Immunity boosting vitamins -
Vitamin E supplementation did not affect the incidence of upper or lower respiratory tract infections or the total durations of the infections. Vitamin E supplementation for a median of 6. Among the 5, participants who smoked more than 19 cigarettes per day or did not exercise, however, vitamin E supplementation did not affect the risk of pneumonia.
All intake levels of vitamin E found naturally in foods are considered safe. These ULs, however, do not apply to people taking vitamin E under the care of a physician. Vitamin E supplementation might interact with certain medications, including anticoagulant and antiplatelet medications.
It might also reduce the effectiveness of radiation therapy and chemotherapy by protecting tumor cells from the action of these agents [ 76 , , ].
More information on vitamin E is available in the ODS health professional fact sheet on vitamin E. For information on vitamin E and COVID, please see the ODS health professional fact sheet, Dietary Supplements in the Time of COVID Selenium is an essential mineral contained in many foods , including Brazil nuts, seafood, meat, poultry, eggs, and dairy products as well as bread, cereals, and other grain products.
The RDA for selenium is 15 to 70 mcg for infants and children, depending on age, and 55 to 70 mcg for adults, including those who are pregnant or lactating [ 56 ]. Human and animal studies suggest that selenium helps support both the innate and adaptive immune systems through its role in T-cell maturation and function and in natural killer cell activity [ 2 , 25 , 58 , ].
It may also reduce the risk of infections [ 2 , 15 , 25 , 58 , ]. As a component of enzymes that have antioxidant activities, selenium might help reduce the systemic inflammatory response that can lead to ARDS and organ failure [ 27 , 58 , , ]. Low selenium status in humans has been associated with lower natural killer cell activity, increased risk of some bacterial infections, and increased virulence of certain viruses, including hepatitis B and C [ 2 , 5 , 10 , 15 , 27 , , , ].
However, evidence is conflicting whether selenium supplementation enhances immunity against pathogens in humans [ ]. Studies have also examined whether intravenous selenium which is classified as a drug in the United States benefits adults with sepsis; those who are critically ill and requiring mechanical ventilation; adults who are undergoing elective major surgery; or those who are critically ill from burns, head injury, brain hemorrhage, or stroke [ , , ].
The results of these studies provide no clear evidence of benefit. Selenium status varies by geographic region because of differences in the amounts of selenium in soil and in local foods consumed [ 56 , ].
Selenium deficiency is very rare in the United States and Canada, but low selenium status is common in some areas of the world, such as parts of Europe and China [ , ].
In children and adults with HIV, selenium deficiency is associated with a higher risk of morbidity and mortality [ ]. However, studies that examined whether micronutrient supplementation, including selenium, affects risk of HIV transmission or disease outcomes in children and adults have had mixed results.
An observational study in Thailand did not identify associations between selenium status in children with HIV and treatment outcomes [ ]. This study included boys and girls with HIV median age 7. Baseline selenium levels all of which were adequate showed no associations with ART treatment outcomes.
Clinical trials have found limited beneficial effects of selenium supplementation on immune function in people with HIV. Selenium supplementation provided no benefits in another trial that randomized men and women with HIV mean age Two Cochrane Reviews also concluded that selenium supplements offer little, if any, benefit for people with HIV.
The authors found that evidence was insufficient to determine whether supplementation with selenium alone is beneficial. Researchers have also examined whether blood selenium levels or selenium supplementation affect pregnancy outcomes in people with HIV.
Findings from these studies suggest that low blood selenium levels are associated with a higher risk of preterm delivery and that selenium supplementation might reduce the risk of preterm delivery but has mixed effects on other outcomes. For example, a cross-sectional study in Nigeria of pregnant individuals age 15—49 years with HIV found that those with a selenium deficiency defined as blood selenium less than 0.
In a clinical trial in Nigeria, researchers examined whether selenium supplementation affects pregnancy outcomes and disease progression in 90 pregnant individuals mean age These ULs, however, do not apply to people taking selenium under the care of a physician.
