Increasing Fiber Decreases Major Health Risks

high fiber foods

Story at-a-glance -

  • A recent study revealed that when people who’ve been diagnosed with colon cancer increase their fiber intake, their risk of dying from it drops below the risk of those who don’t eat a lot of fiber
  • For each additional 5 grams of dietary fiber eaten by colon cancer patients, their odds of dying from the disease decreased by 22 percent, with a 14 percent lower risk of dying from any cause compared to those who ate the least
  • Fiber derived from vegetables and foods such as inulin-rich garlic, leeks, chicory root, Jerusalem artichoke and bananas is the best way to get fiber into your system, as opposed to fiber gotten via grains
  • A compromised microbiome may be the culprit in inflammatory bowel disease, autoimmune disease, allergies and even neuropsychiatric illnesses such as schizophrenia and attention deficit hyperactivity disorder

By Dr. Mercola

It’s become increasingly clear in recent years that fiber intake is a more crucial “mover and shaker” in the fight against cancer and other serious diseases than was previously realized. A perfect example, a recent study1 reveals, is the discovery that people with colon cancer who add extra fiber to their overall food intake may have a lower risk of mortality compared to people who don’t consume much fiber.

Adequate fiber intake is so crucial to health, asserts senior study author Dr. Andrew Chan of Harvard Medical School and Massachusetts General Hospital in Boston, that consuming more fiber after such a diagnosis can positively impact patients’ risk of dying from the disease, independent of how much fiber those patients ate before the diagnosis.

How Do You Like Them Odds?

Chan and his team used the data of 1,575 adults with colon cancer to determine how much fiber they were used to eating, then followed half of them for eight years. Of that number, 733 of them died — 174 of that number from colon or rectal cancer tumors.

However, the numbers confirmed that for each additional 5 grams of dietary fiber a patient consumed, their odds of dying of colorectal cancer decreased by 22 percent. In addition, those patients also had a 14 percent lower risk of dying from any cause when compared to those who reported the lowest dietary fiber consumption.

It’s clear that when an individual learns they have colon cancer — and as a consequence changes their diet to add more fiber — their survival rate increases. But notice that the term “dietary” fiber is used. While the researchers promoted cereal grains as among the best ways to increase fiber intake, I do not recommend this. Grains will raise your insulin and leptin levels, which is a major driver of most chronic diseases. There are far healthier forms of fiber, including that from vegetables, berries, psyllium seed husk, flax and chia seeds.

So What Factors Are the Biggest Contributors to Disease?

Dr. Samantha Hendren, a researcher at the University of Michigan (not involved in the study) maintains what many doctors believe, that the most telling risk factors for colon cancer are family history, a personal history of cancerous polyps, diseases such as ulcerative colitis and failure to get screened for the disease.

However, other factors can influence risk, Hendren noted, mentioning lifestyle.2 Another researcher, Nour Makarem, at Columbia University in New York (and also not involved in Chan’s study), said that for her part, diet is very important, particularly as it relates to dietary fiber, as eating foods high in fiber can lower the risk of developing colon cancer.

“Therefore, consuming a healthy diet that is high in … fiber sources such as fruits and vegetables, may protect from colorectal cancer. (It) also improves outcomes and reduces risk of death among colorectal cancer survivors.”3

Dr. Jennifer Wargo, a surgeon and research scientist working with the Parker Institute for Cancer Immunotherapy, conducted research showing that the intestinal flora of cancer patients play a significant role in whether or not they respond to “breakthrough” immunotherapy.4 Some have thought specific bacteria had to be present for a person’s gut health to be considered healthy; Wargo believes it’s the diversity.

“I don’t think it’s one bacteria per se that’s driving this entire response. I think it’s probably a community of bacteria. And what we found is that, in patients who responded to the treatment, they actually had a much higher diversity of bacteria in their gut microbiomes compared to non-responders.”5

This is important, as low-fiber diets have been linked to less microbial diversity in the gut in animal studies.6 So eating a fiber-rich diet, which in turn may improve the microbial diversity in your gut, may be linked to better responses during immunotherapy cancer treatment.

Wargo also explained that the question of diet for health and disease prevention can’t be ignored, wondering aloud if patients with a fiber-rich and more microbiome-friendly diet may fare better during cancer treatment and whether eating in this way may help facilitate and enhance the immune system, ultimately preventing cancer.7

Fiber Should Be on Your ‘High Priorities’ List

One of the biggest problems with the American diet (and arguably that of much of the world) is that fiber is low on the list of priorities. While the U.S. Food and Drug Administration (FDA) recommends 25 grams of fiber per day based on a 2,000 calorie diet,8 to which most people don’t even come close, my recommendation is more than that: 50 grams per 1,000 calories.

For some, this would mean an utter diet transformation, but one that could improve not just your digestive health but likely transform your health overall. Fiber in your diet is not only important for helping foods “swish” the inside of your large intestine and colon to help move everything through properly, your gut microbiome also benefits, and the rest of your body does, too, from the other nutrients in the whole foods you eat.

Interestingly, it’s actually your body’s inability to digest some types of fiber that makes it so important in the digestive process. Soluble fiber, found in foods such as Brussels sprouts, blueberries and flaxseeds, attracts water and helps these foods dissolve into a gel-like texture, which helps slow down your digestion.

Why do you want digestion to take more time? Because you’ll feel full longer, which helps you eat less. Insoluble fiber is found in dark green leafy vegetables, celery and carrots, among other whole foods. Like its name suggests, it doesn’t dissolve, so this type helps food move through your digestive tract more quickly for healthy elimination.

