Background and Aim: The Dietary Approaches to Stop Hypertension (DASH) diet is a non-pharmacological intervention recommended for the prevention and treatment of hypertension, a primary risk factor for cardiovascular disease (CVD). Evidence on its effect on hard outcomes is mixed. We conducted an updated systematic review and meta-analysis to quantify the association between DASH diet adherence and all-cause, CVD, stroke, cancer, and colorectal cancer-specific mortality, and to determine whether these associations differ between healthy, subclinical-risk, and diseased populations.

Methods: We conducted a search of MEDLINE (Ovid), Embase, and Web of Science for studies published until 7 May 2026. The risk of bias was assessed using the Newcastle–Ottawa Scale. Highest versus lowest adherence comparisons were pooled using random-effects meta-analysis. Studies were classified as healthy, subclinical, or diseased populations based on baseline health status. Heterogeneity was quantified using I² and publication bias was assessed using Egger's regression test. This review was registered with PROSPERO (CRD420261338738).

Results: A total of 4,814 non-duplicate title and abstract records were screened. From these, 144 full texts were screened for eligibility, and seventy studies were retained for the meta-analysis. All studies were moderate or high quality, and the median follow-up was 11 years. Fifty-eight studies showed that highest DASH adherence was associated with lower all-cause mortality compared with lowest adherence (HR 0.83, 95% CI 0.81–0.86; I²=62%). Findings were consistent for CVD mortality (38 studies; HR 0.79, 95% CI 0.76–0.83; I²=56%) and cancer mortality (21 studies; HR 0.86, 95% CI 0.83–0.89; I²=38%). Directionally consistent but non-significant associations were observed for stroke (4 studies; HR 0.79, 95% CI 0.62–1.02) and colorectal cancer-specific mortality (5 studies; HR 0.86, 95% CI 0.73–1.01). Subgroup analysis showed no significant difference in the DASH–mortality association across healthy, subclinical, and disease populations for any outcome. There was no evidence of publication bias.

Conclusions: Higher DASH diet adherence was associated with significantly lower all-cause (17%), CVD (21%), and cancer (14%) mortality, and this benefit appears consistent regardless of baseline health status. Trends toward lower stroke and colorectal cancer-specific mortality warrant confirmation in future studies.

Background and Aim: Dietary fibre is one of the most consistently cardio-protective components of the diet, with higher levels associated with lower blood pressure. Yet Australian dietary fibre intake has remained below national recommendations and it is unknown whether this gap has narrowed over the past decade. This study aimed to profile fibre intake and adequacy in the Australian population in 2023 and to compare findings with those from 2011–12.

Methods: The 2023 National Nutrition and Physical Activity Survey is a nationally representative survey conducted by the Australian Bureau of Statistics(ABS). We analysed individual-level dietary data from 11,199 participants, including 8,746 adults aged ≥19 years and 2,453 children aged 2–18 years. Fibre was estimated from the 24-hour dietary recall. Median fibre intake and interquartile ranges were calculated by sex, age group and household socio-economic status. The proportion meeting the age- and sex-specific Adequate Intake (AI) and Suggested Dietary Target (SDT) was calculated using the NHMRC’s Reference Values. Estimates were weighted to the national population, with sampling variance estimated via the ABS Jackknife replicate-weight method.

Results: In 2023, median fibre intake was 18.4 (IQR: 13.1–24.6 g/day) in children and 18.7 (13.0–26.2 g/day) in adults. The AI was met by 40.2% of children (37.4–42.9%) and 21.7% of adults (20.5–22.8%). No SDT is defined for children and only 13.0% of adults (12.0–14.1%) met the SDT. Median intake was higher in men than women (20.1 vs 17.4 g/day), but SDT attainment was lower in men (9.8% vs 16.1%). AI attainment also varied by socio-economic status, rising from 18.5% in the lowest to 24.1% in the highest socio-economic quintile among adults. Compared with 2011–12, adult median fibre intake declined from 20.7 to 18.7 g/day, while AI attainment fell from 28.2% to 21.7% and SDT attainment from 17.0% to 13.0%. Declines were observed across all adult age groups and both sexes.

Conclusions: Dietary fibre intake among Australians has declined over the past decade and remains markedly below the recommended levels. Given robust evidence that higher fibre intake lowers blood pressure, our findings point to a growing opportunity to strengthen fibre-focused dietary strategies in hypertension prevention efforts.

