Effect of fruit juice on glucose control and insulin sensitivity in adults: a meta-analysis of 12 randomized controlled trials

Two-Month Consumption of Orange Juice Enriched with Vitamin D3 and Probiotics Decreases Body Weight, Insulin Resistance, Blood Lipids, and Arterial Blood Pressure in High-Cardiometabolic-Risk Patients on a Westernized Type Diet: Results from a Randomized Clinical Trial

This study examined the effects of orange juice (OJ) supplemented with vitamin D3 (2000 IU) and probiotics (Lacticaseibacillus casei Shirota and Lacticaseibacillus rhamnosus GG, 108 cfu/mL) on cardiometabolic risk factors in overweight and obese adults following a Westernized-type diet. Fifty-three high-risk individuals were randomly assigned to one of two groups. Over 8 weeks, one group consumed a vitamin D3 and probiotic-enriched OJ and the other regular OJ (control). Diets remained unchanged and were documented through food diaries. Measures of metabolic and inflammatory markers and blood pressure were measured at the start and end of the study. Post-intervention, the enriched OJ group showed the following significant metabolic improvements (without changes in triglycerides, inflammation, or central blood pressure): reduced fasting insulin, peripheral blood pressure, body weight (-1.4 kg 95% CI: -2.4, -0.4), energy (-270 kcal 95% CI: -553.2, -13.7), macronutrient (dietary fat -238 kcal 95% CI: -11.9, -1.0; carbohydrates -155 kcal 95% CI: -282.4, -27.3; sugars -16.1 g 95% CI: -11.9, -1.0) intake, and better lipid profiles (total cholesterol -10.3 mg/dL 95% CI: -21.4, 0.9; LDL-C -7 mg/dL 95% CI: -13.5, -0.5). The enriched OJ led to weight loss, less energy/macronutrient consumption, improved lipid profiles, and increased insulin sensitivity after 8 weeks in those following a Westernized diet, thus indicating potential benefits for cardiometabolic risk. This study was a part of FunJuice-T2EDK-01922, which was funded by the EU Regional Development Fund and Greek National Resources.

Intake of Fruit and Glycemic Control in Korean Patients with Diabetes Mellitus Using the Korea National Health and Nutrition Examination Survey

BACKGRUOUND

Despite the well-recognized health benefits of fresh fruit consumption, there is still substantial uncertainty about its potential effects on glycemic control in patients with type 2 diabetes mellitus (T2DM).

METHODS

We examined the association of fresh fruit consumption and glycemic control in patients with T2DM using data from the 6th Korea National Health and Nutrition Examination Survey. The study sample was divided into three groups based on weekly fruit consumption frequency for the analysis.

RESULTS

Patients with the highest fruit intake were older than those in the other two groups, and women were more likely to consume fruits in general. Being a current smoker and weekly alcohol intake also showed negative correlations according to the fruit intake tertiles. Fruit consumption was positively correlated with better hemoglobin A1c (HbA1c) levels. Moreover, patients in the highest tertile of fruit intake were 3.48 times more likely to be in good glycemic control defined as HbA1c <7%.

CONCLUSION

We observed that fruit consumption can be helpful in glycemic control in Korean patients with T2DM.

Short-Term Effects of Fruit Juice Enriched with Vitamin D3, n-3 PUFA, and Probiotics on Glycemic Responses: A Randomized Controlled Clinical Trial in Healthy Adults

This study aimed to determine the glycemic index (GI) of a commercial mixed fruit juice (apple, orange, grape, and pomegranate; FJ) fortified with vitamin D3 or n-3 polyunsaturated fatty acids (PUFA) or probiotics, and their combination, and their effects on glycemic responses and salivary insulin concentrations. In a randomized controlled, double-blind, crossover study, 11 healthy participants (25 ± 2 years; five women; body mass index = 23 ± 1 kg/m²) were randomly assigned to receive five types of FJs [vitD (with vitamin D3); n-3 (with n-3 PUFA); probiotics (with Lacticaseibacillus casei Shirota and Lacticaseibacillus rhamnosus GG); vitD-n-3-probiotics FJ (combination of vitD3-n-3-probiotics), control (regular FJ)], all containing 50 g available carbohydrate, and glucose as reference drink. All FJs provided low GI values (control: 54; vitD3: 52; n-3: 51; probiotics: 50; and vitD-n-3-probiotics combination: 52, on glucose scale). Compared to the FJ control, the enriched FJs produced different postprandial glycemic and insulinemic responses and affected satiety scores. All FJ types, regardless of the added biofunctional ingredients, attenuated postprandial glycemic responses, which may offer advantages to glycemic control.

Breakfast Quality and Insulin Resistance in Spanish Schoolchildren: A Cross-Sectional Study

Background: Breakfast has traditionally been considered one of the most important meals of the day; however, there is little evidence for the influence of breakfast quality and insulin resistance (IR). This study aimed to assess the quality of breakfast in a group of schoolchildren, and its association with IR. Methods: A cross-sectional study with 852 children (8−13 years) was carried out. Fasting plasma glucose, insulin and anthropometric parameters were measured. A three-day dietary record was used to assess their diet and to calculate the Breakfast Quality Index (BQI). The sample was divided into tertiles according to the BQI (tertile 3: better breakfast quality). The homeostatic model was used to assess insulin resistance (HOMA-IR), and IR was defined as HOMA-IR > 3.16. Results: The prevalence of IR was 5.2%. The mean BQI score was 4.50 ± 1.25, and boys had lower scores than girls. Children in the BQI tertile 3 had a better global diet quality. In boys, being in the BQI tertile 3 was associated with a lower risk of IR (OR [95% CI]: 0.10 [0.01−0.77], p < 0.05). Conclusions: A higher-quality breakfast was associated with better overall diet quality and a lower risk of IR, especially in boys.

