Asthma, allergy and inflammation have a lot to do with fruits and vegetables. Our trademark mantra has always been “raw, fresh and colourful” (which consists in eating small pieces of raw fruits and vegetables before any meal, breakfast included) and it is one of the strengths of the anti-allergic and anti-inflammatory therapies that we conceive in our centre.
Recently, we also discovered its innermost scientific grounds, that is, elements giving the right value to the water-soluble fibre found mainly in fruits, vegetables, legumes and cereals.
Fibres are not digestible by humans, but thanks to the action of intestinal bacteria (which form our personal microbiome), fibres processing leads to the production of short chain fatty acids, which reduce the level of eosinophils, of total IgE and of all those inflammatory molecules related to allergy, as well as reducing the production of mucus by the mucous membranes themselves.
A group of researchers from the centre of pulmonology in Lausanne published a highly detailed piece of research in Nature Medicine, which highlighted the significant evidence of the abovementioned effects in mice, possibly applicable also to humans (Trompette A et al, Nat Med 2014 Feb; 20 (2):159-66. doi: 10.1038/nm.3444. Epub 2014 Jan 5).
The American Gary Huffnagle studied the same theme more in depth and confirmed the anti-allergic respiratory action produced by the microbiome action on dietary fibre (Huffnagle GB. Nat Med 2014 Feb; 20 (2):120 -1. Doi: 10.1038/nm .3472).
The vegetal fibre is classified as water-soluble and non-water soluble. The soluble one can be found in fresh fruit and vegetables (for example, in green leaves, fibrous vegetables like celery, fennel and peppers) and in wholegrain cereals.
The industrial processing tends to remove this type of fibre, since its link to water means foods that deteriorate more quickly; therefore, it is virtually absent in industrial products, which tend to have a longer due date if compared to fresh foods.
The actions of this type of fibre (also known as pectins, gums, mucilage) are numerous, and in part already known:
- The increase in satiating potential;
- The reduced intestinal fats absorption (especially cholesterol);
- The reduction of the glycaemic index of a meal (slowing the absorption).
Today, knowing that fibre synergy with the microbiome confirms its anti-allergic properties, we have an additional weapon to deal with food-related inflammation and its consequences.
Here then, bananas, apples, pears, plums, artichokes, onions, peaches, and legumes such as chickpeas and peas are able to provide soluble fibre that can help the action of the microbiome in the production of short chain fatty acids, which can stimulate the immune system in the lung and in the respiratory tract (increasing the activity without inducing any allergic reaction) and check the severity of the allergic inflammation.