A Feasibility Study Exploring the Impact of a Low Advanced Glycation End-product (AGE) Diet on Skin Autofluorescence (SAF) Levels in Kidney Transplant Recipients
Trial Snapshot
- Phase
- Not Applicable
- Status
- Completed
- Enrollment
- 38
- Locations
- 1
- Primary Endpoint
- Skin Autofluorescence (SAF) Levels at 6 Months
Study Overview
Brief Summary
The purpose of the present study is to test the feasibility of conducting a larger randomised controlled trial (RCT) which will investigate whether a diet low in toxins called advanced glycation end-products (AGEs) decreases skin autofluorescence (SAF; AGE accumulation in the skin) levels and improves heart and circulatory (i.e. cardiovascular) health in persons with a kidney transplant.
Detailed Description
Kidney transplantation is the optimal treatment option for end-stage kidney disease. Cardiovascular disease is the leading cause of death in persons with kidney disease, even after receiving a kidney transplant. Advanced glycation end-products (AGEs) are compounds that form naturally in our bodies from the chemical reaction of sugars with proteins. If the concentration of AGEs becomes excessive in our bloodstream, they can cause damage to almost every tissue and organ in our bodies, which eventually may lead to an increased risk of cardiovascular death and ill health. AGEs are also found naturally in foods and the content of AGEs in foods is increased considerably by using cooking methods that require high temperatures, such as frying, roasting and grilling.
Skin autofluorescence (SAF) is a relatively new, non-invasive, validated and easy to perform technique that measures the skin accumulation of AGEs. It has been reported that kidney transplant recipients have significantly lower SAF levels when compared to persons receiving dialysis; however, these are higher than the general population.
Because of the adverse outcomes (e.g. increased risk of death) strongly associated with higher levels of SAF, several options focused on reducing the accumulation of AGEs have been proposed. One of these promising interventions is the reduction of dietary intake of AGEs. It has been suggested that cooking techniques that avoid very high temperatures such as poaching, steaming, stewing and boiling can significantly reduce the AGE content of food when compared to frying, broiling, grilling and roasting. Several studies conducted in healthy overweight and/or obese volunteers, persons with diabetes and in those with chronic kidney disease and performing peritoneal dialysis have reported that reducing dietary AGE intake is associated with a reduction in blood levels of AGEs, suggesting that a low AGE diet may also be associated with a decrease in SAF. Nevertheless, most of the evidence regarding diet modifications to reduce dietary AGE intake is of low quality and therefore further studies are required. Furthermore, this simple dietary intervention has not been previously study in the kidney transplant population. Therefore, if this proposed feasibility study is successful, we will use these findings to identify ways to design future larger research projects to improve the care of persons with a kidney transplant.
This is a feasibility study that will be conducted in two parts:
Part 1:
Study Design
- Study Type
- Interventional
- Allocation
- Randomized
- Intervention Model
- Parallel
- Primary Purpose
- Other
- Masking
- None
Eligibility Criteria
- Ages
- 18 Years to — (Adult, Older Adult)
- Sex
- All
- Accepts Healthy Volunteers
- No
Inclusion Criteria
- •Adults (>18 years) with a functioning (not on dialysis) kidney transplant.
- •More than 12 months post-transplant.
- •Able and willing to give informed consent.
- •Skin Autofluorescence levels above the general population mean value for age.
Exclusion Criteria
- •Persons with dark skin colour (i.e. Fitzpatrick skin colour type 5-6).
- •Persons with malnutrition (Subjective Global Assessment [SGA] score <5).
- •Pregnancy or breast feeding or intending pregnancy.
- •Active infection.
- •Active rejection.
- •Persons with learning difficulties.
- •Prisoners.
Arms & Interventions
Standard diet - Control group
The standard diet will include energy intake of 30-35 kcal/kg of ideal body weight (IBW)/day and protein intake of 0.75 g/kg of IBW/day for females and 0.84 g/kg of IBW/day for males
Low AGE diet - Intervention group
The low AGE diet will be the same as the standard diet in terms of calories (i.e. 30-35 kcal/kg/day) and protein (0.75-0.84 g/kg/day). However, it will reduce the dietary AGE content by changing cooking methods in food preparation to avoid exposure to dry heat such as frying, broiling, grilling and roasting, and to favour cooking with lower temperatures and high-water content as in stewing, steaming, boiling and poaching. In addition, the low-AGE group will be instructed to choose foods with low content of AGEs based on a food choice list that will contain examples of foods commonly available in the UK to be chosen as "allowed," "moderate intake," or "occasional." The goal will be to reduce dietary AGE intake to less than 8000 kU/day.
Intervention: Diet low in Advanced Glycation End-Products (AGE) (Other)
Outcomes
Primary Outcomes
Skin Autofluorescence (SAF) Levels at 6 Months
Time Frame: 6 months
Tissue accumulation of advanced glycation end-products was assessed by measuring skin autofluorescence (SAF) using a validated Autofluorescence Reader. SAF is calculated as the ratio between emission and excitation and is expressed as arbitrary units (AU). Three measurements were conducted and the average value of these was used for statistical analysis. SAF reference value for the age group of 50-60 years is 2.1±0.4 AU
Secondary Outcomes
- Participant Adherence to Diets(6 months)
- Skin Autofluorescence (SAF) Trend.(0, 3 and 6 months)
- Dietary AGE Intake at 6 Months(6 months)