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A recent study found that significantly increasing  dietary fiber intake after a diagnosis of colorectal cancer was associated with a lower death rate - from both colorectal cancer and overall mortality (from any cause). The 1575 men and women (all healthcare professionals) in the study had received a nonmetastatic colorectal cancer diagnosis (it had not spread beyond the colon), and the follow-up was about 8 years. These results were from food, not supplements.

How much did extra dietary fiber lower the death rate? For each additional 5  grams of fiber added to their daily diet (after diagnosis) was associated with a 18% lower colorectal cancer death rate, and a 14% lower death rate from any cause. In this study, whole grains, especially in cereals, were found to be the most beneficial. Current dietary guidelines recommend a fiber intake of 25 to 38 grams per day, but most Americans eat far lessDietary fiber is found in plant foods, such as beans, whole grains, nuts, seeds,  vegetables, and fruits. Plant fiber feeds the millions of gut microbes, especially beneficial microbes (here, here, and here) - something that was not really discussed in the study.

The researchers pointed out that a high fiber diet (especially from whole grains and cereals) is linked to a lower risk of getting colorectal (colon) cancer in the first place.  Also, that "higher intake of fiber, especially cereal fiber", has been linked to improved insulin sensitivity, reduced inflammation, type 2 diabetes, cardiovascular disease, and total mortality. Other studies have found that  vitamin D supplementation, exercise, and eating fish all increase survival from colorectal cancer. From From Medical Xpress:

Fiber-rich diet boosts survival from colon cancer

A diet rich in fiber may lessen the chances of dying from colon cancer, a new study suggests. Among people treated for non-metastatic colon cancer, every 5 grams of fiber added to their diet reduced their odds of dying by nearly 25 percent, said lead researcher Dr. Andrew Chan. He is an associate professor in the department of medicine at Harvard Medical School.

"What you eat after you've been diagnosed may make a difference," Chan said. "There is a possibility that increasing your intake of fiber may actually lower the rate of dying from colon cancer and maybe even other causes." Chan cautioned, however, that the study does not prove that the additional fiber caused people to live longer, only that the two were associated.

Fiber has been linked to better insulin control and less inflammation, which may account for better survival, he suggested. In addition, a high-fiber diet may protect people from developing colon cancer in the first place. The greatest benefit was attributed to fiber from cereals and whole grains, according to the report. Vegetable fiber was linked to an overall reduction in death, but not specifically in death from colon cancer, and fiber from fruit was not linked to a reduction in death from any cause. 

For the study, Chan and his colleagues collected data on 1,575 men and women who took part in the Nurses' Health Study and Health Professionals Follow-up Study, and who had been treated for colon or rectal cancer that had not spread beyond the colon. Specifically, the study looked at total fiber consumption in the six months to four years after the participants' cancer diagnosis. The researchers also looked at deaths from colon cancer and any other cause. In an eight-year period, 773 participants died, including 174 from colorectal cancer. [Original study.]

A major new report about colorectal cancer found that a number of lifestyle factors (diet, physical activity) increase or lower the risk of colorectal cancer. The report was an analysis of global research studies and was published by the American Institute for Cancer Research and World Cancer Research Fund.

They found that there is strong evidence that: being physically active, consuming whole grains, consuming foods containing dietary fiber, consuming dairy products, and taking calcium supplements all decrease the risk of colorectal cancer. On the other hand, there is strong evidence that: consuming red meat, consuming processed meat, consuming 2 or more alcoholic drinks per day, being overweight or obese, and being tall all increase the risk of colorectal cancer.

Also, that there is some evidence that: consuming foods containing vitamin C, consuming fish, vitamin D, consuming multivitamin supplements lower the risk of colorectal cancer. And there is some evidence that: low consumption on non-starch vegetables, low consumption of fruit, and consumption of foods containing haem iron might increase the risk of colorectal cancer. [NOTE: There are 2 types of iron in food: haem and non-haem iron. Haem iron is only found in meat, chicken, and fish, and is easily absorbed. Non-haem iron is found in plant foods, such as vegetables, cereals, beans, and lentils, but is not absorbed as well by the body.]