Metabolic and Blood Pressure Effects of Consuming Two Kiwifruit Daily for 7 Weeks: A Randomised Controlled Trial

Background: Eating two kiwifruit before breakfast by equi-carbohydrate partial exchange of cereal has been associated with lower postprandial glucose and insulin, but it increases the intake of fruit sugar. We assessed the effects of kiwifruit ingestion at breakfast over 7 weeks on metabolic and physiologic factors. Method: Forty-three healthy Asian participants were randomised to ingest 500 mL of carbonated water (control) or 500 mL of carbonated water plus two kiwifruit (intervention), before breakfast. Three-day weighed diet records were taken before and at week 4 during the intervention. Overnight fasting blood samples were taken at baseline and week 7. Forty-two participants completed the study (n = 22 control, n = 20 intervention). Results: The kiwifruit group consumed more fructose, vitamin C, vitamin E, and carbohydrates as a percentage of energy compared with the control group (p < 0.01). There was no evidence of between-group changes in metabolic outcomes at the end of the intervention, with the following mean (95% confidence interval) differences in fasting blood samples: glucose 0.09 (−0.06, 0.24) mmol/L; insulin −1.6 (−3.5, 0.3) μU/mL; uric acid −13 (−30, 4) μmol/L; triglycerides −0.10 (−0.22, 0.03) mmol/L; and total cholesterol −0.05 (−0.24, 0.14) mmol/L. There was a −2.7 (−5.5, 0.0) mmHg difference in systolic blood pressure for the intervention group compared with the control group. Conclusion: Eating two kiwifruit as part of breakfast increased fruit consumption and intake of antioxidant nutrients without a change in fasting insulin. There was a difference in systolic blood pressure and no adverse fructose-associated increases in uric acid, triglycerides, or total cholesterol. This simple intervention may provide health benefits to other demographic groups.

Therapeutic Potential of Pomegranate in Metabolic Disorders

Metabolic syndrome and associated disorders have become one of the major challenging health problems over the last decades. Considerable attention has been paid to natural products and herbal medicines for the management of metabolic disorders in recent years. Many studies have investigated the therapeutic effects of different parts (arils, peels, seeds, and flowers) of pomegranate (Punica granatum L.) for the prevention and treatment of this syndrome. This study aims to provide an updated review on the in vitro and in vivo studies as well as clinical trials investigating the effects of pomegranate and its active compounds on different components of metabolic problems such as hyperglycemia, hyperlipidemia, hypertension, as well as obesity over the last two decades. Besides, the key mechanisms by which pomegranate affects these pathogenic conditions are also discussed. The studies show that although pomegranate has promising beneficial effects on diabetes, hypertension, hyperlipidemia, and obesity in various cellular, animal, and clinical models of studies, there are some conflicting results, particularly for hyperglycemic conditions. The main mechanisms include influencing oxidative stress and anti-inflammatory responses. Overall, pomegranate seems to have positive effects on the pathogenic conditions of metabolic syndrome according to the reviewed studies. Although pomegranate is not suggested as the first line of therapy or monotherapy, it could be only used as an adjunctive therapy. Nevertheless, further large and long-term clinical studies are still required.

Daily 100% watermelon juice consumption and vascular function among postmenopausal women: A randomized controlled trial

BACKGROUND AND AIMS

Watermelon juice is a rich food source of cardioprotective compounds such as arginine, citrulline, and lycopene. Preventative interventions are warranted as risk of cardiovascular disease increases among women after menopause, and age alone is an independent risk factor for vascular dysfunction. Thus, this study evaluated the effects of 100% watermelon juice on measures of vascular function.

METHODS AND RESULTS

In this randomized, double-blind, placebo-controlled, crossover trial, 21 healthy postmenopausal women were randomized to consume two 360 mL servings of 100% watermelon juice per day or an isocaloric placebo for four weeks. Following a two-week washout period, they consumed the other beverage for an additional four weeks. Before and after each treatment arm, a fasting blood sample was taken for measurement of serum arginine, citrulline, lycopene, glucose, and insulin. Assessments of vascular function included pulse pressure, pulse wave velocity, 24-h ambulatory blood pressure, and flow-mediated dilation. General linear mixed models with intent-to-treat analyses were used to examine the effects of the intervention. Despite a significant treatment effect for circulating lycopene (p = 0.002), no changes in arginine, citrulline, or any vascular measures were observed. Although the juice intervention resulted in a slight but significant increase in fasting serum glucose (p = 0.001), changes in glucose homeostasis were not clinically significant.

CONCLUSION

In contrast to findings from previous studies in younger adults and those with pre-existing hypertension, measures of vascular function in this cohort of healthy postmenopausal women were not impacted by supplemental watermelon juice. CLINICALTRIALS.

GOV IDENTIFIER

NCT03626168.

100% Fruit juice intake and cardiovascular risk: a systematic review and meta-analysis of prospective and randomised controlled studies

PURPOSE

The relationship between 100% fruit juice (100%FJ) consumption and cardiovascular risk is object of debate: indeed, recently published investigations provided new but discrepant evidence on this important question and International dietary guidelines are not in agreement on recommendations about fruit juice consumption. Therefore, we performed a meta-analysis of the prospective studies and the randomised controlled trials (RCTs) that explored the relationship between 100%FJ intake, cardiovascular risk profile and risk of cardiovascular events.

METHODS

We performed a systematic search of publications up to August 2019. Summary relative risks and exploration of linearity of the association were estimated for prospective studies and summary mean differences (MDs) calculated for RCTs.

RESULTS

A total of 21 prospective studies and 35 RCTs met the inclusion criteria. Dose-response analysis detected a significant inverse association between low-moderate 100%FJ consumption and risk of stroke (up to 200 ml/day) or total CV events (up to 170 ml/day) compared with no consumption, with a non-linear relationship (p for non-linearity < 0.05). No significant association was found for coronary heart disease and diabetes risk. In RCTs, a favorable and significant effect of 100%FJ intake was detected on blood pressure (systolic, MD: - 3.14 mmHg; diastolic, MD: - 1.68 mmHg), arterial compliance (carotid-femoral pulse wave velocity, - 0.38 m/s) and endothelial function (flow-mediated dilation, 2.10%). Neutral effects were found on body weight, blood lipids and glucose metabolism.

