This the unedited version of my article from Edition 9 of
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Australia, like all Western societies, is suffering from an epidemic of fibre deficiency. In an article published in the May edition of Nutrition, written by researchers from Nutrition Research Australia and the Department of Statistics, the authors reported on fibre intakes among Australian children and adults, using the 2011–2012 National Nutrition and Physical Activity Survey. They found that only 42.3% of children and 28.2% of adults met the Adequate Intake (AI), and “less than 20% of adults met the Suggested Dietary Target (SDT) to reduce the risk of chronic disease.”
These statistics were gathered before the latest carbophobic ketogenic diet fad kicked in, so the current figures may be worse. When people assume ALL carbs bad, they are effectively throwing the baby (the fibre) out with the bathwater (the refined carbohydrates). Thankfully, popular concepts such as superfoods, nutrient density, gut health, and the anti-sugar movement, have been helping to turn the tide. Anytime we step away from refined, processed foods and embrace whole plant-foods, we’re repairing our broken relationship with fibre and giving ourselves an opportunity to live longer, healthier and happier lives.
Fibre is a macronutrient found in whole plant-foods. There are many kinds of fibre, all of which are categorised in nutrition as complex carbohydrates. Fibre-rich foods are whole plant-foods that haven’t been refined or processed in ways that remove the fibre. Unprocessed or minimally processed foods rich in complex carbohydrates, such as wholegrains, are staple foods in the diets of countries where chronic diseases are rarely seen. As dietician and Julieanna Hever points out in The Complete Idiots Guide to Plant-Based Nutrition, “Societies have survived and thrived on a whole-grain-based diet since the beginning of recorded history.” Sadly, when these communities modernise these diets, replacing carbohydrate-rich foods with animal products and highly processed foods, several chronic diseases become more common.
Nutritional anthropologists estimate pre-agricultural fibre intake to range between 70 – 150g per day. In modern times, rural communities are the only populations whose fibre intakes come anywhere close to these figures. In rural Africa, for example, fibre intakes range between 60-120g per day. Rural Chinese consume up to 77g per day. The World Health Organisation (WHO) recommend at least 25g of dietary fibre per day for adults. Unfortunately, modern Western diets only average about 15 – 17g per day.
Fibre is completely absent in animal products (meat, fish, eggs, dairy, honey etc) and added sugars. Added sugars are created when food manufacturers remove sugars from whole plant-foods. Once isolated from the rest of the plant, these highly concentrated sugars are used as additives in processed foods or sold directly to consumers who add the sugar to their foods and beverages. The WHO warns that not more than 10% of calories should come from these ‘added sugars’.
Fibre content is significantly reduced in processed grains, such as white flour and white rice. These foods have had most or all of their fibre removed, along with the nutrients that were embedded in that fibre. Foods made out of these processed grains such as white bread, cakes, biscuits and so on, are fibre-deficient foods.
Supplements or wholefoods?
Dietary fibre was first made popular by researcher Dennis Burkitt in the 1970’s when he discovered that rural Africans were free of the western diseases that have become leading causes of death in first world countries, such as heart disease, diabetes, obesity and colon cancer. When comparing the diets of rural Africans with the diets of westerners, Burkitt realised that it was the relative absence of fibre in the western diet that was making all the difference. Unfortunately, while this message was embraced by the public, our rather short-sighted solution was to add wheat-bran to everything! In essence, we were missing the point: the fibre benefits experienced by rural Africans were coming from a broad range of fibres found in whole plant-foods.
Supplementing a fibre-poor diet with a ‘fibre supplement’ is madness. Imagine for a moment you were holding a superfood in your hand. How would you feel if I took it off you, ‘refined’ it by removing 75% of the nutritional content, gave it back to you, and then compensated you for the nutrient loss by selling you a supplement that only replaced 10% of what I took from you? Every time you eat plant foods that have been ‘refined’, you aren’t just losing one kind of fibre that could be easily replaced with a supplement, you are losing multiple fibres as well as all the nutrients that were attached to that fibre.
For example, white rice (being the refined, processed version of brown rice) contains less than ¼ of the original fibre content. By taking the fibre out of brown rice, we also lose 67% of the vitamin B3 content, 80% of vitamin B1, 90% of vitamin B6, half the manganese, half the phosphorus, 60% of the iron, all of the essential fatty acids and an untold number of valuable phytonutrients. A few nutrients are added back in after the rice is fully milled and polished, but vast majority are not, especially not the phytonutrients. Phytonutrients are micronutrients in plants that don’t fit into the current ‘vitamin’ or ‘mineral’ categories. Many phytonutrients are vital in the prevention and management of health problems such as inflammation, cancer, and atherosclerosis.
