Effect of Blueberry Consumption on Metabolic Syndrome & DNA Damage

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.

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.