Your immune system is a biological miracle, consisting of many different components, making it possible to distinguish between the Self (you) and the Non-Self such as bacteria, viruses, fungi, but also transplanted organs or foreign objects like pacemakers and artificial joints.

Anything that might be a potential threat is attacked by the body’s immune system. It also plays a role in auto-immune diseases. Here the system gets misinformed and overactive and starts to attack tissues and organs that are your own. (1)

But in many cases and for many different reasons the immune system can be weakened. This makes it possible for bacteria and viruses to multiply and cause harm. Important cause is e.g. taking immunosuppressing substances in case of organ transplants to prevent rejection of the transplanted organ.  More often the immune system is compromised by corticosteroids or prednisone. Even if you are not taking any medication your immune system can be compromised.

Stress is a well-known cause. In case of stress the body has to shift its priorities.  In the case or the perception of a life-threatening situation. A long time ago this could be saber-toothed tiger chasing you, having a great dinner in mind, your body secretes survival hormones like adrenaline and cortisol to mobilize energy in order to flight or flee. And energy will be left to supply the immune system.

The amino acid glutamine, which is a fuel for the brain and the body as well as the immune system, plays an important role in this situation. A low level of glutamine has been related to overtraining in sports as the result of the fight for glutamine by the brain, the body and the immune system. (2)  Anyhow, sports and certainly endurance sports might create an ideal situation for infections. First of all there is the increased contact with air, containing bacteria, viruses, fungi and other particles, in the mouth, nose, windpipe and lungs, increasing the risk of upper respiratory tract infection (URTI) in athletes. This is often combined with the higher level of (physical) stress, that is what exercise is!. Weakening the immune system, giving bacteria and viruses a chance to attack and to multiply. (3,4)

Unfortunately, we often see this happening close to major championships like Olympics games or World Championships, where fit and well-trained athletes often run into an unexpected infection like a cold, flu or gastrointestinal infection.

Maybe you are familiar with the small blisters on the lips: the herpes simplex virus. This virus is always present and grabs the opportunity when the immune system is weakened. These herpes lip blisters are often related to stressful periods.

For many years, people have been trying to boost the immune system. A well-functioning immune system also contributes to a longer and healthier life. Many elderly people may suffer from lethal respiratory infections. Every year many people are affected by the flu and this has a negative impact on sick days and productivity as well. And for athletes, valuable days of training are lost and sometimes participation in competitions becomes impossible due to the flu.

Therefore many reasons to try and protect and improve our immune system. Below some often used measures to boost our immune system. It is like recruiting, arming and feeding your army of defenders. Like mentioned above;

• Glutamine is important for athletes, so taking 1-2 grams of extra glutamine could be of help here.

• Keep up your Vitamin C level. After many years of denial and resistance Vitamin C finally finds scientific support. It keeps your immune system charged.

• 2-3 grams of Vitamin C is a normal dose in case of stress, however more Vitamin C might be necessary and it never causes any harm. (5,6)

• Zinc levels are also important for immunity, extra zinc, e.g. zinc picolinate (50 mg) or zinc gluconate (45 mg) (7)

Many immune stimulants come from plants. They manufacture chemical compounds in order to protect themselves against outside attackers like viruses, fungi or bugs. (8,9,10,11)

Don’t forget that these organisms also supply the building blocks for the classical medications like antibiotics or antiviral components e.g. Acyclovir (Zovirax) from marine sponges.

One of the most well-known herbal immunostimulants in Europe is Echinacea purpurea. Available as a fluid. Take a teaspoon during periods when infection is likely, dependent on the season and the training load or stress levels. (12)

Other useful immunostimulants from plants are:

• Astragalus membranaceus (13)
• Andrographis paniculata (14)
• Glycyrrhiza glabra (licorice) (15)

Even more options:

• Beta-glucans from the cell-walls of mushrooms or yeasts have a well-established effect on the immune system. Beta-glucan is now widely available as a nutritional supplement. (16)

• Lactoferrin is an interesting immune-stimulating component from milk and colostrum, supporting the not yet fully developed immune system of the newborn. It is now available as nutritional supplement.(17)

• If  the upper respiratory tract is involved, inhaled air with essential oils (aromatherapy) might also be helpful. Interesting essential oils stimulating the immune system or having direct antibiotic properties are eucalyptus, tea tree, thyme, lavender, frankincense, citrus oils, cinnamon, or peppermint. (18,19,20)
  • Simply put a few drops of these essential oils in a pot of hot water, put your head above it without scorching it, put a towel over your head and inhale slowly and deeply. And… if it is not an adequate solution, at least you smell good.

MWi would like to Henk Kraaijenhof for writing this article and supporting our community with his expert insights.  Follow this link to read the original article: