Evaluating the substance use disorder treatment gap in the United States, 2016-2019: A population health observational study.

BACKGROUND AND OBJECTIVES: Only 10% of Americans with substance use disorders (SUDs) receive treatment with insufficient treatment access and screening practices proposed and potential contributing factors. METHODS: This retrospective cross-sectional study used National Survey on Drug Use and Health (NSDUH) data to assess individuals with SUDs receiving treatment between 2016 and 2019 (survey n = 12,111; weighted n = 12,394,214). Demographic, access, and screening characteristics were investigated as predictors of treatment receipt using time-series logistic regression analyses to test trends and assessed treatment receipt odds, controlling for demographic and treatment characteristics. RESULTS: For those with past-year SUDs, 13.0% reported receiving past-year SUD treatment (survey n = 1605; weighted n = 1,612,154). The SUD treatment receipt rate remained statistically stable from 2016 to 2019, with a nonsignificant treatment receipt trend declining from 14% to 12%. Treatment changes were notable among Native Americans (+53.80%), Pacific Islanders (+94.10%), multiracial (-59.96%), ages 65+ (-70.18%), and ages 12-17 (-50.70%). In the regression model, race, sex, age, insurance status, and receiving mental health treatment were associated with SUD treatment receipt. DISCUSSION AND CONCLUSIONS: The treatment gap remains substantial and stable. Annually, about 87% of Americans with SUDs are not receiving the treatment they need. Asian Americans were less likely and those attending general mental health services were more likely to receive treatment. SCIENTIFIC SIGNIFICANCE: We present an updated SUD treatment gap evaluation, and identify access and screening characteristics associated with SUD treatment receipt. Policymakers, clinicians, and researchers must continue improving access and identification of those in need of care.

Tobacco Cessation Curriculum in Medical Schools: a Scoping Review.

This scoping review aims to identify interventional training courses on tobacco cessation counseling skills of medical students, identify the most appropriate teaching method, and the ideal stage to provide such training. We retrieved articles published since 2000 from two electronic peer-reviewed databases (PubMed and Scopus) and hand-searched reference lists of selected articles. Articles published in English, with a clearly defined curriculum, reporting knowledge, attitude, cessation counseling skills of medical students post-training, and cessation-related outcomes of patients participating in student-led counseling sessions, were considered for inclusion. We used the York framework to guide this scoping review. First, data from studies meeting the inclusion criteria were charted using a standardized form. Subsequently, related studies were organized under three themes that emerged in the review process-lectured-based, web-based, and multi-modal curriculum. We concluded that a short but focused lecture-based curriculum combined with peer role-play or standardized/real patient interactions effectively develops the necessary knowledge and skills of undergraduate medical students to provide tobacco cessation counseling to patients. However, studies consistently report that the gains in knowledge and skills after cessation training is acute. Therefore, continued participation in cessation counseling and periodic review of cessation-related knowledge and skills post-training is warranted.

A Review of Parental Vaccine Hesitancy for Human Papillomavirus in Japan.

Globally, Japan has the lowest rate of vaccine confidence. The persistent parental vaccine hesitancy has been attributed to safety and efficacy concerns and is primarily driven by the negative experience with human papillomavirus (HPV) vaccines. This literature review aimed to identify factors associated with HPV vaccine uptake and potential strategies to reduce vaccine hesitancy among Japanese parents. Articles published in English or Japanese between January 1998 and October 2022 that examined Japanese parental factors for HPV vaccine uptake were identified from PubMed, Web of Science, and Ichushi-Web. In total, 17 articles met the inclusion criteria. Four key themes which affected HPV vaccine hesitancy and acceptance were identified: perceptions of risk and benefits, trust and recommendation, information and knowledge, and sociodemographic characteristics. While governmental and healthcare provider recommendations are important factors, efforts to improve parental confidence in the HPV vaccine are required. Future interventions to counteract HPV vaccine hesitancy should actively disseminate information on vaccine safety and effectiveness, along with information on the severity and susceptibility of HPV infection.