Finally, their cancer prevention recommendations for preventing cancer in general include: maintaining a healthy weight, being physically active and eating a healthy diet. (other posts on this - here, here, here). They also advise eating a healthy diet (think Mediterranean style diet) rather than relying on supplements to protect against cancer. The report also noted that inflammatory bowel disease and smoking increase the risk of colorectal cancer. From Science Daily:

Whole grains decrease colorectal cancer risk, processed meats increase the risk

Eating whole grains daily, such as brown rice or whole-wheat bread, reduces colorectal cancer risk, with the more you eat the lower the risk, finds a new report by the American Institute for Cancer Research (AICR) and the World Cancer Research Fund (WCRF). This is the first time AICR/WCRF research links whole grains independently to lower cancer riskDiet, Nutrition, Physical Activity and Colorectal Cancer also found that hot dogs, bacon and other processed meats consumed regularly increase the risk of this cancer. There was strong evidence that physical activity protects against colon cancer.

The new report evaluated the scientific research worldwide on how diet, weight and physical activity affect colorectal cancer risk. The report analyzed 99 studies, including data on 29 million people, of whom over a quarter of a million were diagnosed with colorectal cancer.

Other factors found to increase colorectal cancer include:  - Eating high amounts of red meat (above 500 grams cooked weight a week), such as beef or pork, - Being overweight or obese, - Consuming two or more daily alcoholic drinks (30 grams of alcohol), such as wine or beer. The report concluded that eating approximately three servings (90 grams) of whole grains daily reduces the risk of colorectal cancer by 17 percent. It adds to previous evidence showing that foods containing fiber decreases the risk of this cancer.

In the US, colorectal cancer is the third most common cancer among both men and women, with an estimated 371 cases diagnosed each day. AICR estimates that 47 percent of US colorectal cancer cases could be prevented each year through healthy lifestyle changes[The report.]

 Nice research that basically says: food is medicine. In other words, eat lots of whole grains and legumes (beans) for gut health - to feed the beneficial microbes in your gut and prevent (hopefully) colon cancer. While the clinical trial studied colorectal cancer survivors and the effects of 4 weeks of adding rice bran or navy beans or placebo (nothing extra) daily to their diet - the positive effects of adding the extra dietary fiber included increased microbiome richness and diversity in the rice bran group (which is good).

And when researchers treated colorectal cancer cells with stool extracts from these groups, they saw reduced cell growth from the groups that had increased rice bran and navy bean consumption. This was an important finding and stresses that adding fiber to the diet is beneficial to gut health, and perhaps may prevent colorectal cancer.

Other studies have also found a diet with lots of legumes (beans), whole grains, vegetables, fruits, nuts, and seeds to be beneficial for gut microbes and gut health. A classic study (from 2015) found dramatic changes in the colon (specifically in the colonic mucosa) from dietary changes in as little as 2 weeks. They compared the typical low-fat, high fiber diet of South Africa with an “American” high-fat, low-fiber diet, and found that after two weeks on the high fiber African diet, there was significantly less inflammation in the colon and reduced biomarkers of cancer risk. On the other hand, measurements indicating cancer risk dramatically increased after two weeks on the western diet. That study found that a major reason for the changes in cancer risk was the way in which the bacteria in the gut (the microbiome) were altered in adapting to the new diet. The researchers suggested trying for at least 50 grams of fiber per day for gut health benefits.

From Medical Xpress: Phase II trial: Rice bran adds microbiome diversity, slows growth of colon cancer cells

Today at the American Association for Cancer Research (AACR) Annual Meeting 2017, University of Colorado Cancer Center researchers at Colorado State University present results of a phase II clinical trial of 29 people exploring the effects of adding rice bran or navy beans to the diets of colorectal cancer survivors. After the 4-week randomized-controlled trial during which people added rice bran, navy bean powder or neither, both the rice bran and navy bean groups showed increased dietary fiber, iron, zinc, thiamin, niacin, vitamin B6, folate, and alpha-tocopherol. The rice bran group also showed increased microbiome richness and diversity. When researchers treated colorectal cancer cells with stool extracts from these groups, they saw reduced cell growth from the groups that had increased rice bran and navy bean consumption.

