Lesley Hamill

Dose-response effect of fruit and vegetables on insulin resistance in people at high risk of cardiovascular disease: a randomized controlled trial.

OBJECTIVE The purpose of this randomized controlled trial was to investigate the dose-response effect of fruit and vegetable (F&V) intake on insulin resistance (IR) in people who are overweight and at high risk of cardiovascular disease (CVD). RESEARCH DESIGN AND METHODS A total of 105 participants (mean age 56 years) followed a 4-week washout diet (one to two portions of F&Vs per day). Ninety-two participants completed the washout and were randomized to receive one to two, four, or seven portions of F&Vs per day for 12 weeks. IR was assessed at the start and end of this 12-week period by the two-step euglycemic-hyperinsulinemic clamp. Compliance was monitored using a combination of 4-day food diaries and plasma biomarkers of F&V intake. RESULTS A total of 89 participants completed the study. Participants attained self-reported F&V intakes of 1.8, 3.8, and 7.0 portions per day (P < 0.001) per group. There was a significant linear increase in serum lutein status across the groups, indicating good compliance (P < 0.001), and body weight was maintained (P = 0.77). No significant difference was found between groups in terms of a change in measures of whole-body, peripheral, or hepatic IR or adiponectin multimers. CONCLUSIONS Increased consumption of F&Vs, as advocated in public-health advice, has no effect on IR in overweight individuals who are at high risk of CVD when body weight is maintained. Recent evidence from systematic reviews indicates that particular classes or types of F&Vs may have particular antidiabetic properties; hence, it is possible that benefits may only be observed in response to a more specific fruit or vegetable intervention.

Increasing Fruit and Vegetable Intake Has No Dose-Response Effect on Conventional Cardiovascular Risk Factors in Overweight Adults at High Risk of Developing Cardiovascular Disease

BACKGROUND Improving diet and lifestyle is important for prevention of cardiovascular disease (CVD). Observational evidence suggests that increasing fruit and vegetable (FV) consumption may lower CVD risk, largely through modulation of established risk factors, but intervention data are required to fully elucidate the mechanisms by which FVs exert benefits on vascular health. OBJECTIVE The aim of this study was to examine the dose-response effect of FV intake on cardiovascular risk factors in adults at high CVD risk. METHODS This was a randomized controlled parallel group study involving overweight adults (BMI: >27 and ≤35 kg/m(2)) with a habitually low FV intake (≤160 g/d) and a high total risk of developing CVD (estimated ≥20% over 10 y). After a 4-wk run-in period where FV intake was limited to <2 portions/d (<160 g/d), 92 eligible participants were randomly assigned to 1 of 3 groups: to consume either 2, 4, or 7 portions (equivalent to 160 g, 320 g, or 560 g, respectively) of FVs daily for 12 consecutive weeks. Fasting venous blood samples were collected at baseline (week 4) and post-intervention (week 16) for analysis of lipid fractions and high-sensitivity C-reactive protein (hsCRP) concentrations. Compliance with the FV intervention was determined with use of self-reported FV intake and biomarkers of micronutrient status. Ambulatory blood pressure and body composition were also measured pre- and post-intervention. RESULTS A total of 89 participants completed the study and body composition remained stable throughout the intervention period. Despite good compliance with the intervention, no significant difference was found between the FV groups for change in measures of ambulatory blood pressure, plasma lipids, or hsCRP concentrations. CONCLUSIONS There was no evidence of a dose-response effect of FV intake on conventional CVD risk factors measured in overweight adults at high CVD risk. This trial was registered at clinicaltrials.gov as NCT00874341.

Effect of implementation of a preconception counselling resource for women with diabetes: A population based study.

AIM To evaluate the effect of regional implementation of a preconception counselling resource into routine diabetes care on pregnancy planning indicators. METHODS A preconception counselling DVD was distributed to women by diabetes care teams and general practices. Subsequently, in a prospective population-based study, pregnancy planning indicators were evaluated. The post-DVD cohort (n=135), including a viewed-DVD subgroup (n=58), were compared with an historical cohort (pre-DVD, n=114). Primary outcome was HbA1c at first diabetes-antenatal visit. Secondary outcomes included preconception folic acid consumption, planned pregnancy and HbA1c recorded in the 6 months preconception. RESULTS Mean first visit HbA1c was lower post-DVD vs. pre-DVD: 7.5% vs. 7.8% [58.4 vs. 61.8mmol/mol]; p=0.12), although not statistically significant. 53% and 20% of women with type 1 and 2 diabetes, respectively, viewed the DVD. The viewed-DVD subgroup were significantly more likely to have lower first visit HbA1c: 6.9% vs. 7.8% [52.1 vs. 61.8mmol/mol], P<0.001; planned pregnancy (88% vs. 59%, P<0.001); taken folic acid preconception (81% vs. 43%, P=0.001); and had HbA1c recorded preconception (88% vs. 53%, P<0.001) than the pre-DVD cohort. CONCLUSIONS Implementation of a preconception counselling resource was associated with improved pregnancy planning indicators. Women with type 2 diabetes are difficult to reach. Greater awareness within primary care of the importance of preconception counselling among this population is needed.

