By Dr. Mercola
The type and amount of fiber in your diet plays an important role in health — in part by positively affecting your intestinal microflora, which we now know is important for maintaining optimal health and preventing chronic disease.
I've been interested in the health benefits of fiber ever since my early days in medical school — so much so, my classmates nicknamed me "Dr. Fiber."
Fiber does far more than just keep you "regular." Mounting research suggests a high-fiber diet can help reduce your risk of premature death from any cause, likely because it helps to reduce your risk of some of the most common chronic diseases.
This includes type 2 diabetes, heart disease, stroke,1 and cancer. Studies have also linked a high-fiber diet to beneficial reductions in cholesterol and blood pressure, improved insulin sensitivity, and reduced inflammation — all of which can influence your mortality risk.
A meta-analysis2,3 published in 2014 evaluated the impact of a high-fiber diet on mortality and found that each 10-gram per day increase in fiber corresponded to a 10 percent reduction in all-cause mortality.
Another study4,5 published that same year produced similar results. Here, every 10-gram increase of fiber intake was associated with a 15 percent lower risk of mortality.
Those who ate the most fiber had a 25 percent reduced risk of dying from any cause within the next nine years, compared to those whose fiber intake was lacking.
Microbes That Ferment Fiber Are Important for Health
Recent research reveals that certain microbes in your gut specialize in fermenting fiber found in legumes, fruits, and vegetables, and the byproducts of this fermenting activity help nourish the cells lining your colon.
Some of these fermentation byproducts also help calibrate your immune system, thereby preventing inflammatory disorders such as asthma and Crohn's disease.6,7
As reported by MedicineNet.com,8 fiber-fermenting microbes are likely part of what makes a Mediterranean-style diet so beneficial for your health.
During the fermentation process these intestinal bacteria produce short-chain fatty acids, which have been shown to reduce your risk of diabetes, heart disease, and other inflammatory diseases.
According to the featured article:9
"The study of 153 Italian adults found higher levels of short-chain fatty acids in vegans, vegetarians, and those who closely followed a Mediterranean diet.
The diet includes large amounts of fruits, vegetables, legumes, nuts and cereals; moderately high amounts of fish; low levels of saturated fat, red meat and dairy products; and some alcohol...
'Multiple studies have shown the benefits of the Mediterranean diet,' noted one U.S. expert, cardiologist Dr. Suzanne Steinbaum.
The new research 'shows that the benefits may occur through the GI (gastrointestinal) tract and the metabolites that are released during the digestive process,' she said."
These findings support previous research, in which it was shown that these short-chain fatty acids produced by intestinal bacteria selectively expand regulatory T cells called Tregs, which are critical for regulating intestinal inflammation.10
According to one such study:11
"Treg cells suppress the responses of other immune cells, including those that promote inflammation. This finding provides a new link between bacterial products and a major anti-inflammatory pathway in the gut."
Other research12,13 has linked Tregs to the prevention and reversal of metabolic syndrome, in part by stimulating oxidative metabolism in your liver and adipose tissue.
Reducing Your Sugar Intake Is Also Important
It's also worth noting that a Mediterranean-style diet tends to be far lower in sugars than your typical American processed food diet, and sugar is a preferred food source for fungi that produce yeast infections and sinusitis.
So the beneficial impact of a Mediterranean-style diet is really two-fold: the high-fiber content promotes healthy bacteria that produce health-promoting fatty acids and other beneficial byproducts, and the absence of sugar depletes harmful microbes, allowing the beneficial ones to thrive and thoroughly colonize.
For Gut Health, You Need the Right Kind of Fiber
As mentioned, one way fiber benefits your health is by providing beneficial bacteria in your gut with the fodder they need to thrive. These beneficial bacteria assist with digestion and absorption of your food, and play a significant role in your immune function.
Alterations of the human microbiome through inappropriate and unnatural diet changes appear to be part and parcel of rising disease rates. In essence, we've strayed too far from our natural diet that promotes a healthy gut flora.
Detrimental dietary changes that have led to a general fiber deficiency14 include switching from fermented and raw vegetables to processed cereal grains.
Cereal grains may have been a good source of fiber in the past, but not anymore. These days, most grains are grown using agricultural chemicals such as glyphosate, which has now been identified as a "probable human carcinogen" and a promoter of antibiotic resistance.
Glyphosate contamination has also been linked to celiac disease and other gut dysfunction, which is the exact converse of what you're trying to achieve by adding fiber to your diet.
Moreover, a high-grain diet tends to promote insulin and leptin resistance, and that too is counterproductive as it actually promotes many of the chronic diseases that healthy fiber can help reduce, most notably type 2 diabetes, heart disease, and cancer.
So when it comes to boosting your fiber intake, be sure to focus on eating more vegetables, nuts, and seeds. Organic whole husk psyllium is a great source, as are sunflower sprouts and fermented vegetables, the latter of which are essentially fiber preloaded with beneficial bacteria.
The following whole foods also contain high levels of soluble and insoluble fiber.
Flax, hemp, and chia seeds Berries Vegetables such as broccoli and Brussels sprouts Root vegetables and tubers, including onions, sweet potatoes, and jicama Almonds Peas Green beans Cauliflower Beans
The Health Benefits of Organic Psyllium
Organic whole husk psyllium is one of my personal fiber favorites. Most people need roughly 50 grams of fiber per 1,000 calories consumed, and taking psyllium three times daily could add as much as 18 grams of dietary fiber (soluble and insoluble) to your diet. Conventional psyllium is a heavily sprayed crop, so I strongly recommend opting for an organic version to prevent exposure to pesticides, herbicides, and chemical fertilizers.
