Join Dr. James Odell for Season 2 of the Science of Self-Healing Podcast! He's the medical and executive director for BRMI, as well as a practicing naturopathic doctor for over 35 years, and he's here to share with you his extensive knowledge of medicine from a different perspective.
Think you're getting enough fiber? Chances are, you're not - a shocking 90% of us fall short. But this isn't just about staying regular. Join us as we reveal why it's the unsung hero of nutrition. From feeding your gut bacteria (so they don't eat your intestinal lining!) to boosting brain health, controlling blood sugar, and even helping your body remove toxins - fiber does way more than you might think. Learn the difference between soluble and insoluble fiber, discover the best food sources, and get practical tips for gradually increasing your intake without the uncomfortable side effects. This episode explains why fiber is so important and deserves more attention, whether you're very health-conscious or just starting to improve your diet.
Transcript: An Important Nutrient Your Diet Probably Lacks (and how to get more of it)
Hello, everyone, and welcome to the Science of Self-Healing podcast. For health and wellness knowledge from a different perspective. Produced by the Bioregulatory Medicine Institute, also known as BRMI. We are your source for unparalleled information about how you can naturally support your body's ability to regulate, adapt, regenerate, and self-heal. I'm your host, Dr. James Odell, the medical and executive director for BRMI, as well as a practicing naturopathic doctor for over 35 years. And remember, this podcast is for informational purposes only and is not intended to be a substitute for the direct care of a qualified health professional who oversees and provides unique and individual care. The information here is to broaden our different perspectives and should not be construed as medical advice or treatment. Let's get started.
In today’s podcast we’ll be talking all about dietary fiber and why you really need to make sure that you are getting enough of this important dietary staple.
You've probably heard a constant reminder about eating more fiber - from health experts, doctors, and maybe even your grandmother. But what's all the fuss about this seemingly mundane dietary component? The truth is, fiber might be one of the most underappreciated heroes in the nutrition world, and shockingly, only about 10% of us are getting enough of it. Let's dig into what makes fiber so special, untangle the differences between its two main types, explore its remarkable health benefits (some of which might surprise you), and discover practical ways to “up your fiber game.”
Let’s start with what dietary fiber is.
Well, it’s actually a type of carbohydrate that your body can't digest or absorb. It comes in two main forms: soluble and insoluble fiber, each with distinct roles for influencing our health. It is mostly found in fruits, vegetables, and whole grains, but NOT in meat, fish, poultry, eggs, or dairy products.
Let’s talk about the two main types of fiber, starting with soluble fiber.
Soluble fiber dissolves in water and forms a gel-like substance when it mixes with water in the GI tract which slows digestion. Found in foods like oats, beans, apples, sweet potatoes, and citrus fruits, it has some pretty impressive benefits – from helping food move through the gut at just the perfect pace – to feeding the beneficial bacteria in your gut.
Insoluble fiber doesn't dissolve in water but adds bulk to stool and helps food move through your digestive system. It’s found primarily in whole grains, nuts, brown rice, leafy greens, and vegetables and is mostly unchanged as it moves through the digestive tract. Its main attribute is that it helps prevent constipation and supports regular bowel movements.
Okay, so now that you know what it is, let's talk about why it’s so important for your health.
You have probably heard that fiber is really important for digestive health and regularity, so let’s start there.
One of the most important jobs of soluble fiber happens in our digestive system, where it becomes food for the beneficial bacteria living there. This is important because different types of fiber feed different kinds of bacteria and this helps create a diverse and healthy gut environment. As these bacteria digest the fiber, they produce several important compounds called short-chain fatty acids. One of these, called butyrate, provides energy to the cells lining our colon and helps protect against colon cancer. Other compounds produced during this process travel to our liver – and throughout our body – helping to control inflammation, and stimulate immune cell activity – which enhances the body's ability to fight off infections.
Through its effects on our gut bacteria, fiber can even influence our brain health, potentially improving mood and memory while reducing the risk of certain brain diseases. The connection between fiber, gut bacteria, and brain health is a remarkable example of how our diet affects our entire body, including our mind. When we eat fiber, our gut bacteria breaks it down and creates important chemicals that can actually communicate with our brain through what scientists call the "gut-brain axis." This is like a two-way communication highway between our digestive system and our brain, where messages travel back and forth constantly.
When our gut bacteria digest fiber, they produce several important compounds, including neurotransmitters - the same type of chemicals our brain uses to send messages. For example, these bacteria can help produce serotonin (often called the "happy chemical") and other substances that affect our mood and thinking. About 90% of our body's serotonin is actually made in our gut, showing just how important this connection is. When we feed our gut bacteria well with fiber, they're better able to produce these helpful brain-supporting compounds.
But here’s where it gets a little crazy….When we don't eat enough fiber, our gut bacteria face a serious food shortage because fiber is their primary source of nutrition. These bacteria need to eat something to survive, so when they run out of fiber, they turn to the next available food source: the protective mucus layer that lines our intestines. This mucus layer is actually a complex barrier that helps protect our gut wall from harmful substances and maintains gut health.
Think of it like a living protective coating on the inside of our intestines. When bacteria start consuming this protective layer because they're starving for fiber, it becomes thinner and weaker. This can lead to a condition often called "leaky gut," where the intestinal barrier becomes more permeable than it should be. When this happens, substances that should stay in our gut might pass through into our bloodstream, potentially causing inflammation and other health issues throughout our body.
This is why consistent fiber intake is so crucial - it's not just about feeding ourselves, but about feeding our gut bacteria so they don't have to resort to eating our protective barriers. When we give these bacteria enough fiber, they thrive and actually help strengthen our gut barrier by producing beneficial compounds like short-chain fatty acids, which help maintain and repair the gut lining. It's a mutually beneficial relationship: we feed the bacteria fiber, and in return, they help protect and maintain our gut health instead of breaking down our protective barriers.