Trends of Dietary Intakes and Metabolic Diseases in Japanese Adults: Assessment of National Health Promotion Policy and National Health and Nutrition Survey 1995-2019.

Health Japan 21 is Japan's premier health promotion policy encompassing preventive community health measures for lifestyle-related diseases. In this repeated cross-sectional survey, we report 24-year trends of type 2 diabetes mellitus (T2DM), obesity, hypertension, and their association with dietary intakes to evaluate Health Japan 21's impact and identify gaps for future policy implementation. We analyzed data from 217,519 and 232,821 adults participating in the physical examination and dietary intake assessment, respectively, of the National Health and Nutrition Survey 1995-2019. Average HbA1c and BMI have significantly increased along with the prevalence of T2DM and overweight/obesity among males. Despite a significant decrease in daily salt intake, the decline in the combined prevalence of Grades 1-3 hypertension was non-significant. Seafood and meat intakes showed strong opposing trends during the study period, indicating a dietary shift in the Japanese population. Neither salt nor vegetable/fruit intake reached the target set by Health Japan 21. Metabolic disease trend differences between males and females highlight the need for a gender-specific health promotion policy. Future Health Japan 21 implementation must also consider locally emerging dietary trends.

Factors supporting substance use improvement for Black Americans: A population health observational study.

BACKGROUND: Black clients in substance use disorder (SUD) treatment are associated with the lowest successful completion and substance use reductions. More work is needed to identify specific factors that support successful recovery of Black clients. METHODS: Data from U.S. outpatient SUD treatment facilities receiving public funding from 2015 to 2019 were analyzed (N = 2239,197). Primary analyses consisted of Black clients (n = 277,726) reporting admission and discharge substance use frequency. Multiple logistic regression was used to predict substance use frequency improvement from Black client demographic, recovery capital, treatment characteristics, and state. Disparities were compared between Black and non-Black clients. RESULTS: The overall Black client improvement percentage was 46.95%. Mutual-help group attendance and Length of Stay demonstrated clinically meaningful effect sizes controlling for all other variables and state. Attending mutual-help groups 8-30 times per month (State aOR = 2.54, 95% CI = 2.43, 2.64) and outpatient treatment stays of 4 months or more (State aOR = 2.50, 95% CI = 2.44, 2.56) were factors supporting Black client improvement. Importantly, states are associated with disparate Black client risk differences and only South Dakota had greater Black improvement (RD = 6.35, 95% CI = 1.00, 11.71). CONCLUSIONS: Black client factors supporting substance use improvement include ancillary mutual-help group attendance and increased treatment retention. These factors may be more critical in states with larger Black improvement disparities. In general, treatment providers increasing access to mutual-help groups, and adjusting program inclusiveness and motivational factors for retention, would make strides in increasing improvement outcomes for Black clients.

HIV epidemic in fishing communities in Uganda: A scoping review.

BACKGROUND: Fishing communities in many Sub-Saharan African countries are a high-risk population group disproportionately affected by the HIV epidemic. In Uganda, literature on HIV in fishing communities has grown extensively since the first country's documented case of HIV in a fishing community in 1985. The current study describes the status of the HIV burden, prevention, and treatment in Ugandan fishing communities. METHOD: This scoping review was conducted based on the York Framework outlined by Arksey and O'Malley. We searched the PubMed, Embase, and Web of Science databases to identify relevant quantitative and qualitative studies on HIV incidence, HIV prevalence, HIV-related risk factors, HIV testing, antiretroviral therapy coverage and adherence, and interventions to improve treatment outcomes and reduce HIV risk factors. RESULTS & CONCLUSION: We identified 52 papers and 2 reports. Thirty-four were quantitative, 17 qualitative, and 3 had a mixed-methods design. Eleven studies reported on the prevalence of HIV and 8 on HIV incidence; 9 studies documented factors associated with HIV incidence or HIV positive status; 10 studies reported on HIV testing coverage and/or associated factors; 7 reported on antiretroviral therapy coverage/adherence/outcomes; and 1 study reported on the impact of combination HIV interventions in fishing communities. This scoping review revealed a significant lack of evidence in terms of what works in HIV prevention and for improving adherence to ART, in contrast to the relatively large amount of evidence from observational quantitative and qualitative studies on HIV prevalence, incidence and related risk factors in Ugandan fishing communities. Intervention studies are urgently needed to fill the current evidence gaps in HIV prevention and ART adherence.