I also recommend choosing one that does not contain additives or sweeteners, as these tend to have a detrimental effect on your microbiome. Psyllium has a number of well-established health benefits, including the following:15
- Maintaining regular bowel movements: Psyllium absorbs water in your gut, allowing for easier, smoother bowel movements. As such, it helps counteract constipation, and over the long-term will help you develop more regular bowel movements. It can also help ease hemorrhoids and anal fissures, which are aggravated by constipation.
- Optimizing cholesterol ratios and promoting heart health: Research has shown that psyllium helps optimize cholesterol ratios,16 and reduces your risk of heart disease17 by lowering blood pressure, strengthening your heart muscle, and improving lipid levels.
- Weight management: Psyllium (and other fiber sources) can also help you manage your weight. Part of this effect is related to the fact that fiber helps normalize your blood sugar. In one study,18 a mere five grams of psyllium a day helped diabetics control their blood sugar levels. Since fiber adds bulk, it can also help you feel fuller, thereby reducing overeating.
Chia Seeds — Another Health-Boosting Type of Fiber
Chia seeds are another good source of fiber, providing about five grams per tablespoon — plus a whole lot more.19 They're also a rich source of omega-3 fats, antioxidants, and minerals, including calcium, phosphorus, magnesium, and manganese. These minerals are important for regulating blood pressure, body weight, energy metabolism, and DNA synthesis.
Their high antioxidant content also gives chia seeds the benefit of a long shelf-life. They can stay fresh without refrigeration for about two years. Chia seeds have also been linked to a number of health benefits, including:
- Improved satiety: Like psyllium, they add bulk and make you feel fuller longer.
- Improved blood lipids: Research has shown that chia seeds can help lower triglycerides optimize cholesterol ratios, and increase high density lipoprotein (HDL, typically known as "good" cholesterol).
- Blood sugar regulation: Chia seeds have also been shown to help reduce insulin resistance, and reduce the levels of insulin in your blood.
Mushrooms, a Novel Source of Dietary Fiber
Another novel source of dietary fiber is mushrooms. According to a 2013 study,20 edible mushrooms vary greatly in their fiber content, but the highest levels are typically found in the sclerotium21 — the dense mass of filaments (mycelium) that make up the body of the mushroom. An added benefit of mushrooms is that they also tend to have medicinal properties, such as immune-boosting and even anti-cancer activity. Like so many other fiber-rich foods, mushrooms can also help control blood lipids and glucose levels.
According to the authors:
"Compared to other conventional sources of dietary fiber (DF), such as cereals, fruits, legumes, and vegetables, mushrooms or fungi are underutilized. In fact, edible mushrooms or macrofungi are a rich source of some novel DFs that have various beneficial health effects to humans...."
Percentage-wise, the approximate fiber ratio of some of the most common edible mushrooms is as follows:
- Button mushroom: 8 to 10 percent
- Chantarelle: 11 percent
- Maitake: 10 percent
- Shiitake: 7 to 8 percent
- Oyster mushroom: 7.5 to 8.5 percent
For Optimal Health, Eat More Fiber and Fermented Veggies
Remember, dietary fiber has many benefits, as long as most of it is coming from high quality sources, such as organic, vegetables, organic psyllium, and chia seeds. Adding more mushrooms to your diet is also recommended, as they have great medicinal value over and above any fiber content. Fiber undoubtedly contributes to overall good health and longevity, and can have a positive influence on your disease risk by feeding and promoting the proliferation of healthy gut bacteria. They also contribute to the production of short-chain fatty acids like butyrate, which increase mucin in the gut that decreases leaky gut and also improves the health of the gut lining.
As briefly mentioned, fermented vegetables are another excellent choice, as not only are you getting valuable fiber from the vegetables, this fiber is also 'preloaded' with beneficial bacteria that nourish your gut. And gut health is really paramount if you're seeking to improve your health and prevent or treat disease. As noted in a previous Your Buddhi22 article that addresses the benefits of fiber and fermented veggies, the former is a prebiotic, whereas the latter are probiotic. Both are essential for a healthy gut:
"Fiber found in whole plant foods (fruits, veggies, grains, nuts, and seeds) is used by the large intestine to influence 'transit' time length. Fiber also feeds the gut flora, which are the healthy bacteria that use fiber as a medium to synthesize nutrients like vitamin K, and B-vitamins that are essential for GI cells. Fermented foods such as miso, tempeh, cultured dairy (kefir, yogurt), kombucha tea, kimchi, chutneys, and any fruit/vegetable fermented using lactic acid support a healthy intestinal flora. They also provide Lactobacillus acidophilus, a healthy source of bacteria."
Avoid relying on grain-based fiber sources, as this can threaten your health in too many ways, from raising your insulin and leptin levels, to increasing your risk of glyphosate exposure. Processed grains are particularly harmful, and are second only to refined sugar and fructose in terms of promoting chronic disease. If there's one thing you do NOT need, it's processed sugar — from any source. Instead, get your fiber from fresh locally grown organic vegetables, nuts, and seeds. If you still fall short of the recommended 50 grams of fiber per 1,000 calories consumed, supplementing with organic psyllium husk can help bring you closer to this ideal amount.