Higher intakes of selenium can cause a garlic odor in the breath and a metallic taste in the mouth as well as hair and nail loss or brittleness [ 56 ]. Other signs and symptoms of excess selenium intakes include nausea, diarrhea, skin rashes, mottled teeth, fatigue, irritability, and nervous system abnormalities.
Cisplatin, a chemotherapy agent used to treat ovarian, bladder, lung, and other cancers, can reduce selenium levels in hair, plasma, and serum [ , ]. The evidence from studies examining whether selenium supplementation helps reduce the side effects of cisplatin and other chemotherapy agents is uncertain [ , ].
More information on selenium is available in the ODS health professional fact sheet on selenium. For information on selenium and COVID, please see the ODS health professional fact sheet, Dietary Supplements in the Time of COVID Zinc is an essential nutrient contained in a wide variety of foods , including oysters, crab, lobster, beef, pork, poultry, beans, nuts, whole grains, and dairy products.
The RDA for zinc is 2—13 mg for infants and children, depending on age, and 8—12 mg for adults, including those who are pregnant or lactating [ 29 ]. Zinc is involved in numerous aspects of cellular metabolism.
It is necessary for the catalytic activity of approximately enzymes and it plays a role in many body processes, including both the innate and adaptive immune systems [ 2 , 5 , 29 , 58 , ].
Zinc also has antiviral and anti-inflammatory properties, and it helps maintain the integrity of tissue barriers, such as the respiratory epithelia [ 5 , 58 , 83 , ]. Zinc deficiency adversely affects immune function by impairing the formation, activation, and maturation of lymphocytes.
In addition, zinc deficiency decreases ratios of helper to suppressor T cells, production of interleukin-2, and activity of natural killer cells and cytotoxic T cells [ 2 , 4 , 5 , 27 , , , ].
Furthermore, zinc deficiency is associated with elevated levels of proinflammatory mediators [ ]. These effects on immune response probably increase susceptibility to infections [ ] and inflammatory diseases, especially those affecting the lungs [ ].
Studies have found associations between low zinc status and higher risk of viral infections [ 79 ], and people with zinc deficiency have a higher risk of diarrhea and respiratory diseases [ 2 ]. Poor zinc status is also common among people with HIV or hepatitis C and is a risk factor for pneumonia in older adults [ 27 , 58 , , , ].
Some research suggests that zinc supplementation increases the number of T cells in the blood of older adults living in nursing homes [ ]. population might obtain marginal amounts of zinc [ ].
Older adults are among the groups most likely to have low intakes. Researchers have hypothesized that zinc could reduce the severity and duration of cold symptoms by directly inhibiting rhinovirus binding and replication in the nasal mucosa and suppressing inflammation [ , ].
In studies of the effects of zinc supplements on the common cold, zinc is usually administered in a lozenge or syrup that temporarily sticks to the mouth and throat, placing the zinc in contact with the rhinovirus in those areas.
The results from clinical trials that have examined the effects of supplemental zinc on the common cold have been inconsistent. Overall, however, supplemental zinc in lozenge or syrup form appears to reduce the duration, but not the severity, of signs and symptoms of the common cold when taken shortly after a person develops a cold [ ].
In one clinical trial that found beneficial effects of zinc on the common cold, 50 adults took a zinc acetate lozenge In comparison with placebo, the zinc lozenges reduced the duration of colds by 3 days and the severity of cold symptoms cough, nasal discharge, and muscle aches [ ].
Results were more mixed in another clinical trial in which adults with experimentally induced colds took lozenges containing zinc gluconate Illnesses lasted 1 day less with the zinc gluconate lozenges than with the placebo, but the lozenges had no effect on symptom severity.
Furthermore, the 5. In a second trial described in the same report, neither zinc gluconate nor zinc acetate lozenges affected the duration or severity of cold symptoms in comparison with placebo in adults with colds [ ].
