Cocoa Flavanol Supplementation in Raynaud's Phenomenon

University of Nottingham

Status: Completed

Conditions: Primary Raynaud Phenomenon

Treatments: Dietary Supplement: High Flavanol Cocoa extract; Dietary Supplement: Alkalised cocoa

Study type: Interventional

Funder types: Other

Identifiers

NCT03815162

112-1809

Details and patient eligibility

About

The study aims to investigate the effect that supplementing the diet with cocoa flavanols has on vasospasm symptoms and temperature regulation in women with primary Raynaud's phenomenon (PRP). Participants will be randomised to consume either high flavanol cocoa extract or low flavanol cocoa (placebo) daily for 3 months.

Full description

Primary Raynaud's phenomenon (PRP) is characterised by periodic vasospasm of the fingers and toes precipitated by exposure to cold or emotional stimuli and stress. Previous studies have demonstrated that underlying this condition there can be vascular endothelium dysfunction. Pharmacological interventions used to relieve symptoms and complications in PRP include drugs targeted at increasing nitric oxide (NO; transdermal nitrates) levels. Cocoa derived products, rich in the phytonutrients 'flavanols', have been shown to increase the bioavailability of NO at the vascular endothelium and promote vasodilation, which may address an underlying cause of PRP and mitigate symptoms. Previous work carried out in the research group has indicated that the acute consumption of cocoa does not compromise the counter-regulatory responses to localised cold exposure in those with PRP.

30 individuals with PRP will be recruited. Those interested in taking part will attend a medical screening and consent visit. If recruited, a participant number will be assigned to them sequentially and they will be randomised to either experimental or control group, with neither the participants nor the research team knowing which group they have been allocated to. Participants will be asked to complete a diet diary before attending 4 further visits over a period of 3 months.

Visit 1 (pre-intervention) and 4 (end of intervention); immediately on arrival, participants will be asked to lie semi-supine on a hospital bed. Skin temperature (surface thermocouples) and 'core' temperature (infrared tympanic thermometer) will start to be recorded to identify when these parameters have stabilized in room temperature (set at 25oC). Blood pressure will be taken using an arm cuff. Then a Finometer cuff will be attached to the left middle finger to record cardiovascular parameters (Blood pressure /heart rate/ cardiac output) and a laser Doppler probe will be attached to the dorsum of both index fingers to assess skin blood flow. Once the finger skin temperature has remained stable for 6 minutes, baseline Finometer and laser Doppler measurements will be recorded and the skin and 'core' temperature will be noted. Then, the right hand will be placed in a temperature regulated box which is set at an air temperature of 0oC. The hand will be cooled to a finger skin temperature of 15oC, then the box temperature will be modified to maintain the skin temperature at 15oC. The time that it takes for the skin temperature on the fingers to reach 15oC will be recorded. With the finger skin temperature stable at 15oC, Finometer and laser Doppler measurements will be repeated and the 'core' temperature at this point noted. Then, the hand will be removed from the chamber, and allowed to equilibrate in room temperature. The time taken for the skin temperature to reach stability will be recorded, as will the absolute temperature that it stabilises to. Measures above will be repeated once hand temperature is stable. Once these measures have been made, all equipment will be removed and a 15ml blood sample will be taken (for epicatechin, glucose and insulin analysis). The participant will be asked to complete 3 questionnaires (SF-36, Raynaud's symptoms and a food frequency questionnaire). Participants will also return a 4-day diet diary at visits 1 and 4, and their symptom diary at visit 4.

Visits 2 (end of month 1) and 3 (end of month 2); participants will return a 4-day diet diary, symptom diary and any unused capsules. They will also have a resting blood pressure measurement made, weight measured and be asked to complete 3 questionnaires (SF-36, Raynaud's symptoms and a food frequency questionnaire).

At the end of Visits 1, 2 and 3, participants will be given a months' supply of capsules, a symptom diary and a diet diary (to be completed in the week prior to the next visit).

Enrollment: 27 patients

Sex: All

Ages: 18 to 60 years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• Experience symptoms of Primary Raynaud's Phenomenon, with >1 attack / week through the winter months
• Daily consumption of caffeine containing foods/drinks.
• BMI <27kg/m2

Exclusion criteria

• pregnant or breast feeding (women only),
• clinically significant metabolic or endocrine abnormalities
• fasting glucose >6.5mmol/l,
• taking Bosentan, aspirin, dipyridamole, heparin or transdermal nitrates,
• herbal supplement use,
• food allergies related to the investigational product (cocoa, peanuts, milk),
• sensitivity to methylxanthines (e.g. caffeine, theobromine).
• Presence or history of digital ulceration,
• blood parameters suggesting secondary Raynaud's,
• history of migraines

Trial design

Primary purpose: Prevention

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Quadruple Blind

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27 participants in 2 patient groups, including a placebo group

High Flavanol Cocoa extract

Experimental group

Description:

278mg total flavanols (38.3mg epicatechin) per opaque cellulose capsule 3 capsules consumed once per day (836 mg total flavanols; 115mg epicatechin) for 3 months

Treatment:

Dietary Supplement: High Flavanol Cocoa extract

Alkalised cocoa

Placebo Comparator group

Description:

0mg total flavanols (0mg epicatechin) per opaque cellulose capsule 3 capsules consumed once per day (0mg total flavanols; 0mg epicatechin) for 3 months

Treatment:

Dietary Supplement: Alkalised cocoa