Rainbow Diet

The Mediterranean Diet, fibre and cardiovascular risk

Reducing cholesterol, metabolic syndrome and blood pressure

The colourful Mediterranean Diet, or Rainbow Diet, is a naturally high fibre diet – both 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.

According to the American College of Cardiology and new research (1) presented at their 2019 Annual Conference, patients with hypertension and Type 2 diabetes who consume a high fiber diet had improvement in their blood pressure, cholesterol and fasting glucose. Hypertension and diabetes are major risk factors for future cardiovascular disease.

It is well-known that diet also plays a role in the severity of cardiovascular disease. In the study, people on a high fibre diet were shown to have lower cholesterol, lower blood sugar and lower blood pressure. The researchers commented that, however, only 25% of people in the Western World consume enough fibre.

Fibre feeds the gut microbiome

High fibre? All those vegetables, nuts like walnuts and almonds, seeds like sesame, pumpkin and sunflower, fruit and pulses like lentils and chickpeas of the Rainbow Diet could not be anything else. And natural fibre such as lignans, ellagitannins, pectins and inulins have a number of important health benefits.

Fibre is either soluble or insoluble.

   * Soluble fibre dissolves in water to make a gel in the gut, which is the favorite food of your commensal (good) gut bacteria in your microbiome. People who eat the highest levels of soluble fibre have strong microbiomes and strong immune systems.

 * Insoluble fibre absorbs water to make your stools softer and help the passage of food through your gut.

A high soluble fibre diet promotes volume and diversity in the gut microbiome particularly encouraging bacteria that make health promoting compounds such as Short-chain fatty acids (SCFAs). These control inflammation, keep the gut healthy, control glucose, cholesterol and even cancer (1).

A high fibre diet 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 with little or no dementia.

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, and all those fibrous cell walls causes the slow release of glucose, avoiding glucose rushes which can have a number of disastrous effects, not just causing insulin spikes 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.


Helpful Links

Go to: Bacteria linked to cardiovascular disease, atherosclerosis

Go to: Metabolic Syndrome

Go to: 20 links between sugar and cancer


  1. 2019 Research – high fibre diet – reduced hypertension, cardiovascular risk, diabetes risk
  2. European Journal of Nutrition, 2018, 57 (1): 1-24; Ian Rowland et al.

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