The high fibre Mediterranean diet contains good levels of both soluble and insoluble fibres, providing health benefits in diseases such as cancer, cardiovascular disease, diabetes, obesity, dementia; and in carbohydrate and cholesterol management; all thanks to your gut bacteria.
When people hear that a diet is high in fibre, they simply assume that means it keeps you regular. Many people refer to ingested fibre as ‘roughage’.
But the high fibre Mediterranean Diet does far more for your health than that. Fibre is an important nutrient derived from plants and the plant-based Rainbow Diet is nutrient-rich.
First, there are two types of fibre – Soluble Fibre and Insoluble Fibre. You need both in in the right balance. But your body left to its own devices cannot break down (digest) and absorb fibre, so how does fibre provide nutrients and health benefits? How can Harvard Health suggest a high fibre diet would reduce, say, Breast cancer risk? (1)
The high soluble fibre Rainbow Diet
Certain Mediterranean foods provide high levels of soluble fibre:
- Pulses or legumes (red kidney beans, lentils, chickpeas, broad beans, peas),
- Nuts (walnuts, almonds) and seeds (sunflower and sesame)
- Vegetables and citrus fruits
Soluble fibre becomes a gel-like substance in the liquid of the gut and this mix is one of the favourite foods of your gut bacteria in your microbiome, who ‘ferment’ it. For this reason, soluble fibre is called a Prebiotic.
Soluble fibre intake boosts the immune system
By eating copious amounts of their favourite foods, the population of the microbiome increases, which means your immune system increases in response to this. In fact the strength of you microbiome controls your
immune response (2).
More volume and more diversity in the gut microbiome means a stronger immune system – both the immune response and immune memory of the body. For example, immunotherapy drugs have been shown to produce a much better anti-cancer response when accompanied by a high soluble fibre diet (3).
Soluble Fibre boosts levels of health compounds More gut bacteria also means more compounds made – for example, they make your B vitamins, Vitamin K, serotonin to boost your mood, melatonin to help you sleep, short-chain esters known for their anti-inflammatory properties.
Soluble fibre boosts crucial Short Chain Fatty Acids
Short chain esters – also called short-chain fatty acids, or SCFAs – actually perform a number of crucial functions in the body, enhancing your overall health and reducing the risk of diseases from Alzheimer’s to cardiovascular disease, obesity, diabetes and cancer.
There are three principal SCFAs produced from soluble fibre in the gut –Butyrate, Acetate and Propionate.
1. Butyrate is produced by Eubacterium rectale, Faecalibacterium prausnitzii, Firmicutes and Roseburia family members from soluble fibre. Butyrate produced from ten or more members of these families was shown recently to activate the Vitamin D in your body so it could then bind to your immune T-cells and they could then attack rogue cells – from cancer cells to Covid (4).
Butyrate reduces inflammation and cancer activity in the body, feeds and nourishes colon cells, helps repair a leaky gut and attacks colorectal cancer cells. It is also known to be an important part of the gut-brain axis and involved in mental health (5).
2. Acetate – is produced by Lactic Acid Bacteria from soluble fibre (Bifidobacterium, Lactobacillus, Akkermansia, Ruminocoocus and Prevotella family members). Acetate nourishes butyrate-producing bacteria, regulates the acidity of your gut, crucial for good digestion and appetite and restricting the activities of pathogens. It also regulates fat storage in the body, and has been shown in mice to limit hypertension and heart failure (6).
3. Propionate is produced from soluble fibre by membreas of the families Firmicutes, Bacteroidetes and Lachnospiraceae, for example, It can lower your cholesterol levels, control obesity through suppressing diet and, like acetate, can activate hormones telling our bodies that they don’t need more food. Propionate is known to control inflammation throughout the body and play a defensive role in cardiovascular disease (7).
Although not technical a SCFA, Lactate is produced by a number of Lactic Acid bacteria (such as Lactobacillus) and is the precursor to butyrate, an important acidity regulator, a colon lining cell stimulator and repairer and a controller of inflammation in the body, even crossing the blood-brain barrier (8).
All this health from eating a high soluble fibre Rainbow Diet!!
The high insoluble fibre Rainbow Diet : Examples of high Fibre
Many foods contain both soluble and insoluble fibre. The high fibre Mediterranean Diet contains both. Foods high in insoluble fibre include:
- Greens – dark and leafy
- Pine Nuts
- Apples and pears
- Potatoes, turnips
- Pulses, legumes
Unlike soluble fibre which ‘dissolves’ in watery gut liquids and is fermented by gut bacteria, insoluble fibre instead absorbs these liquids, swells and forms the basis for your stools. It improves digestion, slows absorption of carbohydrates and sugars, and aids the passage of waste from the body.
The high fibre Mediterranean Diet thus has huge health benefits provided by the ‘indigestible’ fibre!.
- High Fibre Diet reduces breast cancer risk
- The microbiome controls your immune response
- Increasing Fibre intake improves immunotherapy outcomes
- Vitamin D activated by butyrate producing bacteria
- Butyrate improves you health significantly
- Acetate producing bacteria reduce hypertension and heart failure
- Propionate, gut bacteria and health
- Lactic Acid Bacteria explained