Previous work shows the ability of these diets to decrease colorectal cancer risk in animal models. The current trial confirms that people can eat enough bean- and rice bran-enhanced foods to promote gut health at levels shown to prevent colorectal cancer in animals. Guidelines from the American Institute for Cancer Research recommend reducing the risk of cancer by eating more vegetables, fruits, whole grains and legumes, such as beans. Ryan has established from these studies that eating a half-cup of beans and 30 grams of rice bran per day is enough to see changes in small molecules that can confer protection against colorectal cancer.

"The simple message is, 'Food is medicine,' and we are looking at how to simplify that and make it apply to our everyday lives," says study co-author Regina Brown, MD, assistant professor at the CU School of Medicine and oncologist for CUHealth...."The evidence is there in animals and we can now study this in people. The question is, what are we doing to achieve adequate levels of intake of these foods?" Ryan said. "It's not enough to say 'I eat them once in a while.' That's not going to work, particularly if you are at higher risk. You have to meet a dose, just like you need a dose of a certain drug, you need to reach intake levels and consume increased amounts of these foods, and that's where people, including me, are challenged. Not everyone wants to open up a can of beans and eat them every day."

Image result for meat, fish, eggs It is important to eat a varied diet for health, one that focuses on the food groups (and no - cookies and cake are not necessary foods). The first study looks at liver cancer risk and selenium - which is found in fish, shellfish, meat, milk, eggs, and certain South American nuts, such as Brazil nuts. The second article focuses on colorectal cancer and retinoic acid, a compound derived in the body from vitamin A. Vitamin A rich foods can provide you with retinoic acid, such as the lungs, kidneys, and liver of beef, lamb, pork. Also poultry giblets, eggs, cod liver oil, shrimp, fish, fortified milk, butter, cheddar cheese and Swiss cheese. Red and orange vegetables and fruits such as sweet potatoes, squash, carrots, pumpkins, cantaloupes, apricots, peaches and mangoes all contain significant amounts of beta-carotene, thus retinoids. Note that research generally has found health benefits from real foods, not from supplements.

From Science Daily:  Selenium status influence cancer risk

As a nutritional trace element, selenium forms an essential part of our diet. Researchers have been able to show that high blood selenium levels are associated with a decreased risk of developing liver cancer. Selenium (Se) is found in foods like fish, shellfish, meat, milk and eggs; certain South American nuts, such as Brazil nuts, are also good sources of selenium. It is a trace element that occurs naturally in soil and plants, and enters the bodies of humans and animals via the food they ingest. European soil has a rather low selenium concentration, in comparison with other areas of the world, especially in comparison to North America. Deficiencies of varying degrees of severity are common among the general population, and are the reason why German livestock receive selenium supplements in their feed.

While in Europe, neither a selenium-rich diet nor adequate selenium supplementation is associated with adverse effects, selenium deficiency is identified as a risk factor for a range of diseases. "We have been able to show that selenium deficiency is a major risk factor for liver cancer," says Prof. Dr. Lutz Schomburg of the Institute of Experimental Endocrinology, adding: "According to our data, the third of the population with lowest selenium status have a five- to ten-fold increased risk of developing hepatocellular carcinoma -- also known as liver cancer."....Previous studies had suggested a similar relationship between a person's selenium status and their risk of developing colon cancer, as well as their risk of developing autoimmune thyroid disease. (Original study)

From Science Daily: Retinoic acid suppresses colorectal cancer development, study finds

Retinoic acid, a compound derived in the body from vitamin A, plays a critical role in suppressing colorectal cancer in mice and humans, according to researchers at the Stanford University School of Medicine. Mice with the cancer have lower-than-normal levels of the metabolite in their gut, the researchers found. Furthermore, colorectal cancer patients whose intestinal tissues express high levels of a protein that degrades retinoic acid tend to fare more poorly than their peers.

