The effects of blueberry and strawberry serum metabolites on age-related oxidative and inflammatory signaling

Authors: Rutledge, Grant; Fisher, Derek; MILLER, MARSHALL - Former ARS Employee; KELLY, MEGAN - Former ARS Employee; BIELINSKI, DONNA - Jean Mayer Human Nutrition Research Center On Aging At Tufts University; Shukitt-Hale, Barbara

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 2/27/2020
Publication Date: 3/6/2020
Citation: Rutledge, G.A., Fisher, D.R., Miller, M.G., Kelly, M.E., Bielinski, D.F., Shukitt Hale, B. 2020. The effects of blueberry and strawberry serum metabolites on age-related oxidative and inflammatory signaling [abstract]. Program book for Translational Research Day, Poster #20, p. 14.

Interpretive Summary:

Technical Abstract: Age-related decrements in cognition are thought to result from the increased susceptibility to and accumulating effects of oxidative stress and inflammation. Berry fruits contain a variety of bioactive polyphenolic compounds that exhibit antioxidant and anti-inflammatory activities. We have previously shown that consumption of freeze-dried whole berry powder, equivalent to 1 cup/day of blueberry (BB) or 2 cups/day of strawberry (SB), improved executive function and working memory in healthy, older adults, compared to placebo-supplemented controls. We investigated whether fasting and two hour postprandial serum from BB- or SB-supplemented older adults (60-75yo), taken at baseline or after 45 or 90 days of supplementation, would reduce the production of inflammatory and oxidative stress signals, as measured by western blot and ELISA techniques, compared to a placebo group, in LPS-stressed HAPI rat microglial cells, in vitro. We also measured levels of free brain-derived neurotrophic factor (BDNF) in serum of subjects. Serum from both blueberry- and strawberry-supplemented participants reduced nitrite production, iNOS and COX-2 expression, and TNF-alpha release relative to serum from placebo controls (p < 0.05). These effects were highest in response to serum obtained from the 90-day time-point, suggesting that ongoing supplementation may provide the most health benefits. Serum was protective in both fasted and postprandial conditions, suggesting that the effects are not acute and that the meal did not challenge subjects’ ability to regulate oxidative and inflammatory stress. We found that there was a trend towards blueberry supplementation increasing free BDNF levels in the serum; however, this effect was not significant (p=0.07). Strawberry supplementation did not alter BDNF levels in the serum (p=0.8). These results suggest that berry metabolites, present in the circulating blood, may be mediating the anti-inflammatory effects of dietary berry fruit.