This back-to-school season in 2020 is a little unusual, and we have never heard so much about immune boosting. Without going into the details related to COVID-19 and the circumstances surrounding it, we know that the back-to-school period is the time for the joyful mixing of germs — with or without masks — minor colds, and declining daylight… Having good immunity is a holistic approach, but what can we do concretely?

Here are a few pointers…

Fatigue and sleep

A generous, protein-rich breakfast; a balanced lunch with proteins and carbohydrates (rich in plant foods); a snack of fruit, nuts, and dark chocolate (min 70%); and a light dinner with a predominance of carbohydrates (rich in plant foods and vegetarian) favour better mitochondrial output, energy availability during the day, and a slowed metabolism at night — the period of recovery, repair, and maintenance, including immune maintenance.

The key anti-stress and anti-fatigue nutrient is magnesium, which plays a role at every stage of energy production.

The gut: the seat of immunity

80% of our immunity is located at the intestinal level, so good gut flora is essential for optimal protection. Today, many people suffer from dysbiosis or “leaky gut syndrome” due to our Western lifestyles. We might think first of probiotics, but the balance of our microbiome is delicate: it also depends on our “microbiotic” identity at birth, early childhood (birth route, breastfeeding), lifestyle (antibiotic use, diet), stress, and thyroid function — it is a complex and multi-factorial subject.

To favour a friendly flora, let’s think about limiting sugars, saturated and trans fats, and meat; and providing plenty of seasonal fruits and vegetables rich in fibre, as well as omega-3s. Moreover, from another angle, omega-3s will make the double membranes of our cells more flexible, increasing the filterability of red blood cells for a better “respiratory burst” of leucocytes — which is paramount for better defence. These same omega-3s, found in rapeseed and linseed oils, walnuts, and small fatty fish, will also make bacterial membranes more flexible and thus more oxidisable, since bacteria use our fatty acids to build their membranes… Saturated and trans fats have the opposite effect.

Note: omega-3 supplements are contraindicated in cases of risk of bleeding or haemorrhage, as they are powerful inhibitors of platelet aggregation (via series-3 prostaglandins). Also, meat is rich in iron, which is among other things a factor in the proliferation of viruses and bacteria. But we must not be deficient in it — the key is reasoned meat consumption according to our needs… And accompanying it with anti-oxidant and anti-inflammatory spices such as ginger, turmeric…

Limiting gluten intake: it is responsible for the opening of tight junctions between enterocytes that ensure the integrity of the intestinal barrier, which particularly exposes us.

Moving and building muscle — it’s not just aesthetic

Regular physical activity is at least as important as diet for improving immune defences. Maintaining good muscle mass means having good reserves of glutamine, an amino acid that serves as “fuel” for white blood cells. Getting good oxygenation is equally important — walks in the forest would increase the number of Natural Killers, white blood cells involved in innate immunity.

Vitamin D

We often see winter and its microbial pleasures arrive because the temperature drops, and we try to avoid getting cold. True. But what if we looked at it through a different lens? In summer, we synthesise more vitamin D thanks to the sun, and in winter — especially at our latitudes — UVB rays don’t allow us to have optimal vitamin D. Yet vitamin D deficiency is associated with increased susceptibility to infections… It is capable of producing anti-microbial peptides important in innate immunity and (among a multitude of other qualities) participates in the tightening of tight junctions at the intestinal level.

Vitamin C

It participates in immune defences, among other things associated with iron via the Fenton reaction (oxidative secretions of white blood cells). It then plays a pro-oxidant role — beneficial. But one of its best-known roles is that of a sacrificial antioxidant: it helps recycle glutathione. It also participates in antibody synthesis (as does vitamin B6) and improves iron absorption when taken at the end of a meal. It is sensitive to heat and light, which is why it is preferable to eat fruits and vegetables that contain it (peppers, parsley, kiwi, papaya, citrus fruits…) fresh and raw. (They have other benefits when cooked — all the more reason to vary cooking methods 😉)

Zinc

A powerful antiviral, we heard a lot about zinc in relation to the loss of taste and smell symptoms linked to COVID-19. It is indeed involved in gustin, a zinc protein. It is the key to anabolism and, as such, participates in the synthesis of white blood cells and antibodies. It is found in both the plant and animal kingdoms, but is better absorbed from animal proteins.

Green tea and protective polyphenols

Commensal bacteria are very fond of polyphenols… They have anti-inflammatory and antioxidant virtues, and some have been documented as antiviral through several mechanisms. The catechins in green tea slow iron absorption, reducing access to this growth factor for viruses, bacteria, yeasts, and parasites.

Let’s celebrate colourful fruits and vegetables: blueberries, citrus fruits (rich in citroflavonoids), olive oil (rich in hydroxytyrosol), turmeric, beetroot…

Take care of yourselves.