Blueberries improve biomarkers of cardiometabolic function in participants with metabolic syndrome-results from a 6-month, double-blind, randomized controlled trial
Curtis PJ, van der Velpen V, Berends L, Jennings A, Feelisch M, Umpleby AM, Evans M, Fernandez BO, Meiss MS, Minnion M, Potter J, Minihane AM, Kay CD, Rimm EB, Cassidy A
The American journal of clinical nutrition · 179 citations
Review labels
Neutral facts our review recorded about how this study was done. They describe method, never whether we like the result.
How it was studied
- Design
- Randomized controlled trial (indexed by PubMed)
- Studied in
- People
- Main outcome
- Health markers and function
- Intake measured by
- Food provided by researchers
Who paid for it
- Funding
- Independent funding
- Government
- U.S. Department of Agriculture
- University or hospital
- University of Cambridge
- University or hospital
- University of East Anglia
- University or hospital
- University of Surrey
- Government
- Directorate for Biological Sciences
- Government
- Biotechnology and Biological Sciences Research Council
Based on 6 listed funder(s) and full-text disclosure statement.
Publication
- Published
- 2018-12-12 · Am J Clin Nutr · vol. 109 · issue 6 · pp. 1535–1545
- Publisher
- Elsevier BV
- Cited
- 251 citations · more than 99% of similar papers · 8.6× the field average
- Impact
- Top 10% most cited in its field
- References
- 60 works
- Access
- Open access (hybrid journal) · CC-BY
- Research areas
- Phytochemicals and Antioxidant Activities · Pharmacology and Obesity Treatment · Sirtuins and Resveratrol in Medicine
- Keywords
- Insulin resistance, Medicine, Internal medicine, Metabolic syndrome, Type 2 diabetes, Endocrinology, Insulin, Body mass index, Lipoprotein, Lipoprotein particle, Homeostatic model assessment, Diabetes mellitus, Cholesterol, Very low-density lipoprotein
- MeSH
- heart, humans, fruit, insulin resistance, apolipoproteins, prospective studies, double-blind method, blood pressure, aged, middle aged, female, male, cholesterol, ldl, cholesterol, hdl, pulse wave analysis, biomarkers, blueberry plants, metabolic syndrome
15 authors
From GB, US
- Peter J. CurtisUniversity of East Anglia
- Vera van der VelpenUniversity of East Anglia
- Lindsey M. BerendsUniversity of East Anglia
- Amy JenningsUniversity of East Anglia
- Martin FeelischUniversity Hospital Southampton NHS Foundation Trust; University of Southampton
- Anne Margot UmplebyUniversity of Surrey
Abstract
Background
Anthocyanin-rich blueberry intake is associated with reduced type 2 diabetes and cardiovascular disease (CVD) risk in prospective studies, although long-term randomized controlled trials (RCTs) have not been conducted in at-risk populations.
Objective
In the longest-duration RCT to date, we examined the effect of 6-mo blueberry intake on insulin resistance and cardiometabolic function in metabolic syndrome.
Methods
A double-blind, parallel RCT (n = 115; age 63 ± 7 y; 68% male; body mass index 31.2 ± 3.0 kg/m2) was conducted, which fed 2 dietarily achievable blueberry intakes [equivalent to 1/2 and 1 cup/d (75/150 g)] compared with matched placebo. Insulin resistance was assessed via the homeostasis model assessment of insulin resistance (primary endpoint) and confirmed by [6-6-2H2]-glucose-labeled, 2-step hyperinsulinemic clamp (n = 20). Clinically relevant cardiometabolic endpoints [including flow-mediated dilatation, augmentation index, lipoprotein status (by nuclear magnetic resonance spectroscopy), and nitric oxide (NO)-related metabolite assay] and anthocyanin metabolism were assessed.
Results
A daily intake of 1 cup of blueberries improved endothelial function (flow-mediated dilatation: +1.45%; 95% CI: 0.83%, 2.1%; P = 0.003), systemic arterial stiffness (augmentation index: -2.24%; 95% CI: -3.97%, -0.61%; P = 0.04) and attenuated cyclic guanosine monophosphate concentrations. In statin nonusers (n = 71), elevated high-density lipoprotein cholesterol (+0.08 mmol/L; P = 0.03), high-density lipoprotein particle density (+0.48n, ×10-6; P = 0.002) and apolipoprotein A-I (+0.05 g/L; P = 0.01) concentrations were observed following the 1-cup/d intervention. Treatment compliance was 94.1% (wrapper returns) and total concentrations of anthocyanin-derived phenolic acid metabolites significantly increased, dose-dependently, in serum and 24-h urine (P < 0.01 and P < 0.001, respectively). Insulin resistance, pulse wave velocity, blood pressure, NO, and overall plasma thiol status were unaffected. Likewise, a half cup per day had no effect on any biomarkers.
Conclusions
Despite insulin resistance remaining unchanged we show, to our knowledge, the first sustained improvements in vascular function, lipid status, and underlying NO bioactivity following 1 cup blueberries/d. With effect sizes predictive of 12-15% reductions in CVD risk, blueberries should be included in dietary strategies to reduce individual and population CVD risk. This study was registered at clinicaltrials.gov as NCT02035592.
Abstract via Europe PMC. Copyright remains with the authors or publisher (CC BY).
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