dehydrogenase activity. Among the nine cereals, P. miliaceum L. showed the highest anti-adipogenic activity. The effects of P. miliaceum L. on mRNA expression of peroxisome proliferator-activated receptor-γ, sterol regulatory element-binding protein 1, and the CCAAT/enhancer binding protein-α were evaluated, revealing that the extract significantly decreased the expression of these genes in a dose-dependent manner. Moreover, P. miliaceum L. extract changed the ratio of monounsaturated fatty acids to saturated fatty acids in adipocytes, which is related to biological activity and cell characteristics. These results suggest that some cereals efficiently suppress adipogenesis in 3T3-L1 adipocytes. In particular, the effect of P. miliaceum L. on adipocyte differentiation is associated with the downregulation of adipogenic genes and fatty acid accumulation in adipocytes.

The effect of Mediterranean diet on metabolic syndrome and its components: a meta-analysis of 50 studies and 534,906 individuals

OBJECTIVES

The aim of this study was to meta-analyze epidemiological studies and clinical trials that have assessed the effect of a Mediterranean diet on metabolic syndrome (MS) as well as its components.

BACKGROUND

The Mediterranean diet has long been associated with low cardiovascular disease risk in adult population.

METHODS

The authors conducted a systematic review and random effects meta-analysis of epidemiological studies and randomized controlled trials, including English-language publications in PubMed, Embase, Web of Science, and the Cochrane Central Register of Controlled Trials until April 30, 2010; 50 original research studies (35 clinical trials, 2 prospective and 13 cross-sectional), with 534,906 participants, were included in the analysis.

RESULTS

The combined effect of prospective studies and clinical trials showed that adherence to the Mediterranean diet was associated with reduced risk of MS (log hazard ratio: -0.69, 95% confidence interval [CI]: -1.24 to -1.16). Additionally, results from clinical studies (mean difference, 95% CI) revealed the protective role of the Mediterranean diet on components of MS, like waist circumference (-0.42 cm, 95% CI: -0.82 to -0.02), high-density lipoprotein cholesterol (1.17 mg/dl, 95% CI: 0.38 to 1.96), triglycerides (-6.14 mg/dl, 95% CI: -10.35 to -1.93), systolic (-2.35 mm Hg, 95% CI: -3.51 to -1.18) and diastolic blood pressure (-1.58 mm Hg, 95% CI: -2.02 to -1.13), and glucose (-3.89 mg/dl, 95% CI:-5.84 to -1.95), whereas results from epidemiological studies also confirmed those of clinical trials.

CONCLUSIONS

These results are of considerable public health importance, because this dietary pattern can be easily adopted by all population groups and various cultures and cost-effectively serve for primary and secondary prevention of the MS and its individual components.

Dietary saturated fat, gender and genetic variation at the TCF7L2 locus predict the development of metabolic syndrome

Transcription factor 7-like 2 (TCF7L2) is the strongest genetic determinant of type 2 diabetes (T2DM) and insulin-related phenotypes to date. Dietary fat is a key environmental factor which may interact with genotype to affect risk of metabolic syndrome (MetS) and T2DM. This study investigated the relationship between the TCF7L2 rs7903146 polymorphism, insulin sensitivity/resistance and MetS in the LIPGENE-SU.VI.MAX study of MetS cases and matched controls (n=1754) and determined potential interactions with dietary fat intake. Female minor T allele carriers of rs7903146 had increased MetS risk (odds ratio [OR] 1.66, confidence interval [CI] 1.02-2.70, P=.04) and displayed elevated insulin concentrations (P=.005), impaired insulin sensitivity (P=.011), increased abdominal obesity (P=.008) and body mass index (P=.001) and higher blood pressure (P<.05) compared to the CC homozygotes. Metabolic syndrome risk was also modulated by dietary saturated fat (SFA) intake (P=.035 for interaction). High dietary SFA intake (≥15.5% energy) exacerbated MetS risk (OR 2.35, 95% CI 1.29-4.27, P=.005) and was associated with further impaired insulin sensitivity in the T allele carriers relative to the CC homozygotes (P=.025) and particularly to the T allele carriers with the lowest SFA intake (P=.008). No significant genotype effect on MetS risk or insulin sensitivity was evident among low-SFA consumers. In conclusion, the TCF7L2 rs7903146 polymorphism influences MetS risk, which is augmented by both gender and dietary SFA intake, suggesting novel gene-diet-gender interactions.

