The polyphenol fraction of extra-virgin olive oil may be partly responsible for its cardioprotective effects. The aim of this systematic review and meta-analysis was to evaluate the effect of high versus low polyphenol olive oil on cardiovascular disease (CVD) risk factors in clinical trials. In accordance with PRISMA guidelines, CINAHL, PubMed, Embase and Cochrane databases were systematically searched for relevant studies. Randomized controlled trials that investigated markers of CVD risk (e.g. outcomes related to cholesterol, inflammation, oxidative stress) were included. Risk of bias was assessed using the Jadad scale. A meta-analysis was conducted using clinical trial data with available CVD risk outcomes. Twenty-six studies were included. Compared to low polyphenol olive oil, high polyphenol olive oil significantly improved measures of malondialdehyde (MD: -0.07µmol/L [95%CI: -0.12, -0.02µmol/L]; I²: 88%; p = 0.004), oxidized LDL (SMD: -0.44 [95%CI: -0.78, -0.10µmol/L]; I²: 41%; P = 0.01), total cholesterol (MD 4.5mg/dL [95%CI: -6.54, -2.39mg/dL]; p<0.0001) and HDL cholesterol (MD 2.37mg/dL [95%CI: 0.41, 5.04mg/dL]; p = 0.02). Subgroup analyses and individual studies reported additional improvements in inflammatory markers and blood pressure. Most studies were rated as having low-to-moderate risk of bias. High polyphenol oils confer some CVD-risk reduction benefits; however, further studies with longer duration and in non-Mediterranean populations are required.

Background: Non‐alcoholic fatty liver disease (NAFLD) is predominantly managed by lifestyle intervention, in the absence of effective pharmacotherapies. Mediterranean diet (MedDiet) is the recommended diet, albeit with limited evidence.Aims: To compare an ad libitum MedDiet to low‐fat diet (LFD) in patients with NAFLD for reducing intrahepatic lipids (IHL) by proton magnetic resonance spectroscopy (¹H‐MRS). Secondary outcomes include insulin resistance by homeostatic model of assessment (HOMA‐IR), visceral fat by bioelectrical impedance analysis (BIA), liver stiffness measurement (LSM) and other metabolic outcomes.Methods: In this parallel multicentre RCT, subjects were randomised (1:1) to MedDiet or LFD for 12 weeks.Results: Forty‐two participants (25 females [60%], mean age 52.3 ± 12.6 years) were included, 23 randomised to LFD and 19 to MedDiet.; 39 completed the study. Following 12 weeks, there were no between‐group differences. IHL improved significantly within the LFD group (−17% [log scale]; p = .02) but not within the MedDiet group (−8%, p = .069). HOMA‐IR reduced in the LFD group (6.5 ± 5.6 to 5.5 ± 5.5, p < .01) but not in the MedDiet group (4.4 ± 3.2 to 3.9 ± 2.3, p = .07). No differences were found for LSM (MedDiet 7.8 ± 4.0 to 7.6 ± 5.2, p = .429; LFD 11.8 ± 14.3 to 10.8 ± 10.2 p = .99). Visceral fat reduced significantly in both groups; LFD (−76% [log scale], p = <.0005), MedDiet (−61%, p = <.0005).Conclusions: There were no between‐group differences for hepatic and metabolic outcomes when comparing MedDiet to LFD. LFD improved IHL and insulin resistance. Significant improvements in visceral fat were seen within both groups. This study highlights provision of dietary interventions in free‐living adults with NAFLD is challenging.