Types of Fibre
When fibre is isolated from a whole food and marketed as a supplement (eg wheat bran), it’s commonly referred to as ‘functional fibre’, whereas the intact fibre in whole plant foods is referred to as ‘dietary fibre’.
There are many different kinds of fibre. In times past, fibre was traditionally divided into two broad groups: soluble and non-soluble. These terms still have some relevance when dealing with functional fibre like wheat bran but they aren’t useful or accurate when talking about dietary fibre in whole foods.
It was once believed that ALL soluble fibres form viscous gels that can be fermented (broken down) by gut bacteria with the by-products having a favourable effect on blood sugar and cholesterol, while ALL insoluble fibres couldn’t be broken down by gut bacteria and were only useful for stool bulk and regularity. Now we know the differences between soluble and insoluble fibre aren’t so black and white! Some kinds of soluble fibre have surprised us by not providing much blood sugar and cholesterol benefits at all, while being very useful for improving gut health. Likewise, some kinds of insoluble fibre have ‘gone against the grain’ by being rapidly and completely fermented in the large intestine.
The blurry lines between soluble and insoluble dietary fibre will eventually result in these terms being phased out and replaced with a much more accurate system based on fibre viscosity and fermentability. Viscosity measures how gel-like, sticky and gooey a soluble fibre can become when it soaks up water in the gut, while fermentability measures how easily a fibre is fermented (broken down or digested) by bacteria in the colon who use fibre as a food source.
Bowel Health, Prebiotics and Friendly Bacteria
Low-fat, high-carbohydrate, high-fibre diets are good for treating intestinal disorders such as constipation, inflammatory bowel disease, peptic ulcer, and gastro-esophogeal reflux disorder (GERD).
When viscous fibres absorb water, they turn into a thick, jelly-like, sticky mass. A form of viscous fibre you might be familiar with is pectin, a fruit fibre. Anyone who has made jam will recognise the classic gel-like consistency of pectin! I have a special place in my heart for herbs and foods rich in viscous fibres, like marshmallow root, slippery elm bark, chia seeds, licorice, asparagus, legumes (beans) and oats, many of which are famous in herbal medicine for the soothing, anti-inflammatory effect they have on the gut. The gooey consistency of viscous fibre functions like a cushioning shield for the gut lining, protecting it from irritants and giving it a chance to heal. Another way viscous fibre-type supports gut health is by binding bile acids in the gut. This helps protect us from colon cancer.
Non-viscous dietary fibres such as cellulose and lignin have a special role to play making our stools softer and heavier, helping them pass more easily and quickly through the colon. Cellulose is naturally found in nuts and seeds, wholegrains like brown rice and whole wheat, and in the skins of fruits and vegetables. Besides functioning as ‘nature’s laxative’, foods rich in cellulose help lower the risk of diverticulitis. Fermentable fibres also contribute to stool softening and bulk. With every 100g of fermentable fibre we consume, a whopping 30g of extra bacteria is produced and added to our stool.
Fermentable fibre functions as a prebiotic by feeding helpful bacteria living in our colon. As the bacteria digest or ‘ferment’ the fibre, by-products are produced, such as short-chain fatty acids (SCFA’s) and intestinal gases. SCFA’s then produce a substance called butyrate, which is the preferred food of colonocytes, the cells lining our colon. Leading gut researchers are uncovering evidence that suggests a lack of butyrate may contribute to inflammatory gut diseases and colon cancer.
Both our good bacteria and the wonderful by-products that are produced when they feed on prebiotics, help inhibit the growth of harmful yeasts and bacteria that produce carcinogens and toxins, cause infections, putrefy protein in our gut and mess up bowel function. Aside from keeping the bad guys in line, friendly bacteria enhance mineral absorption (eg calcium and magnesium), reduce food sensitivities and allergies, go into battle with cancer cells, help disarm carcinogens and improve our metabolism of fat and sugar.
The fermentable fibres that feed our helpful gut bacteria can be found in fruits, vegetables, grains (especially the outer husks ie wholegrains), legumes, nuts and seeds. Pathobionts, the disease-causing bacteria that can disrupt our microbial balance, appear to be fed by meat, dairy, eggs, junk food, and fast food, with researchers finding that strict vegetarian diets result in reduced intestinal inflammation. As Dr. Greger of Nutritionfacts.org so succinctly says, when we eat fibre-rich foods, “fiber-munching bacteria multiply, and we get more anti-inflammatory, anti-cancer short-chain fatty acids. Eat less fiber, and our fiber-eating bacteria starve away.”
