September 18, 2013
Immune Function May Increase By Eating Red Grapes, Blueberries
April Flowers for redOrbit.com - Your Universe Online
A research team at the Linus Pauling Institute at Oregon State University (OSU) analyzed 446 compounds for their ability to boost the innate immune system in humans. Their findings, published in Molecular Nutrition and Food Research, reveal two compounds that stand out -- the resveratrol found in red grapes and a compound called pterostilbene from blueberries.
These compounds are both called stilbenoids. They work in synergy with vitamin D and both have a significant impact in raising the expression of the human cathelicidin antimicrobial peptide (CAMP) gene that is involved in immune function.
The scientists stress that their findings were made in laboratory cell cultures and do not prove that similar results would occur as a result of dietary intake. They do believe the findings, supported by the National Institutes of Health (NIH), add more interest to the potential of some foods to improve the immune response.
"Out of a study of hundreds of compounds, just these two popped right out," said Adrian Gombart, an LPI principal investigator and associate professor in the OSU College of Science. "Their synergy with vitamin D to increase CAMP gene expression was significant and intriguing. It's a pretty interesting interaction."
Dozens of prior studies have focused on resveratrol for a wide range of benefits. Those benefits extend from improving cardiovascular health to fighting cancer and reducing inflammation. The current study is the first to show a clear synergy with vitamin D that increased CAMP expression by several times.
Scientists have studied the CAMP gene itself rather extensively as it has been shown to play a key role in the "innate" immune system, which is the body's first line of defense and ability to combat bacterial infection. As many antibiotics are increasingly losing their effectiveness, the body's innate immune response is especially important.
Prior research has shown a strong link between adequate vitamin D levels and the function of the CAMP gene. The current study suggests that other compounds may play a role as well.
Plants produce stilbenoids to fight infections. In human biology, they seem to affect some of the signaling pathways that allow vitamin D to do its job. The researchers found that combining these compounds with vitamin D has considerably more biological impact than any of them separately.
The scientists said that further research could lead to better understanding of how diet and nutrition affect the functioning of the immune system, and possibly lead to the development of therapeutically useful natural compounds that could boost the innate immune response, the researchers said in their report.
The bioavailability of compounds such as resveratrol and pterostilbene is still in question, despite the scientific interest in them. The researchers say some applications that may evolve could be with topical use to improve barrier defense in wounds or infections.
Gombart discovered the regulation of the CAMP gene by vitamin D. Researchers are still learning more about how that compound and others affect immune function. Only humans and non-human primates have been found to have these unique biological pathways. The reason they survived millions of years of evolution might be the important role they play in the immune response.