CONCLUSIONS

The results of these analyses indicate that 100%FJ consumption is not associated with higher CV risk. A non-linear inverse dose-response relationship occurs between 100%FJ consumption and CV disease, in particular for risk of stroke, probably mediated by the decrease in blood pressure.

TRIAL REGISTRATION

PROSPERO registration number (CRD42019135577).

Fruit Juices: Are They Helpful or Harmful? An Evidence Review

Dietary guidelines often deal with 100% fruit juice (FJ) inconsistently because it represents a source of free sugars. However, FJ also provides bioavailable micronutrients and plant bioactives at levels similar to those found in whole fruits. The present review weighs up the evidence from high-quality studies investigating a potential health harm for FJ against evidence from studies which indicate a potential health benefit. The findings reveal that FJ consumption, at moderate intakes consistent with the dietary guidelines for the US and some European countries (75-224 mL daily), does not increase the risk of obesity, type 2 diabetes, cardiovascular disease or poor glycaemic control. In contrast, regular consumption of FJ-even up to 500 mL per day in short-to-medium-term studies-appears to confer a health benefit in terms of vascular function and reduced blood pressure. Emerging evidence for cognitive health benefits requires further investigation in human trials. Observational studies report associations between FJ and nutrient adequacy and suggest that FJ consumption is associated with reduced risk of stroke. In conclusion, FJ appears to offer more benefit than risk and there appears to be no justification for discouraging FJ within a balanced diet for children and adults.

Saccharide Characteristics and Their Potential Health Effects in Perspective

To understand the effects of saccharides on our metabolism and health, we need a clear understanding of what they are, how they differ, and why some types are deemed "less healthy" and others "better for health." There are various ways to look at this topic. Firstly, saccharides can be classified according to their degree of polymerization (DP). This classification is useful when qualitative or quantitative analysis and calculation of intakes are required or for food-labeling definitions. However, it does not account for the fact that saccharides with a similar DP can differ in molecular composition, which will influence digestion, absorption, and metabolism. Secondly, another approach widely used in the biomedical and nutritional sciences is therefore a physiological classification, which addresses the rate and degree of digestibility and absorption, the glycemic response, and the metabolic fate. The individual health status also plays a role in this respect. An active, lean person will have a metabolic response that differs from an inactive person with overweight and insulin resistance. However, this approach will not give a complete answer either because the characteristics of the matrix/meal in which these carbohydrates (CHOs) are present will also influence the responses of our body. Thirdly, one can also rank CHOs by comparing their functional/technological properties, such as relative sweetness, viscosity, and solubility. Understanding CHO characteristics and related physiological responses will help understand health and disease implications. Therefore, a brief outline of different carbohydrate classifications is presented. This outline will be placed in the context of potential overall effects after consumption. The answer to the question whether we should we eat less of certain sugars depends on the angle from which you look at this matter; for example, do you address this question from a single molecular characteristic point of view or from a meal quality perspective? Looking at one particular CHO characteristic will almost always lead to a different conclusion (e.g., the labeling of fructose as toxic) than evaluating from a "total perspective" (fructose has adverse effects in certain conditions). Examples are given to help understand this matter for the benefit of justified dietary/food-based recommendations.

Consumption of Raw Orange, 100% Fresh Orange Juice, and Nectar- Sweetened Orange Juice-Effects on Blood Glucose and Insulin Levels on Healthy Subjects

Objective: The aim of this study is to investigate the effect of consumption of raw orange (RO), 100% fresh orange juice (FOJ), and nectar-sweetened orange juice (NSOJ) on postprandial glucose and insulin levels in non-diabetic young Emirati women. Research Methods: This is a prospective, three-way, crossover study design. Blood records of thirteen normal weight and seven healthy obese university students were analyzed from Zayed University on three random days with the following three meal samples: 2 ROs, 100% FOJ, and NSOJ. Venous blood was collected at 0, 30, 60, 90, and 120 minutes after the respective meal consumption. Statistical analyses included repeated measures analysis of variance and calculations of the area under the glucose and insulin curves (AUC) for each one of the meal samples. Results: Total fasting glucose and insulin levels did not differ by treatment in the normal versus obese group. All three meals had no significant effects on the plasma glucose levels. However, there was a significant change in plasma insulin concentrations at 120 min compared with that at 0 min for RO: −14 (−27.05, −0.90, P < 0.001); 100% FOJ −13.7 (−28.80, 1.44, P < 0.001); and NSOJ: −9.2 (−28.75, 10.30, P < 0.001). Conclusions: This study shows that whole fresh fruit, 100% fruit juice, and sweetened fruit juice did not have a significant effect on the blood glucose levels in non-diabetic Emirati university students. However, a significant decrease in insulin response and HOMA-IR on all three sample meals was observed.

Authentic tart cherry juice reduces markers of inflammation in overweight and obese subjects: a randomized, crossover pilot study

Subclinical inflammation is frequently noted in chronic diseases such as diabetes, cardiovascular disease (CVD) and obesity. Accumulating epidemiological evidence demonstrates that diets rich in vegetables and fruits, e.g., cherries, may significantly reduce the risk of chronic disease, in part, via antioxidant and anti-inflammatory activities. In this randomized, placebo-controlled crossover study, we recruited 10 at-risk participants (38.1 ± 12.5 years; 8 females, 2 males) with BMI >25.0 kg m-2 (32.2 ± 4.6 kg m-2; 5 obese, 5 overweight) to consume 240 mL (8 ounces) daily of either 100% tart cherry juice (TCJ) or an alternate placebo beverage, for 4 weeks with a 2-week intervening washout period before switching to the alternate beverage for four weeks. Fasting blood samples were collected at the beginning and end of each arm for measurement of biomarkers of inflammation. The erythrocyte sedimentation rate (ESR), an indicator of chronic inflammation, was significantly (p < 0.05) lower with TCJ than with the placebo beverage, which increased ESR by 19%. Mean baseline hsCRP, an indicator of acute inflammation, was 7.0 ± 5.2 mg L-1 and consumption of TCJ did not affect hsCRP levels. The chemokine MCP-1 and cytokine TNF-alpha were lower in participants after consuming TCJ compared to those consuming the placebo beverage. Plasma IL-6 and IL-l0 were not different between treatments. Collectively, the data suggest that authentic 100% TCJ may reduce biomarkers of inflammation often noted in chronic disease and may be a preferable dietary selection compared to artificially flavored beverages with added sugars.

