The change of season from summer to autumn usually comes with a higher incidence of respiratory infections. Sudden changes in temperature, increased humidity and lower temperatures promote an ideal environment for the survival and proliferation of all kinds of viruses and bacteria. In addition, contagion between people tends to be greater as a result of living together for longer periods of time in enclosed spaces. On the other hand, as we move towards winter, the days become shorter and sun exposure is less. This means that our immune system is weakened and respiratory infections are more frequent. Therefore, and now more than ever, strengthening our immune system during these seasonal changes can help protect us or at least make it possible for us to overcome a respiratory infection by reducing the symptoms and the duration of the infection.
Acute Respiratory Infection (ARI) is a group of diseases that occur in the respiratory system and are mostly caused by viruses, although they can also be caused by bacteria or parasites. They are transmitted from one human being to another through droplets of saliva that we expel when we cough or sneeze or by contact with contaminated surfaces. They usually appear suddenly and usually last less than two weeks. Infections can affect the upper respiratory tract (nose, ears, throat, trachea and bronchi) or the lungs. Normally most of these infections affect the upper respiratory tract, are usually mild and end up being what is known as the common cold, but sometimes if the immune system of the infected person does not work properly, the infection can go down to the lungs and cause serious health problems, as in the case of pneumonia. The most affected population are children under 5 years old, due to the incipient development of immunity and on the other hand the elderly, whose immune system is deteriorated. The main symptoms include: general malaise, cough, headache, fever, sore throat, nasal secretion, expectoration and difficulty breathing.
Treatment of respiratory infections is usually based on the use of drugs to relieve symptoms. Antipyretics, antitussives, antihistamines or nasal decongestants are the most commonly used. Antibiotics should not be used for viral infections, as they are only effective against bacteria. Most respiratory infections are usually caused by viruses, so overuse of antibiotics may carry certain risks and lead to the emergence of resistant strains.
Currently, respiratory infections are one of the most frequent causes of medical attention and in “coronavirus times” represent an important public health issue in our country. With the exception of the flu, there are no effective vaccines against respiratory viruses, so our best ally is prevention. Washing your hands well, avoiding contact with affected people, eating a proper diet and being well hydrated is essential to keep the body in optimal condition. That is why we must take care of our defences and prepare our organism to face the most common pathologies of winter.
If you are looking for a natural, powerful and effective alternative to support your immune system and alleviate the typical discomfort of respiratory viral diseases, here we analyse the most suitable nutrients for this purpose. The combination of vitamins A and C with mushrooms such as Chaga and Sun Mushroom and different herbal extracts such as Drosera, Elder, Pelargonium and Grey Rockrose along with different essential oils that facilitate respiratory function and enhance immunity can be an excellent choice to prevent flu-like processes and reduce the associated symptoms.
CHAGA (Inonotus obliquus)
Chaga (Inonotus obliquus) is a medicinal mushroom that in recent decades has attracted community attention due to its antimicrobial, antioxidant, anti-inflammatory, immunostimulant, and anticancer properties. (1) It commonly grows on birch trees located in cold countries of Eastern Europe, Asia, and North America and has been used for hundreds of years in traditional Siberian medicine to treat stomach ailments, liver disease, cardiovascular disease, and even tumours. The medicinal properties it exhibits are attributed to its active principles: polysaccharides, terpenoids, phenolics, amino acids, inotidiol and beta-glucans. (2)
Chaga extract has been shown to inhibit the action of HIV-1 virus proteases, (3) has shown antiviral activity against hepatitis C virus (4) and even against two strains of influenza virus (A and B). (5) In addition, it has shown an antiviral effect against herpes simplex virus type 1. (6) Some authors postulate that this antiviral activity is due to the content of betulin, lupeol and mycosterols present in the fungus. On the other hand, the antioxidant capacity of Chaga has been demonstrated by reducing intracellular levels of ROS and MDA as well as increasing the activity of antioxidant enzymes such as SOD, whose function is to prevent the generation of free radicals. (7) Some studies demonstrate the efficacy of aqueous and phenolic extracts of Chaga in reducing nitric oxide (NO), as well as inhibiting some markers of inflammation: IL-1β, IL-6 and TNF-α. (8) Another study indicates that inhalations of Chaga extracts along with other herbs reduces airway inflammation and facilitates breathing. (9) As for its immunostimulant and antitumor properties, it has been shown that the polysaccharides present in Chaga have the ability to stimulate the immune response by promoting macrophage activation through MAPK and NF-κB signalling pathways. (10) Numerous in vitro studies with cancer cell lines show that polysaccharides extracted from Chaga have cytotoxic and apoptotic effects. (11).
