Researchers at Pennington Biomedical Research Center say the additional fruits, vegetables and whole grains that people consume while on the DASH--or Dietary Approaches to Stop Hypertension--diet provide "an abundance" of food compounds such as lycopene, beta carotene and isoflavones, which are increasingly associated with disease reduction.
"It therefore is possible that the health benefits of the DASH diet are partly attributable to the phytochemicals and might extend beyond cardiovascular disease reduction," according to registered dietitian and lead researcher Marlene M. Most.
Phytochemicals are substances that plants naturally produce to protect themselves against viruses, bacteria, and fungi. And, they include hundreds of naturally occurring substances, including carotenoids, flavonoids, indoles, isoflavones, capsacin and protease inhibitors. The exact role of phytochemicals in promoting health is unclear; however, they may help protect against some cancers, heart disease, and other chronic health conditions.
In addition to consumption of fruits, vegetables and whole grains, the DASH diet advises people to consume low-fat and fat-free dairy foods and lean meat, poultry and fish.
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IL-8 (interleukin-8) and GM-CSF (granulocyte-macrophage colony-stimulating factor) are important in the inflammation development, they noted, because IL-8 plays a major role in the recruitment of inflammatory leukocytes, particularly neutrophils, and GM-CSF is a cell survivor factor, thus prolonging the resident time of inflammatory cells. "The differential inhibitory effects of resveratrol on IL-8 and GM-CSF release (shown in this study) further suggest that resveratrol is not simply acting as a general inhibitor of inflammatory mediator release but exhibits some selectivity."
Next steps: further narrow mechanisms of broad anti-inflammatory
Donnelly et al. conclude that resveratrol and quercetin "can act as novel anti-inflammatory agents. Their mechanism of action is not via the estrogen or glucocorticoid receptor; thus these agents might be beneficial in inflammatory diseases where glucocorticosteroids have proved to be ineffective, such as COPD, steroid-resistant asthma, and arthritis. These compounds may provide candidate molecules for the development of novel anti-inflammatory therapies."
The current study "excluded a lot" of potential mechanisms of action, Donnelly said, but we "still don't know what its target receptor is as it binds like a protein, but acts like an estrogen," which it's not. "The good thing is that it does stop inflammation" across a broad range of systems, she added.
Source and funding: The article, "Anti-inflammatory effects of resveratrol in lung epithelial cells: molecular mechanisms," appears in the October issue of American Journal of Physiology-Lung Cellular and Molecular Physiology, published by the American Physiological Society.
In addition to Donnelly, other members of the research team, all from the Department of Thoracic Medicine, National Heart & Lung Institute, Imperial College London, England, are: Robert Newton, Gina E. Kennedy, Peter S. Fenwick, Rachel H.F. Leung, Kazuhiro Ito, Richard E.K. Russell and Peter J. Barnes.
Research was funded by grants from Pharmascience Inc., Pharmacia (part of Pfizer Inc.), the British Lung Foundation and the National Asthma Campaign (UK).
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