Impact of food pattern on glycemic control among type 2 diabetic patients: a cross-sectional study in the United Arab Emirates

BACKGROUND

Optimum nutrition has an integral role in glycemic control of diabetic patients. In this study, we intend to explore the frequency of food group/item consumption and its association with the risk of poor glycemic control (Hb_A1c >7%) among type 2 diabetes (T2D) patients in the United Arab Emirates (UAE), since there are no data available in this region.

METHODS

In this retrospective cross-sectional study, data on frequency of food group/item consumption of 843 T2D patients aged ≥18 years were collected from records documented by dietitians in a tertiary care center in the UAE.

RESULTS

The trends of food consumption demonstrate that one-third of the participants consumed all five major food groups, and 10% adhered to the recommended "MyPlate" meal pattern with the optimum mix of food groups. Univariate analysis indicated that participants who adhered to the MyPlate meal pattern presented lower Hb_A1c (β=-0.78, 95% CI -1.22, -0.25; P<0.01). Daily intake of fresh fruit was shown to be protective (β=-0.64, 95% CI -1.26, -0.04; P=0.04) while fruit juice intake >1 time/day increased the risk of poor glycemic control (β=1.53, 95% CI 0.72, 2.35; P<0.001). Multiple logistic regression models (area under the receiver operating characteristics curve =0.67) showed consumption of fizzy drinks and fast food ≥1 time/week increased the odds of poor glycemic control by 2.05 (95% CI 1.16, 3.68; P=0.01) and 1.83 (95% CI 1.02, 3.3 P=0.04), respectively, while fresh fruit consumption indicated a clinically relevant protective effect  (OR=0.65, 95% CI 0.23, 1.79; P=0.4).

CONCLUSION

Consuming food such as fizzy drinks and fast food ≥1 time/week could possibly serve as an independent predictor for poor glycemic control, while fresh fruit could have a protective effect on glycemic control among T2D patients.Clinical Trial Registry: ClinicalTrials.gov Identifier: NCT03388229.

Protocol for the scientific opinion on the Tolerable Upper Intake Level of dietary sugars

In June 2016, EFSA received a mandate from the national food competent authorities of five European countries (Denmark, Finland, Iceland, Norway and Sweden) to provide a dietary reference value (DRV) for sugars, with particular attention to added sugars. A draft protocol was developed with the aim of defining as much as possible beforehand the strategy that will be applied for collecting data, appraising the relevant evidence, and analysing and integrating the evidence in order to draw conclusions that will form the basis for the Scientific Opinion on sugars. As EFSA wished to seek advice from stakeholders on this draft protocol, the NDA Panel endorsed it for public consultation on 12 December 2017. The consultation was open from 9 January to 4 March 2018. A technical meeting with stakeholders was held in Brussels on 13 February 2018, during the consultation period. After consultation with stakeholders and the mandate requestors, EFSA interprets this mandate as a request to provide scientific advice on an Tolerable Upper Intake Level (UL) for (total/added/free) sugars, i.e. the maximum level of total chronic daily intake of sugars (from all sources) judged to be unlikely to pose a risk of adverse health effects to humans. The assessment concerns the main types of sugars (mono- and disaccharides) found in mixed diets (i.e. glucose, fructose, galactose, sucrose, lactose, maltose and trehalose) taken through the oral route. The health outcomes of interest relate to the development of metabolic diseases and dental caries. The final version of the protocol was endorsed by the EFSA Panel on Dietetic Products, Nutrition and Allergies on 28 June 2018.

Review of 100% Fruit Juice and Chronic Health Conditions: Implications for Sugar-Sweetened Beverage Policy

Whether or not drinking 100% fruit juice causes poor health is controversial. Although 100% fruit juice may contain as much sugar as regular soda, it provides needed nutrients to Americans' diets. We systematically reviewed the current evidence of the association of 100% fruit juice consumption and chronic health conditions in children and adults. We focused on data from systematic reviews and meta-analyses about cardiometabolic health outcomes, liver disease, and caries. Aside from increased risk of tooth decay in children and small amounts of weight gain in young children and adults, there is no conclusive evidence that consumption of 100% fruit juice has adverse health effects. Guidelines from groups like the American Academy of Pediatrics and Dietary Guidelines for Americans recommending that 100% fruit juice may be consumed in moderation are consistent with the available evidence and should be used to inform food policies.

Perspective: Total, Added, or Free? What Kind of Sugars Should We Be Talking About?

There is consistent public guidance to limit sugars intakes. However, WHO recommendations are for "free" sugars, whereas some other guidance documents and public discussion focus on "added" sugars, and globally most food labeling states "total" sugars. Total sugars comprise all mono- and disaccharides, regardless of source, whereas both added and free sugars exclude the sugars that naturally occur in dairy products and intact fruit and vegetables. Definitions of added and free sugars differ mainly in their respective exclusion or inclusion of sugars in juiced or pureed fruit and vegetables. To date, there has been little evidence-based analysis of the scientific basis for these different sugar classifications or implications of their adoption for consumer communication and nutrition labeling. Evidence of discriminating relations of total compared with added or free sugars with weight gain or energy intake, type 2 diabetes, and dental caries was identified from recent systematic reviews and meta-analyses. The relations were weakest for total sugars and most consistent for dietary sources corresponding to free sugars (including sugars added to and in fruit juices). Consideration of these health outcomes suggests that the emphasis for intake monitoring, public health guidance, and consumer communication should be on free sugars. However, at present, the adoption of free sugars for these purposes would also carry challenges related to implementation, including consumer understanding, consensus on specifications, and current (labeling) regulations.

