Natural and effective antimicrobials found also in our kitchen
Updated: Aug 21, 2021
Infectious diseases are one of the main causes of morbidity and mortality worldwide and antibiotics are one of the most prescribed medications – in fact, often overprescribed. Broad-spectrum antibiotics are also very commonly prescribed for conditions in which they have no use, such as viral infections. The more antibiotics are prescribed on a global scale, the more bacteria figure out how to resist them. Researchers found that 50 percent of all prescribed antibiotics are broad-spectrum types, mainly for respiratory conditions (Hersh and Kronman, 2017). In times of increasing antibiotic resistance, it is worth remembering about plants and substances that have been recognized for centuries as antibacterial and antifungal agents as well as natural antiviral drugs. Some of them can be found in our kitchen and their effectiveness is confirmed by scientific research.
No. 1: Garlic
Garlic (Allium sativum) is a proven natural remedy for respiratory tract infections. The active component of garlic, called allicin, successfully targets many strains of bacteria. Garlic supplementation (180mg allicin) over the course of twelve weeks reduces the frequency and duration of the common cold (63% and 70% respectively) and modestly lowers the actual severity of symptoms (Josling, 2001). High dose of aged garlic extract (2.56 grams per day), given for 90 days to otherwise healthy persons, enhances immune cell function and reduces severity of colds and flu (Nantz et al., 2012). In children, daily supplementation with garlic powder (600 milligrams) over five months is effective for prevention of acute respiratory infections without side effects (Andrianova et al., 2003). Moreover, allicin can inhibit the growth of fungi and bacteria, including antibiotic-resistant strains like methicillin-resistant Staphylococcus aureus (MRSA) (Borlinghaus et al., 2014). MRSA is responsible for severe infections mostly in hospitalised patients. Helicobacter pylori, the most common pathogenic bacteria in the stomach, is associated with gastric ulcers and cancer. Some research shows that garlic can be used against Helicobacter pylori and to promote healing of stomach ulcers (Zardast et al., 2016; Si et al., 2019). However, it is suggested that these results be treated with caution due to limited quality.
No. 2: Onion
Onion (Allium cepa L.) does not only kill bacteria, but also clears the respiratory tract thanks to its volatile oils. Studies have proven the effectiveness of onion extract against the main causal bacteria of adult periodontitis, an infection of the gums.Antibacterial properties persist for up to 48 hours after administration of the extract. Interestingly, grated onions stored at 37°C were no longer an effective antibiotic, as also observed in onions steamed for 10 minutes at 100°C (Kim, 1997).
No. 3: Fermented foods
Fermented sauerkraut, cucumbers, or kimchi are food products rich in beneficial lactic acid bacteria which restore the balance of gut microbiota by fighting against Staphylococcus aureus, Escherichia coli, or Salmonella (Tamang et al., 2016). In vitro study has shown that sauerkraut juice successfully stopped the growth of several fungi (including Aspergillus fumigates, Aspergillus sp., and Candida albicans) more effectively than the anti-fungal drug clotrimazole (Kumar et al., 2013). Fermented milk products are useful against Helicobacter pylori infection implicated in peptic and duodenal ulcer diseases, chronic gastritis, or gastric adenocarcinoma (Sachdeva et al., 2014).
No. 4: Honey
Already in ancient times honey was considered an effective remedy for many diseases. Manuka honey obtained from the nectar of the manuka shrub, which grows in Australia and New Zealand, has been tested the most. It has been proven to have antibacterial properties against Clostridium difficile, Helicobacter pylori, Escherichia coli, Salmonella, Shigella, Staphylococcus aureus, Staphylococcus epidermidis, and Klebsiella oxytoca which can cause gut, respiratory and skin diseases (Mandal and Mandal, 2011; Eteraf-Oskouei and Najafi, 2013). Several studies have demonstrated that Manuka can help to treat and prevent gingivitis and periodontal disease (English et al., 2004). Honey can also inhibit the harmful effects of fungal toxins (mycotoxins) and improve the growth of ‘good’ bacteria in the intestine (Ezz El-Arab et al., 2006). An interesting study conducted among patients with superficial burns has shown that topical application of honey kept the wounds sterile for 7 days (91% efficiency compared to 7% in the control group). In addition, the recovery time was shortened to about 2 weeks (87% of healed wounds in the honey group and 10% in the control group) (Subrahmanyam, 1991). In another study, topical application of multi-flower honey, olive oil and beeswax showed benefit in infants suffering from diaper dermatitis(Al-Waili, 2005). Moreover, honey has great potential for therapeutic use for urinary tract infection treatment cause by 11 multidrug-resistant bacterial strains (Bouacha et al., 2018).