Incorporating Medical Supply and Demand into the Index of Physician Maldistribution Improves the Sensitivity to Healthcare Outcomes.

BACKGROUND: Since the association between disparity in physician distribution and specific healthcare outcomes is poorly documented, we aimed to clarify the association between physician maldistribution and cerebrovascular disease (CeVD), a high-priority health outcome in Japan. METHODS: In this cross-sectional study, we conducted multivariable regression analysis with the Physician Uneven Distribution Index (PUDI), a recently developed and adopted policy index in Japan that uniquely incorporates the gap between medical supply and demand, as the independent variable and CeVD death rate as the dependent variable. Population density, mean annual income, and prevalence of hypertension were used as covariates. RESULTS: The coefficient of the PUDI for the CeVD death rate was -0.34 (95%CI: -0.49--0.19) before adjusting for covariates and was -0.19 (95%CI: -0.30--0.07) after adjusting. The adjusted R squared of the analysis for the PUDI was 0.71 in the final model. However, the same multivariable regression model showed that the number of physicians per 100,000 people (NPPP) was not associated with the CeVD death rates before or after adjusting for the covariates. CONCLUSION: Incorporating the gap between the medical supply and demand in physician maldistribution indices could improve the responsiveness of the index for assessing the disparity in healthcare outcomes.

Challenges and opportunities for greater tobacco control in Japan.

Japan is a high tobacco burden country with over 20 million smokers in 2017. Tobacco control measures in Japan has been criticised as largely inadequate and ineffective despite ratifying the World Health Organization's Framework Convention on Tobacco Control in 2004. Numerous factors such as pro-tobacco legislators, regulatory oversight of the primary Japanese tobacco company from the Ministry of Finance and industry interference on the policy-making process in Japan have prevented aggressive tobacco control efforts. Given the intricate challenges in Japan, it is important to develop feasible and effective smoking cessation strategies. In this paper, we have analysed the trends in tobacco prices, sale and smoking prevalence, major tobacco/smoking policies and some of the industry-related challenges that have prevented the development of effective tobacco control measures in Japan. We have emphasised the need for stronger implementation of the World Health Organization's Framework Convention on Tobacco Control and its MPOWER policy package and to separate the tobacco industry from the tobacco control policymaking process to promote cessation and abstinence from smoking and better sensitisation against exposure to second-hand smoke.

Medium-chain triglyceride diet stimulates less GIP secretion and suppresses body weight and fat mass gain compared with long-chain triglyceride diet.

Gastric inhibitory polypeptide (GIP) is an incretin secreted from enteroendocrine K cells and potentiates insulin secretion from pancreatic ß-cells. GIP also enhances long-chain triglyceride (LCT) diet-induced obesity and insulin resistance. Long-term intake of medium-chain triglyceride (MCT) diet is known to induce less body weight and fat mass gain than that of LCT diet. However, the effect of MCT diet feeding on GIP secretion and the effect of GIP on body weight and fat mass under MCT diet-feeding condition are unknown. In this study, we evaluated the effect of single MCT oil administration on GIP secretion and compared the effect of long-term MCT and LCT diet on body weight and fat mass gain in wild-type (WT) and GIP-knockout (GIP KO) mice. Single administration of LCT oil induced GIP secretion but that of MCT oil did not in WT mice. Long-term intake of LCT diet induced GIP hypersecretion and significant body weight and fat mass gain compared with that of control fat (CF) diet in WT mice. In contrast, MCT diet did not induce GIP hypersecretion, and MCT diet-fed mice showed smaller increase in body weight and fat mass gain compared with CF diet-fed mice. In GIP KO mice, body weight and fat mass were markedly attenuated in LCT diet-fed mice but not in MCT diet-fed mice. Our results suggest that long-term intake of MCT diet stimulates less GIP secretion and suppresses body weight and fat mass gain compared with that of LCT diet.