Many whole foods, especially fruits and vegetables, contain both soluble and insoluble fiber. So, both types of fiber are good for you, imparting benefits that range from fewer hemorrhoids and a lower risk of kidney stones and gallstones to, more importantly, a lower incidence of stroke, heart attack and diabetes.

Your skin may even improve once toxins make their way out of your body. Additionally, as fiber helps escort yeast and fungus out, their potential for being excreted through your skin to cause acne, rashes and other skin problems is diminished.

Cause and Effect: ‘Which Came First, the Disease or the Disrupted Microbiota?’

An example of the importance of how gut bacteria impacts a person’s health is how the absence of it increases a person’s propensity toward obesity. The New York Times notes the work of microbiologist Claire M. Fraser-Liggett and geneticist Dr. Alan R. Shuldiner, from the University of Maryland’s School of Medicine:

“Previous studies have already found differences in the gut microbiota of lean and obese adults. There is also evidence that the typical high-calorie American diet rich in sugar, meats and processed foods may adversely affect the balance of microbes in the gut and foster the extraction and absorption of excess calories from food.

A diet more heavily based on plants — that is, fruits and vegetables — may result in a microbiome containing a wider range of healthful organisms. In studies, mice that had a microbiota preconditioned by the typical American diet did not respond as healthfully to a plant-based diet.”9

Studies have explored this phenomenon and found that the gut microbiome more directly influences your health and disease than previously thought. Besides the obesity and problems that result due to “colonization with multidrug-resistant organisms,” one study10 listed health conditions that can occur when the microbiome is compromised:

  • Clostridium difficile infection, aka C. diff, a “sometimes devastating intestinal infection” that can occur when powerful antibiotics annihilate healthy bacteria that otherwise keep your microbiome balanced. Fecal transplant is one treatment that’s been used to treat such debilitating disorders, and has a 90 percent success rate.11
  • Inflammatory bowel diseases (IBDs) such as Crohn’s and ulcerative colitis, evidenced by such symptoms as frequent diarrhea, rectal bleeding, abdominal cramps, nausea and fatigue.
  • Allergic diseases such as asthma and eczema were observed less in the children of a rural African village who ate fiber-rich diets that positively affected their gut health, compared to children exposed to a more Western diet, and protected them from disease-causing illnesses and infections.12
  • Autoimmune diseases may be one result of how “bad” gut microbes and too few good ones can affect your entire body. Rheumatoid arthritis is one example, the study authors suggested, as animal studies have demonstrated that some bacteria can cause antibodies to attack and wreck joint health.13
  • Neuropsychiatric illnesses such as schizophrenia, attention deficit hyperactivity disorder (ADHD), autism and obsessive-compulsive disorder are conditions possibly rooted in a damaged microbiota. Depending on your genetic makeup, altered microbes may disrupt the blood-brain barrier to modify normal brain development.14

Want a Little Fiber With That?

It’s quite sobering to realize that your diet can either make or break not just the ecosystem in which your gut bacteria reside, but also your mental health. And it’s not just the food you eat but all kinds of other factors, including the chemicals and pollution you’re exposed to. All of it can alter the composition of gut bacteria, Belfast Telegraph contends.15

As such, the recommendation is to “eat with your gut in mind” as at least one thing you can control to improve your immune system and other aspects of health through fiber consumption for better intestinal bacteria.

Interestingly, while you can augment your intestines with probiotics from raw grass fed yogurt, sauerkraut and kefir, you can also do it by eating inulin-rich, gut-beneficial foods like raw garlic, leeks, chicory root, Jerusalem artichoke and bananas, according to Dr. Dan Robertson, a medical officer at Push Doctor, who advises:

“Looking after your gut is really important. That means eating a balanced diet and not bombarding your microbiome with foods that are hard to break down, such as refined carbs, trans fats and foods high in added sugar. Try to stick to regular mealtimes too, so that your gut can get into a regular pattern.”16

The latter foods (raw garlic, leeks, chicory root, Jerusalem artichoke and bananas) are examples of prebiotics, which help nourish beneficial bacteria and have been found to beneficially alter gut microbiota and significantly reduce body weight and body fat.17 Since obesity is linked to cancer, it stands to reason that consuming more prebiotic fiber may also help lower your cancer risk by helping with weight loss. Additional healthy foods containing high amounts of fiber include:

  • Vegetables: Acorn squash, Brussels sprouts, cauliflower, broccoli
  • Seeds: Chia seeds, flaxseeds and psyllium husk
  • Berries: Elderberries, raspberries, loganberries, blackberries
  • Nuts: Almonds, pistachios, walnuts
  • Fruits: Fresh pears, oranges and avocados; dried figs, prunes

While berries are fruits, too, they contain such high amounts of fiber they can be placed in a category all their own.

Caveats When Eating Anything, Even When It’s ‘Healthy’

That said, keep other ingredients and food factors in mind when you eat. Many fruits contain high amounts of natural sugar, known as fructose, which is why I recommend eating most fruit in moderation and focusing on vegetables to increase your fiber intake.

No matter what foods you eat, organic is always best. While eating organic foods won’t always guarantee your food will be free of every pesticide, chemical or genetically modified organism (which, while genetic engineering isn’t allowed in organics, could potentially contaminate organic crops), it’s among your best bets in dealing with some of the unknowns, which goes not only for exotic foods but also some of the time-honored staple crops grown throughout the U.S.

As gut genomics specialist from Washington University School of Medicine, Dr. Jeffrey Gordon, explains, “The nutritional value of food is influenced in part by the microbial community that encounters that food.”18 And you can improve your gut microbiome by eating plenty of fiber. If you’re not sure how much you’re consuming daily, Cronometer.com is a free online nutrient tracker that can help.

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