Immune System

Immunity is the ability of our body to defend itself against external aggressions that threaten its correct functioning, such as an infection with a microbe. Our environment is populated by microbes (viruses, bacteria, etc.) and foreign bodies (pollen, allergens, etc.) to which our bodies are constantly exposed. The human body is an environment conducive to the development of microbes, so it is natural that they try to infiltrate it. When this is the case, our bodies establish defense mechanisms through the immune system.

The immune response: our defense mechanism

To deal with pathogens (microbes), our immune system establishes 2 types of response: innate immunity and adaptive immunity. These two responses occur when one or more antigens have been identified as “foreign” to our body.

Innate immunity

Our body has physical barriers to deal with invasions. They are found in the skin, the digestive mucosa (a protective surface of approximately 300 m2), the lungs, and the urogenital system. If these are insufficient, an immediate response is triggered. It is the first reaction of our immune system to aggression. This detects and eliminates invading microorganisms.

Adaptive immunity

If innate immunity is not sufficient to block the invasion of microorganisms, a second immune response is triggered approximately 96 hours after contact with the foreign body. It is a specific reaction to each microorganism. Our immune system recognizes the antigens present and directs your attack directly at them, systemically. This means that it is not limited to the contact area, but it unfolds in our body. What is special about the adaptive response? She has a memory of attacks. Therefore, with each new exposure to a pathogen already found, our body will react stronger and faster.

Immune System-health care

Signs of a weakened immune system

Certain signs may indicate a weakened immune system, such as:

– Persistent fatigue can be the result of chronic stress and/or lack of sleep.

– Poor healing or even an increased risk of infections (the immune system is, in fact, involved in the healing and healing process: when it weakens, healing takes longer).

– Repeated infections (colds, cystitis …) reveal that the body can no longer cope with pathogens that enter our body.

Immune System healty care

Weakened immunity: the factors

Many factors can depress the immune system:


In babies, the immune response is weaker because the immune system is not yet mature. However, at birth, he has antibodies that his mother passed on to him to compensate for this deficiency. Breastfeeding during the baby’s first months of life prolongs this protection as it still benefits from its mother’s antibodies.

During aging, we find that innate and adaptive immune responses are less efficient1. Therefore, the elderly are prone to frequent and prolonged infections.

The hygiene of life

Unhealthy lifestyles have negative repercussions on immunity: smoking contributes to weakening the immune response3, lack of sleep makes the body more vulnerable to infections4.

Chronic stress negatively affects immunity: it has an immunosuppressive effect and induces a dysregulation of the immune response2.

Strenuous physical activity can alter immunity1, while moderate exercise has a beneficial effect5.

Naturally strengthens your defenses: vitamin C and zinc

The role of food and more particularly that of vitamins and minerals in the optimal functioning of the immune system is widely documented. A varied and balanced diet is undoubtedly a real asset to have an efficient immune system6. Vitamin C and zinc are particularly interesting. They contribute to the defense of the organism by protecting it from the oxidative stress generated to eliminate foreign agents. Therefore, it is necessary to favor foods that contain it (seasonal fruits and vegetables for vitamin C and oysters, wheat germ, a crab for zinc). Several studies have also shown the beneficial effect of vitamin C and zinc supplements in the treatment of colds in particular.

Other micronutrients not to be overlooked

Vitamin D

It is also involved in the immune response. Vitamin D deficits are more common in winter because this vitamin is synthesized in part from sunlight on the skin. It is found in fermented milks, sardines, almonds, or hazelnuts …

The iron

It plays an important role in the immune response. It is found in blood sausage, beef, lentils, white beans, chickpeas …


Limiting cell oxidation also contributes to good defenses. Seasonal fruits and vegetables are good providers of antioxidants.

Probiotics: an unstoppable shield

Recent studies have particularly highlighted the influence of poorly diversified gut microbiota on the dysfunctions of the immune system at the origin of certain autoimmune pathologies7. Probiotics have the advantage of being “friendly bacteria” that help the intestinal microbiota to restore its properties and balance. They help prevent the spread of unwanted germs. Administered orally in an adequate amount, they positively modulate the defense mechanisms provided by our mucous membranes and our immune system.

Probiotics are present in fermented milks (yogurts, cheeses, white cheeses …) and are available in the form of food supplements.

When to strengthen your immunity?

While of course good immunity is required throughout the year, our immune system is particularly exposed at two key times of the year. Autumn/winter is a good time for the spread of pathogens that cause colds, flu, and other infections. Spring, meanwhile, heralds the return of allergies. However, it is possible to prepare for it.

Depending on your situation, your needs, your history, your lifestyle, and your micronutrient status, a healthcare professional can advise you on a personalized food program. It can also offer you a supply of probiotics to restore the properties of the gut microbiota that may have been altered by taking particular antibiotics.