But what about the flatulence?
One of the most fibre-rich foods we can eat are legumes (beans), which notorious for causing wind. But if you’ve grown up eating legumes, or you’ve been eating them for a long time, you won’t notice this at all! I certainly don’t, and neither do my fellow whole-foodies. If legumes aren’t a regular food in your diet, you might not have cultivated the gut-flora necessary to ferment them. When first introduce legumes to their diet, some people might experience more flatulence than usual until their gut flora adjusts. The same situation occurs when people consuming a Standard Australian Diet (SAD) swap out the junk foods, fast foods and animal products for healthy plant-based wholefoods. The trick is to transition slowly! Give your gut time to adjust.
To some extent, the “beans = flatulence” card has been overplayed. A recent study found that only about 50% of participants who added half a cup of beans to their daily diet experienced an increase in flatulence. By the second week or third of daily use, 70% of those who experienced increased flatulence found that this problem went away completely. It’s also worth pointing out that gas production protects the colon against genetic damage that may lead to cancer. It does this by improving the gut pH, stimulating beneficial bacteria growth, diluting carcinogens and improving the function of the cells in the gut lining.
To reduce the likelihood of intestinal gas when increasing the amount of fibre in your diet, eat slowly with your mouth closed, chew your food well and consider supporting your gut flora with a probiotic supplement or using fermented foods. When introducing legumes to your diet, start with fresh beans and peas rather than dried legumes, then progress to sprouted mung beans, lentils and peas. When you start using dried legumes, choose smaller, spilt and skinless ones like mung dahl, split peas and red lentils. From there, try green lentils, adzuki, black beans and chickpeas. Soak them for about 12 hours or overnight, rinse them properly before use, and cook them thoroughly (you should be able to crush them easily between the tongue and the roof of the mouth). Increasing the portion size gradually over time and consider adding spices that counteract intestinal gas such as cloves, turmeric, garlic, ginger, cinnamon and black pepper.
Weight Loss, Cravings, Blood Sugar and Diabetes
Consuming fibre helps more than any other factor when it comes to losing weight. To begin with, the usable calories in high-fibre, high-carbohydrate foods may be over-estimated in nutrient databases. When it comes to carbohydrates that reach the large intestine intact (i.e. fibre), some experts are suggesting the calories count should be 2 calories per gram rather than 4 calories per gram.
Researchers have found that you can cut your calorie intake by 10% just by adding an extra 14 grams of fibre each day! And when they compare high-fibre plant-based breakfasts with bacon and egg breakfasts, volunteers eating the plant-based breakfast snack 75% less through the day, consuming almost 1000 fewer calories. Some of the ways whole foods rich in fibre reduce food cravings and overeating are by slowing digestion, helping us feel full, and keeping our blood sugar steady.
High fibre foods require more chewing, which can slow the rate of eating, giving us more time to register the feeling of fulness before over-eating. Think for a moment about those water-absorbing viscous fibres that swell to many times their original size and you’ll immediately understand why fibre can so easily promote a feeling of fullness in the stomach, making it much less likely you will over-eat. Viscous fibres also help delay stomach emptying (making us feel full for longer) and stabilise blood sugar.
Low-fat, high-carbohydrate, high-fibre diets significantly reduce the need for insulin and oral hypoglycemic agents in patients with type 2 diabetes. People who consume approximately 3 servings of wholegrain foods per day have 20% to 30% lower risk of developing type 2 diabetes than individuals consuming less than 3 servings per week. Wholegrains meet all our nutritional requirements except vit D, B12, C and A. They not only decrease our blood sugar levels and reduce the risk of type 2 diabetes, they also lower the risk for colon cancer and heart disease.
Heart disease, Strokes, Atherosclerosis and High Cholesterol
Low-fat, high-carbohydrate, high-fibre diets bring significant improvements in blood lipid concentrations, blood pressure and atherosclerosis (thickening of the artery walls). Coronary artery disease, caused by atherosclerosis in the arteries, is almost non-existent in plant-based cultures around the world, as is the case with all five Blue Zones. Blue Zones are the places where large portions of the population live healthy active lives well into their 90’s and beyond. Legumes and wholegrains are staple foods in these communities.
Viscous fibre is famous for its ability to bind bile acids in the gut, which can result in lower serum cholesterol and LDL levels, and a lowered risk of coronary artery disease. When bile acids are bound, this prevents them from being reabsorbed into the blood. The liver responds by producing more bile to replace what has been lost. The body needs cholesterol to make bile, so the liver uses up the cholesterol in the blood, which reduces the amount of LDL cholesterol circulating in the blood. With less cholesterol, we get less atherosclerosis and heart disease. A person’s cholesterol profile can take a dramatic turn for the better after only 3 weeks on a fibre-rich wholefoods diet.
