Dietary Polyphenols and Glycation in Renal Insufficiency

Summary

Type 2 diabetes mellitus (T2DM) is associated with an increased risk of kidney failure, with high levels of glycohaemoglobin (HbA1c) presenting a sharper decline in renal function and an increase in the risk of mortality and end-stage renal disease (ESRD). Polyphenols may improve renal insufficiency in patients with diabetes with chlorogenic acids (CGA) one of the principle polyphenol groups in the diet - coffee/tea, stone fruits (especially plums/prunes) and some vegetables (artichoke, chicory). CGA (3-4 cups of coffee) has been associated with 25% lower risk of T2DM and a favourable reduction of HbA1c, blood pressure, and oxidative stress levels. This randomised controlled trial, therefore, aims to evaluate the effect of high CGA food on glycation and oxidative stress in T2DM subjects with early renal insufficiency (glomerular filtration rate of 35-60 mL/min) as well as progression of renal insufficiency and the risk of cardiovascular diseases.

The study will have two phases - phase I, an interventional study of 3 months followed by phase II, an observational study of 21 months.

In phase I, subjects will be randomized into 2 groups: CGA-enriched diet group, or control (habitual) diet group. The treatment group will be provided with a chlorogenic acid-rich food (coffee) with instructions to achieve an intake of 400 mg per day (equivalent to 3-4 coffee cups per day) for 12 weeks. The control group will receive a conventional coffee low in chlorogenic acid.

Participants will attend three sessions during phase I; baseline, 6 weeks, and 12 weeks. At baseline, general information, medical history, dietary habits and medication use will be recorded and a Food Frequency Questionnaire completed. Urine and blood samples will be collected and blood pressure, waist circumference, height and weight recorded. Participants' diet over the previous 3 days will be assessed by estimated food diary analysis.

In phase II, written dietary recommendations will be provided at three time points (months 6, 12 and 24) - treatment group to achieve a CGA-rich diet (total polyphenol intake of at least 1g per day, and at least 400mg per day of CGA) and standard dietary advice for the control group. Anthropometric/dietary data will be collected as well as blood and urine samples to assess markers of renal function, glycation and oxidative stress, and proteomic markers of cardiovascular disease, coronary artery disease and diabetes.

Conditions

• Diabetes Mellitus, Type 2
• Renal Insufficiency, Chronic

Interventions

DIETARY_SUPPLEMENT

Chlorogenic Acid (CGA) enriched coffee

Chlorogenic Acid (CGA) enriched coffee Phase I: CGA-enriched coffee provided with a CGA content of 70-90 mg/100g. Daily CGA intake of 400mg. Phase II: recommendation for achieving a CGA-rich diet of at least 400mg/day (total polyphenol intake of at least 1g/day)

DIETARY_SUPPLEMENT

Conventional coffee

Phase I: conventional coffee provided (low in CGA) Phase II: standard dietary advice

Sponsors & Collaborators

• University of Glasgow

  collaborator OTHER

• NHS Greater Glasgow and Clyde

  lead OTHER

Principal Investigators

• Emilie Combet, PhD · University of Glasgow

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

NONE

Model

PARALLEL

Eligibility

Min Age

40 Years

Max Age

80 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2016-06-01

Primary Completion

2022-09-30

Completion

2022-09-30

Countries

• United Kingdom

Study Locations