SUN MUSHROOM (Agaricus blazei Murrill)
Agaricus blazei Murrill, better known as sun mushroom, is a mushroom native to Brazil that is gaining popularity in the field of integrative medicine due to its pharmacological properties. It has a wide spectrum of biological activities and has been found useful as a complementary treatment for cancer, chronic hepatitis, diabetes, atherosclerosis, hypercholesterolemia, etc. (12). It contains a number of bioactive components: polysaccharides, proteins, lectins, amino acids, vitamins and sterols. Many of these are modulators of the immune response and activate our defence mechanisms. For example, the polysaccharides present in this fungus are known to have anticancer, antiviral and immunomodulatory effects. (13, 14) In addition, it contains β-glucans and enzymatically hydrolysed oligosaccharides, which show antihyperglycemic, antihypertriglyceridemic and anti-arteriosclerotic activities. (15) On the other hand, it is well known that the β-glucans present in the sun mushroom also contribute to a normal immune response and help to have the defences in optimal conditions.
ELDER (Sambucus nigra)
Elderberries are very rich in nutrients. They contain carbohydrates, proteins, fatty acids, minerals (calcium, magnesium, iron and zinc), B vitamins, vitamin C and essential oils. Their bluish colour is due to their high content of anthocyanidins and polyphenols. These bioactive substances have a high antioxidant capacity and reduce oxidative stress by eliminating free radicals, which makes them potential chemo-preventive agents. Among the main flavonoids present in the fruit are quercetin-3-rutinoside (rutin) and cyanidin-3-glucoside. Due to its properties, elderberry has been used for many years in complementary medicine as a diaphoretic, antipyretic and diuretic agent. In recent years the scientific community has discovered that it also has antimicrobial, antiviral and hypoglycemic properties. (16) For this reason, it is used as a remedy to treat common symptoms related to the common cold: fever, cough, nasal congestion, mucous secretion, as well as preventively to strengthen the immune system. (17) Recent studies show in vitro efficacy against at least 10 different strains of influenza virus. In a randomized, double-blind, placebo-controlled study, a reduction in the duration of flu symptoms to 3-4 days was observed. (18)
GREY ROCKROSE (Cistus incanus)
Another marvel of nature is the Grey Rockrose. This wild plant is typical of the Mediterranean slope, so we can find it in southern European countries. For its therapeutic properties it has been used since ancient times as a natural remedy for the treatment of symptoms of the common cold and flu. It has immunostimulatory properties so it helps the body to generate resistance to any type of pathogen. In this way it acts shortening the duration and reducing the symptoms of viral processes. (19) It is also a powerful antioxidant, anti-inflammatory, antifungal, antiviral and antibacterial. Like elderberry, rockrose is a plant rich in terpenoids and polyphenols, including flavonoids and proanthocyanidins. Some studies seem to suggest that the polyphenols present in rockrose may bind to the surface of certain viruses, thus inhibiting the binding of hemagglutinin (HA) to infected cells and thus preventing the infection from spreading. (20) Moreover, these antioxidant active ingredients are very potent in neutralizing free radicals and help our body to eliminate toxins. (21)
Also known as Sun Dew, it is a carnivorous plant with excellent medicinal properties. It has been used for centuries as an antitussive, antispasmodic and anti-asthmatic agent for the treatment of respiratory diseases. The most important active principles of this plant are the naphthoquinones, specifically plumbagin and 7-methyljuglone. These metabolites have antiviral, antibacterial, antifungal, anti-sclerotic and anticancer properties. (22) For all these reasons, sundew has been found to be an excellent natural remedy for maintaining bronchial health. It helps to breathe more freely, decongesting the airways and is very effective in soothing dry and irritative coughs and has a soothing effect in case of throat, pharynx and vocal cord irritation.
