The second line of defense of our body is the immune system. Mucous membranes and the skin are the first defense line of our body. In fact the mucous membranes are the interior of walls of the respiratory, reproductive and digestive systems. If the bacteria and viruses break these barriers (the physical barriers), then they will be in the immune system. The function of our immune system is to fight against these microorganisms. Our immune system is working all the time (24/7) to protect our body from the negative effects of the microorganisms because they can cause us serious diseases. Also this part of our body has one of the best features and that is the memory. Our immune system remembers who has attacked us before (some virus or bacteria) and it prevents them from attacking it again. Our immune system has blood cells such as eosinophils, monocytes, basophils, neutrophils and lymphocytes as its component. Our immune system can get week from many causes such as vitamins and minerals deficiency, body toxins, abuse of antibiotics, exposure to harmful substances, stress in day-to-day life, lack of sleep, intake of high cholesterol food, excessive workout etc. You can find many home remedies and medications which can improve your immune system. They will boost it. It is the best decision to talk with your doctor before you start using some of the mentioned natural remedies. Here are some natural remedies which you can try if you suffer from weak immune system:
Coconut oil: Coconut oil can boost your immune system. This oil has many properties such as antifungal, antiviral and antibacterial properties and acids such as antimicrobial lipids, capric acid, caprylic acid and lauric acid. These properties will also help you to protect you from other types of diseases such as influenza, herpes and cytomegalovirus [1,2].
Green tea: This kind of tea can help you to boost your immune system. It has anti – carcinogenic, antioxidant, anti – inflammatory and polyphenols properties . This tea can help you to boost your immune system according to the Department of Dermatology at the University of Alabama. Also in this study was shown that if you have overexposure to the UV light, then it can counteract the negative effects of it.
Wheat grass powder: You can take this home remedy if you want to boost your immune system. There was a study which was done by the American Cancer Society in which they have studied the effects of the wheat grass and the immune system. It was shown that this herb will reduce a throat and mouth infections, mucous membranes, bronchitis, diarrhea and cold. This is possible because it has high amounts of minerals, vitamins and antioxidant components.
Shed some extra pound: If you are overweight, then you can easily notice that your immune system is not functioning properly. There were studies in which was shown that the overweight people have decreased function of the immune system compared with the immune system of normal and healthy people. You should lose your weight but with healthy food not with diets. In this way you will improve the function of the immune system.
Yogurt: People who have weak immune system should consume yogurt at daily basis because in this way they will improve their immune system . When you are drinking yogurt at regular basis, then you are increasing the number of the L.casei in your digestive system. Also this product is important for the development of antibodies and white blood cells. Lactobacillus cases is the name of L.casei bacteria. This bacteria is very helpful in the prevention of enteric infections. Also when you drink yogurt at regular base, then you have effective natural remedy to fight against the cancer.
Goldenseal: This is antibiotic herb which can fight against the viral and bacterial infections. There was a study in which was shown that the antigen – specific immunoglobulin production can be increased when we consume goldenseal. We not guarantee you that this or any of the mentioned home remedies will help you to improve your immune system. This is a reason why you must not take any of the mentioned home remedies without talking with your doctor. 
Echinacea: This is type of American herb. People who were native to this part of the world have been using this herb with decades. If you suffer from flu, cold, sinusitis, urinary tract infections, ear infections and skin infections, then you should use Echinacea as your natural remedy. Also there are studies in which is shown that this herb has positive effects on the immune system .
Garlic: This vegetable is part of every kitchen. It has many health benefits which can help us for our overall health. This kind of vegetable can fight against the viruses, bacteria and fungi. If you suffer from cold or flu, then you should consume garlic because it can help you a lot. 
Home remedy for strong immune system: You will need: ½ teaspoon of peppermint leaves, ½ teaspoon of chamomile leaves, 2 cups of water, ½ teaspoon of shizandra berries and one teaspoon of Echinacea root. You will need to make the mixture from the mentioned items if you want to boost your immune system.
Eat medicinal mushrooms: You should add medicinal mushrooms in your diet such as maitake and shiitake. There was a study in which was shown that women who suffer from breast cancer and who had consumed concentrated extract of shiitake have improved the function of their immune system.
