Colorful fruits and vegetables owe much of their healthful reputation to the antioxidants called polyphenols and carotenes.
Natural non-Dutched cocoa and dark chocolate are by far the richest known food sources of the particularly potent polyphenols called flavanols and procyanidins.
Wild blueberries are also very rich in polyphenols … especially procyanidins and anthocyanins, with modest amounts of flavanols and another potent phenol called chlorogenic acid.
Although they’re commonly called “antioxidants”, polyphenols and carotenes don’t appear to exert major, direct antioxidant effects in the body … just in test tubes.
Instead, the apparent health benefits of carotenes and polyphenols almost certainly flow from their “nutrigenomic” influences on cellular gene switches (Wu X et al. 2010).
Those nutrigenomic influences tend to reduce unhealthful oxidation and inflammation – in large part by boosting the body’s own antioxidant network, which includes enzymes and compounds such as CoQ10 and alpha lipoic acid.
Interestingly, an Italian clinical study found that eating berries along with milk products blunted the berries’ antioxidant effects (Serafini M et al. 2009).
This likely applies to all berries, so those who mostly enjoy berries with milk-based yogurt, smoothies, or cereal should take note.
Wild berries beat farmed for polyphenol content
Wild, “low-bush” blueberries and organic blueberries generally possess more beneficial polyphenols than their conventionally grown “high-bush” counterparts (Kalt W et al. 2001; Wang SY et al. 2008; Rodriguez-Mateos A et al. 2012).
This advantage stems from the defensive roles that polyphenols play in plants, and the polyphenol-reducing effects of large amounts of synthetic fertilizers.
Wild, organic blueberries are less pest-protected than cultivated ones, and get less fertilizer, from entirely natural sources like manure.
The results of numerous animal and cell studies and a few clinical studies suggest that blueberries confer substantial benefits related to heart, brain, and metabolic health.
Now, evidence from a small clinical study suggests that drinking wild blueberry juice may help protect people’s DNA from damage by free radicals.
Pilot study finds wild blueberry juice blunted DNA and cell damage
The small, placebo-controlled clinical study was conducted by researchers from The University of Maine and Italy’s University of Milan (Riso P et al. 2012).
They recruited 18 men – average age 48 years – who had a minimum of one risk factor for cardiovascular disease.
Before and after the study, the scientists measured the levels of DNA damage in the men’s white blood cells.
The men either drank a wild blueberry juice containing 375 mg of anthocyanins – one of the key polyphenols in blueberries – or a placebo drink low in polyphenols, daily for six weeks.
After six weeks, the rate of DNA damage among the men in the wild blueberry group dropped from 12.5% to 9.6%.
In contrast, the men in the placebo group showed no drop in DNA damage.
The researchers also drew blood from all of the men, and exposed it to hydrogen peroxide, which oxidizes (damages) DNA and cellular structures.
That test tube study revealed a reduction in DNA damage in the wild blueberry group – from 45.8% to 37.2% – but no drop occurred in the placebo group.
Perhaps unsurprisingly, given the greater oxidation damage that smokers suffer, the results were stronger in smokers and ex-smokers when compared with non-smokers.
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Kalt W, Ryan DA, Duy JC, Prior RL, Ehlenfeldt MK, Vander Kloet SP. Interspecific variation in anthocyanins, phenolics, and antioxidant capacity among genotypes of highbush and lowbush blueberries (Vaccinium section cyanococcus spp.). J Agric Food Chem. 2001 Oct;49(10):4761-7.
Kay CD, Holub BJ. The effect of wild blueberry (Vaccinium angustifolium) consumption on postprandial serum antioxidant status in human subjects. Br J Nutr. 2002 Oct;88(4):389-98.
Kristo AS, Kalea AZ, Schuschke DA, Klimis-Zacas DJ. A wild blueberry-enriched diet (Vaccinium angustifolium) improves vascular tone in the adult spontaneously hypertensive rat. J Agric Food Chem. 2010 Nov 24;58(22):11600-5. Epub 2010 Oct 22.
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Rodriguez-Mateos A, Cifuentes-Gomez T, Tabatabaee S, Lecras C, Spencer JP. Procyanidin, Anthocyanin, and Chlorogenic Acid Contents of Highbush and Lowbush Blueberries. J Agric Food Chem. 2012 Jan 24. [Epub ahead of print]
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- Wu X, Kang J, Xie C, Burris R, Ferguson ME, Badger TM, Nagarajan S. Dietary blueberries attenuate atherosclerosis in apolipoprotein E-deficient mice by upregulating antioxidant enzyme expression.
Wild blueberry juice reduced DNA damage and oxidation in middle aged men.
Wild blueberries and organic berries have higher antioxidant levels than farmed berries.
Milk may block the antioxidant benefits of berries.