The colourful Mediterranean Diet is a high fibre diet – soluble and insoluble – linked with lowered blood pressure, blood glucose and lowered cholesterol and a reduced risk of metabolic syndrome, diabetes, cardiovascular disease and cancer.
Fibre feeds the gut microbiome
High fibre? All those pulses, vegetables, nuts, seeds and fruit of the Rainbow Diet could not be anything else. And natural fibre such as lignans, ellagitannins, pectins and inulins have a number of important benefits.
Fibre is either soluble or insoluble. Both are carbohydrate-based but neither can be broken down by your normal digestive processes. However, your good gut bacteria love them and feed on them, growing and dividing. Since the immune system develops in response to the volume and diversity of the gut microbiome, not surprisingly, research has shown that a high fibre diet rapidly increases the strength of the immune system (better than popping pills!!).
A high fibre diet also reduces the level of plasma glucose, and people who indulge in high fibre diets, such as the people in the mountains of Sardinia, live significantly longer than average.
Weight loss can also be a benefit of a high fibre diet as people feel fuller and consume less. Also the slow release of the glucose prompts less of an insulin response and lowered inflammation in the body. This helps reduce diabetes, cardiovascular and cancer risk.
Fibre slows digestion, reduces insulin spikes
All types of soluble fibre slow the digestion process, whereas insoluble fibre helps move the waste through the intestines.
Fibrous cell membranes prevent the rapid release of sugar from the cells, but over-cooking destroys these cellulose membranes, which is why (for example) raw carrots have a very low Glycemic Index, but cooked carrots have a high GI. Whole brown rice is good for you but eating refined white rice is like eating neat sugar. Ditto pasta, breakfast cereals and various grains.
The colourful Mediterranean diet, or Rainbow Diet, involves the slow release of glucose avoiding glucose rushes which can have a number of disastrous effects, not just increasing insulin and chronic inflammation levels. Glucose can stimulate, cause and spread cancer.
Cardiovascular experts, Dr. Chauncey Crandall in the USA and the UK’s Dr. Aseem Malhotra have both argued that without this glucose-insulin-inflammatory effect, arteries would not inflame and fat would not stick to them.
Soluble fibre seems to be able to bind to fats before they are absorbed, reducing plasma cholesterol levels.
Gut bacteria also use fibre to bind chemicals, heavy metals and hormones to them, removing them effectively from the body.
Overall, people on a high fibre diet are shown in research (1) to have lower cholesterol, lower blood sugar and lower blood pressure. However, only 25% of people in the Western World consume enough fibre.