Effect of Soft Fruit on Postprandial Blood Glucose

Study Overview
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Brief Summary
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Dietary strategies for alleviating health complications associated with type 2 diabetes (T2D) are being pursued as alternatives to pharmaceutical interventions. Berries such as blackcurrants that are rich in polyphenols may influence carbohydrate digestion and absorption and thus postprandial glycaemia. In addition berries have been reported to alter incretins as well as to have anti-oxidant and anti-inflammatory properties that may also affect postprandial glycaemia. This study investigated the acute affect blackcurrants on glucose metabolism in overweight/obese volunteers .

Detailed Description
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Sixteen overweight/obese volunteers from the Aberdeen area will be recruited into a randomised controlled study. Volunteers will be randomised into four groups matched for BMI and age and given 200 grams of blackcurrants (which contain anthocyanins) or greencurrants (which naturally contain no anthocyanins), followed by an OGTT. The consumption of the currants will be followed by an oral glucose tolerance test (OGTT) with Polycal (complex carbohydrate) or glucose (simple carbohydrate) as the carbohydrate load. There will be a one week minimum wash out period between each intervention. All interventions will be randomised and blinded as far as possible in a cross-over design where the volunteers are acting as their own control. The volunteers will be asked to consume a low phytochemical diet three days prior to taking the currants all occasions. In addition, they will be asked to record what they ate over the same period in a simple food diary. The following intervention will be carried out on 16 overweight/obese male/postmenopausal female non-smoker volunteers: Control: sugar matched (matched to currant sugar content) water with polycal (complex carbohydrate load) Blackcurrants (which contain anthocyanins; 200grams) with polycal (complex carbohydrate load) Blackcurrants (which contain anthocyanins; 200grams) with glucose (simple carbohydrate load) Greencurrants (which naturally contain no anthocyanins; 200grams) with polycal (complex carbohydrate load) Note: the polycal will contain the equivalent glucose load as given in intervention 3 assuming complete hydrolysis of all carbohydrates.

Official Title
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Effect of Soft Fruit on Postprandial Blood Glucose

Conditions
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Type 2 Diabetes

Intervention / Treatment
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* Dietary Supplement: Blackcurrants with polycal OGTT
* Dietary Supplement: Greencurrants with polycal OGTT
* Dietary Supplement: Blackcurrants with glucose OGTT
* Dietary Supplement: Sugar matched water with polycal OGTT


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Obese male or female (postmenopausal) healthy non-smoking volunteers (BMI over 25kg/m2) Aged >21 and <70 years Exclusion Criteria: Medical exclusion criteria Chronic illness, including: thromboembolic or coagulation disease unregulated thyroid disease kidney disease hepatic disease severe gastrointestinal disorders pulmonary disease (e.g. chronic bronchitis, COPD) diabetes Alcohol or any other substance abuse Eating disorders Psychiatric disorders (including severe depression, lithium treatment, schizophrenia, severe behavioural disorders) Non-postmenopausal women Medication exclusion criteria Oral steroids Tricyclic antidepressants, neuroleptics Anticoagulants Digoxin and anti-arrhythmics Chronic use of anti-inflammatories (e.g. high doses of aspirin, ibuprofen), Insulin, -Sulphonylureas, Thiazolidinediones (glitazones), metformin. Anti-obesity medication e.g. Orlistat

