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Chronic low-grade inflammation in humans is drawing a lot of interest because it is linked to so many diseases (diabetes, cancer, etc). Key ways to lower this inflammation appear to be losing weight (if overweight), exercising, not smoking, and eating a healthy diet rich in fruits, vegetables, whole grains, nuts, and seeds (thus lots of fiber). Research also shows that the type of diet a person generally eats has an effect on the composition of gut microbes (you want to feed beneficial microbes!). But which is more important for health and lowering inflammation - whole grains or fruits and vegetables or neither?

A recent study attempted to answer this question. They put 49 overweight or obese individuals, who typically ate low amounts of fruits, vegetables, and whole grains (less than 1 serving per day), into 1 of the following 3 groups for 6 weeks: 1) Whole grains (WG), 2) Fruits and vegetables (FV), and 3) a Control group (who ate refined grains). All persons were given 3 servings per day of "treatment" foods to eat at home, but the rest of their Western style diets stayed the same. The individuals did not all consume the same foods, but rather consumed their choice of foods from their group's food category.

The researchers collected blood and stool samples (both at the beginning of the study and after 6 weeks) to measure inflammation levels, and types of microbes and fatty acids in the gut. Inflammatory markers that they measured were: tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), lipopolysaccharide binding protein (LBP), and high sensitivity C-reactive protein (hs-CRP).

The researchers found an increase in microbial diversity in the FV group (perhaps due to the new variety of fibers in the fruits and vegetables), but otherwise there were no significant changes in gut microbiome composition among the groups. [Note: but each group had only some dietary changes, not drastic changes]

The researchers found that whole grains and fruits and vegetables lowered markers of inflammation - but each treatment (FV or WG) lowered different types of inflammation markers. And note that for the fruit/vegetable group - the 3 servings per day, was still below government recommendations of 5 servings per day for adults. And the rest of their diet was the same Western diet that they normally ate. So the whole grains or fruits and vegetables were not major dietary changes. And yet there were positive changes - lowering of inflammation.

So the final answer is that it is best for your health  (and gut microbes) to eat a diet rich in fruits, vegetables, and also whole grains. And they didn't even mention legumes, nuts, and seeds - all high fiber foods with lots of micronutrients, and known to be good for beneficial gut microbes. So yes, eat them also. What was a serving in this study? 1 serving = 1 cup fruits or vegetables, and 1 serving = 1 oz of whole or refined grains...continue reading "Fruits, Vegetables, and Whole Grains Lower Inflammation"

For years medicine has viewed cancer as a "malignant seed" and looked for ways to kill these seeds before they spread throughout the body (metastasis). This past week two provocative articles stresses that we should also look at the "environments" that the cancer cells grow in - that some environments in the person nourish and encourage the growth of cancer, while other environments suppress the growth of cancer and don't allow its spread.

This is a very different approach to cancer, but it also makes sense. Studies find that small cancers can just sit there harmlessly or regress on their own - even breast and prostate cancers, but it raises the questions: Why? Why do they regress or are suppressed in some people, but grow malignantly in others? What is different about those people and their bodies?

Researchers are starting to do research along these lines - that is, looking at the environment that cancer may or may not grow in. Yesterday's post discussed amazing research showing that cancer tumors are continuously shedding cancer cells in a person's body, but only in some people do they actually take root and grow. It's as if some people have environments that encourage growth of cancer, while other people have environments that do not.

Today's article, besides discussing the micro-environment in which cancer grows, also discusses the role of inflammation in cancer and how things causing inflammation (e.g., smoking, inactivity, poor diet) are also associated with cancer. So some micro-environments are good for cancer, and some are not. Some of the research I've posted in the past has tried to see if influencing the person's environment with "lots of exercise and activity"(here and here), or vitamin D levels in the body, or a person's diet somehow prevents or keeps cancer in check. From Nautilus:

The Problem with the Mutation-Centric View of Cancer

To better understand and treat cancer, physicians need to stop oversimplifying its causes. Cancer results not solely from genetic mutations but by adapting to and thriving in micro-environments in the body. That’s the point of view of James DeGregori, a professor in the Department of Biochemistry and Molecular Genetics at the University of Colorado School of Medicine.... In our conversation, DeGregori expanded on how a renewed focus on micro-environments and Darwinian evolutionary pressures can benefit cancer research.

How should we study the origins of cancer? My lab has been researching the origins of cancers for the last 15 to 17 years. We’re trying to understand cancer from an evolutionary viewpoint, understanding how it evolves. A lot of people think about cancer from an evolutionary viewpoint. But what sets us apart is that we’ve really come to understand cancer by the context these cells find themselves in.

What’s an example of such a context? While other people will think about aging as the time for mutations to cause advantageous events [for cancer] in cells, we see aging as a very different process. It’s not about the time you get mutations—you get many mutations when you’re young. It’s the tissue environment for the cells that changes dramatically as we age. Those new tissue environments basically stimulate the evolution. So the evolution isn’t a process that’s limited by the mutation so much as a process that is limited by micro-environment changes.

Instead of just attacking the cancer, we should be altering the micro-environment to disfavor the cancer. What we’ve shown is that you could take the same oncogenic mutation and put it into young cells in a young environment and it’s not advantageous [for cancer]. It doesn’t cause expansions and it doesn’t cause the cancer. You make that same mutation in old tissue and it can be adaptive for cancer.

