Gene Discovery Reveals Importance of Eating Your Greens

From Science Daily

Mar. 3, 2013 — Eating your greens may be even more important that previously thought, with the discovery that an immune cell population essential for intestinal health could be controlled by leafy greens in your diet.

The immune cells, named innate lymphoid cells (ILCs), are found in the lining of the digestive system and protect the body from ‘bad’ bacteria in the intestine. They are also believed to play an important role in controlling food allergies, inflammatory diseases and obesity, and may even prevent the development of bowel cancers.

Dr Gabrielle Belz, Ms Lucie Rankin, Dr Joanna Groom and colleagues from the Walter and Eliza Hall Institute’s Molecular Immunology division have discovered the gene T-bet is essential for producing a population of these critical immune cells and that the gene responds to signals in the food we eat.
Dr Belz said the research team revealed T-bet was essential for generating a subset of ILCs which is a newly discovered cell type that protects the body against infections entering through the digestive system. “In this study, we discovered that T-bet is the key gene that instructs precursor cells to develop into ILCs, which it does in response to signals in the food we eat and to bacteria in the gut,” Dr Belz said. “ILCs are essential for immune surveillance of the digestive system and this is the first time that we have identified a gene responsible for the production of ILCs.”

The research was published today in the journal Nature Immunology.

Dr Belz said that the proteins in green leafy (cruciferous) vegetables are known to interact with a cell surface receptor that switches on T-bet, and might play a role in producing these critical immune cells. “Proteins in these leafy greens could be part of the same signaling pathway that is used by T-bet to produce ILCs,” Dr Belz said. “We are very interested in looking at how the products of these vegetables are able to talk to T-bet to make ILCs, which will give us more insight into how the food we eat influences our immune system and gut bacteria.”

ILCs are essential for maintaining the delicate balance between tolerance, immunity and inflammation. Ms Rankin said the discovery had given the research team further insight into external factors responsible for ILC activation. “Until recently, it has been difficult to isolate or produce ILCs,” Ms Rankin said. “So we are very excited about the prospect for future research on these cells which are still poorly understood.”

ILCs produce a hormone called interleukin-22 (IL-22), which can protect the body from invading bacteria, Dr Belz said. “Our research shows that, without the gene T-bet, the body is more susceptible to bacterial infections that enter through the digestive system. This suggests that boosting ILCs in the gut may aid in the treatment of these bacterial infections,” she said.
ILCs help to maintain a ‘healthy’ environment in the intestine by promoting good bacteria and healing small wounds and abrasions that are common in the tissues of the gut. They may also have a role in resolving cancerous lesions. “The discovery of these immune cells has thrown open a completely new way of looking at gut biology,” Dr Belz said. “We are just starting to understand how important these immune cells are in regulating allergy and inflammation, and the implications for bowel cancer and other gastrointestinal disorders such as Crohn’s disease,” she said.

“Understanding the biology of ILCs and the genes that are essential for generating them will help us to develop methods of targeting these cells,” Dr Belz said. “This might include boosting ILCs in situations where they may not be active enough, such as infections or some cancers, or depleting them in situations where they are overactive, such as chronic inflammatory disease,” she said.

Coffee, Green Tea, May Help Lower Stroke Risk, Research Shows

From Science Daily

Mar. 14, 2013 — Green tea and coffee may help lower your risk of having a stroke, especially when both are a regular part of your diet, according to research published in Stroke: Journal of the American Heart Association.

“This is the first large-scale study to examine the combined effects of both green tea and coffee on stroke risks,” said Yoshihiro Kokubo, M.D., Ph.D., F.A.H.A., F.A.C.C., F.E.S.C., lead author of the study at Japan’s National Cerebral and Cardiovascular Center. “You may make a small but positive lifestyle change to help lower the risk of stroke by adding daily green tea to your diet.”

Researchers asked 83,269 Japanese adults about their green tea and coffee drinking habits, following them for an average 13 years. They found that the more green tea or coffee people drink, the lower their stroke risks.

• People who drank at least one cup of coffee daily had about a 20 percent lower risk of stroke compared to those who rarely drank it.
• People who drank two to three cups of green tea daily had a 14 percent lower risk of stroke and those who had at least four cups had a 20 percent lower risk, compared to those who rarely drank it.
• People who drank at least one cup of coffee or two cups of green tea daily had a 32 percent lower risk of intracerebral hemorrhage, compared to those who rarely drank either beverage. (Intracerebral hemorrhage happens when a blood vessel bursts and bleeds inside the brain. About 13 percent of strokes are hemorrhagic.)

Participants in the study were 45 to 74 years old, almost evenly divided in gender, and were free from cancer and cardiovascular disease.

During the 13-years of follow-up, researchers reviewed participants’ hospital medical records and death certificates, collecting data about heart disease, strokes and causes of death. They adjusted their findings to account for age, sex and lifestyle factors like smoking, alcohol, weight, diet and exercise.

Green tea drinkers in the study were more likely to exercise compared to non-drinkers.

Previous limited research has shown green tea’s link to lower death risks from heart disease, but has only touched on its association with lower stroke risks. Other studies have shown inconsistent connections between coffee and stroke risks.

Initial study results showed that drinking more than two cups of coffee daily was linked to increasing coronary heart disease rates in age- and sex-adjusted analysis. But researchers didn’t find the association after factoring in the effects of cigarette smoking — underscoring smoking’s negative health impact on heart and stroke health.

A typical cup of coffee or tea in Japan was approximately six ounces. “However, our self-reported data may be reasonably accurate, because nationwide annual health screenings produced similar results, and our validation study showed relatively high validity.” Kokubo said. “The regular action of drinking tea, coffee, largely benefits cardiovascular health because it partly keeps blood clots from forming.”

Tea and coffee are the most popular drinks in the world after water, suggesting that these results may apply in America and other countries.

It’s unclear how green tea affects stroke risks. A compound group known as catechins may provide some protection. Catechins have an antioxidant anti-inflammatory effect, increasing plasma antioxidant capacity and anti-thrombogenic effects.

Some chemicals in coffee include chlorogenic acid, thus cutting stroke risks by lowering the chances of developing type 2 diabetes.

Further research could clarify how the interaction between coffee and green tea might help further lower stroke risks, Kokubo said.