It is a plant native to southern Africa. Its root has been used for centuries by Zulu tribes for the treatment of respiratory infections due to its antiviral, antibacterial and immunomodulatory properties. It acts by soothing the respiratory tract and soothing typical cold symptoms such as cough and sore throat. Its active metabolites include gallic acid and its methyl ester. Its clinical efficacy in the treatment of respiratory problems has been demonstrated and currently countries such as the United Kingdom, Austria and Germany have developed drugs based on the extract of this plant. (23) It has proven to be effective in the treatment of acute bronchitis, sinus infection, pharyngitis and even as a natural treatment for asthma. (24) It reduces both the duration and severity of symptoms and has no adverse effects when taken for long periods of time. Besides presenting antiviral and antibacterial properties, it is an excellent immunomodulator, which allows it to approach the disease from different ways, either by exerting a direct action on the pathogen or indirectly through the stimulation of the immune system of the infected person. In this sense, it acts by inhibiting bacterial adhesion, activates macrophages and modulates the release of reactive oxygen species (ROS), TNF-α and different proinflammatory cytokines. (25)
VITAMINS A AND C
The main property of these vitamins lies in their high antioxidant power, protecting cells against oxidative damage. Both contribute to the normal functioning of the immune system and good levels of both vitamins are necessary for the maintenance of good bronchial health. For example, insufficient intake of vitamin A can cause the cilia in the mucous membranes of the nose and lungs to move less easily and make it more difficult to expel microbes and debris from the airways. In addition, when the cilia remain immobile, the mucus becomes denser, making it an ideal medium for the proliferation of germs. On the other hand, vitamin A modulates a wide range of immune processes such as the formation and differentiation of white blood cells, the differentiation of T-helper cells, the localization of tissue-specific lymphocytes and the production of specific antibodies (26) In contrast, vitamin C contributes to the functioning of the immune system by accumulating in high concentrations in phagocytic cells such as neutrophils, enhancing chemotaxis, phagocytosis and ROS reduction. (27) It is necessary for apoptosis and the elimination of pathogens at local sites of infection as it acts by enhancing the differentiation and proliferation of B and T cells, which are responsible for microbial recognition. Some studies show that taking vitamin C can help reduce the duration and severity of symptoms of the common cold. (28)
Aromatherapy is the use of essential oils (EO) as a natural therapy to improve physical and mental well-being. There is a wide variety of EOs and each of them has a different therapeutic window. The active compounds present in EOs (terpenes, terpenoids and aromatic compounds, among others) act directly on the symptoms of various pathologies and help to strengthen immunity. (29) When faced with a respiratory viral process, a mixture of essential oils with antiviral, expectorant and mucolytic action can be a natural and effective alternative to reduce the severity and duration of the disease. Among the EOs that exhibit these properties are: eucalyptus, ravintsara, Scots pine, oregano, star anise and lemon. While each one has excellent antimicrobial properties on its own, for optimal results, it is best to use them together as they tend to work synergistically. The combination of these oils promotes the health of the respiratory organs, helps to eliminate the mucus stored in the respiratory tract and stimulates the immune system thus avoiding relapses. They are extremely effective in case of respiratory viral processes.
Black cumin (Nigella sativa) contains antimicrobial active substances, which enhance the immune response, inactivating all viruses, fungi, microbes, parasites and bacteria. In addition, it is a powerful antioxidant and bronchodilator. (30)
Eucalyptus EO (Eucalyptus globulus) has been traditionally used as a treatment for pulmonary tuberculosis, diabetes, asthma and also as a disinfectant, antioxidant agent and antiseptic agent, especially in the treatment of respiratory tract infections. It has excellent antimicrobial properties and provides relief and soothing effect in case of throat irritation. (31)
Ravintsara EO (Cinnamomum camphora formosana) contains mostly 1,8-cineole and α-terpinene, which gives it antibacterial, antiviral, anti-inflammatory and immune-stimulating properties. It is commonly used in case of viral infections such as herpes or flu. It acts by decongesting the respiratory tract, relieves muscle tension and combats associated pain. (32)
Scots pine (Pinus sylvestris) EO is used as an antiseptic, expectorant, antiviral, antipyretic, immunostimulant and capillary vasodilator. It reduces the symptoms of respiratory conditions such as flu, sinusitis, pharyngitis, bronchitis and asthma, among others. It acts by decongesting the throat and blocked respiratory tract and helps to clear the nose and breathe more freely.