"The intestine is constantly bombarded by foreign organisms," said Edgar Engleman, MD, professor of pathology and of medicine. "As a result, its immune system is very complex. There's a clear link in humans between inflammatory bowel disease, including ulcerative colitis, and the eventual development of colorectal cancer. Retinoic acid has been known for years to be involved in suppressing inflammation in the intestine. We wanted to connect the dots and learn whether and how retinoic acid levels directly affect cancer development."

"We found that bacteria, or molecules produced by bacteria, can cause a massive inflammatory reaction in the gut that directly affects retinoic acid metabolism," said Engleman. "Normally retinoic acid levels are regulated extremely tightly. This discovery could have important implications for the treatment of human colorectal cancer."

Further investigation showed that retinoic acid blocks or slows cancer development by activating a type of immune cell called a CD8 T cell. These T cells then kill off the cancer cells. In mice, lower levels of retinoic acid led to reduced numbers and activation of CD8 T cells in the intestinal tissue and increased the animals' tumor burden, the researchers found. "It's become very clear through many studies that chronic, smoldering inflammation is a very important risk factor for many types of cancer," said Engleman.

 Coffee consumption overall seems to be beneficial to health in various ways, such as lowering the risk of colorectal cancer. But there are times one should limit how much one drinks, such as during the  preconception period for both the male and female, and also during pregnancy, to lower the risk of miscarriage.

From Science Daily: Coffee consumption linked to decreased risk of colorectal cancer

Researchers have found that coffee consumption, including decaf, instant and espresso, decreases the risk of colorectal cancer. Moreover, these benefits increase the more coffee you drink. The study examined over 5,100 men and women who had been diagnosed with colorectal cancer within the past six months, along with an additional 4,000 men and women with no history of colorectal cancer to serve as a control group. Participants reported their daily consumption of boiled (espresso), instant, decaffeinated and filtered coffee, as well as their total consumption of other liquids.....

The data showed that even moderate coffee consumption, between one to two servings a day, was associated with a 26 percent reduction in the odds of developing colorectal cancer after adjusting for known risk factors. Moreover, the risk of developing colorectal cancer continued to decrease to up to 50 percent when participants drank more than 2.5 servings of coffee each day. The indication of decreased risk was seen across all types of coffee, both caffeinated and decaffeinated.

Coffee contains many elements that contribute to overall colorectal health and may explain the preventive properties. Caffeine and polyphenol can act as antioxidants, limiting the growth of potential colon cancer cells. Melanoidins generated during the roasting process have been hypothesized to encourage colon mobility. Diterpenes may prevent cancer by enhancing the body's defense against oxidative damage. "The levels of beneficial compounds per serving of coffee vary depending on the bean, roast and brewing method," said first author Stephanie Schmit, PhD, MPH. 

Colorectal cancer is the third most common cancer that is diagnosed in both men and women in the United States, with nearly five percent of men and just over four percent of women developing the disease over their lifetime. The American Cancer Society (ACS) estimates that in the United States, over 95,000 new cases of colon cancer and 39,000 new cases of rectal cancer will be diagnosed in this year alone.

Both males and females should limit coffee consumption in the preconception period to no more than 2 caffeinated drinks daily to lower the female's risk of miscarriage. From Medscape:

Even Men Need to Cut Back on Coffee Before Pregnancy

Women already know they need to cut back on coffee during pregnancy, if not sooner, to lower the risk of miscarriage. But a new study suggests the men in their lives need to limit caffeine too. Pregnant women who had more than two caffeinated drinks a day while trying to conceive had a 74% higher risk of miscarriage than their peers who drank less coffee, tea, soda and energy drinks, the study found.

When their husbands and boyfriends had more than two caffeinated drinks a day during the preconception phase, however, these pregnant women ended up with almost the same increased risk of miscarriage they would get from drinking coffee or soda themselves...."We did not find drinking one to two daily caffeinated beverages to increase the risk of miscarriage." Scientists aren't sure how caffeine contributes to miscarriage, but it's possible it affects egg or sperm production, implantation of the fertilized egg, or the ability of the embryo to grow in the uterus.