Participation of nurses and care workers in the decision-making process for people with dementia in Japan: Discussion paper.

Numerous socio-legal factors make the process of surrogate decision-making for people living in dementia very complicated in Japan. In this discussion paper, we argue that the lack of early consultation between patients, surrogate decision-makers and healthcare providers and the overreliance of patients and their families on doctors to assume the decision-making role lead to healthcare practices that may not align with the patient's wishes. Further, we argue that lack of laws on surrogate decision-making, changing family structure and the liabilities associated with the care of people living with dementia contribute to the complexity of the decision-making process in Japan. Finally, given the rapidly changing social and healthcare norms in Japan, we call for greater involvement of nurses and care workers in the decision-making process to ensure patient-centric treatment and care are adopted.

Alteration in the liver metabolome of rats with metabolic syndrome after treatment with Hydroxytyrosol. A Mass Spectrometry And Nuclear Magnetic Resonance - based metabolomics study.

Metabolic syndrome (MetS) represents a group of abnormalities that enhances the risk for cardiovascular disease, diabetes and stroke. The Mediterranean diet seems to be an important dietary pattern, which reduces the incidence of MetS. Hydroxytyrosol (HT) - a simple phenol found in olive oil - has received increased attention for its antioxidant activity. Recently, the European Foods Safety Authority (EFSA) claimed that dietary consumption of HT exhibits a protective role against cardiovascular disease. In this study, an experimental protocol has been setup, including isolated HT administration in a diet induced model of MetS in young Wistar rats, in order to find out whether HT has a protective effect against MetS. Rats were randomly divided into two groups nurtured by high-carbohydrate high-fat (H) (MetS inducing diet) and high-carbohydrate high-fat + HT (HHT). HT (20mg/kg/d oral gavage, water vehicle) was administered for 8 weeks on the basal diet. Previous pharmacological evaluation of HT showed that hepatic steatosis was reduced and the inflammatory cells into the liver were infiltrated. These indicate that HT shows bioactivity against metabolic syndrome. Therefore, the metabolomics evaluation of liver extracts would indicate the putative biochemical mechanisms of HT activity. Thus, the extracts of liver tissues were analyzed using Ultra Performance Liquid Chromatography - High Resolution Mass Spectrometry (UPLC-HRMS, Orbitrap Discovery) and Nuclear Magnetic Resonance (NMR) spectroscopy (Bruker Avance III 600MHz). Multivariate analysis was performed in order to gain insight on the metabolic effects of HT administration on the liver metabolome. Normalization employing multiple internal standards and Quality Control-based Robust LOESS (LOcally Estimated Scatterplot Smoothing) Signal Correction algorithm (QC-RLSC) was added in the processing pipeline to enhance the reliability of metabolomic analysis by reducing unwanted information. Experimentally, HHT rats were clearly distinguished from H in PLS-DA, showing differences in the liver metabolome between the groups and specific biomarkers were determined supporting the pharmacological findings. More specifically, HT has shown to be effective towards the mobilization of lipids as various lipid classes being differentially regulated between the H and HHT groups. Interestingly branched fatty acid esters of hydroxy oleic acids (OAHSA) lipids have been shown to be up regulated to the HHT group, denoting the alleviation of the MetS to the animals administered with HT.

The LC-MS-based metabolomics of hydroxytyrosol administration in rats reveals amelioration of the metabolic syndrome.