Oregano EO (Origanum vulgare) is rich in carvacrol, thymol, p-cymene, polyphenols, triperpenoids and sterols, which give it excellent properties as an antioxidant, anti-inflammatory, antiviral, antispasmodic, antiproliferative and neuroprotective. It promotes the health of respiratory organs, reduces bronchial inflammation and improves immunity. (33)
Star anise EO (Illicium verum) contains anethole, phellandrene and limonene, aldehydes and ketones, cineoles and some safrole. It has traditionally been used for the treatment of flu-like symptoms. It offers support and soothing effect in case of tickling and scratchy throat. It also supports the immune system by contributing to the body’s natural defences. (34)
Lemon EO (Citrus limon) is one of the richest in vitamins, especially vitamin C and carotenes. It also contains limonene, β-pinene, γ-terpinene and sabinene, which give it a pain-relieving effect. It has antibacterial and antiviral properties as well as expectorant and antipyretic properties. It boosts the immune system and helps the respiratory tract. (35)
An important detail to keep in mind when supplementing orally with EOs is that not all of them are suitable for consumption. They must be chemo-typed and be 100% pure and natural. Daily intake limits must be respected, as they are very potent agents and in high doses can be cytotoxic.
- Illana-Esteban, C. Medicinal interest of “chaga” (Inonotus obliquus). Soc. Micol. 2011, Madrid 35: 175-185.
- Rogers, R. The fungal pharmacy. North Atlantic Books, Berkeley, CA. 2011.
- Ichimura T. et al. Inhibition of HIV-1 protease by water-soluble lignin-like substance from an edible mushroom, Fuscoporia obliqua. Biotechnol. Biochem. 1998; 62: 575-577.
- Shibnev VA et al. Antiviral Activity of Inonotus Obliquus Fungus Extract towards Infection Caused by Hepatitis C Virus in Cell Cultures. Bull Exp Biol Med. 2011; 151: 612-614.
- Kahlos, K. Prueba preliminar de actividad antiviral de dos cepas de Inonotus obliquus. Fitoterapia 1996; 67: 344–347.
- K Kapp. et al. Antiviral effect of Inonotus obliquus (Pers.:Fr.) Pilat extract against herpes simplex virus type 1 in vitro. Planta Medica International Open 2017; 4(S 01): S1-S202.
- Trishna Debnath et al. Anti-oxidant and anti-inflammatory activities of Inonotus obliquus and germinated brown rice extracts. Molecules, 2013; 18(8):9293-304.
- Q Van et al. Anti-inflammatory effect of Inonotus obliquus, Polygala senega L., and Viburnum trilobum in a cell screening assay. J Ethnopharmacol; 2009; 125(3):487-93.
- Shashkina M.Y. et al. Chemical and medicobiological properties of chaga (review). Chem. J. 2006; 40: 560-568.
- Dong Pil Won et al. Immunostimulating activity by polysaccharides isolated from fruiting body of Inonotus obliquus. Mol Cells, 2011; 31(2):165-73.
- A) Sung Hak Lee et al. Antitumor activity of water extract of a mushroom, Inonotus obliquus, against HT-29 human colon cancer cells. Phytother Res. 2009; 23(12):1784-9. B) Myung-Ja Youn et al. Chaga mushroom (Inonotus obliquus) induces G0/G1 arrest and apoptosis in human hepatoma HepG2 cells. World J Gastroenterol; 2008 Jan 28;14(4):511-7.
- Chunchao Han et al. The Medicinal Values of Culinary-Medicinal Royal Sun Mushroom (Agaricus blazei Murrill). Evidence-Based Complementary and Alternative Medicine; Volume 2013, Article ID 842619, 6 pages.
- Liyan Jiang et al. Low-molecular-weight polysaccharides from Agaricus blazei Murrill modulate the Th1 response in cancer immunity. Oncology Letters, 2018; 15: 3429-3436.