If that’s not enough to convince you to make sure that you are consuming enough fiber, consider this. Fiber also helps manage bile acids - substances our liver makes to help digest fats. Normally, these bile acids get reused by our body in a recycling process. But when we eat fiber, it acts like a sponge, soaking up these bile acids and stopping them from being recycled. This forces our liver to make new bile acids using cholesterol from our blood, which helps lower our cholesterol levels. At the same time, this process helps our body get rid of harmful substances like toxins and excess hormones (present in the bile) that would otherwise be recycled back into our system. For example, by removing excess estrogen from our body, we may be able to help prevent certain types of cancer.
Fiber also helps control blood sugar in several ways. When we eat, the fiber in our food turns into a gel-like substance that slows down digestion. This means sugar enters our bloodstream more slowly, preventing sudden spikes in blood sugar levels. This gel also affects various hormones in our digestive system and changes how quickly food moves through our stomach, all of which helps our body handle sugar better over time.
The benefits of fiber extend even further throughout our body. During digestion, fiber actually helps our body absorb important minerals like calcium, magnesium, and iron better. And it may also improve skin health by reducing inflammation, help prevent allergies and asthma, support liver function, and even contribute to better sleep.
So, you might be wondering what problems arise from not getting enough fiber, so let’s briefly talk about that for a moment.
A diet very low in fiber can lead to several significant health problems, both short-term and long-term:
The Short-term Effects:
- Constipation and irregular bowel movements
- Harder stools that are difficult to pass
- Feeling less full after meals, leading to overeating
- Blood sugar spikes and crashes
- Less regular digestion
- Bloating and discomfort
Long-term Health Risks:
- Increased risk of colorectal cancer
- Higher chance of developing diverticular disease (small pouches in the colon that can become inflamed)
- Elevated risk of heart disease
- Greater likelihood of developing type 2 diabetes
- Higher risk of obesity due to reduced satiety
- Poor gut health with less diverse beneficial bacteria
- Increased risk of hemorrhoids
- Higher cholesterol levels
- Potential nutrient deficiencies (since fiber-rich foods often contain important vitamins and minerals)
So, here’s what to expect once you start introducing more fiber into your diet:
Changing your gut microbiome is like nurturing a garden inside your body, so it will take time, patience, and consistent care to flourish. When you start increasing your fiber intake, your microbiome begins a transformation that unfolds over several weeks and months.
In the first two weeks, your existing gut bacteria start to react to the new food sources you're introducing. This initial period can feel a bit uncomfortable - you might experience some gas or bloating as your internal ecosystem begins to shift.
As you move into weeks three and four, something exciting starts to happen –new strains of bacteria begin to multiply. During this time, your body begins producing more short-chain fatty acids, which will begin to gradually strengthen your intestinal barrier.
By weeks five through eight, your microbiome starts to stabilize and become more diverse. You'll likely notice that your digestive system feels more comfortable, and the beneficial bacteria populations are growing significantly. The variety of microbes increases, making your gut more robust.
The real magic happens between months three and six. With sustained dietary fiber intake, your microbiome becomes better established and can withstand various environmental challenges. Your metabolic functions improve, your immune response becomes more sophisticated, and inflammation in your body becomes better regulated.
So, here’s the short list of high-fiber foods. We have a more extensive list for you on our website in the episode show notes.
- Legumes (beans, lentils, peas)
- Whole grains (oats, quinoa, brown rice)
- Fruits (especially berries, apples, pears)
- Vegetables (particularly avocados, leafy greens, Brussels sprouts, broccoli)
- Nuts and seeds (chia seeds, flaxseeds, almonds)
And lastly, here are my recommendations…
Most plant-based foods consist of both soluble and insoluble fiber, but in varying amounts. Eating the skin or peel of fruits and vegetables (when appropriate) provides more insoluble fiber, while the flesh often contains more soluble fiber.
The recommended daily fiber intake for women is 25 grams per day, and for men it’s about 38 grams per day.
Increase intake gradually to avoid digestive discomfort. Remember that rapid increases in fiber intake can cause bloating and gas, so gradual changes are best.
A practical tip for increasing fiber intake is to add one high-fiber food to each meal, starting with breakfast. Read nutrition labels and aim for foods with at least 3 grams of fiber per serving.
Drink plenty of water, as fiber works best with adequate hydration.
This is an important one…Get fiber from whole foods rather than supplements when possible. Eat a variety of different fiber-rich foods for a more diverse gut microbiota, which is generally associated with better health outcomes. Since more diverse gut microbiota are more adept at responding to environmental challenges such as resisting colonization of gut pathogens.
In addition, consuming ultra-processed (aka refined) fibers added to foods is not recommended. They are being incorporated by food manufacturers in a variety of processed foods with the intent to enhance their health benefits and narrow the fiber-intake gap, but they have been associated with risks to both gastrointestinal and liver health.
Here’s another important one…spread fiber intake throughout the day rather than all at once.
Keep in mind that some medical conditions may require limiting certain types of fiber.
Cooking does not change the amount of fiber in foods; cooked and puréed vegetables contain the same amount of fiber as raw vegetables.
If you feel as though you need to take a supplement -- and I don’t mean a replacement for fiber – consider taking psyllium, and remember to take it with PLENTY of water. Psyllium fiber is a soluble prebiotic fiber that has been shown to alter the gut microbiome in a positive way, decrease inflammation, reduce cholesterol, and regulate bowels.
So, I’ll leave you with this final thought…. consuming dietary fiber, naturally present in whole foods, is extremely beneficial for overall health. Until next time, be well.
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