Self-reported energy intake by FFQ compared with actual energy intake to maintain body weight in 516 adults

It is generally assumed that a FFQ is not suitable to estimate the absolute levels of individual energy intake. However, in epidemiological studies, reported nutrients by FFQ are often corrected for this intake. The objective of the present study was to assess how accurately participants report their energy intakes by FFQ. We compared reported energy intake with actual energy intake needed to maintain stable body weights during eleven controlled dietary trials. FFQ were developed to capture at least 90 % of energy intake. Participants, 342 women and 174 men, with a mean BMI of 22·8 (sd 3·1) kg/m2 filled out the FFQ just before the trials. Energy intakes during the trials were calculated from provided foods and reported free-food items, representing 90 and 10 % of energy intake, respectively. Mean reported energy intake was 97·5 (sd 12·7) % of actual energy intake during the trials; it was 98·9 (sd 15·2) % for women and 94·7 (sd 16·3) % for men (P = 0·004 for difference between sexes). Correlation coefficients between reported and actual energy intakes were 0·82 for all participants, 0·74 for women and 0·80 for men. Individual reported energy intake as a percentage of actual intake ranged from 56·3 to 159·6 % in women and from 43·8 to 151·0 % in men. In conclusion, the FFQ appeared to be accurate for estimating the mean level of energy intakes of these participants and for ranking them according to their intake. However, the large differences found on the individual level may affect the results of epidemiological studies in an unknown direction if nutrients are corrected for energy intakes reported by FFQ.

Plasma protein profiling reveals protein clusters related to BMI and insulin levels in middle-aged overweight subjects

Background

Biomarkers that allow detection of the onset of disease are of high interest since early detection would allow intervening with lifestyle and nutritional changes before the disease is manifested and pharmacological therapy is required. Our study aimed to improve the phenotypic characterization of overweight but apparently healthy subjects and to identify new candidate profiles for early biomarkers of obesity-related diseases such as cardiovascular disease and type 2 diabetes.

Methodology/Principal Findings

In a population of 56 healthy, middle-aged overweight subjects Body Mass Index (BMI), fasting concentration of 124 plasma proteins and insulin were determined. The plasma proteins are implicated in chronic diseases, inflammation, endothelial function and metabolic signaling. Random Forest was applied to select proteins associated with BMI and plasma insulin. Subsequently, the selected proteins were analyzed by clustering methods to identify protein clusters associated with BMI and plasma insulin. Similar analyses were performed for a second population of 20 healthy, overweight older subjects to verify associations found in population I. In both populations similar clusters of proteins associated with BMI or insulin were identified. Leptin and a number of pro-inflammatory proteins, previously identified as possible biomarkers for obesity-related disease, e.g. Complement 3, C Reactive Protein, Serum Amyloid P, Vascular Endothelial Growth Factor clustered together and were positively associated with BMI and insulin. IL-3 and IL-13 clustered together with Apolipoprotein A1 and were inversely associated with BMI and might be potential new biomarkers.

Conclusion/ Significance

We identified clusters of plasma proteins associated with BMI and insulin in healthy populations. These clusters included previously reported biomarkers for obesity-related disease and potential new biomarkers such as IL-3 and IL-13. These plasma protein clusters could have potential applications for improved phenotypic characterization of volunteers in nutritional intervention studies or as biomarkers in the early detection of obesity-linked disease development and progression.

Dietary monounsaturated fatty acids appear not to provide cardioprotection

Dietary interventions have been consistently proposed as a part of a comprehensive strategy to lower the incidence and severity of coronary heart disease (CHD), in the process providing long-term cardioprotection. Replacement of dietary saturated fatty acids (SFA) with higher intakes of monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA) has been reported to be inversely associated with risk of CHD. The observed lower incidence of CHD among populations consuming a Mediterranean-type diet, mainly enriched in MUFA from olive oil, has long supported the belief that MUFA are an optimal substitution for SFA. However, both epidemiologic and interventional studies suggest that although substituting MUFA-rich foods for SFA-rich foods in the diet can potentially lower total plasma cholesterol concentrations, this substitution does not lower the extent of coronary artery atherosclerosis. In addition, although recent evidence suggests that the source of MUFA (animal fat vs vegetable oils) may differentially influence the correlation between MUFA intake and CHD mortality, animal studies suggest that neither source is cardioprotective.