Ages Eligible for Study
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Minimum Age: 21 Years
Maximum Age: 70 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Sugar matched water with polycal OGTT<br>Control: sugar matched (matched to currant sugar content) water with polycal Blackcurrants (200grams) with polycal Blackcurrants (200grams) with glucose Greencurrants (200grams) with polycal Sixteen overweight/obese volunteers from the Aberdeen area will be recruited into a randomised controlled study. Volunteers will be randomised into four groups matched for BMI and age and given 200 grams of blackcurrants (which contain anthocyanins) or greencurrants (which naturally contain no anthocyanins), followed by an OGTT. The OGTT will be carried out with glucose as a simple carbohydrate load or polycal as a complex carbohydrate load. Volunteers will be randomised into four groups (n=4 per group). One week wash out between treatments | Dietary Supplement: Sugar matched water with polycal OGTT<br>* Sixteen overweight/obese volunteers from the Aberdeen area will be recruited into a randomised controlled study. Volunteers will be randomised into four groups matched for BMI and age and given 200 grams of blackcurrants (which contain anthocyanins) or greencurrants (which naturally contain no anthocyanins), followed by an OGTT. The consumption of the currants will be followed by an oral glucose tolerance test (OGTT) with Polycal (complex carbohydrate) or glucose (simple carbohydrate) as the carbohydrate load. The equivalent carbohydrate load will be standardised across the groups<br>|
| Experimental: Blackcurrants with polycal OGTT<br>Blackcurrants (200grams) with polycal Blackcurrants (200grams) with glucose Greencurrants ( 200grams) with polycal Control: sugar matched (matched to currant sugar content) water with polycal Sixteen overweight/obese volunteers from the Aberdeen area will be recruited into a randomised controlled study. Volunteers will be randomised into four groups matched for BMI and age and given 200 grams of blackcurrants (which contain anthocyanins) or greencurrants (which naturally contain no anthocyanins), followed by an OGTT. The OGTT will be carried out with glucose as a simple carbohydrate load or polycal as a complex carbohydrate load as decribed above. Volunteers will be randomised into four groups (n=4 per group). One week wash out between treatments | Dietary Supplement: Blackcurrants with polycal OGTT<br>* Sixteen overweight/obese volunteers from the Aberdeen area will be recruited into a randomised controlled study. Volunteers will be randomised into four groups matched for BMI and age and given 200 grams of blackcurrants (which contain anthocyanins) or greencurrants (which naturally contain no anthocyanins), followed by an OGTT. The consumption of the currants will be followed by an oral glucose tolerance test (OGTT) with Polycal (complex carbohydrate) or glucose (simple carbohydrate) as the carbohydrate load. The equivalent carbohydrate load will be standardised across the groups<br>|
| Experimental: Blackcurrants with glucose OGTT<br>Blackcurrants (200grams) with glucose Greencurrants (200grams) with polycal Control: sugar matched (matched to currant sugar content) water with polycal Blackcurrants (200grams) with polycal Sixteen overweight/obese volunteers from the Aberdeen area will be recruited into a randomised controlled study. Volunteers will be randomised into four groups matched for BMI and age and given 200 grams of blackcurrants (which contain anthocyanins) or greencurrants (which naturally contain no anthocyanins), followed by an OGTT. The OGTT will be carried out with glucose as a simple carbohydrate load or polycal as a complex carbohydrate load as decribed above Volunteers will be randomised into four groups (n=4 per group). One week wash out between treatments | Dietary Supplement: Blackcurrants with glucose OGTT<br>* Sixteen overweight/obese volunteers from the Aberdeen area will be recruited into a randomised controlled study. Volunteers will be randomised into four groups matched for BMI and age and given 200 grams of blackcurrants (which contain anthocyanins) or greencurrants (which naturally contain no anthocyanins), followed by an OGTT. The consumption of the currants will be followed by an oral glucose tolerance test (OGTT) with Polycal (complex carbohydrate) or glucose (simple carbohydrate) as the carbohydrate load. The equivalent carbohydrate load will be standardised across the groups<br>|
| Experimental: Greencurrants with polycal OGTT<br>Greencurrants (200grams) with polycal Control: sugar matched (matched to currant sugar content) water with polycal Blackcurrants (200grams) with polycal Blackcurrants (200grams) with glucose Sixteen overweight/obese volunteers from the Aberdeen area will be recruited into a randomised controlled study. Volunteers will be randomised into four groups matched for BMI and age and given 200 grams of blackcurrants (which contain anthocyanins) or greencurrants (which naturally contain no anthocyanins), followed by an OGTT. The OGTT will be carried out with glucose as a simple carbohydrate load or polycal as a complex carbohydrate load as decribed above. Volunteers will be randomised into four groups (n=4 per group). One week wash out between treatments. | Dietary Supplement: Greencurrants with polycal OGTT<br>* Sixteen overweight/obese volunteers from the Aberdeen area will be recruited into a randomised controlled study. Volunteers will be randomised into four groups matched for BMI and age and given 200 grams of blackcurrants (which contain anthocyanins) or greencurrants (which naturally contain no anthocyanins), followed by an OGTT. The consumption of the currants will be followed by an oral glucose tolerance test (OGTT) with Polycal (complex carbohydrate) or glucose (simple carbohydrate) as the carbohydrate load. The equivalent carbohydrate load will be standardised across the groups<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Plasma Glucose Area Under the Curve |  | Plasma was collected at -15, -10 and -5 (fasted) and at 15, 30, 45, 60, 90, 120, 150 and 300 min post currant ingestion | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Plasma Insulin Area Under the Curve |  | Plasma was collected at -15, -10 and -5 (fasted) and at 15, 30, 45, 60, 90, 120, 150 and 300 min post currant ingestion | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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anthocyanin, blackcurrant, greencurrant, glucose, polyphenol, post prandial glucose