- C. Faccin et al., Antiviral activity of aqueous and ethanol extracts and of an isolated polysaccharide from Agaricus brasiliensis against poliovirus type 1, Letters in Applied Microbiology, 2007; 45 (1), 24–28.
- -W. Kim et al. Anti-diabetic activity of -glucans and their enzymatically hydrolyzed oligosaccharides from Agaricus blazei, Biotechnology Letters, 2005; 27 (7), 483–487.
- Karolina Młynarczyk et al. Bioactive properties of Sambucus nigra L. as a functional ingredient for food and pharmaceutical industry. Journal of Functional Foods, 2018; 40, 377–390.
- A) Evelin Tiralongo et al. Elderberry Supplementation Reduces Cold Duration and Symptoms in Air-Travellers: A Randomized, Double-Blind Placebo-Controlled Clinical Trial. Nutrients, 2016; 8, 182 B) Shahla Shahsavandi et al. Interfering With Lipid Raft Association: A Mechanism to Control Influenza Virus Infection By Sambucus Nigra. IJPR, 2017; 16 (3): 1147-1154.
- Barak, Vivian et al. The effect of Sambucol, a black elderberry-based, natural product, on the production of human cytokines: I. Inflammatory cytokines. European cytokine network. 2001; 12. 290-6.
- Ulrich Kalus et al. Cistus incanus (CYSTUS052) for treating patients with infection of the upper respiratory tract. A prospective, randomised, placebo-controlled clinical study. Antiviral Research, 2009; 84,267–271.
- Roodabeh Bahramsoltani et al. The Preventive and Therapeutic Potential of Natural Polyphenols on Influenza, Expert Review of Anti-infective Therapy, 2015.
- Vanya Dimcheva. Cistus incanus from Strandja Mountain as a Source of Bioactive Antioxidants. Plants, 2018; 7, 8.
- Dominika Durechova et al. antibacterial activity of drosera rotundifolia l. against gram-positive and gramnegative bacteria. J Microbiol Biotech Food Sci, 2016; 5, 20-22.
- Herbert Kolodziej et al. Antimicrobial, Antiviral and Immunomodulatory Activity Studies of Pelargonium sidoides (EPs® 7630) in the Context of Health Promotion. Pharmaceuticals 2011, 4, 1295-1314.
- Matthys H, et al. Efficacy and safety of an extract of Pelargonium sidoides (EPs 7630) in adults with acute bronchitis. A randomised, double-blind, placebo-controlled trial. 2003; 10(suppl 4):7-17.
- Kayser O, et al. Immunomodulatory principles of Pelargonium sidoides. PhytotherRes, 2001; 15:122-6.
- Kim CH. Roles of retinoic acid in induction of immunity and immune tolerance. Endocr Metab Immune Disord Drug Targets. 2008; 8(4):289–94.
- Anitra C. Carr. et al. Vitamin C and Immune Function. Nutrients; 2017, 9, 1211.
- Hemilä, H. Vitamin C intake and susceptibility to the common cold. Br. J. Nutr. 1997, 77, 59–72.
- Amandine Brochot et al. Antibacterial, antifungal, and antiviral effects of three essential oil blends. 2017; 6: e459.
- Yimer E.M, et al. Nigella sativa L. (Black Cumin): A Promising Natural Remedy for Wide Range of Illnesses. Evid Based Complement Alternat Med. 2019; 2019:1528635.
- Claudio Cermelli et al. Effect of Eucalyptus Essential Oil on Respiratory Bacteria and Viruses. Curr Microbiol. 2008; 56:89–92.
- Ying Z. et al. Conservation and applications of camphor tree (Cinnamomum camphora) in China: Ethnobotany and genetic resources. Resour. Crop Evol. 2016; 63:1049–1061.
- Oniga I, et al. Origanum vulgare ssp. vulgare: Chemical Composition and Biological Studies. 2018; 23(8):2077.
- Benmalek Y. et al. Anti-microbial and anti-oxidant activities of Illicium verum, Crataegus oxyacantha ssp monogyna and Allium cepa red and white varieties. 2013; 4(4):244-248.
- Dosoky N.S, et al. Biological Activities and Safety of Citrus spp. Essential Oils. Int J Mol Sci. 2018; 19(7):1966.