Hydroxytyrosol (HT), an important component of olive fruit and olive oil, improves the signs of metabolic syndrome in rats following chronic treatment. At a dose of 20mg/kg/day, HT decreased adiposity and improved cardiovascular and liver structure and function in rats fed with a high-carbohydrate, high-fat diet. An untargeted metabolomics approach has been employed using both UPLC-Orbitrap and -QqTOF methods to identify the changes induced by chronic HT administration on the plasma metabolome. 31 metabolites have been found to be differentially expressed between the examined groups. HT was shown to decrease biosynthesis of unsaturated fatty acids, fatty acid biosynthesis, and the metabolism of linoleic acid, retinol, sphingolipids and arachidonic acid, whereas glycerolipid metabolism is up-regulated. These are plausible mechanisms for the attenuation by HT of cardiovascular, liver and metabolic changes in high-carbohydrate, high-fat diet fed rats.

Hydroxytyrosol ameliorates metabolic, cardiovascular and liver changes in a rat model of diet-induced metabolic syndrome: Pharmacological and metabolism-based investigation.

Metabolic syndrome is a clustering of interrelated risk factors for cardiovascular disease and diabetes. The Mediterranean diet has been proposed as an important dietary pattern to confer cardioprotection by attenuating risk factors of metabolic syndrome. Hydroxytyrosol (HT) is present in olive fruit and oil, which are basic constituents of the Mediterranean diet. In this study, we have shown that treatment with HT (20mg/kg/d for 8 weeks) decreased adiposity, improved impaired glucose and insulin tolerance, improved endothelial function with lower systolic blood pressure, decreased left ventricular fibrosis and resultant diastolic stiffness and reduced markers of liver damage in a diet-induced rat model of metabolic syndrome. These results were accompanied by reduced infiltration of monocytes/macrophages into the heart with reduced biomarkers of oxidative stress. Furthermore, in an HRMS-based metabolism study of HT, we have identified 24 HT phase I and II metabolites, six of them being over-produced in high-starch, low-fat diet fed rats treated with HT compared to obese rats on high-carbohydrate, high-fat diet. These results provide direct evidence for cardioprotective effects of hydroxytyrosol by attenuation of metabolic risk factors. The implications of altered metabolism of HT in high-carbohydrate, high-fat diet fed obese rats warrant further investigation.

Green and Black Cardamom in a Diet-Induced Rat Model of Metabolic Syndrome.

Both black (B) and green (G) cardamom are used as flavours during food preparation. This study investigated the responses to B and G in a diet-induced rat model of human metabolic syndrome. Male Wistar rats were fed either a corn starch-rich diet (C) or a high-carbohydrate, high-fat diet with increased simple sugars along with saturated and trans fats (H) for 16 weeks. H rats showed signs of metabolic syndrome leading to visceral obesity with hypertension, glucose intolerance, cardiovascular remodelling and nonalcoholic fatty liver disease. Food was supplemented with 3% dried B or G for the final eight weeks only. The major volatile components were the closely related terpenes, 1,8-cineole in B and α-terpinyl acetate in G. HB (high-carbohydrate, high-fat + black cardamom) rats showed marked reversal of diet-induced changes, with decreased visceral adiposity, total body fat mass, systolic blood pressure and plasma triglycerides, and structure and function of the heart and liver. In contrast, HG (high-carbohydrate, high-fat + green cardamom) rats increased visceral adiposity and total body fat mass, and increased heart and liver damage, without consistent improvement in the signs of metabolic syndrome. These results suggest that black cardamom is more effective in reversing the signs of metabolic syndrome than green cardamom.

Should the pharmacological actions of dietary fatty acids in cardiometabolic disorders be classified based on biological or chemical function?

