Blueberries Increase Insulin Sensitivity
new DBPC study:
Bioactives in blueberries improve insulin sensitivity in obese, insulin-resistant men & women
J Nutr. 2010;140(10):1764-1768.
n = 32 middle aged, obese, insulin resistant peeps who haven't gotten a diabetes dx
15 in the treatment group, 17 in placebo group
used a Mediterranean diet score
participants consumed smoothies that either had or didn't have 22.5g of bluberry bioactives
bid x6wks, equaling approx 2 cups fresh bbs/day
bb bioactives made from 50/50 mix of Tifblue (Vaccinium ashei) and Rubel (Vaccinium corymbosum) blueberries
blueberries freezedried and powdered
measured insulin sensitivity after 10 hour fast at baseline, middle and end
measured using hyperinulinemic-euglycemic clamps ???
measured hsCRP, TNFa and MCP-1 (monocyte chemoattractant protein 1) and lipids in serum at same times
result: bb group had better insulin sensitivity by the end
result: no major changes in body weight, caloric intake, or inflammatory markers
other things that influence insulin sensitivity:
improves it:
large amounts of cereal fiber, such as oat bran or rye, works in short time, also lowers chol
chromium, in pts who have highest fasting glucose and A1C: works best in most dysglycemic pts
decreases it:
low vitamin D levels in African American women (not caucasian)
no change:
chromium, after 6mo 500 or 1000mcg/day no change relative to placebo in pop not dxd with DM
SOURCE
http://www.naturalmedicinejournal.com/ac_oct10_schor.shtml