Globally, liver cancer is the sixth most common cause of cancer mortality, with hepatocellular carcinoma (HCC) being the most common type of primary liver cancer. Emerging evidence states that diet is recognised as a potential lifestyle-related risk factor for the development of HCC. The aim of this systematic review is to determine whether there is an association between diet and the development of HCC. Using the PRISMA guidelines, three databases (MEDLINE Complete, CINAHL and Embase) were systematically searched, and studies published until July 2020 were included. Thirty observational studies were selected. The protocol was registered with PROSPERO (CRD42019135240). Higher adherence to the Mediterranean dietary pattern, Alternative Healthy Eating Index-2010, the Urban Prudent Dietary Pattern, the Traditional Cantonese Dietary Pattern, intake of vegetables, wholegrains, fish, poultry, coffee, macronutrients such as monounsaturated fats and micronutrients such as vitamin E, vitamin B9, β-carotene, manganese and potassium were associated with a reduced risk of HCC. The results suggest a potential role of diet in the development of HCC. Further quantitative research needs to be undertaken within a range of populations to investigate diet and the relationship with HCC risk.

Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease worldwide. In the absence of effective pharmacotherapies, clinical guidelines focus primarily on weight loss to treat this condition. Established consensus, evidence-based, and clinical dietary recommendations for NAFLD are currently lacking. The aim of this paper is to provide evidence-based practical dietary recommendations for the prevention and management of NAFLD in adults. A literature review focusing on established principles for the development of clinical practice recommendations was employed using the following criteria: based on substantial evidence, ensures risk minimization, is flexible for an individual patient approach, and is open to further modification as evidence emerges. The Practice-based Evidence in Nutrition classification system was used to grade these principles. Five key dietary recommendations were developed: 1) follow traditional dietary patterns, such as the Mediterranean diet; 2) limit excess fructose consumption and avoid processed foods and beverages with added fructose; 3) PUFAs, especially long-chain omega-3 rich foods and MUFAs, should replace SFAs in the diet; 4) replace processed food, fast food, commercial bakery goods, and sweets with unprocessed foods high in fiber, including whole grains, vegetables, fruits, legumes, nuts, and seeds; and 5) avoid excess alcohol consumption. Improving diet quality may reduce the incidence and progression of NAFLD and associated risk factors. Many of the benefits are likely to result from the collective effect of dietary patterns. High-quality research—in particular, randomized clinical trials assessing dietary interventions that focus on liver-specific endpoints—are needed as a priority.

Non-alcoholic fatty liver disease, the most prevalent liver disease in developed countries, remains difficult to manage with no proven safe and effective pharmacotherapy available. While weight reduction is the most commonly practiced treatment strategy, this is difficult to both achieve and/or maintain in the majority. Furthermore evidence-based dietary recommendations to guide the nutritional management of these patients are lacking. Using a randomised controlled trial design, this study compares the effectiveness of the Mediterranean diet to a standard low fat diet in terms of differences in insulin sensitivity, hepatic steatosis and metabolic outcomes in participants with non-alcoholic fatty liver disease. Ninety four eligible patients who have non-alcoholic fatty liver disease and who are insulin resistant, will be randomised into either a Mediterranean or low fat diet group for a 3 month intervention period. Insulin sensitivity will be measured on peripheral blood using Homeostatic Model Assessment and liver fat content quantified using Magnetic Resonance Spectroscopy. Both arms will consist of three face to face and three telephone call follow up consultations delivered by an Accredited Practicing Dietitian. The intervention arm focuses on recommendations from the traditional Mediterranean diet which have been tailored for use in the Australian population The standard arm uses the Australian Guide to Healthy Eating and the Australian National Heart Foundation dietary guidelines. Study recruitment will take place at four major metropolitan hospitals in Melbourne, Australia. Data collection will occur at all face to face reviews including baseline, 6, and 12 weeks. A follow up assessment to measure sustainability will take place at 6 and 12 months. The primary end point is improved insulin sensitivity scores at the 12 week time point. This trial aims to demonstrate in a large cohort of participants with NALFD that a Mediterranean diet independent of weight loss can result in significant benefits in liver fat and insulin sensitivity and that these changes are sustained at 12 months. These metabolic changes would potentially lead to reductions in the risk of chronic liver disease, heart disease, type 2 diabetes and liver cancer. Australia and New Zealand Clinical Trials Register ACTRN: ACTRN12615001010583 .