Increasing fruit and vegetable intake has no effect on retinal vessel caliber in adults at high risk of developing cardiovascular disease

BACKGROUND AND AIM Retinal vessel abnormalities are associated with cardiovascular disease (CVD) risk. To date, there are no trials investigating the effect of dietary factors on the retinal microvasculature. This study examined the dose response effect of fruit and vegetable (FV) intake on retinal vessel caliber in overweight adults at high CVD risk. METHODS AND RESULTS Following a 4 week washout period, participants were randomized to consume either 2 or 4 or 7 portions of FV daily for 12 weeks. Retinal vessel caliber was measured at baseline and post-intervention. A total of 62 participants completed the study. Self-reported FV intake indicated good compliance with the intervention, with serum concentrations of zeaxanthin and lutein increasing significantly across the groups in a dose-dependent manner (P for trend < 0.05). There were no significant changes in body composition, 24-h ambulatory blood pressure or fasting blood lipid profiles in response to the FV intervention. Increasing age was a significant determinant of wider retinal venules (P = 0.004) whereas baseline systolic blood pressure was a significant determinant of narrower retinal arterioles (P = 0.03). Overall, there was no evidence of any short-term dose-response effect of FV intake on retinal vessel caliber (CRAE (P = 0.92) or CRVE (P = 0.42)). CONCLUSIONS This study demonstrated no effect of increasing FV intake on retinal vessel caliber in overweight adults at high risk of developing primary CVD. CLINICAL TRIAL REGISTRATION NCT00874341.

Serum 25-hydroxyvitamin D and insulin resistance in people at high risk of cardiovascular disease: a euglycaemic hyperinsulinaemic clamp study

In observational studies, low serum 25‐hydroxyvitamin D (25‐OHD) concentration is associated with an increased risk of type 2 diabetes mellitus (DM). Increasing serum 25‐OHD may have beneficial effects on insulin resistance or beta‐cell function. Cross‐sectional studies utilizing suboptimal methods for assessment of insulin sensitivity and serum 25‐OHD concentration provide conflicting results.

Neonatal TSH levels in Northern Ireland from 2003 to 2014 as a measure of population iodine status: XXXX

The re‐emergence of iodine deficiency in the UK has recently been reported in a large cohort of teenage girls including from Northern Ireland (NI) using the gold standard spot urinary iodine concentration. We wished to explore and confirm this by analysing neonatal thyroid‐stimulating hormone (nTSH) levels in the NI population.

Analyses of a polyphenol aglycone profile in broccoli and carrots by LC-MS QToF

Epidemiological data indicates that increased intake of fruit and vegetables (FV) is associated with decreased incidence of chronic diseases. FV contain an array of potentially protective components which may account for the health benefits associated with increased intakes. This array includes polyphenols, which are predominantly flavonoids. However, to determine polyphenol intake from FV it is important to accurately assess food content, and the effects of cooking. Unpublished data, collected within our research centre, identified broccoli and carrots as two of the most commonly consumed vegetables in a Northern Irish population. The aim of this study was to measure the polyphenol content of these two vegetables and to establish if domestic cooking had an effect on content. Although there are numerous published methods for analyses of individual polyphenols employing modern techniques such as liquid chromatography-mass spectrometry (LC-MS), this work utilises a sensitive and specific LC-MS method which analyses a representative panel of polyphenols within a single run. The methodology used is summarised below. Broccoli and carrots were purchased from a local supermarket and prepared on the day of purchase. They were cooked by boiling in water for 15 min. A raw sample (n 2) and a cooked sample (n 2) of each were frozen, lyophilised, milled and 0.05 g was hydrolysed with beta-glucuronidase and sulfatase from Helix pomatia. A profile of 14 polyphenol aglycones (including at least one representative from each of the main flavonoid subclasses and selected phenolic acids) were analysed by LC-MS quadrupole time of flight (QToF). Flavonols (kaempferol, quercetin) were detected in broccoli. Phenolic acids (para-coumaric acid, caffeic acid) were detected in broccoli and carrots.