A systematic review and meta-analysis found that zinc appears to reduce the duration of the common cold but has mixed effects on the severity of signs and symptoms [ ]. It included 28 clinical trials including the three described above with a total of 5, participants mostly adults younger than 65 years who had a community-acquired viral respiratory tract infection or were inoculated with a rhinovirus.
Most trials provided zinc in the form of zinc acetate or gluconate lozenges with total daily zinc doses of 45 to mg for up to 2 weeks, but some trials used nasal sprays or gels.
In participants who used products containing zinc, symptoms resolved an average of 2 days earlier than in those who took a placebo.
Zinc also reduced the severity of symptoms on the third day of illness. However, average daily symptom severity did not differ between those who were and were not treated with zinc supplements.
In addition, zinc did not affect the risk of developing a cold after rhinovirus inoculation. Other recent systematic reviews and meta-analyses have also found that zinc shortens the duration of the signs and symptoms of colds but does not reduce the risk of colds [ 54 , 67 , ].
Poor zinc status is associated with greater susceptibility to pneumonia, more severe disease, and higher mortality risk in children [ ]. Several clinical trials have examined the effects of zinc supplementation on the incidence of pneumonia and as an adjunctive treatment for pneumonia.
However, most research suggests that the adjunctive use of zinc supplements to treat pneumonia in children does not affect mortality or time to recovery. A systematic review and meta-analysis included 11 clinical trials in children age 2 to 60 months with mostly severe pneumonia in low- and middle-income countries [ ].
Another meta-analysis of six placebo-controlled trials that included 2, children age 2 to 60 months found that zinc supplementation reduced mortality rates from severe pneumonia but not rates of treatment failure or changes in antibiotic therapy [ ]. Diarrhea is associated with high mortality rates among children in low-income countries, where it causes about , deaths annually [ , ].
Zinc supplementation may benefit children with acute diarrhea, especially in low-income countries, where zinc deficiency is common. Clinical trials show that zinc supplementation helps shorten the duration of diarrhea in children in low-income countries.
A Cochrane Review included 33 trials that compared the effects of zinc supplementation with those of placebo in 10, children age 1 month to 5 years who had acute or persistent diarrhea [ ].
Most studies were conducted in Asian countries that had high rates of zinc deficiency. Zinc was administered in the form of zinc acetate, zinc gluconate, or zinc sulphate. In addition, evidence that the authors deemed to have high certainty showed that zinc supplementation reduces the duration of diarrhea in children with signs of malnutrition by about a day.
In children younger than 6 months, however, zinc supplementation did not affect mean duration of diarrhea or persistence of diarrhea for 7 days. A systematic review and meta-analysis had similar findings. It examined the use of zinc alone or in combination with other treatments for acute diarrhea and gastroenteritis in studies in 32, children, mostly from low- and middle-income countries [ ].
Analyses showed that zinc alone or in combination reduced the duration of diarrhea by about ¾ to 1½ days. The authors concluded that zinc was one of the most effective interventions of those examined, especially when it was combined with Saccharomyces boulardii a probiotic or smectite a natural clay that contains minerals , for reducing the duration of acute diarrhea and gastroenteritis in children.
The WHO and UNICEF recommend supplementation with 20 mg zinc per day, or 10 mg for infants younger than 6 months, for 10 to 14 days to treat acute childhood diarrhea [ ].
However, most trials of zinc supplementation for diarrhea have been conducted in low-income countries [ ]. In well-nourished children, zinc supplements might have only a marginal effect on diarrhea duration.
HIV infection reduces the absorption and metabolism of zinc from foods [ ]. In addition, people with HIV often have diarrhea, which can result in excessive losses of zinc. For these reasons, people with HIV often have low plasma or serum zinc levels.
Several clinical trials have found some beneficial effects of zinc supplementation to manage the morbidity and mortality associated with HIV infection.
However, findings were less positive in two Cochrane Reviews and another trial not included in either Cochrane Review that assessed the potential benefits of supplementation with micronutrients, including zinc, or placebo in various populations with HIV.