100 % Fruit juice and measures of glucose control and insulin sensitivity: a systematic review and meta-analysis of randomised controlled trials

Studies on the effects of consuming 100 % fruit juice on measures of glycaemic control are conflicting. The purpose of the present study was to systematically review and quantitatively summarise results from randomised controlled trials (RCT) examining effects of 100 % fruit juice on glucose-insulin homeostasis. Eligible studies were identified from a systematic review of PubMed and EMBASE and hand searches of reference lists from reviews and relevant papers. Using data from eighteen RCT, meta-analyses evaluated the mean difference in fasting blood glucose (sixteen studies), fasting blood insulin (eleven studies), the homeostatic model assessment of insulin resistance (HOMA-IR; seven studies) and glycosylated Hb (HbA1c; three studies) between the 100 % fruit juice intervention and control groups using a random-effects model. Compared with the control group, 100 % fruit juice had no significant effect on fasting blood glucose (-0·13 (95 % CI -0·28, 0·01) mmol/l; P = 0·07), fasting blood insulin (-0·24 (95 % CI -3·54, 3·05) pmol/l; P = 0·89), HOMA-IR (-0·22 (95 % CI -0·50, 0·06); P = 0·13) or HbA1c (-0·001 (95 % CI -0·38, 0·38) %; P = 0·28). Results from stratified analyses and univariate meta-regressions also largely showed no significant associations between 100 % fruit juice and the measures of glucose control. Overall, findings from this meta-analysis of RCT suggest a neutral effect of 100 % fruit juice on glycaemic control. These findings are consistent with findings from some observational studies suggesting that consumption of 100 % fruit juice is not associated with increased risk of diabetes.

Effects of a mixed berry beverage on cognitive functions and cardiometabolic risk markers; A randomized cross-over study in healthy older adults

Background

Berries and associated bioactive compounds, e.g. polyphenols and dietary fibre (DF), may have beneficial implications with respect to the metabolic syndrome, including also cognitive functions. The aim of this study was to evaluate effects on cognitive functions and cardiometabolic risk markers of 5 wk intervention with a mixture of berries, in healthy humans.

Methods

Forty healthy subjects between 50–70 years old were provided a berry beverage based on a mixture of berries (150g blueberries, 50g blackcurrant, 50g elderberry, 50g lingonberries, 50g strawberry, and 100g tomatoes) or a control beverage, daily during 5 weeks in a randomized crossover design. The control beverage (water based) was matched with respect to monosaccharides, pH, and volume. Cognitive tests included tests of working memory capacity, selective attention, and psychomotor reaction time. Cardiometabolic test variables investigated were blood pressure, fasting blood concentrations of glucose, insulin, blood lipids, inflammatory markers, and markers of oxidative stress.

Results

The daily amounts of total polyphenols and DF from the berry beverage were 795 mg and 11g, respectively. There were no polyphenols or DF in the control beverage. The berry intervention reduced total- and LDL cholesterol compared to baseline (both P<0.05), and in comparison to the control beverage (P<0.005 and P<0.01, respectively). The control beverage increased glucose concentrations (P<0.01) and tended to increase insulin concentrations (P = 0.064) from base line, and increased insulin concentrations in comparison to the berry beverage (P<0.05). Subjects performed better in the working memory test after the berry beverage compared to after the control beverage (P<0.05). No significant effects on the other test variables were observed.

Conclusions

The improvements in cardiometabolic risk markers and cognitive performance after the berry beverage suggest preventive potential of berries with respect to type 2 diabetes, cardiovascular disease, and associated cognitive decline. Possibly the polyphenols and DF contributed to the beneficial effects.

Trial registration

ClinicalTrials.gov: NCT01562392.

Nutrient-extraction blender preparation reduces postprandial glucose responses from fruit juice consumption

Although whole-fruit consumption is regarded as protective against type 2 diabetes (T2DM), conventionally prepared fruit juice is associated with increased T2DM risk, and current public health advice recommends its restriction. ‘Nutrient extractor’ style blenders are increasing in popularity worldwide as an alternative means of juicing fruit, but little is known about their effect on postprandial glucose levels. The current study investigated the effect of nutrient extraction on postprandial blood glucose response and glycemic index (GI) compared with a glucose control for both mixed fruit and a high GI fruit (mango). Remarkably, consumption of nutrient-extracted mixed fruit resulted in a significant lowering of the GI (32.7±8.5) compared with whole mixed fruit (66.2±8.2, P<0.05). For the high GI mango, there were no differences between nutrient-extracted and whole fruit, indicating that even for a high GI fruit the effect of nutrient extraction does not increase GI compared with the whole fruit. These findings suggest that, in contrast to conventionally prepared fruit juice, fruit juice prepared by nutrient extraction in some cases elicits a more favorable postprandial glycemic response than whole fruit and even for high GI fruits do not worsen the response. The mechanism responsible for this effect is currently unclear. However, these results suggest that fruit homogenized by nutrient extraction should be considered as a potential dietetic strategy for glycemic control.

The effects of 100% wild blueberry (Vaccinium angustifolium) juice consumption on cardiometablic biomarkers: a randomized, placebo-controlled, crossover trial in adults with increased risk for type 2 diabetes

Background

Wild blueberries have a high content of polyphenols, but there is limited data evaluating their health benefits in adults at risk for type 2 diabetes. The objective of the study was to investigate whether consumption of 100% wild blueberry juice improves cardiometabolic biomarkers associated with type 2 diabetes risk.

Methods

A single-blind, randomized, placebo-controlled, crossover design trial was conducted in which adults (women, n = 19, ages 39–64 y) at risk for type 2 diabetes consumed 240 mL of wild blueberry juice or a placebo beverage as part of their free-living diet for 7 days. Blood was collected to determine various biomarkers such as fasting plasma glucose, fasting serum insulin, surrogate markers of insulin sensitivity, triglycerides, inflammation (interleukin-6, interleukin-10, high-sensitivity C-reactive protein, tumor necrosis factor-alpha, serum amyloid A), adhesion molecules (soluble intercellular adhesion molecule-1, soluble vascular adhesion molecule-1), oxidative stress (LDL-oxidation, total 8-isoprostanes), and nitric oxide. Endothelial function and blood pressure were also assessed.