A study published in the American Journal of Clinical Nutrition in 2013 followed hundreds of children for a period of 24 years, from junior high school to adulthood. The researchers found that low fibre intake early in life was associated with stiffening of the arteries leading to the brain, a key risk factor for stroke. Looking at all the evidence available from various studies, it appears as if the best reduction in stroke risk appears to come from eating a minimum of 25g of viscous fibre and 47g of non-viscous fibre daily! That’s a big ask for most people eating a Standard Australian Diet (SAD), but even increasing your fibre intake by 7g a day can bring about a 7% risk reduction. To accomplish this, you could start your day with serving of baked beans, or a bowl of oatmeal with berries.
Dementia (e.g. Alzheimer’s) and Cognitive Health
In the 2014 “Dietary and Lifestyle Guidelines for the Prevention of Alzheimer’s Disease,” published in the journal Neurobiology of Aging, the core advice was that “Vegetables, legumes (beans, peas, and lentils), fruits, and wholegrains should replace meats and dairy products as primary staples of the diet. As stated previous, viscous fibre’s ability to bind bile acids in the gut results in lower serum cholesterol and LDL levels, which reduces the atherosclerotic plaque.
Autopsies have repeatedly shown that people with Alzheimer’s tend to have significant atherosclerotic plaque build-up and narrowing of the arteries, so it probably won’t surprise you to hear that diseases affecting the health of our blood vessels are considered one of possible causes of dementia. It makes sense when you think about it: if blood vessels can’t efficiently deliver nutrients and oxygen to brain cells and then take waste products away, this could certainly compromise cognitive function.
Our blood vessels can be damaged by insulin resistance, diabetes, excess cholesterol, and high blood lipids, all of which can be prevented with a high-fibre plant-based diet. One nine-year-long prospective study on elderly Catholics found that type 2 diabetes increased the risk of cognitive decline by 65%, while a study by Yaffe et al showed that women with impaired fasting glucose were at twice the risk of developing dementia.
In terms of well-known mainstream diets that are often studied for their health benefits, the Mediterranean diet is the only one that approximates a diet rich in fibrous whole-foods, featuring plenty of fruits and vegetables, cereals, and legumes. Several epidemiological studies have shown the Mediterranean diet to be associated with the prevention of the most common form of dementia known as Alzheimer’s disease.
Lung Health, Immunity and Breast Cancer
Strangely, even though it’s impossible for viscous fibre to comes into contain with any part of the body except the inside of the gut, many herbs rich in viscous fibre have a proven ability to soothe irritation and inflammation at other locations, such as the lungs. It’s thought that some of this this magical sharing of relief between the gut lining and other mucous membranes throughout the body may be a nerve reflex, perhaps mediated via the vagus nerve. To grasp this theory (in a very oversimplified way!) picture the viscous fibre singing a lullaby to millions of irritated nerve endings in the gut lining. The nerve endings are soothed, and this calmness travels along the length of these nerves, eventually ‘arriving’ in other tissues.
Some kinds of fibre bind together with one another or with protein molecules to form what herbalists refer to as immunomodulating polysaccharides (IP’s). Ip’s stimulate the immune system whilst simultaneously reducing inflammation. We don’t know exactly how they do this, but it looks as though they may be interacting with parts of the immune system throughout our gut, and the metabolism of Ip’s by our gut flora may also play a role. A good example of foods rich in Ip’s are medicinal mushrooms!
Researchers at Yale found that premenopausal women who eat more than 6g of soluble fibre daily have around 60% lower risk of breast cancer compared with women who eat less than 4g a day. And when it comes to estrogen-receptor-negative tumours, a high-fibre wholefoods diet can reduce your risk by a massive 85%! While this is only one study, dozens of other breast cancer case-control studies have reported similar findings.
Fibre as a synergistic nutrient : Seeing the bigger picture
Many of the health benefits gained by eating high-fibre whole plant-foods are not, of course, just coming from the fibre content. As I’ve pointed out in previous articles, plants contain thousands of nutrients (phytonutrients). We have been living alongside this natural pharmacy our entire history as humans, with our cell receptor sites and body chemistry having evolved to take positive advantage of these medicinal compounds, but the true magic lies in the complex wholeness of thousands of nutrients working synergistically together as a whole, rather than any one ‘active ingredient’. Let’s stop throwing out these medicines and embrace plant-based whole-foods for the true treasures that they are!