To assess how lifestyle choices may influence miscarriage risk, Louis and colleagues followed 344 couples in Texas and Michigan through the first seven weeks of pregnancy....Overall, 98 women, or 28%, experienced a miscarriage during the study, as reported March 24 in the journal Fertility and Sterility. Women 35 or older had nearly double the miscarriage risk of younger women, the study found. When women took daily multivitamins, their miscarriage risk was 55% lower than for their peers who didn't do this.

One surprise in the study is that researchers didn't find an increased miscarriage risk associated with smoking or alcohol, however. This doesn't mesh with previous research, noted Dr. Jeffrey Goldberg, a reproductive health researcher at Cleveland Clinic in Ohio who wasn't involved in the study. 

This latest study finding health benefits of eating nuts was a review of 36 observational studies, involving a total of 30,000 people. Nut consumption was associated with a lower risk of cancer in general, and a decreased risk of some types of cancer (colorectal, endometrial, pancreatic), but not with type 2 diabetes. So go ahead - eat a small handful of nuts for your health at least several times a week.From Medpage Today:

A Nutty Way to Prevent Cancer?

Nut consumption was associated with a decreased risk of some types of cancer but not with type 2 diabetes in a large review.When patients eating the most nuts were compared with those eating the least, those in the first group had a lower risk of colorectal cancer in three studies (RR 0.76, 95% CI 0.61-0.96; I2=51.3%), of endometrial cancer in two studies (RR 0.58, 95% CI 0.43-0.79; I2=0%), and pancreatic cancer in one study (RR 0.68, 95% CI 0.48-0.96; I2 not available). Those results were reported in the meta-analysis of 36 observational studies, with a total population of more than 30,000 patients.

Nut consumption was also associated with a lower risk of cancer in general (RR 0.85, 95% CI 0.76-0.95;I2=66.5%), according to the authors. But it was not associated with other types of cancer or with type 2 diabetes (RR 0.98, 95% CI 0.84-1.14; I2=74.2%), found the researchers, who were led by Lang Wu, a PhD candidate at the Mayo Clinic. They published their results on June 16 in Nutrition Reviews.

"Overall, nut intake was associated with a decreased risk of cancer," wrote Wu and colleagues. "Given the scarcity of currently available data, however, evidence from additional studies is required to more precisely determine the relationship between nut consumption and risk of individual cancer types." Evidence for the association between nuts and cancer has been mixed, according to the authors. Follow-up time in the studies ranged from 4.6 years to 30 years, found the review.

The amount of nuts eaten ranged from none for some of the patients to eating nuts more than seven times a week....No associations were found between nut consumption and acute myeloid leukemia, breast cancer, gastric cancer, glioma, hepatocellular carcinoma, leukemia, lymphoma, ovarian cancer, prostate cancer, or stomach cancer.

What was really interesting in the findings was not just that vegetarian diets are associated with an overall lower incidence of colorectal cancers, but that pescovegetarians (eat fish) had the lowest risk of all compared to nonvegetarians. That is really strong support for eating fish. From Science Daily:

Vegetarian diet linked to lower risk of colorectal cancers

Eating a vegetarian diet was associated with a lower risk of colorectal cancers compared with nonvegetarians in a study of Seventh-Day Adventist men and women, according to an article published online by JAMA Internal Medicine.

Colorectal cancer is the second leading cause of cancer death in the United States. Although great attention has been paid to screening, primary prevention through lowering risk factors remains an important objective. Dietary factors have been identified as a modifiable risk factor for colorectal cancer, including red meat which is linked to increased risk and food rich in dietary fiber which is linked to reduced risk, according to the study background.

Among 77,659 study participants, Michael J. Orlich, M.D., Ph.D., of Loma Linda University, California, and coauthors identified 380 cases of colon cancer and 110 cases of rectal cancer. Compared with nonvegetarians, vegetarians had a 22 percent lower risk for all colorectal cancers, 19 percent lower risk for colon cancer and 29 percent lower risk for rectal cancer. Compared with nonvegetarians, vegans had a 16 percent lower risk of colorectal cancer, 18 percent less for lacto-ovo (eat milk and eggs) vegetarians, 43 percent less in pescovegetarians (eat fish) and 8 percent less in semivegetarians, according to study results.

