Sweet & Sour: Dietary Acid Load in Type 2 Diabetes and Kidney Disease Across Sex and Ethnic Groups (Sweet & Sour)

Sweet & Sour: Exploring Dietary Acid Load in Type 2 Diabetes & Kidney Disease Across Sex and Ethnicity

Chronic kidney disease (CKD) is a common condition and a major global cause of illness and mortality. The most common cause of kidney damage is diabetes, a condition that disrupts metabolism, leading to increased risk of damage to the kidneys and blood vessels. There is evidence suggesting that a diet with high acid load - consisting of acid-forming foods such as meat, cheese, and grain products - may contribute to this damage. People with such a diet often have poorer blood sugar control and more kidney damage. However, it is not yet well understood whether reducing dietary acid load can improve kidney function and diabetes management. Additionally, the role of ethnicity and sex in this process remains insufficiently explored.

The goal of this clinical trial is to understand how diet affects kidney function and blood sugar regulation in individuals with diabetes type 2 and chronic kidney disease, as well as to explore the role of sex and ethnicity in these effects. The main questions it aims to answer are:

Does a diet with lower acid load (e.g. less meat, cheese, and grain products) improve kidney function and blood sugar regulation in people with diabetes type 2 and chronic kidney disease?

Does the effect of diet on kidney function and blood sugar differ between ethnic groups, specifically between White-Dutch and South-Asian Surinamese descent people?

Participants will:

• be randomly assigned to follow either a high- or low-acid load diet for 8 weeks;
• Visit the study center four times (including screening)
• Complete food diaries three times per week and keep in regular contact with a dietitian;
• Collect 2x24-hour urine samples and morning feces at each visit ;
• Undergo blood sampling and an oral glucose tolerance test (OGTT).
• Spend a total of 8 hours at the study center (2 visits of 3 hours for OGTT and body composition tests, and 2 visits of 1 hour for additional assessments);
• Have up to 200 ml of blood collected during the study.

Study Overview

• Status: Not yet recruiting
• Conditions: Type 2 Diabetes; Chronic Kidney Disease
• Intervention / Treatment: Other: Low Dietary Acid Load

• Study Type: Interventional
• Enrollment (Estimated): 80
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Ilias Attaye, Dr.; Phone Number: +31 10 704 0704; Email: i.attaye@erasmusmc.nl

Study Locations

• Netherlands
  • Rotterdam, Netherlands
    • Erasmus Medical Center
    • Contact: Ilias Attaye, Dr.; Phone Number: +31 10 704 0704; Email: i.attaye@erasmusmc.nl
    • Principal Investigator: Ilias Attaye, Dr.
    • Sub-Investigator: Dagmar Dekker, MSc

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Age >18 years
• Presence of T2D and CKD stage G1-3a with albuminuria (>10mg/mmol)
• BMI≥ 25kg/m2 - Use of metformin on a stable dose (i.e. no changes in the last three months)
• Adequate knowledge of the Dutch language to comprehend the provided study information
• If incretin therapy is used, then subject must have used that for a minimum of 6 months before starting with the trial
• Use of ACE inhibitors or angiotensin II receptor blokkers
• Of white European Dutch or South-Asian Surinamese descent

Exclusion Criteria:

• Use of insulin
• serum bicarbonate < 20 mmol/L
• Use of antibiotics 3 months before inclusion
• Vegetarian diet - Presence of inflammatory bowel disease or other chronic inflammatory disease
• Alcohol consumption of more than 14 units per week in women, or more than 21 units per week in men
• Active malignancy - bariatric or other weight loss surgery in the history
• patients diagnosed with eating disorders (such as bulimia nervosa, anorexia nervosa or binge-eating disorder)
• HbA1c >9% (75mmol/mol) at screening
• Unmotivated or not able to adhere to a specific diet
• The subject is already currently involved in a clinical trial

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
No Intervention: High Dietary Acid Load; This arm will follow their usual diet, which is between DAL> 50 or <120mEq H⁺/day (current western diets are generally all high DAL)
Experimental: Low Dietary Acid Load; This arm will follow a DAL lowering diet with the aim to reach <25mEq H⁺/day	Other: Low Dietary Acid Load; This arm will follow a DAL lowering diet with the aim to reach <25mEq H⁺/day; Other Names: Low Acid Load Diet

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Percentage change in urinary albumin-to-creatinine ratio (UACR)	Log-transformed urinary albumin-to-creatinine ratio (UACR), following an 8-week dietary intervention.	Change between baseline and 8 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in estimated glomerular filtration rate (eGFR)	eGFR calculated using serum creatinine and/or cystatin C	Change between baseline and 8 weeks
Change in serum bicarbonate	Serum bicarbonate concentration measured in blood	Change between baseline and 8 weeks
Change in urinary citrate	Urinary citrate excretion measured in 24-hour urine collections	Change between baseline and 8 weeks
Glucose response during Oral Glucose Tolerance Test	Area under the curve (AUC) of plasma glucose during oral glucose tolerance test (OGTT)	Change between baseline and 8 weeks
Change in glucose variability (MAGE)	Mean amplitude of glycemic excursions (MAGE) derived from continuous glucose monitoring (CGM) data.	Change between baseline and 8 weeks
Change in gut microbiota composition	Gut microbiota composition assessed in morning fecal samples collected using stool collection kits analyzed by 16S rRNA gene sequencing.	Change between baseline and 8 weeks
Change in serum metabolite profiles	Serum metabolite profiles measured using untargeted metabolomics analysis.	Change between baseline and 8 weeks

Collaborators and Investigators

• Sponsor: Erasmus Medical Center
• Investigators: Principal Investigator: Ilias Attaye, Dr., Erasmus Medical Center

Publications and helpful links

Helpful Links

• Current Clinical Trials of the Rotterdam Kidney Lab and more information about the team and our research

Study record dates

Study Major Dates

• Study Start (Estimated): June 1, 2026
• Primary Completion (Estimated): June 1, 2028
• Study Completion (Estimated): June 1, 2028

Study Registration Dates

• First Submitted: April 22, 2026
• First Submitted That Met QC Criteria: May 7, 2026
• First Posted (Actual): May 14, 2026

Study Record Updates

• Last Update Posted (Actual): May 14, 2026
• Last Update Submitted That Met QC Criteria: May 7, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: sex differences; Ethnic; kidney health; acid lowering diet; Sweet & Sour
• Additional Relevant MeSH Terms: Urogenital Diseases; Endocrine System Diseases; Pathologic Processes; Male Urogenital Diseases; Kidney Diseases; Urologic Diseases; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Chronic Disease; Disease Attributes; Metabolic Diseases; Glucose Metabolism Disorders; Diabetes Mellitus; Renal Insufficiency; Pathological Conditions, Signs and Symptoms; Nutritional and Metabolic Diseases; Diabetes Mellitus, Type 2; Renal Insufficiency, Chronic
• Other Study ID Numbers: NL-010928

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Publication will be open access. All data is available upon resonable request from the Principal Investigator. Of note: All data will be pseudoanonymzed.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No