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The immune system is the body’s defense against foreign pathogens like bacteria, viruses and parasites. It also defends against sick cells in the body like e.g. cancer cells by killing them.

How does the immune system work?

The immune system consists of many different types of cells, with specialized functions, of proteins called antibodies that can latch on to intruders and flag them for destruction, call other cells in for help, kill the intruders directly, and of many other kinds of small proteins that can kill pathogens or work as messengers enabling communication between the cells.

The cells of the immune system constantly patrol the entire body in the search for intruders and sick cells. Organs of the immune system like the spleen, the tonsils, and the lymph nodes are sites in the body, where the cells go to communicate with other immune cells and coordinate the immune response. The bone marrow is where the cells of the immune system develop from common progenitors together with the red blood cells. The thymus, a small organ that sits above the trachea in the chest cavity, is an organ were a specific kind of immune cells called T-cells receive their final education, after they developed in the bone marrow. The cells of the immune system have a high turn over which makes them sensitive to noxious environmental stimuli like pollutants, cigarette smoke, ionizing radiation and malnutrition.

Immune system boosters for children and parents

The immune system is a very complex system and it is intricately connected to the endocrine system (that produces hormones) and the brain. Therefore stress can be a major factor in a weakened immune system. Any activities that relieve stress, whether it is a 30 min walk every day, meditation, quality time spend with your kids or pets, a short vacation, getting together regularly with your friends, and for your kids the after school sports, can be a very effective immune booster.

Regular moderate exercise is not only effective because of its stress relieving effect, but also because it can help you sleep, increases the blood circulation throughout the body, and helps you loose eight. However, extreme exercise like e.g. in a marathon can exhaust the body and make it more susceptible to infections.

Being overweight induces hormonal changes that can alter the way the immune system functions, so loosing weight is also a good way to boost the immune system.

Good nutrition with lots of vegetables, lean protein, and fruit is very important for proper functioning of the immune system. The effector molecules of the immune system like messenger molecules and antibodies are all made from protein, so not getting an adequate amount with your diet can interfere with the proper functioning not only of the muscles, but also of the immune system. Antioxidants and vitamins contained in fruit and vegetables are also important for the cells of the immune system.

Good fats like in nuts and vegetable oils eaten in moderation help digest certain vitamins, and are needed for the function of the cell membranes and enable cells to communicate with each other.

Vitamins can also be taken in the form of vitamin supplements, but taking too much of a specific vitamin can be harmful to the body and affect the immune system in a negative way. Most doctors recommend taking a daily multivitamin that has a balanced composition with all major vitamins and minerals in a dose that avoids getting too much of a specific kind.

Getting adequate amounts of sleep is very important for the immune system, as getting not enough sleep can lead to stress and the production of stress hormones. Stress hormones are a very strong immuno-suppressant.

Quit smoking! Smoking contains many pollutants that are harmful to the cells of the immune system. It also harms the lining of your respiratory tract making it easier for intruders to invade the body. Smoking does exert its negative effects on the immune system not only on the smoker, but also on people that are exposed to second –hand smoke. A good way to help your children staying healthy during the flu season is therefore to avoid exposing them to your second-hand smoke by either quitting entirely or at least staying away from smoking inside the house.

If you received cancer treatments like radiation therapy or chemotherapy, it is particularly important to eat well, sleep enough and moderately exercise regularly, as these treatments can damage your immune system making you extra susceptible to infections.

Caveats, Echinacea-extracts, high dose of Vitamin C

The internet is full of miracle immune boosters like Echinacea-extracts, high dose of Vitamin C etc. Is there any evidence that any of these work? There is some evidence that Echinacea-extracts are able to moderately affect the duration of a cold, if taken for 7-10 days starting when the first symptoms appear. However, there is no evidence that Echinacea-extracts can prevent the common cold or the flu, and a number of other diseases and the effect on the cold duration is modest at best.

High dose Vitamin C supplement are also very popular as a means to boost the immune system and to prevent and treat the common cold and the seasonal flu. Most people grab the Vitamin C bottle and pop a gram a day as soon as they feel the symptoms of a cold hitting them. However, scientific evidence has been very inconsistent. A metanalysis of studies covering the last 60 years done in 2007 found that when taken after the onset of a cold, Vitamin C does not make a cold shorter and does not lessen the symptoms. When taken daily as a preventative measure, however, it could shorten the duration of a cold in adults by 8% and in children by 14%. Under extreme conditions like e.g. when marathon athletes took high doses of Vitamin C daily, it could cut the risk of catching a cold in half. While some vitamins can cause severe and even fatal poisonings when taken in too high a dose, taking high doses of vitamin C below 1g/day is generally considered as safe. However, doses above 2g/day can cause kidney stones, diarrhea  and nausea.