However, zinc supplementation did not affect viral load or mortality rates in this second trial. However, the supplements blunted the rise in hemoglobin concentrations between baseline and 6 weeks after delivery. These ULs, however, do not apply to people taking zinc under the care of a physician.
Higher intakes can cause nausea, vomiting, loss of appetite, abdominal cramps, diarrhea, headaches, and a metallic taste in the mouth [ 29 , 32 ]. In clinical trials in children, zinc supplementation to treat diarrhea increased the risk of vomiting more than placebo [ , ].
Zinc supplements might interact with several types of medications. For example, zinc can reduce the absorption of some types of antibiotics and penicillamine, a drug used to treat rheumatoid arthritis [ , ].
Other medications, such as thiazide diuretics and certain antibiotics, can reduce zinc absorption [ , ]. More information on zinc is available in the ODS health professional fact sheet on zinc.
For information on zinc and COVID, please see the ODS health professional fact sheet, Dietary Supplements in the Time of COVID Andrographis paniculata , also known as Chuān Xīn Lián, is an herb that is native to subtropical and Southeast Asia [ ].
Its leaves and other aerial above-ground parts are used in traditional Ayurvedic, Chinese, and Thai medicine for relieving symptoms of the common cold, influenza, and other respiratory tract infections [ ]. The active constituents of andrographis are believed to be andrographolide and related compounds, which are diterpene lactones that might have antiviral, anti-inflammatory, and immune-stimulating effects [ , , ].
Results from several clinical trials suggest that andrographis might reduce the duration of upper respiratory tract infections and the severity of symptoms. One of these trials used a common andrographis preparation called Kan Jang.
The trial included 50 men and women age 18 to 50 years with the common cold who took four tablets of Kan Jang each containing 85 mg of an andrographis extract three times daily for 5 days 1, mg total daily dose or placebo within 3 days of developing cold symptoms [ ].
Participants who took Kan Jang experienced milder symptoms, recovered sooner, and took fewer days of sick leave than those who took placebo. In another clinical trial, men and women age 18 to 60 years with upper respiratory tract infections took either KalmCold containing mg of an andrographis extract twice daily or placebo for 5 days [ ].
The results showed no differences in symptom severity during days 1 to 3 of treatment. However, between days 3 and 5, participants who took KalmCold experienced milder symptoms—including cough, nasal discharge, headache, fever, and sore throat but not earache —than those who took placebo.
Two systematic reviews and meta-analyses of clinical trials found that andrographis preparations had beneficial effects on symptoms and duration of the common cold. The more recent of these analyses, published in , included 33 clinical trials including the two described above that evaluated the effects of andrographis alone or in combination with other herbs on symptoms of acute upper and lower respiratory tract infections in a total of 7, participants [ ].
Treatment protocols varied widely, but typical daily doses ranged from to 1, mg andrographis extract for 3 to 7 days; studies compared andrographis with placebo, usual care, or other herbal interventions.
The analyses showed that andrographis significantly reduced the severity of cough, sore throat, and overall symptoms. However, the authors noted that the findings should be interpreted with caution because the studies were heterogenous and many were of poor quality. Similar findings were reported from a systematic review and meta-analysis [ ].
It included six clinical trials including the two described above that administered Kan Jang or KalmCold All studies in this analysis compared andrographis with placebo, not usual care or other herbal interventions as in the meta-analysis described above.
Andrographis reduced the frequency and severity of cough to a greater extent than placebo. Three earlier systematic reviews also showed that andrographis appears to alleviate symptoms of upper respiratory tract infections [ , , ].
Although these findings suggest that andrographis might be useful to manage the symptoms and reduce the duration of upper respiratory tract infections, the evidence has several weaknesses. For example, the studies used different andrographis formulations, and many of the clinical trials were conducted by investigators affiliated with the manufacturer of Kan Jang or KalmCold [ , ].