Very interesting. Gives people a way to eat red meat, but not increase their colorectal cancer risk (by also eating resistant starch, e.g., potato salad or beans). From Science Daily:

Eating resistant starch may help reduce red meat-related colorectal cancer risk

Consumption of a type of starch that acts like fiber may help reduce colorectal cancer risk associated with a high red meat diet, according to a study. "Red meat and resistant starch have opposite effects on the colorectal cancer-promoting miRNAs, the miR-17-92 cluster," said one researcher. "This finding supports consumption of resistant starch as a means of reducing the risk associated with a high red meat diet.

Unlike most starches, resistant starch escapes digestion in the stomach and small intestine, and passes through to the colon (large bowel) where it has similar properties to fiber, Humphreys explained. Resistant starch is readily fermented by gut microbes to produce beneficial molecules called short-chain fatty acids, such as butyrate, she added.

"Good examples of natural sources of resistant starch include bananas that are still slightly green, cooked and cooled potatoes [such as potato salad], whole grains, beans, chickpeas, and lentils. Scientists have also been working to modify grains such as maize so they contain higher levels of resistant starch," said Humphreys.

After eating 300 g of lean red meat per day for four weeks, study participants had a 30 percent increase in the levels of certain genetic molecules called miR-17-92 in their rectal tissue, and an associated increase in cell proliferation. Consuming 40 g of butyrated resistant starch per day along with red meat for four weeks brought miR-17-92 levels down to baseline levels.

The study involved 23 healthy volunteers, 17 male and six female, ages 50 to 75. Participants either ate the red meat diet or the red meat plus butyrated resistant starch diet for four weeks, and after a four-week washout period switched to the other diet for another four weeks.

Some recent studies have explored the link between bacteria in the gut and colorectal cancer. The beneficial Prevotellaceae bacteria (mentioned in the Nov. 5 study below) have been discussed elsewhere as liking whole grain foods. So go feed your gut with some nice whole grain bread or cereal. And some fruits and veggies while you're at it. As mom used to say: "You are what you eat."

A study published December 6, 2013 found that decreased diversity of the gut microbiome and the presence of certain types of bacteria were associated with colorectal cancer in humans: Decreased Diversity of Bacteria Microbiome in Gut Associated Colorectal Cancer

From the November 5, 2013 Science Daily: Microbes in the Gut Help Determine Risk of Tumors

Transferring the gut microbes from a mouse with colon tumors to germ-free mice makes those mice prone to getting tumors as well, according to the results of a study published in mBio®, the online open-access journal of the American Society for Microbiology. The work has implications for human health because it indicates the risk of colorectal cancer may well have a microbial component.

Scientists have known for years that inflammation plays a role in the development of colorectal cancer, but this new information indicates that interactions between inflammation and subsequent changes in the gut microbiota create the conditions that result in colon tumors.

Known risk factors for developing colorectal cancer include consuming a diet rich in red meat, alcohol consumption, and chronic inflammation in the gastrointestinal tract (patients with inflammatory bowel diseases, such as ulcerative colitis, are at a greater risk of developing colorectal cancer, for instance).

The results were stark: mice given the microbiota of the tumor-bearing mice had more than two times as many colon tumors as the mice given a healthy microbiota. What's more, normal mice that were given antibiotics before and after inoculation had significantly fewer tumors than the mice that got no antibiotics, and tumors that were present in these antibiotic-treated mice were significantly smaller than tumors in untreated mice. This suggests that specific populations of microorganisms were essential for the formation of tumors...

Looking at the microorganisms, they found that tumor-bearing mice harbored greater numbers of bacteria within the Bacteroides, Odoribacter, and Akkermansia genera, and decreased numbers of bacteria affiliated with members of the Prevotellaceae and Porphyromonadaceae families. Three weeks after they were inoculated with the communities from the tumor-bearing mice, the germ-free mice had a gut microbiome that was very similar to the tumor-bearing mice, and they had a greater abundance of the same bacterial groups associated with tumor-formation.