Results

Wild blueberry juice consumption for 7 days produced no significant changes in glucose, insulin, insulin sensitivity, triglycerides, inflammatory markers, adhesion molecules, oxidative stress, endothelial function or blood pressure. However, wild blueberry juice consumption showed a trend for lowering systolic blood pressure: 120.8 ± 2.2 mmHg in the placebo group vs 116.0 ± 2.2 mmHg in the blueberry juice group (P = 0.088). Serum concentrations of nitrates and nitrites, an index of nitric oxide production, increased from 2.9 ± 0.4 μM after placebo drink to 4.1 ± 0.4 μM after drinking wild blueberry juice (P = 0.039).

Conclusions

Short-term consumption of wild blueberry juice may promote cardioprotective effects, by improving systolic blood pressure, possibly through nitric oxide production, in adults at risk for type 2 diabetes. This outcome warrants longer-term human studies of blueberries, including defined amounts of either the whole fruit or juice, to clarify whether polyphenol-rich foods can be efficacious for improving cardiometabolic biomarkers in adults at risk for type 2 diabetes.

Trial registration

NCT02139878, clinicaltrials.gov; date of registration: May 4, 2014.

Fresh fruit consumption in relation to incident diabetes and diabetic vascular complications: A 7-y prospective study of 0.5 million Chinese adults

BACKGROUND

Despite the well-recognised health benefits of fresh fruit consumption, substantial uncertainties remain about its potential effects on incident diabetes and, among those with diabetes, on risks of death and major vascular complications.

METHODS AND FINDINGS

Between June 2004 and July 2008, the nationwide China Kadoorie Biobank study recruited 0.5 million adults aged 30-79 (mean 51) y from ten diverse localities across China. During ~7 y of follow-up, 9,504 new diabetes cases were recorded among 482,591 participants without prevalent (previously diagnosed or screen-detected) diabetes at baseline, with an overall incidence rate of 2.8 per 1,000 person-years. Among 30,300 (5.9%) participants who had diabetes at baseline, 3,389 deaths occurred (overall mortality rate 16.5 per 1,000), along with 9,746 cases of macrovascular disease and 1,345 cases of microvascular disease. Cox regression yielded adjusted hazard ratios (HRs) associating each disease outcome with self-reported fresh fruit consumption, adjusting for potential confounders such as age, sex, region, socio-economic status, other lifestyle factors, body mass index, and family history of diabetes. Overall, 18.8% of participants reported consuming fresh fruit daily, and 6.4% never/rarely (non-consumers), with the proportion of non-consumers about three times higher in individuals with previously diagnosed diabetes (18.9%) than in those with screen-detected diabetes (6.7%) or no diabetes (6.0%). Among those without diabetes at baseline, higher fruit consumption was associated with significantly lower risk of developing diabetes (adjusted HR = 0.88 [95% CI 0.83-0.93] for daily versus non-consumers, p < 0.001, corresponding to a 0.2% difference in 5-y absolute risk), with a clear dose-response relationship. Among those with baseline diabetes, higher fruit consumption was associated with lower risks of all-cause mortality (adjusted HR = 0.83 [95% CI 0.74-0.93] per 100 g/d) and microvascular (0.72 [0.61-0.87]) and macrovascular (0.87 [0.82-0.93]) complications (p < 0.001), with similar HRs in individuals with previously diagnosed and screen-detected diabetes; estimated differences in 5-y absolute risk between daily and non-consumers were 1.9%, 1.1%, and 5.4%, respectively. The main limitation of this study was that, owing to its observational nature, we could not fully exclude the effects of residual confounding.

CONCLUSION

In this large epidemiological study in Chinese adults, higher fresh fruit consumption was associated with significantly lower risk of diabetes and, among diabetic individuals, lower risks of death and development of major vascular complications.

Consumption of a flavonoid-rich açai meal is associated with acute improvements in vascular function and a reduction in total oxidative status in healthy overweight men

BACKGROUND

Açai (Euterpe oleracea) is a polyphenol-rich fruit marketed as beneficial for health. Experimental data showing improvements in health markers arising from açai consumption in humans is limited.

OBJECTIVE

The objective of the present study was to investigate the effect of açai consumption on acute changes in vascular function and on other disease risk markers, including postprandial plasma insulin, glucose, and oxidative stress.

DESIGN

Twenty-three healthy male volunteers, aged 30-65 y and with a body mass index (in kg/m²) of 25-30, completed a randomized, controlled, high-fat challenge, double-blind, crossover, acute dietary intervention trial. The volunteers consumed either an açai-based smoothie (AS) or a macronutrient-matched control smoothie (PS) together with a high-fat breakfast meal challenge. The primary endpoint was the assessment of endothelial function in the brachial artery by flow-mediated dilatation (FMD).

RESULTS

The acute consumption of an AS containing 694 mg total phenolics improved vascular function, with postprandial increases in FMD from baseline of 1.4% at 2 h compared with 0.4% after consumption of the PS (P = 0.001) and increases at 6 h of 0.8% for the AS compared with -0.3% for the PS (P < 0.001). There was also a significantly lower incremental area under the curve (iAUC) for total peroxide oxidative status after açai consumption relative to the control. No significant changes were observed in blood pressure, heart rate, or postprandial glucose response. However, the first postprandial insulin peak (after breakfast) and the iAUC for insulin were elevated for the AS relative to the PS.

CONCLUSIONS

In this acute study in overweight men, açai consumption was associated with improvements in vascular function, which may lower the risk of a cardiovascular event. Future intervention studies, perhaps with a chronic design, in wider populations and with other biomarkers of disease risk are needed to fully elucidate the benefits of açai to health. This trial was registered at clinicaltrials.gov as NCT02292329.

Dietary phytochemical index and the risk of insulin resistance and β-cell dysfunction: a prospective approach in Tehran lipid and glucose study

BACKGROUND

In this study, we aimed to investigate the association of dietary phytochemical index (DPI) with insulin resistance, β-cell dysfunction, and insulin sensitivity.

METHODS

This longitudinal study was conducted on 1141 participants of the Tehran Lipid and Glucose Study. Dietary data were collected using a validated semi-quantitative FFQ with 168 food items at baseline and DPI was calculated. Fasting serum insulin and glucose were measured at baseline and again after a 3-year of follow-up.

