From a Scientific American online release:
One of the immune system’s jobs is to protect us from harmful bacterial. And the beneficial organisms that we refer to as probiotics contribute to this effort in a number of ways. In the gut, a robust population of beneficial bacteria can help crowd out harmful bacteria, making it harder for them to thrive. In addition, probiotic bacteria can influence the activity of our own immune cells, regulating inflammation, barrier function, and cell-to-cell signaling.
One way to foster healthy intestinal bacteria is to eat more of the foods these bugs like to eat—namely, fiber. Increasing your intake of plant fibers from vegetables, fruits, legumes, whole grains, nuts, and seeds is like filling a bird-feeder with the kind of seeds that the beautiful songbirds you want attract like best. If you feed them, they will come!
And if we want to attract a lot of different types of songbirds—er, bacteria—then we want to put out a variety of foods. That means you don’t just want to get all your fiber from a single source, such as a fiber supplement. You want to get it fiber from lots of different kinds of vegetables, fruits, legumes, grains, nuts and seeds.
Hear this week’s science news, with Nick Howe and Shamini Bundell. This week, a new 3D printer allows quick shifting between many materials, and understanding the link between gut microbes and liver disease.
Copenhagen’s legendary bicycle setup has been propelled by all of these aspirations, but the critical element is the simplest: People here eagerly use their bicycles — in any weather, carrying the young, the infirm, the elderly and 
“But what’s really intriguing is that we can now see how vitamin D might help the immune system fight cancer. We know when the Wnt/beta-catenin pathway is active in melanoma, it can dampen down the immune response causing fewer immune cells to reach the inside of the tumor, where they could potentially fight the cancer better.
“This study identifies a new molecular connection between exercise and inflammation that takes place in the bone marrow and highlights a previously unappreciated role of leptin in exercise-mediated cardiovascular protection,” said Michelle Olive, program officer at the National Heart, Lung, and Blood Institute Division of Cardiovascular Sciences. “This work adds a new piece to the puzzle of how sedentary lifestyles affect cardiovascular health and underscores the importance of following physical-activity guidelines.”
The investigators discovered that patients with a higher genetic risk for depression were more likely to be diagnosed with depression over the next 2 years. However, more physically active patients at baseline were less likely to depression, even after they accounted for genetic risks.
“The results we saw were stunning and suggest that holistically addressing aging via gene therapy could be more effective than the piecemeal approach that currently exists,” said first author Noah Davidsohn, a former research scientist at the Wyss Institute and HMS who is now chief technology officer of Rejuvenate Bio. “Everyone wants to stay as healthy as possible for as long as possible, and this study is a first step toward reducing the suffering caused by debilitating diseases.”
“Another behavior change is physical exercise,” Pillemer said. “A paradox of pain is that exercise helps reduce it, but it’s difficult for people in pain to think about exercising. So they don’t exercise, they get more sedentary and the pain increases; it’s a vicious circle. So how do you get people to actually change their behavior?”
