The past few weeks brought us a wealth of research confirming that berries confer bountiful preventive health benefits, thanks in large part to their vibrant colors.
Blueberries are blue, raspberries are red, and eggplant is purple, all thanks to polyphenol pigments called anthocyanins: a family of potent antioxidants also found in red cabbage, eggplants, prunes, plums, grapes, cocoa, and other blue-red-purple fruits and vegetables. You wouldn’t think that colors could be so important, but anthocyanins are responsible for much of the potent preventive health power of these plant foods.
Wild Blueberries May Counter Cancer Cells
Anthocyanin pigments shone in a new study from the University of Illinois that tested the effects of blueberries on prostate and liver cancer cells. The results showed that various compounds in wild blueberries—including anthocyanins—possess the power to help prevent cancer in all three phases: initiation, promotion and proliferation.
Cancer is often initiated when a carcinogen causes cellular DNA damage, which will either get repaired or mutate permanently. The promotion phase also involves cellular damage by carcinogens, causing cells to suffer further, sometimes irreversible, damage.
The new study shows that sterol compounds in blueberries inhibit cancer in the first, or initiation stage, while their anthocyanin pigments can halt cancer in the critical promotion and proliferation stages.
As lead researcher Mary Ann Lila, Ph.D. said, "The results were very positive, adding evidence to a growing body of work coming out of our lab investigating Wild Blueberry fractions and their cancer-fighting properties at all stages: initiation, promotion and proliferation. Wild Blueberry compounds offer a multi-pronged attack against cancer."
Dr. Lila went on to say, “The natural plant compounds in Wild Blueberries may be powerful allies in the fight against oxidative stress and inflammation which can lead to cancer, heart disease as well as several other chronic health problems. While we still need in vivo work to test how much of these compounds get into the body and how they work, we do know that the potential benefit could be great."
Cancer prevention: food versus pills
Many companies now offer extracts of various berries and other fruits, but it is worth noting that they do not, in general, contain all or most of the compounds that show anti-cancer effects——many of which appear synergistic—in the test tube. Since all of the evidence that fruits prevent cancer comes from population studies that correlate higher fruit consumption with lower rates of cancer, it only makes sense to focus on fruit, not supplements, which are a far more expensive and probably less effective anti-cancer ally.
As researchers at Cornell University concluded in a recent review of the scientific literature, “Work performed by our group and others has shown that fruits and vegetable phytochemical extracts exhibit strong antioxidant and antiproliferative activities and that the major part of total antioxidant activity is from the combination of phytochemicals. The evidence suggests that antioxidants or bioactive compounds are best acquired through whole-food consumption, not from expensive dietary supplements.”
The message seems clear: it takes the full complement of compounds in whole fruits and vegetables to exert maximum preventive health effects. So, enjoy colorful berries at will, but take a pass on expensive berry pills.
Blueberries for urinary tract health
Blueberries also made recent news for their ability to help prevent urinary tract infections; an attribute they share with cranberries. Both fruits work by helping prevent bacteria, primarily E. coli, from adhering to urinary tract tissues: the so-called anti-adhesion effect.
A study out of Rutgers University’s Blueberry-Cranberry Research Center shows that the same colorful flavon-3-ol antioxidant pigments that give blueberries part of their anti-cancer effects also prevent UTI-causing bacteria from sticking to bladder cells.
As the lead researcher said, "In terms of antiadhesion, we found the blueberry proanthocyanidins to be very effective. A half-cup of blueberries every day may be a preventative measure to consider for preventing UTIs … "
· Kraft TFB, Schmidt BM, Yousef GG, Knight CTG, Cuendet M, Kang Y-H, Pezzuto JM, Seigler DS, and Lila MA. 2005. Chemopreventive Potential of Wild Lowbush Blueberry Fruits in Multiple Stages of Carcinogenesis. J Food Sci 70(3):S159-66.
· Lila MA. Anthocyanins and Human Health: An In Vitro Investigative Approach. J Biomed Biotechnol. 2004;2004(5):306-313.
· Manach C, Williamson G, Morand C, Scalbert A, Remesy C. Bioavailability and bioefficacy of polyphenols in humans. I. Review of 97 bioavailability studies. Am J Clin Nutr. 2005 Jan;81(1 Suppl):230S-242S. Review.
· Hou DX, Fujii M, Terahara N, Yoshimoto M. Molecular Mechanisms Behind the Chemopreventive Effects of Anthocyanidins. J Biomed Biotechnol. 2004;2004(5):321-325.
· Liu RH. Potential synergy of phytochemicals in cancer prevention: mechanism of action. J Nutr. 2004 Dec;134(12 Suppl):3479S-3485S. Review.
· Schmidt BM, Howell AB, McEniry B, Knight CT, Seigler D, Erdman JW Jr, Lila MA. Effective separation of potent antiproliferation and antiadhesion components from wild blueberry (Vaccinium angustifolium Ait.) fruits. J Agric Food Chem. 2004 Oct 20;52(21):6433-42.