27 Dec The benefits of a fibre-rich diet
There is a LOT to be said about the virtues of a fibre-rich diet. In this article, I will highlight a few benefits of fibre consumption, fibre-rich food sources and how much fibre is enough.
Epidemiological studies have shown that fermentable and non-fermentable fibre consumption leads to less obesity-induced inflammation, lower BMI, decreased risk of metabolic abnormalities associated with inflammation and lower C-reaction protein (an inflammatory marker).
Prevention of cardiovascular events and diabetes:
High-fat and high-calorie diets increases oxidative and inflammatory stress, as well as increased lipopolysaccharide concentrations (LPS; an endotoxin). With the addition of fibre, reactive oxygen species, LPS and pro-inflammatory cytokines were reduced. Endotoxemia (high levels of endotoxins in the blood) was also reduced; endotoxemia prevents the gut microbiome’s ability to protect the body from absorbing toxins during food digestion.
Reduction of brain inflammation in ageing:
You may have heard about the gut-brain axis – communication between central and enteric nervous system that links emotional and cognitive centres of the brain to the intestines. A study on mice shows how growth of good bacteria in the gut can have anti-inflammatory properties on microglia (cells found in brain and spinal cord) and can improve memory. Soluble fibre consumption produces short-chain fatty acids, including one called butyrate, which inhibits production of harmful chemicals that damage microglia.
Reduced risk of breast and ovarian cancer development:
There are non-genetic factors associated with development of breast and ovarian cancer, including long-term exposure to oestrogen, exposure to xenoestrogens, no child-bearing history, late menopause and early menarche. Other lifestyle factors that contribute to cancer development include cigarette smoking, physical inactivity, excessive consumption of fried foods, obesity, stress and environmental pollutants. A diet high in vitamins and fibre, including citrus fruits, olive oil and a combination of raw and cooked vegetables, is protective of breast and ovarian cancer development risk.
Satiety and weight management:
Fibre-rich foods provide volume to food and takes longer to digest; therefore, the feeling of satiety is better balanced and more lasting.
Types of dietary fibre
There are several types of fibre (cellulose, inulin, pectin, resistant starches, lignin, etc.) found in a variety of foods. The physio-chemical characteristics also have different effects on the gut. A simplistic and common differentiation is soluble and insoluble, which is based on its ‘ability to be fully dispersed when mixed with water’, but even within this definition, depending on the plant source and extent of processing, the structures can be either soluble or insoluble. Furthermore, how the fibre is consumed and its interaction with the gastrointestinal tract, varies the type of fibre extensively from a physio-chemical perspective.
To make matters less complicated, I’ve provided a list of fibre-rich foods based on food groups.
Fruits: apples, cherries, grapefruit, mango, orange, peach, pear, pineapple, strawberry, watermelon, figs, apricots, guavas, raspberries, kiwi, plums, grapes, avocado – basically, every and any fresh fruit you can think of!
Vegetables: beets, broccoli, cabbage, carrots, celery, cucumber, iceberg lettuce, tomatoes, sweetcorn, courgettes, brussels sprouts, artichoke, kale, okra, asparagus, mushrooms, cauliflowers, bell peppers, leek – again, every and any fresh vegetable!
Legumes: red lentils, green lentils, yellow lentils, lima beans, green peas, red kidney beans, black beans, mung beans, adzuki beans, pinto beans, navy beans and chickpeas. Essentially, any beans and lentils.
Cereals/grains: rolled oats, rice, millet, pearl barley, quinoa, bulgur, amaranth, wholewheat flour, teff, rye and buckwheat.
Nuts and seeds: sunflower, pumpkin, sesame, chia, almonds, pistachios, hazelnuts, Brazil nuts, walnuts, hemp and flaxseeds.
Root vegetables: sweet potatoes, red potato, russet potato, turnips, butternut squash, pumpkins, onions, ginger, garlic, radishes, beets and fennel.
How much fibre do I need to eat?
Generally, for most people, 30-35g of fibre consumption per day is ideal. Some people might not be able to tolerate this amount of fibre – it depends on whether an individual has a gastrointestinal health condition or general state of gut health. There are always caveats, so it is best to identify what works well for you and consult to your doctor or health practitioner if in doubt.
Nonetheless, the general recommendation is 30-35g of fibre daily or 7-10 portions of fruits and vegetables according to one study. How big is a portion? In my clinic experience and based on what my tutors recommend, I suggest a generous handful constitutes as one portion. I don’t provide specific grams of vegetables/fruits, as this can potentially lead to overscrupulousness and even orthorexia, whereas food should be enjoyed with ease. I’ve NEVER measured my fruits and vegetables by grams; it’s always been by handfuls or how much of my plate is occupied by it. I also prioritise vegetables over fruit, limiting my fruit intake to 1-2 portions daily.
You might not ever truly know how many grams of fibre you are consuming per day, as cooking, chopping, blending and drying fruits and vegetables can lead to significant changes in the fibre content, in terms of quantity and functionality.
If you are not used to eating a lot of fibre-rich foods, start small – say, 1-2 portions. Then over the period of a few weeks, build it up and see how it feels for you.