RESULTS

After 3-years of follow-up, the risk of hyperinsulinemia significantly decreased by 65 (OR = 0.35, 95% CI = 0.21-0.60) and 86% (OR = 0.14, 0.07-0.29), in the third and fourth quartile categories of DPI, respectively. The occurrence of insulin resistance and insulin insensitivity in participants with higher DPI was significantly lower than the others (OR = 0.48, 95% CI = 0.25-0.93 and OR = 0.11, 95% CI = 0.05-0.24, respectively).

CONCLUSION

Higher consumption of phytochemical-rich foods may have protective effects against development of insulin resistance.

Dietary insulin load and insulin index are associated with the risk of insulin resistance: a prospective approach in tehran lipid and glucose study

Background

The aim of this study was to investigate the relationship between dietary insulin load (DIL) and insulin index (DII) and the risk of insulin resistance in Tehranian adults.

Methods

In this study, 927 men and women, aged 22–80 years, participated in Tehran Lipid and Glucose Study were included. Fasting serum insulin and glucose were measured at baseline and again after a 3-year of follow-up. Usual dietary intakes were measured using a validated 168 item semi-quantitative food frequency questionnaire and DIL and DII were calculated. Logistic regression models were used to estimate the occurrence of the IR across tertile categories of DIL and DII with adjustment for potential confounding variables.

Result

Mean age of participants was 40.71 ± 12.14 y, and mean body mass index (BMI) was 27.23 ± 4.9 kg/m², at baseline. Mean of DIL and DII was 937 ± 254 and 84.0 ± 6.3. Participants with higher DIL had higher weight and waist circumference at baseline (P < 0.05). A borderline positive association was observed between DII and the risk of insulin resistance in fully adjusted model (odds ratio = 1.66, 95 % confidence interval = 0.96–2.86, P for trend = 0.06). After adjustment of potential confounders, highest compared to the lowest tertile of DIL was also significantly associated with increased risk of insulin resistance (odds ratio = 1.69, 95 % confidence interval = 1.01–2.89, P for trend = 0.06).

Conclusion

Dietary insulin load and DII could be considered as independent dietary risk factors for development of insulin resistance.

Food intake patterns are associated with the risk of impaired glucose and insulin homeostasis: a prospective approach in the Tehran Lipid and Glucose Study

Objective

To investigate the association of major dietary patterns with the risk of impaired glucose and insulin homeostasis during a 3-year follow-up.

Design

Fasting serum insulin (FSI), fasting (FSG) and 2 h serum glucose (2h-SG) were measured at baseline and again after 3 years. Dietary intakes were evaluated using a validated 168-item semi-quantitative FFQ and major dietary patterns were obtained using principal component analysis. Logistic regression models were used to estimate the occurrence of impaired fasting glucose (IFG), impaired glucose tolerance (IGT), pre-diabetes (IGT/IFG), β-cell dysfunction and hyperinsulinaemia across tertiles of dietary patterns, with adjustment for potential confounding variables.

Setting

Tehran Lipid and Glucose Study.

Subjects

Iranian men and women (n 904).

Results

Mean age of participants was 38·7 (sd 11·3) years and 44·6 % were men. Major dietary patterns were Western, traditional and healthy, which explained 25·2 % of total variance in food intake. There was a positive association between Western and traditional scores with 3-year change in 2h-SG, while the healthy pattern was negatively related to 3-year changes in FSG, 2h-SG, FSI and homeostasis model assessment of insulin resistance. Highest compared with the lowest tertile of the Western dietary pattern was accompanied by a higher risk for development of IGT (OR=3·09; 95 % CI 1·28, 7·50); a higher score on the healthy dietary pattern was associated with a significantly reduced risk of hyperinsulinaemia (OR=0·53; 95 % CI 0·28, 0·94).

Conclusions

Our findings showed that adherence to a Western dietary pattern may be a risk factor for the development of IGT, while a healthy dietary pattern may prevent hyperinsulinaemia.

Dietary and Policy Priorities for Cardiovascular Disease, Diabetes, and Obesity: A Comprehensive Review

Suboptimal nutrition is a leading cause of poor health. Nutrition and policy science have advanced rapidly, creating confusion yet also providing powerful opportunities to reduce the adverse health and economic impacts of poor diets. This review considers the history, new evidence, controversies, and corresponding lessons for modern dietary and policy priorities for cardiovascular diseases, obesity, and diabetes mellitus. Major identified themes include the importance of evaluating the full diversity of diet-related risk pathways, not only blood lipids or obesity; focusing on foods and overall diet patterns, rather than single isolated nutrients; recognizing the complex influences of different foods on long-term weight regulation, rather than simply counting calories; and characterizing and implementing evidence-based strategies, including policy approaches, for lifestyle change. Evidence-informed dietary priorities include increased fruits, nonstarchy vegetables, nuts, legumes, fish, vegetable oils, yogurt, and minimally processed whole grains; and fewer red meats, processed (eg, sodium-preserved) meats, and foods rich in refined grains, starch, added sugars, salt, and trans fat. More investigation is needed on the cardiometabolic effects of phenolics, dairy fat, probiotics, fermentation, coffee, tea, cocoa, eggs, specific vegetable and tropical oils, vitamin D, individual fatty acids, and diet-microbiome interactions. Little evidence to date supports the cardiometabolic relevance of other popular priorities: eg, local, organic, grass-fed, farmed/wild, or non-genetically modified. Evidence-based personalized nutrition appears to depend more on nongenetic characteristics (eg, physical activity, abdominal adiposity, gender, socioeconomic status, culture) than genetic factors. Food choices must be strongly supported by clinical behavior change efforts, health systems reforms, novel technologies, and robust policy strategies targeting economic incentives, schools and workplaces, neighborhood environments, and the food system. Scientific advances provide crucial new insights on optimal targets and best practices to reduce the burdens of diet-related cardiometabolic diseases.