Clinical trials have found minor adverse effects, including nausea, vomiting, vertigo, skin rashes, diarrhea, and fatigue [ , , ]. Allergic reactions might also occur [ , ].
Findings from some animal studies suggest that andrographis might adversely affect fertility, so experts recommend against its use by men and women during the preconception period and by people who are pregnant [ , , ]. According to animal and laboratory studies, andrographis might decrease blood pressure and inhibit platelet aggregation, so it could interact with antihypertensive and anticoagulant medications by enhancing their effects [ ].
Because of its potential immune-stimulating effects, andrographis might also reduce the effectiveness of immunosuppressants [ , ]. For information on andrographis and COVID, please see the ODS health professional fact sheet, Dietary Supplements in the Time of COVID Echinacea, commonly known as purple coneflower, is an herb that grows in North America and Europe [ ].
Although the genus Echinacea has many species, extracts of E. purpurea , E. angustifolia , and E. pallida are the most frequently used in dietary supplements. The echinacea supplements on the market in the United States often contain extracts from multiple species and plant parts [ ].
Echinacea contains volatile terpenes, polysaccharides, polyacetylenes, alkamides, phenolic compounds, caffeic acid esters, and glycoproteins [ ]. Echinacea might have antibacterial activities, stimulate monocytes and natural killer cells, and inhibit virus binding to host cells [ 3 , ].
It might also reduce inflammation by inhibiting inflammatory cytokines [ 3 ]. Most studies of echinacea have assessed whether it helps prevent and treat the common cold and other upper respiratory illnesses, but it has also been used in traditional medicine to promote wound healing [ , ].
Results from clinical trials examining the effects of echinacea for the common cold have been mixed. Overall, studies suggest echinacea might slightly reduce the risk of developing a cold but does not shorten the duration or severity of illness.
For example, one clinical trial examined the effects of echinacea on the risk of the common cold in men and women mean age 23 years [ ]. purpurea extract Echinaforce or placebo; if participants came down with a cold during the study, they increased their dose to 4, mg per day.
Participants taking echinacea had fewer colds and fewer days with cold symptoms than those taking a placebo.
Another clinical trial examined whether echinacea helps treat the common cold in male and female participants age 12 to 80 years who developed cold symptoms within 36 hours before enrollment [ ].
Participants took E. purpurea and E. angustifolia extracts four times a day for a combined dose of 10, mg during the first 24 hours and then 5, mg for 4 days or placebo.
Echinacea did not shorten illness duration or severity. A systematic review and meta-analysis examined the effects of echinacea E. purpurea , E angustifolia , E. pallida , or more than one form to prevent upper respiratory tract infections or reduce the duration of illness [ ].
Nine clinical trials eight in adults and one in children were included in the prevention meta-analysis portion of this analysis, and seven all in adults were included in the duration meta-analysis, including the two trials described above [ , ].
A Cochrane Review of echinacea use for preventing and treating the common cold had similar results [ ]. The review included 24 clinical trials with a total of 4, participants. Limited research has also examined whether echinacea is beneficial for influenza.
One clinical trial found that echinacea had similar effects to oseltamivir Tamiflu , a medication used to treat influenza.
This trial included male and female participants age 12 to 70 who had had influenza symptoms for up to 48 hours [ ]. Participants took either E. The results showed no difference between E. Purpurea and oseltamivir followed by placebo in rapidity of recovery from influenza after 1 day, 5 days, or 10 days of treatment.
In addition, participants taking echinacea experienced fewer adverse events, especially nausea and vomiting. Additional research is needed to confirm this finding. Echinacea appears to be safe.
In rare cases, echinacea can cause allergic reactions [ ]. The safety of echinacea during pregnancy is not known, so experts recommend against the use of echinacea supplements by people who are pregnant [ ]. Echinacea might interact with several medications. For example, echinacea might increase cytochrome P activity, thereby reducing levels of some drugs metabolized by these enzymes [ ].