In a randomised clinical trial (RCT), supplementation with short-chain fatty acids (SCFA), produced via fermentation of dietary fibre, lowered 24-hour systolic blood pressure (BP) by 6.1 mmHg (1). However, the mechanisms remain unclear.

Aim: To identify mechanisms by which SCFAs lower BP in humans.
Methods: Metabolomics and proteomics were performed using high-resolution mass spectrometry (LC-MS) on 80 EDTA plasma samples collected from 20 trial participants across four time points from a cross-over double-blind placebo-controlled RCT, in which participants received SCFAs delivered as acetylated and butyrylated high-amylose maize starch (HAMSAB) (1). A total of 213 metabolites and 3351 proteins were identified across the whole dataset. Statistical analyses of downstream data were conducted using the limma package (ver 3.66.0) in RStudio (2026.07.1, R version 4.5.3). HAMSAB effects were determined using the placebo-subtraction method, and statistical significance was determined using false discovery rate (FDR) adjusted q-value<0.05.

Results: Six metabolites, including 5-hydroxyindoleacetic acid (fold change, FC=0.399, q=0.00083), kynurenic acid (FC=0.686, q=0.041) - products of tryptophan metabolism - and p-cresol glucuronide (FC=0.469, q=0.00075) - a microbiome-based metabolite released under low fibre intake that increases blood pressure, were downregulated with HAMSAB supplementation. Deoxycholic acid, a secondary bile acid and a known aggravator of hypertension, was also downregulated (FC=0.548, q=0.022). Serine, a metabolite with BP-lowering effect, was upregulated (FC=2.59, q=0.011). Of these seven significantly expressed metabolites, six were gut-microbial-derived and known to exacerbate hypertension (3-10). Four proteins were upregulated with HAMSAB supplementation, including OPA1 (FC=2.018 q=0.0022) and COX6C (FC=2.297, q=0.025) - both involved in improving mitochondrial function and reducing oxidative stress.

Conclusions: SCFA supplementation improved metabolomic and proteomic profiles in participants with hypertension, suggesting mechanisms involving neurotransmitters and other gut microbiome-derived metabolites associated with hypertension, as well as mitochondrial-driven oxidative stress.

1. Jama et al., Nat Card Res. 2023;2(1):35-43.

Introduction: Dietary fibre provides a novel mechanism for regulating blood pressure (BP), as its fermentation in the large intestine generates short chain fatty acids (SCFAs), beneficial metabolites that lower BP in animals and humans. Receptors for SCFAs, G protein-coupled receptors (GPCRs), are found on enteroendocrine cells (EECs), which make up less than 1% of the colonic epithelium in mice. EECs produce the majority of the body’s serotonin (5-HT) and are triggered to release 5-HT upon SCFAs binding to GPCRs. Considering 5-HT reduces BP in vivo, this may provide a novel mechanism of BP regulation involving gut–brain communication.

Aims: To determine whether dietary fibre increases the number of 5-HT-producing EECs in hypertensive mice.

Methods: Immunofluorescence was performed on colonic tissue from male C57BJ/6J sham and hypertensive mice (Ang II, 0.5 mg/kg BW/day for 4 weeks) (total n=31). Primary antibodies against EEC marker chromogranin A and 5‑HT were used. The slides were imaged using a Nikon confocal microscope and analysed via QuPath software. All cells were quantified in each tissue section using trained QuPath object classifiers, and statistical analyses (one-way ANOVA) were performed in Prism. Complementary analysis of qPCR (total n=23) and ELISA (total n=37) was performed on proximal colon tissue and analysed using two‑way ANOVA in Prism.

Results: Hypertensive mice showed a slight reduction in the proportion of EECs relative to total epithelial cells across gut regions (-0.0012083-fold difference). qPCR revealed significantly higher levels of serotonin transporter (Sert) mRNA in hypertensive relative to sham mice (1.29-fold, p=0.0091). ELISA of proximal colon tissue demonstrated significantly lower 5‑HT levels in Ang‑II mice compared with sham mice fed a control diet (1.73-fold difference, p=0.0046).

Conclusions: Hypertension may alter serotonergic signalling, with reduced intestinal 5-HT availability due to enhanced re‑uptake rather than altered EEC abundance.