Impact of Natural Juice Consumption on Plasma Antioxidant Status: A Systematic Review and Meta-Analysis

Background: Oxidative stress may lead to overproduction of reactive species and a decrease in antioxidant defenses, resulting in chronic diseases such as diabetes and cancer. The consumption of natural compounds with an antioxidant profile may be a preventive alternative. Therefore, we aimed to obtain evidence regarding the potential antioxidant activity of juices in human plasma. Methods: A systematic review and meta-analysis was performed, which included randomized controlled trials that compared the use of fruit or vegetable juices vs. placebo or other beverages. An electronic search was conducted in PubMed, Scopus, International Pharmaceutical Abstracts, and SciELO. The outcome measures extracted were related to antioxidant status, e.g., vitamin C, superoxide dismutase (SOD), and catalase (CAT) levels and reduction in malondialdehyde (MDA) and antioxidant capacity measured as TEAC. Results: Twenty-eight trials were identified (n = 1089), of which 16 were used for meta-analysis. No significant differences were observed between juices and placebo with regard to TEAC, SOD, and CAT. However, juices were superior to control in enhancing vitamin C and reducing MDA. Conclusions: Natural juices are possible candidates for the management of oxidative stress. The effects of juices should be further investigated by conducting larger and well-defined trials of longer duration.

Effects of kiwi consumption on plasma lipids, fibrinogen and insulin resistance in the context of a normal diet

Background and aims

Among fruits, kiwi is one of the richest in vitamins and polyphenols and has strong anti-oxidant effects. We aimed to analyze the relationship between the consumption of kiwi and plasma lipid values, fibrinogen, and insulin resistance in adults within the context of a normal diet and physical-activity.

Methods

Cross-sectional study. Participants (N = 1469), who were free of cardiovascular diseases, completed a visit, which included the collection of information concerning the participant’s usual diet and kiwi consumption using a previously validated, semi-quantitative, 137-item food-frequency-questionnaire. Fasting laboratory determinations included plasma lipids, fibrinogen and insulin resistance. Regular physical-activity was determined using accelerometry.

Results

Consumers of at least 1 kiwi/week presented higher plasma values of HDL-cholesterol (mean difference 4.50 [95 % CI: 2.63 to 6.36]) and lower triglyceride values (mean difference −20.03 [95 % CI: −6.77 to −33.29]), fibrinogen values (mean difference −13.22 [95 % CI: −2.18 to −24.26]) and HOMAir values (mean difference −0.30 [95 % CI: −0.09 to −0.50]) (p < 0.05, for all comparisons) than those who consumed less than 1 kiwi per week. In an adjusted logistic regression analysis, this group had a lower odds-ratio for presenting plasmatic fibrinogen concentrations above 400 mg/dL (OR = 0.68, 95 % CI 0.49 to 0.95), HDL-Cholesterol plasma values below 45 mg/dL (OR = 0.57, 95 % CI 0.36 to 0.91) and a HOMAir above 3 (OR = 0.61, 95 % CI 0.37 to 1.00).

Conclusions

Consumption of at least one kiwi/week is associated with lower plasma concentrations of fibrinogen and improved plasma lipid profile in the context of a normal diet and regular exercise.

Flavanones protect from arterial stiffness in postmenopausal women consuming grapefruit juice for 6 mo: a randomized, controlled, crossover trial

BACKGROUND

The consumption of citrus fruits is associated with health benefits. However, clinical data regarding the effects of grapefruit flavanone consumption on vascular function are lacking.

OBJECTIVE

The objective of the present study was to address the role of flavanones in the long-term effects induced by grapefruit juice (GFJ) consumption on vascular function in healthy postmenopausal women.

DESIGN

Forty-eight healthy postmenopausal women aged 50-65 y within 3-10 y since menopause, a body mass index (in kg/m(2)) of 19-30, and a waist size >88 cm completed this double-blind, randomized, controlled, crossover trial. These volunteers were randomly assigned to consume 340 mL GFJ/d, providing 210 mg naringenin glycosides, or a matched control drink without flavanones for 6 mo each, with a 2-mo washout between beverages. The primary endpoint was the assessment of endothelial function in the brachial artery by using flow-mediated dilation. Blood pressure, arterial stiffness, and endothelial function in the peripheral arterial bed were also evaluated as indicators of vascular function. These measurements and blood collection for clinical biochemical markers were performed in overnight-fasted subjects before and after the 6-mo treatment periods.

RESULTS

The mean ± SD carotid-femoral pulse wave velocity, which reflects central aortic stiffness, was statistically significantly lower after consumption of GFJ (7.36 ± 1.15 m/s) than after consumption of the matched control drink without flavanones (7.70 ± 1.36 m/s), with a P value of 0.019 for the treatment effect. Endothelial function in macro- and microcirculation, blood pressure, anthropometric measures, glucose metabolism, and biomarkers of inflammation and oxidative stress were not affected by the intervention.

CONCLUSIONS

Regular GFJ consumption by middle-aged, healthy postmenopausal women is beneficial for arterial stiffness. This effect may be related to flavanones present in grapefruit. This trial was registered at clinicaltrials.gov as NCT01272167.

Risks of misinterpretation in the evaluation of the effect of fruit-based drinks in postprandial studies

It has been suggested that some fruit-based drinks (FBD) may delay the onset of postprandial stress, which is involved in the pathogenesis of many diseases. The majority of the studies, which have investigated the effects of FBD on postprandial stress, involved a placebo that was a drink with the same content in sugars or carbohydrates of the FBD, but without the bioactive antioxidant compounds. These studies were aimed more at evaluating the effect of the antioxidants rather than the effect of the FBD as a whole. Only 4 studies compared the effect of FBD with water as control and did not support the hypothesis that FBD could inhibit postprandial dysmetabolism, as well as the studies that compared the effect of orange juice and cola. Overall, the results suggest a complex relationship between postprandial dysmetabolism, inflammation, and oxidative stress. Furthermore, the inflammatory and oxidative stress markers need further analytical validation and normal ranges should be established in order to reach a firm conclusion. Finally, caution should be taken in the interpretation of the effect of FBD in postprandial studies and the reviewed results suggest that dietary recommendations should aim to limit rather than increase sugar-sweetened beverages consumption.