In addition, echinacea might reduce the effectiveness of immunosuppressants due to its potential immunostimulatory activity [ ]. For information on echinacea and COVID, please see the ODS health professional fact sheet, Dietary Supplements in the Time of COVID Elderberry contains many compounds—including anthocyanins, flavonols, and phenolic acids—that might have anti-inflammatory, antiviral, antimicrobial, and immune-stimulating effects [ 3 , ].
Studies of the effects of elderberry have primarily used elderberry extracts, not the berries themselves [ ]. Components of elderberry might help prevent respiratory infections by inhibiting virus binding to host cells and by stimulating the immune system [ ]. A few clinical trials have examined the effects of elderberry on the common cold and influenza.
The results from these trials have been mixed. However, overall, they suggest that elderberry might help relieve symptoms of respiratory tract infections. One clinical trial examined whether elderberry extract helps prevent and treat the common cold [ ]. Elderberry extract did not reduce the number of participants who developed a cold.
However, among participants who did develop a cold, elderberry extract reduced cold duration by about 2 days and reduced the severity of symptoms. A meta-analysis included four clinical trials including the trial described above of the effects of elderberry supplementation on upper respiratory symptoms caused by the common cold or flu in a total of participants age 5 to 59 years [ ].
The analysis showed that elderberry supplementation reduced the duration of upper respiratory symptoms, and the effect was stronger for symptoms of influenza than for those caused by the common cold. A review included the same four trials as well as one that administered an herbal preparation containing both elderberry and Echinacea purpurea [ ].
The results showed that elderberry might help relieve symptoms of the common cold and influenza when taken close to the onset of symptoms and for up to 2 weeks. In contrast, in a clinical trial, 87 male and female participants age 5 years and older with influenza for less than 48 hours took 15 ml 5, mg elderberry extract twice daily for ages 5 to 12 years and four times daily for ages 13 and older or placebo for 5 days [ ].
Elderberry had no effect on the duration or severity of illness. A systematic review of five clinical trials of elderberry to treat viral respiratory illnesses found beneficial effects on some, but not all, outcomes [ ]. The results showed that elderberry supplementation for 2 to 16 days might reduce the severity and duration of the common cold and the duration of flu but does not appear to reduce the risk of the common cold.
However, the authors noted that the studies were small, heterogeneous, and of poor quality. Elderberry flowers and ripe fruit appear to be safe for consumption. However, the bark, leaves, seeds, and raw or unripe fruit of S. nigra contain a cyanogenic glycoside that is potentially toxic and can cause nausea, vomiting, diarrhea, dehydration due to diuresis, and cyanide poisoning [ , , ].
The heat from cooking destroys this toxin, so cooked elderberry fruit and properly processed commercial products do not pose this safety concern [ 3 , , , , ].
Elderberry might affect insulin and glucose metabolism, so according to experts, people with diabetes should use it with caution [ ]. The safety of elderberry during pregnancy is not known, so experts recommend against the use of elderberry supplements by people who are pregnant [ , ].
Recent analyses suggest that some elderberry supplements are highly diluted or have been adulterated with a cheaper ingredient, such as black rice extract, instead of elderberry [ , ].
Due to its potential immunostimulatory activity, elderberry might reduce the effectiveness of immunosuppressant medications [ ].
For information on elderberry and COVID, please see the ODS health professional fact sheet, Dietary Supplements in the Time of COVID Garlic Allium sativum is a vegetable with a long history of culinary use.
Garlic is also available as a dietary supplement in softgel, capsule, tablet, and liquid forms [ ]. Researchers have studied garlic mainly to determine whether it lowers blood pressure and cholesterol levels, but it might also have antiviral properties [ 32 , ].
These properties are often attributed to two compounds in garlic—allicin and ajoen [ ]. Garlic might also have antimicrobial and antifungal activity [ ].
Some dietary supplements contain aged garlic extract, prepared from sliced garlic that is soaked in an aqueous ethanol solution for up to 20 months.