When we’re young, our tissues are relatively constant and well maintained. If you look at the tissues of a 20-year-old and a 35-year-old, or maybe even a 40-year-old, you wouldn’t notice much of a difference. It’s not like we age linearly. It’s only after 45 or 50 that we start to really go downhill. Then that downhill accelerates. As those changes happen, our tissues are no longer presenting that same environment to our cells. What I argue is that we evolve stem cells, or the cells that are continuously making our tissues, to be well adapted to the youthful environment and not to be well adapted to an aged environment.

I’ve been criticized as putting forward a straw man because, essentially, they don’t really talk about micro-environment. But to me that’s the whole point—there’s a major factor that should be considered, and I would say not just “should.” You can’t really model cancer without it and yet they’re not taking it into account. In other words, the difference between a smoker and a nonsmoker isn’t just that the smoker has more mutations. The difference is the smoker’s lung—and I’m sure you’ve seen pictures of the charred blackened lungs of a smoker—and that presents a completely different environment for cells with mutations.

How can your ideas change the way doctors treat cancer? Mostly we now target the cancer cells. That’s changing somewhat. Immune therapies are in some ways targeting the environment. It’s almost like a predator strategy. Instead of just attacking the cancer, we should be altering the micro-environment to disfavor the cancer. If you just attack the cancer, you immediately select for resistance, which is what they see in the clinic so often. You can get a person into remission, but it’s keeping them in remission that’s the hard part. Cancer that comes back is inevitably worse than the cancer you started with.

.... If we can understand what factor about a smoker’s lung, or an old person’s lung, leads to more cancer, then we could modulate that factor to basically prevent the cancers from occurring in the first place. If it’s inflammation, for all we know maybe there are even dietary interventions that will reduce inflammation in the lungs. All the things we know that are associated with cancer are also associated with increased inflammation. Everything we know that basically leads to longer, healthier lives, is known to modulate inflammation. Exercise reduces it. Good diet reduces it. Not smoking, not exposing yourself to too much sun.

 Cancer cells. Credit:Wikipedia, National Cancer Institute

A recent study confirms all my recent posts on the importance of fiber, fruits, vegetables, whole grains, seeds, nuts, and legumes for beneficial gut bacteria health (have to feed the them!). This study found dramatic changes in the colon (specifically in the colonic mucosa) from dietary changes in as little as 2 weeks.

In the study, for 2 weeks the Americans ate the typical low-fat, high fiber diet of South Africa which included foods such as hi-maize corn fritters, beans, salmon croquettes, spinach, red pepper and onions, homemade tater tots, mango slices,okra, tomatoes, corn muffins, black-eyed peas, catfish nuggets, navy bean soup, banana, lentils, rice, fish taco (tilapia), and pineapple. Meanwhile, people in South Africa ate an “American” high-fat, low-fiber diet. Foods included beef sausage links and pancakes for breakfast; hamburger and French fries for lunch; and meatloaf and rice for dinner. Plus all sorts of American favorites such as macaroni and cheese, steak, beef hot dog and beans.

The African style low fat and high fiber diet contained about 55 grams of fiber per day, and the American diet (low fiber and high fat ) had about 14 grams of fiber per day (which is typical of a Western diet). Bottom line: fiber feeds beneficial microbes in the gut, which results in beneficial changes in the gut (in the mucosa of the colon). From Science Daily:

Diet swap has dramatic effects on colon cancer risk for Americans and Africans

Scientists have found dramatic effects on risk factors for colon cancer when American and African volunteers swapped diets for just two weeks. Western diets, high in protein and fat but low in fibre, are thought to raise colon cancer risk compared with African diets high in fibre and low in fat and protein.The new study, published in Nature Communications today, confirms that a high fibre diet can substantially reduce risk, and shows that bacteria living in the gut play an important role in this effect.

Colon cancer is the fourth commonest cause of death from cancer worldwide, accounting for over 600,000 deaths per year. Colon cancer rates are much higher in the western world than in Africa or the Far East, yet in the United States, African Americans shoulder the greatest burden of the disease.

To investigate the possible roles of diet and gut bacteria, an international team including scientists from the University of Pittsburgh and Imperial College London carried out a study with a group of 20 African American volunteers and another group of 20 participants from rural South Africa. The two groups swapped diets under tightly controlled conditions for two weeks.... At the start, when the groups had been eating their normal diets, almost half of the American subjects had polyps -- abnormal growths in the bowel lining that may be harmless but can progress to cancer. None of the Africans had these abnormalities.

After two weeks on the African diet, the American group had significantly less inflammation in the colon and reduced biomarkers of cancer risk. In the African group, measurements indicating cancer risk dramatically increased after two weeks on the western diet.

"The findings suggest that people can substantially lower their risk of colon cancer by eating more fibre. This is not new in itself but what is really surprising is how quickly and dramatically the risk markers can switch in both groups following diet change. These findings also raise serious concerns that the progressive westernization of African communities may lead to the emergence of colon cancer as a major health issue."

Professor Stephen O'Keefe at the University of Pittsburgh, who directed the study, said: "Studies on Japanese migrants to Hawaii have shown that it takes one generation of westernization to change their low incidence of colon cancer to the high rates observed in native Hawaiians. Our study suggests that westernization of the diet induces changes in biomarkers of colon cancer risk in the colonic mucosa within two weeks. Perhaps even more importantly, a change in diet from a westernized composition to a 'traditional African' high fiber low fat diet reduced these biomarkers of cancer risk within two weeks, indicating that it is likely never too late to change your diet to change your risk of colon cancer."

The study found that a major reason for the changes in cancer risk was the way in which the bacteria in the gut -- known as the microbiome -- altered their metabolism to adapt to the new diet. In the American group, the researchers found that the African diet led to an increase in the production of butyrate, a byproduct of fibre metabolism that has important anti-cancer effects.