No. 5: Black cumin oil
Black cumin oil, also called black seed oil, comes from the black cumin (Nigella sativa) plant. It prevents the growth of life-threatening Listeria monocytogenes, a major foodborne pathogen. An in vitro study has indicated a strong antibacterial activity of black cumin oil against all the strains of L. monocytogenes (Nair et al., 2005). Infection with that bacteria is a more frequent cause of death than with Salmonella. L. monocytogenes is especially dangerous for infants as it can cause meningitis, an inflammation of the protective membranes covering the brain and spinal cord. Black cumin can also help to slow down or stop methicillin-resistant Staphylococcus aureus (MRSA) from spreading(Hannan et al., 2008). MRSA plagues hospitals and nursing homes worldwide. Active chemical compounds present in black seed oil showed 100 percent inhibition for the 30 fungal and mould pathogens causing skin and nails infections (Taha et al., 2010).
No. 6: Coconut oil
Coconut oil can help improve gut health by destroying harmful bacteria like Clostridium difficile. C. difficile is the leading cause of hospital-acquired antibiotic-associated diarrhoea worldwide. Moreover, the growth and spreading of antibiotic-resistant C. difficile is becoming a significant problem. Coconut oil turns out to be helpful in controlling C. difficile growth. Although virgin coconut oil does not inhibit its growth, bacterial growth can be inhibited using 0.15-1.2% lipolyzed coconut oil (Shilling et al., 2013). Another study has found that the capric acid and lauric acid in coconut oil are active in killing Candida albicans and may therefore be useful for treatment of yeast infections caused by that pathogen. Furthermore, oil pulling with coconut oil can be used as a way to cleanse the mouth of bacteria and help heal periodontal disease. By swishing the oil in the mouth, the oil damages the cell wall of microorganisms and kills them. Oil pulling should be ideally performed daily each morning on an empty stomach before brushing the teeth, and the oil should not be swallowed (Shanbhag, 2016).
No. 7: Oregano oil
Oregano oil is so potent that it has been the focus of over 800 studies referenced in PubMed. Oregano oil has been shown to inhibit the growth of Escherichia coli and Pseudomonas aeruginosa (Sienkiewicz et al., 2012). In combination with thyme oil, it is an effective weapon against Salmonella, Staphylococcus aureus, MRSA strains, and Bacillus cereus causing food poisoning (Boskovic et al., 2015). Oregano oil can be as effective as the antibiotic ampicillin in the fight against Micrococcus luteus (infection slows down metabolic processes) and in inhibiting the growth of Klebsiella pneumoniae (causes destructive changes to the lungs) and Candida albicans. One study found that oregano oil is also a potential anti-parasitic remedy. Fourteen adults whose stools tested positive for enteric parasites (Blastocystis hominis, Entamoeba hartmanni and Endolimax nana) were supplemented with 600 milligrams of oregano for six weeks. A complete disappearance of Blastocystis hominis was observed in eight cases, Entamoeba hartmanni in four cases, and Endolimax nana in one case. Gastrointestinal symptoms improved in seven of the 11 patients (Force et al., 2000).
No. 8: Thyme Oil
Thyme (Thymus vulgaris) oil is an excellent antimicrobial. Studies evaluated its effect against bacteria found in milk, such as Salmonella. The results indicate that using thyme oil as an antimicrobial preservative for food could be a good option for protecting our bodies from bacteria (Xue et al., 2015). Wouldn’t this be a better choice than the usual chemical approach? Thyme oil was also tested in vitro against 120 strains of bacteria isolated from patients with infections of the oral cavity, the respiratory and genitourinary tracts, and infections acquired from a hospital environment (Sienkiewicz et al., 2011). The results showed that the oil from T. vulgaris exhibited strong effectivity against all of the clinical strains, including some antibiotic-resistant strains (Sienkiewicz et al., 2011).
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