Westernised dietary patterns are characterised by an increased intake of saturated (SFA) and trans fat (TFA) and a high n-6:n-3 polyunsaturated fatty acid (PUFA) ratio. These changes together with increased sugar intake have been implicated in the progression and development of metabolic syndrome. It is now recognised that the type of dietary fat plays a far more significant role in well-being than the absolute amount. This has led to the generalisations that TFA and SFA are detrimental, MUFA is neutral and PUFA is cardioprotective. However, different dietary fatty acids even within the same chemical class elicit different physiological responses. Thus, generalising fatty acids by the degree of unsaturation or the configuration of double bonds alone is unlikely to predict biological responses. In this review, we have examined the effects of different dietary fatty acids on the cardiometabolic risk factors and propose a revised classification based on current evidence of biological activity, rather than chemical structure. Specifically, we propose that dietary fatty acids be classified into five classes as neutral, reduce one or more cardiometabolic risk factors, increase one or more cardiometabolic risk factor, controversial evidence to allow classification and inadequate research to allow classification as a basis for further discussions.

Modulation of tissue fatty acids by L-carnitine attenuates metabolic syndrome in diet-induced obese rats.

Obesity and dyslipidaemia are metabolic defects resulting from impaired lipid metabolism. These impairments are associated with the development of cardiovascular disease and non-alcoholic fatty liver disease. Correcting the defects in lipid metabolism may attenuate obesity and dyslipidaemia, and reduce cardiovascular risk and liver damage. L-Carnitine supplementation was used in this study to enhance fatty acid oxidation so as to ameliorate diet-induced disturbances in lipid metabolism. Male Wistar rats (8-9 weeks old) were fed with either corn starch or high-carbohydrate, high-fat diets for 16 weeks. Separate groups were supplemented with L-carnitine (1.2% in food) on either diet for the last 8 weeks of the protocol. High-carbohydrate, high-fat diet-fed rats showed central obesity, dyslipidaemia, hypertension, impaired glucose tolerance, hyperinsulinaemia, cardiovascular remodelling and non-alcoholic fatty liver disease. L-Carnitine supplementation attenuated these high-carbohydrate, high-fat diet-induced changes, together with modifications in lipid metabolism including the inhibition of stearoyl-CoA desaturase-1 activity, reduced storage of short-chain monounsaturated fatty acids in the tissues with decreased linoleic acid content and trans fatty acids stored in retroperitoneal fat. Thus, L-carnitine supplementation attenuated the signs of metabolic syndrome through inhibition of stearoyl-CoA desaturase-1 activity, preferential ß-oxidation of some fatty acids and increased storage of saturated fatty acids and relatively inert oleic acid in the tissues.

Mechanisms of enhanced insulin secretion and sensitivity with n-3 unsaturated fatty acids.

The widespread acceptance that increased dietary n-3 polyunsaturated fatty acids (PUFAs), especially α-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), improve health is based on extensive studies in animals, isolated cells and humans. Visceral adiposity is part of the metabolic syndrome, together with insulin resistance, dyslipidemia, hypertension and inflammation. Alleviation of metabolic syndrome requires normalization of insulin release and responses. This review assesses our current knowledge of the mechanisms that allow n-3 PUFAs to improve insulin secretion and sensitivity. EPA has been more extensively studied than either ALA or DHA. The complex actions of EPA include increased G-protein-receptor-mediated release of glucagon-like peptide 1 (GLP-1) from enteroendocrine L-cells in the intestine, up-regulation of the apelin pathway and down-regulation of other control pathways to promote insulin secretion by the pancreatic ß-cells, together with suppression of inflammatory responses to adipokines, inhibition of peroxisome proliferator-activated receptor α actions and prevention of decreased insulin-like growth factor-1 secretion to improve peripheral insulin responses. The receptors involved and the mechanisms of action probably differ for ALA and DHA, with antiobesity effects predominating for ALA and anti-inflammatory effects for DHA. Modifying both GLP-1 release and the actions of adipokines by n-3 PUFAs could lead to additive improvements in both insulin secretion and sensitivity.

Osteoporosis and its association with non-gonadal hormones involved in hypertension, adiposity and hyperglycaemia.

