ISRCTN - ISRCTN14597438: Mulberry extract to modulate blood glucose in healthy adults

Plain English Summary

Background and study aims
Reducing the health impact of dietary sugar intake is a public health priority. Mulberry leaf extract may reduce blood glucose responses following dietary sugar intake by reducing absorption of carbohydrates in the gut. Mulberry leaf extracts are widely consumed in Asia. This study will test a water-extracted mulberry-leaf food supplement (currently available over the counter) in adults with normal (non-diabetic) blood sugar levels. The study will test the effect of a single administration of three doses of mulberry leaf extract capsules and a placebo (dummy) capsule when taken at the same time as a standard sugary drink.

Who can participate?
32 healthy adults aged 18-65 with a BMI of 20-30.

What does the study involve?
Participants will be recruited to attend for four visits, at least 48 hours apart, in order to test each of the mulberry and placebo capsules. The capsules will all have an identical appearance. Neither participants nor the study team will be aware of the order that the supplements are given until all of the tests have been completed. Blood glucose and insulin levels will be measured at time-points over 2 hours.

What are the possible benefits and risks of participating?
Mulberry extract has an excellent safety profile, is widely consumed in Asia and is available over the counter in England. As far as we are aware, mulberry extract does not have any reported adverse reactions other than mild stomach symptoms such as wind and bloating. Participants will have a cannula/drip sited (small plastic tube in a vein) and there will be a risk of bruising and a small risk of inflammation/infection at the site. Local infection control/procedures will be followed when inserting the cannula.

Where is the study run from?
The Southampton Wellcome Trust Clinical Research Facility (UK).

When is the study starting and how long is it expected to run for?
The study will commence in the first quarter of 2015 and we aim to run the study over 3-6 months until we have completed four visits for 32 participants.

Who is funding the study?
The study is being funded by the Technology Strategy Board as part of a nutrition for life Programme led by Phynova.

Who is the main contact?
Dr Mark Lown
Tel: +44 (0) 7525493650

Trial website

Contact information

Type

Scientific

Primary contact

Prof Christopher Byrne

ORCID ID

Contact details

Human Development and Health Academic Unit
Faculty of Medicine
University of Southampton
Institute of Developmental Sciences (IDS building)
University of Southampton
Southampton General Hospital
Tremona Road
Southampton
SO16 6YD
United Kingdom
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c.d.byrne@soton.ac.uk

Additional identifiers

EudraCT number

ClinicalTrials.gov number

Protocol/serial number

MULBERRY 1.1

Study information

Scientific title

Mulberry extract to modULate Blood glucosE Responses in noRmoglYcaemic adults (MULBERRY): a pilot study

Acronym

MULBERRY

Study hypothesis

An appropriate dose of mulberry extract co-administered with oral maltodextrin will reduce the incremental area under the curve for plasma glucose concentration over 120 minutes in normoglycaemic adults in a dose-dependent manner when compared to co-administration with placebo.

Ethics approval

Not provided at time of registration - submission pending

Study design

Single-centre double-blind randomised four-arm single-dose cross-over design to determine the efficacy, dose-response relationship and gastrointestinal side effects with respect to placebo

Primary study design

Interventional

Secondary study design

Randomised cross over trial

Trial setting

Other

Trial type

Treatment

Patient information sheet

Not available in web format, please use the contact details below to request a patient information sheet

Condition

Carbohydrate absorption

Intervention

The study will evaluate single doses (500 mg, 250 mg and 125 mg) of mulberry extract given at least 48 hours apart against placebo:

1. 500 mg mulberry extract (IminiNorm capsule) (equivalent to 25 mg deoxynojirimycin [DNJ])
2. 250 mg IminoNorm capsule (containing 12.5 mg DNJ)
3. 125 mg IminoNorm capsule (containing 6.75 mg DNJ)
4. Matched placebo capsule containing 500 mg microcrystalline cellulose

For co-administration with:
Maltodextrin 50 g dissolved in 150 ml water to be consumed within two minutes.

Intervention type

Other

Phase

Drug names

Primary outcome measures

Incremental area-under-the-curve (IAUC) for plasma glucose concentration over 120 minutes. The glucose and insulin values will be measured every 15 mins for two hours eg. 0, 15, 30, 45, 60, 75, 90, 105, 120 mins at each visit.

Secondary outcome measures

1. IAUC for plasma insulin concentration over 120 minutes
2. IAUC for plasma glucose and insulin concentration over 120 minutes
3. Plasma glucose concentration at the nine timepoints
4. Plasma insulin concentration at the nine timepoints
5. Gastrointestinal tolerability - abdominal bloating may be experienced due to reduced carbohydrate absorption. Gastrointestinal symptoms will be measured via questionnaire for 24 hours following each study visit

The glucose and insulin values will be measured every 15 mins for two hours eg. 0, 15, 30, 45, 60, 75, 90, 105, 120 mins at each visit.

Overall trial start date

01/01/2014

Overall trial end date

01/07/2014

Reason abandoned

Eligibility

Participant inclusion criteria

1. Consent to study protocol
2. Age 18-65 years
3. BMI 20-30
4. Normal fasting glucose (fasting plasma glucose concentration <= 7.0 mmol/l)

Participant type

Patient

Age group

Adult

Gender

Both

Target number of participants

32

Participant exclusion criteria

1. Previous diagnosis of impaired fasting glucose or impaired glucose tolerance
2. Type I/II diabetes mellitus
3. BMI <20 or >30
4. Alcohol consumption in the previous 12 hours
5. Current oral hypoglycaemic medication use
6. Pregnancy or breastfeeding
7. Symptomatic irritable bowel syndrome
8. Current participation in another clinical trial
9. History of renal or liver disease
10. History of clotting or bleeding disorders
11. Taken antibiotics in the last 3 weeks prior to screening
12. Taking daily medications or dietary supplements that are not suitable for the study in the opinion of the principal investigator and/or that are prohibited (as per protocol)
13. Known intolerance or allergy to mulberry extract or any ingredients in the study products

Recruitment start date

01/01/2014

Recruitment end date

01/07/2014

Locations

Countries of recruitment

United Kingdom

Trial participating centre

University of Southampton
Southampton
SO16 6YD
United Kingdom

Sponsor information

Organisation

University Hospital Southampton NHS Foundation Trust (UK)

Sponsor details

Tremona Rd
Southampton
Southampton
SO16 6YD
United Kingdom
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c.d.byrne@soton.ac.uk