Effect of changing the amount and type of fat and carbohydrate on insulin sensitivity and cardiovascular risk: the RISCK (Reading, Imperial, Surrey, Cambridge, and Kings) trial

BACKGROUND

Insulin sensitivity (Si) is improved by weight loss and exercise, but the effects of the replacement of saturated fatty acids (SFAs) with monounsaturated fatty acids (MUFAs) or carbohydrates of high glycemic index (HGI) or low glycemic index (LGI) are uncertain.

OBJECTIVE

We conducted a dietary intervention trial to study these effects in participants at risk of developing metabolic syndrome.

DESIGN

We conducted a 5-center, parallel design, randomized controlled trial [RISCK (Reading, Imperial, Surrey, Cambridge, and Kings)]. The primary and secondary outcomes were changes in Si (measured by using an intravenous glucose tolerance test) and cardiovascular risk factors. Measurements were made after 4 wk of a high-SFA and HGI (HS/HGI) diet and after a 24-wk intervention with HS/HGI (reference), high-MUFA and HGI (HM/HGI), HM and LGI (HM/LGI), low-fat and HGI (LF/HGI), and LF and LGI (LF/LGI) diets.

RESULTS

We analyzed data for 548 of 720 participants who were randomly assigned to treatment. The median Si was 2.7 × 10(-4) mL · μU(-1) · min(-1) (interquartile range: 2.0, 4.2 × 10(-4) mL · μU(-1) · min(-1)), and unadjusted mean percentage changes (95% CIs) after 24 wk treatment (P = 0.13) were as follows: for the HS/HGI group, -4% (-12.7%, 5.3%); for the HM/HGI group, 2.1% (-5.8%, 10.7%); for the HM/LGI group, -3.5% (-10.6%, 4.3%); for the LF/HGI group, -8.6% (-15.4%, -1.1%); and for the LF/LGI group, 9.9% (2.4%, 18.0%). Total cholesterol (TC), LDL cholesterol, and apolipoprotein B concentrations decreased with SFA reduction. Decreases in TC and LDL-cholesterol concentrations were greater with LGI. Fat reduction lowered HDL cholesterol and apolipoprotein A1 and B concentrations.

CONCLUSIONS

This study did not support the hypothesis that isoenergetic replacement of SFAs with MUFAs or carbohydrates has a favorable effect on Si. Lowering GI enhanced reductions in TC and LDL-cholesterol concentrations in subjects, with tentative evidence of improvements in Si in the LF-treatment group. This trial was registered at clinicaltrials.gov as ISRCTN29111298.

A saturated fatty acid-rich diet induces an obesity-linked proinflammatory gene expression profile in adipose tissue of subjects at risk of metabolic syndrome

BACKGROUND

Changes in dietary fat composition could lower the risk of developing metabolic syndrome. Adipose tissue is an interesting tissue in this respect because of its role in lipid metabolism and inflammation.

OBJECTIVE

Our objective was to investigate the effect of a saturated fatty acid (SFA)- and a monounsaturated fatty acid (MUFA)-rich diet on insulin sensitivity, serum lipids, and gene expression profiles of adipose tissue in subjects at risk of metabolic syndrome.

DESIGN

A parallel controlled-feeding trial was conducted in 20 abdominally overweight subjects. Subjects received an SFA diet or a MUFA diet for 8 wk. Plasma and subcutaneous adipose tissue samples were obtained, and insulin sensitivity was measured by using a hyperinsulinemic-euglycemic clamp. Adipose tissue samples underwent whole-genome microarray and histologic analysis. Plasma and adipose tissue fatty acid composition and concentrations of serum cholesterol and plasma cytokine were determined.

RESULTS

Consumption of the SFA diet resulted in increased expression of genes involved in inflammation processes in adipose tissue, without changes in morphology or insulin sensitivity. The MUFA diet led to a more antiinflammatory gene expression profile, which was accompanied by a decrease in serum LDL-cholesterol concentrations and an increase in plasma and adipose tissue oleic acid content.

CONCLUSIONS

Consumption of an SFA diet resulted in a proinflammatory "obesity-linked" gene expression profile, whereas consumption of a MUFA diet caused a more antiinflammatory profile. This suggests that replacement of dietary SFA with MUFA could prevent adipose tissue inflammation and may reduce the risk of inflammation-related diseases such as metabolic syndrome. This trial was registered at clinicaltrials.gov as NCT00405197.