Effect of Blueberry Consumption on Metabolic Syndrome & DNA Damage

Highbush Blueberries, the DNA-damage of Obesity, Somatic Mutations and Metabolic Syndrome

Obesity usually brings with it disturbances in the body that increase the chances of developing serious diseases like diabetes and cancer. These disturbances include one or more symptoms of a condition called "metabolic syndrome" that often leads to diabetes. High levels of damage to the DNA that makes up our chromosomes have also been observed in obese people. It is possible that these two disturbances are connected. The goal of this project is to test this whether consumption of blueberries will improve these abnormalities.

Study Overview

• Status: Completed
• Conditions: Metabolic Syndrome; Insulin Resistance; DNA Damage
• Intervention / Treatment: Dietary supplement: Placebo; Dietary supplement: Blueberry Powder

Detailed Description

Unbalanced diets rich in refined carbohydrate calories, saturated fats, and trans fats, but low in vitamins, minerals, fiber, polyphenolics and ω-3 fatty acids are common in the United States, particularly among the obese. Insulin resistance and high levels of DNA damage commonly accompany obesity. There also appears to be a relationship between oxidative DNA-damage and biomarkers that characterize metabolic syndrome. The bioactivity of blueberries is usually attributed to their high content of polyphenolics which can reduce oxidative DNA damage. Since oxidative damage to mitochondrial DNA is a suggested causal factor leading to increased insulin resistance, we will test if blueberry consumption can be an ameliorative dietary factor for insulin resistance as well. If blueberry consumption both shifts metabolism away from insulin resistance and reduces DNA damage, it may be a useful tool to assist in understanding relationships between these two obesity-associated conditions.

• Study Type: Interventional
• Enrollment (Actual): 7
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • California
    • Oakland, California, United States, 94609
      • Children's Hospital & Research Center Oakland

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 30 years to 60 years (Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion criteria:

1. Age 30-60 years;
2. BMI > 30;
3. Blood pressure <140/90 mmHg without antihypertensive medicines or with a stable dose of antihypertensive medicines (no change in last 3 months).;
4. Insulin resistance (HOMA/IR) > 2.0;
5. Willing to restrict intake of high polyphenol-containing foods during the trial period;
6. Willing to forego intake of nutritional supplements other than a multivitamin;
7. Willing to maintain their current daily level of exercise throughout the study.

Exclusion criteria:

1. Known diabetes mellitus according to the 2013 ADA criteria;
2. Medications known to affect glucose metabolism;
3. Weight loss pharmacotherapy;
4. Lipid-lowering medication;
5. Untreated thyroid or chronic liver, renal, or cardiovascular disease;
6. Smoking;
7. Pregnancy- a negative urine pregnancy test will be documented for any women participants of childbearing age prior to enrollment.
8. History of allergic reactions to blueberries.
9. Any pathological condition known to alter white blood cell count over the previous 6 months;
10. Exposure to drugs known to cause mutations or radiation within the previous 6 months;
11. Alcohol consumption greater than 2 drinks/d for males and 1 drink/d for females.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Quadruple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Blueberry Powder; The intervention group will receive the Blueberry freeze-dried powder equivalent to 1 cup of whole Blueberries twice a day for 8 weeks (i.e. 2 cups/day).	Dietary supplement: Blueberry Powder
Placebo Comparator: Placebo Powder; The placebo group will receive placebo powder in the same amounts for the same duration.	Dietary supplement: Placebo

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
DNA damage in peripheral blood mononuclear cells	DNA double-stranded breaks (DSBs) will be measured.	Baseline and 2 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Insulin resistance	Insulin resistance will be measured by a 2-hr glucose tolerance test.	Baseline and 2 months

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Thiol/Redox changes	Metabolomic profile measuring shifts in the plasma redox environment	Baseline and 2 months

Collaborators and Investigators

• Sponsor: UCSF Benioff Children's Hospital Oakland
• Collaborators: U.S. Highbush Blueberry Council; USDA Agricultural Research Station in Albany, CA
• Investigators: Principal Investigator: Ashutosh Lal, MD, Children'S Hospital & Research Center At Oakland; Principal Investigator: Bruce Ames, PhD, Children'S Hospital & Research Center At Oakland

Study record dates

Study Major Dates

• Study Start: January 1, 2014
• Primary Completion (Actual): April 4, 2017
• Study Completion (Actual): April 4, 2017

Study Registration Dates

• First Submitted: February 27, 2014
• First Submitted That Met QC Criteria: February 27, 2014
• First Posted (Estimate): March 3, 2014

Study Record Updates

• Last Update Posted (Actual): December 23, 2020
• Last Update Submitted That Met QC Criteria: December 22, 2020
• Last Verified: December 1, 2020

More Information

Terms related to this study

• Keywords: diabetes; obesity; insulin; DNA damage; metabolic syndrome
• Additional Relevant MeSH Terms: Pathologic Processes; Glucose Metabolism Disorders; Metabolic Diseases; Disease; Hyperinsulinism; Syndrome; Metabolic Syndrome; Insulin Resistance
• Other Study ID Numbers: 2012-033