Astragalus: This is one of the best home remedies which you can use if you want to boost your immune system . It has been used in the Chinese medicine for years. It has some components which can help you to be protected from lack of appetite, cold, allergic rhinitis and stress. Colds and respiratory infections can be treated with astragalus. Also the Integrative Cancer Care located in Illinois has proven that the astragalus has positive effects on the immune system.
Adequate sleep: If you want to have proper function of your immune system, then you should have enough sleep. There was a study in which was shown that people who do not sleep enough have weak immune system compared with people who sleep enough. You should try to avoid the stressful situations. If you do not sleep well and you are constantly under stress, then your body is increasing the hormone cortisol which can suppress the function of our immune system.
Dried fruits: Dried fruits and nuts are rich with vitamins, proteins and carbohydrates. You should add apricots, almonds, cashew nuts, Brazil nuts, pecans, pistachios, raisins, pumpkin seeds and dried cranberries in your diet. All of them are rich with copper, Vitamin A, Vitamin K, iron, calcium and Vitamin E. All of the mentioned micronutrients can improve your immune system and also they can help you to have proper function of it.
Fruits: They are rich with minerals and vitamins. If you consume fruits in your every day diet, then you can have powerful protection from any kind of disease in long period. Lemons and oranges are taking the part of the citrus family. As we know these kinds of fruits are rich with Vitamin C. We know that this vitamin has antioxidant properties which mean it can help us to have normal function of our immune system. 
Vegetables: You should add vegetables in your diet which can improve your immune system such as okra, tomatoes, onions, cabbage, cauliflower, carrots, pumpkins, broccoli, kale, French beans, beetroot, eggplant and green pepper. You should consume them at regular base because in this way you can have healthy body and also your immune system will function properly. [9,10]
Green leafy vegetables: They are rich with minerals and vitamins which mean that they are perfect natural remedy to boost your immune system. You can find many vitamins such as Vitamin B1, Vitamin A, Vitamin E, Vitamin B9 and Vitamin B2. These vitamins can help you to have strong immune system. This is the right choice for you if you suffer from weak immune system. [9,10]
Nutrients in diet: When people say that we have to consume all the right nutrients from the food then we take, then they often think about the vitamins and minerals in foods which we consume. If they are taken in a proper way, then they can help us to have strong immune system. Also the mentioned elements can help you to build up the antioxidant components in our body. It is known fact that when we have enough amount of antioxidants in our body, then they can help us to have strong protection from the side effects of the free radicals.
Drink less alcohol: When you drink too much alcohol, then you are increasing the ability of the immune system to get lung infections and also it can weaken our immune system. This is a reason why you should drink alcohol only in small amounts.
Avoid tobacco smoke: People who smoke tobacco have increased risk of getting pneumonia and bronchitis. Also kids can have middle ear infection from this factor .
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 Law KS, Azman N, Omar EA, et al. The effects of virgin coconut oil (VCO) as supplementation on quality of life (QOL) among breast cancer patients. Lipids in Health and Disease. 2014;13:139.
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 Meydani SN, Ha WK. Immunologic effects of yogurt. The American Journal of Clinical Nutrition. 2000;71(4):861-72.
 Clement-Kruzel S, Hwang SA, Kruzel MC, et al. Immune modulation of macrophage pro-inflammatory response by goldenseal and Astragalus extracts. Journal of Medicinal Food. 2008;11(3):493-8.
 Zhai Z, Liu Y, Wu L, et al. Enhancement of innate and adaptive immune functions by multiple echinacea species. Journal of Medicinal Food. 2007;10(3):423-34.
 Arreola R, Quintero-Fabian S, Lopez-Roa RI, et al. Immunomodulation and anti-inflammatory effects of garlic compounds. Journal of Immunology Research. 2015;2015:401630.
 Auyeung KK, Han QB, Ko JK. Astragalus membranaceus: A review of its protection against inflammation and gastrointestinal cancers. The American Journal of Chinese Medicine. 2016;44(1):1-22.
 Gibson A, Edgar JD, Neville CE, et al. Effect of fruit and vegetable consumption on immune function in older people: a randomized controlled trial. The American Journal of Clinical Nutrition. 2012;96(6):1429-36.
 Li Y, Innocentin S, Withers DR, et al. Exogenous stimuli maintain intraepithelial lymphocytes via aryl hydrocarbon receptor activation. Cell. 2011.
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