Osteoporosis is a high-prevalence disease, particularly in developed countries, and results in high costs both to the individual and to society through associated fragility fractures. There is an urgent need for identification of novel drug targets and development of new anti-osteoporotic agents. Between 30 and 80% of osteoporotic fractures cannot be prevented despite current treatments achieving relative fracture risk reduction of up to 20%, 50%, and 70% for non-vertebral, hip and spine fractures, respectively. Traditionally, the decline in gonadal hormones has been studied as the sole hormonal determinant for the loss of bone mineral density in osteoporosis. However, recent studies have identified receptors for numerous non-gonadal hormones such as PTH, angiotensin II, leptin, adiponectin, insulin and insulin-like growth factor-1 on the osteoblast lineage cells that directly regulate bone turnover. These hormones are also involved in the pathogenesis of metabolic syndrome risk factors, particularly hypertension, type-II diabetes and obesity. By activating their respective receptors on osteoblastic lineage cells, these hormones appear to act through a common mechanism by down-regulating receptors for activation of nuclear factor kappa B ligand (RANKL) and up-regulating osteoprotegerin (OPG) with inverse responses for adiponectin. Receptors for amylin, gastric inhibitory polypeptide and ghrelin and have also been identified on the osteoblast lineage cells although the roles of these receptors in bone turnover are controversial or poorly studied. Moreover, bone turnover may be independently regulated by modulation of osteoclast-osteoblast function and bone marrow adiposity. Leptin appears to be the only hormone that is a known regulator of both bone mineralisation and bone adiposity.

The role of n-3 polyunsaturated fatty acids in human heart failure.

n-3 polyunsaturated fatty acids (PUFA) have been proposed as potential treatments for human heart failure. The cardioprotective effects of n-3 PUFA are supported by extensive cell culture, animal and human studies. Animal studies with n-3 PUFA have shown marked improvements in many independent risk factors for heart failure, including obesity, type II diabetes, insulin resistance, hypertension and inflammation. However, the evidence from observational studies, randomised controlled trials and meta-analyses that these benefits on risk factors lead to improvements in the symptoms of heart failure in patients is much less convincing. Further, most studies have used marine n-3 PUFA; the role of the plant-derived PUFA, α-linolenic acid (ALA), is even less clear. This discontinuity of scientific evidence from animal to human studies suggests that future studies should focus on defining the optimal dosage range and the efficacy of n-3 PUFA compared to standard treatments using standardised study designs. Further studies on ALA would seem justified.

Responses to oleic, linoleic and α-linolenic acids in high-carbohydrate, high-fat diet-induced metabolic syndrome in rats.

We investigated the changes in adiposity, cardiovascular and liver structure and function, and tissue fatty acid compositions in response to oleic acid-rich macadamia oil, linoleic acid-rich safflower oil and α-linolenic acid-rich flaxseed oil (C18 unsaturated fatty acids) in rats fed either a diet high in simple sugars and mainly saturated fats or a diet high in polysaccharides (cornstarch) and low in fat. The fatty acids induced lipid redistribution away from the abdomen, more pronounced with increasing unsaturation; only oleic acid increased whole-body adiposity. Oleic acid decreased plasma total cholesterol without changing triglycerides and nonesterified fatty acids, whereas linoleic and α-linolenic acids decreased plasma triglycerides and nonesterified fatty acids but not cholesterol. α-Linolenic acid improved left ventricular structure and function, diastolic stiffness and systolic blood pressure. Neither oleic nor linoleic acid changed the left ventricular remodeling induced by high-carbohydrate, high-fat diet, but both induced dilation of the left ventricle and functional deterioration in low fat-diet-fed rats. α-Linolenic acid improved glucose tolerance, while oleic and linoleic acids increased basal plasma glucose concentrations. Oleic and α-linolenic acids, but not linoleic acid, normalized systolic blood pressure. Only oleic acid reduced plasma markers of liver damage. The C18 unsaturated fatty acids reduced trans fatty acids in the heart, liver and skeletal muscle with lowered stearoyl-CoA desaturase-1 activity index; linoleic and α-linolenic acids increased accumulation of their C22 elongated products. These results demonstrate different physiological and biochemical responses to primary C18 unsaturated fatty acids in a rat model of human metabolic syndrome.