The extract is then filtered and concentrated [ , ]. Aged garlic extract contains compounds, such as lectins, fructo-oligosaccharide, and N-alpha-fructosyl arginine, that might affect immune cell function [ ].
It also contains S-allyl-L-cysteine and other compounds that might have antioxidant effects and reduce some inflammatory markers [ , ]. Only a few clinical trials have examined whether garlic supplements help prevent or treat the common cold or influenza, and results are inconclusive.
One trial included healthy men and women mean age 26 years who took 2. After 45 days, the researchers took blood samples from the participants and cultured the natural killer cells and gamma delta T cells.
The natural killer cells and gamma delta T cells from participants who took the extract had a higher proliferation rate than those from participants who took placebo. After 90 days, the number of illnesses colds and influenza did not differ between groups, nor did the average number of symptoms per illness.
However, participants who took aged garlic extract reported a smaller total number of symptoms during the study. Results were more positive in another trial, in which men and women mean age 53 years took one capsule of a garlic supplement dose not specified or placebo daily for 12 weeks between November and February [ ].
Participants who took garlic had fewer colds 24 among the full study population during the study than those who took placebo 65 colds. In addition, colds lasted an average of only 1. Garlic is safely consumed worldwide as a culinary ingredient [ ], and garlic and its derivatives are generally recognized as safe, according to the U.
Food and Drug Administration FDA [ ]. The adverse effects of garlic dietary supplements are minor and include bad breath, body odor, and skin rash [ 32 , , ]. Garlic might interact with medications.
For example, garlic might have anticoagulant effects, so it might interact with warfarin Coumadin and similar medications [ , , ].
However, the findings from reported case studies on this interaction are inconclusive [ ]. Garlic might also reduce blood pressure, so it might interact with antihypertensive medications [ ].
Ginseng is the common name of several species of the genus Panax , most commonly Panax ginseng also called Asian ginseng or Korean ginseng and Panax quinquefolius American ginseng [ , ].
Asian ginseng is endemic to China and Korea, whereas American ginseng is endemic to the United States and Canada [ ]. Triterpene glycosides, also known as ginsenosides, are some of the main purported active constituents of ginseng [ , ].
Although ginseng contains numerous ginsenosides, research has focused on the Rb1 ginsenoside and compound K, a bioactive substance formed when the intestinal microbiota metabolize ginsenosides [ , ]. Animal and laboratory studies suggest that ginseng stimulates B-lymphocyte proliferation and increases production of some interleukins and interferon-gamma [ ]; these cytokines affect immune activation and modulation [ 1 ].
Ginseng might also inhibit virus replication and have anti-inflammatory activity. However, whether ginseng has a clinically meaningful effect on immune function in humans is not clear [ , ]. Vitamin D is a fat-soluble nutrient essential to the health and functioning of your immune system.
Vitamin D enhances the pathogen-fighting effects of monocytes and macrophages — white blood cells that are important parts of your immune defense — and decreases inflammation, which helps promote immune response 3. Many people are deficient in this important vitamin , which may negatively affect immune function.
In fact, low vitamin D levels are associated with an increased risk of upper respiratory tract infections, including influenza and allergic asthma 4. Some studies show that supplementing with vitamin D may improve immune response. In fact, recent research suggests that taking this vitamin may protect against respiratory tract infections.
In a review of randomized control studies in 11, people, supplementing with vitamin D significantly decreased the risk of respiratory infections in people deficient in this vitamin and lowered infection risk in those with adequate vitamin D levels 5.
Other studies note that vitamin D supplements may improve response to antiviral treatments in people with certain infections, including hepatitis C and HIV 6 , 7 , 8. Depending on blood levels, anywhere from 1, to 4, IU of supplemental vitamin D per day is sufficient for most people, though those with more serious deficiencies often require much higher doses 4.
Vitamin D has been highly researched in connection with COVID because of its effect on the immune system. Studies have shown that Vitamin D can expedite healing and stall inflammation in the respiratory system 9. In a recent rapid review study, it was concluded that more research is needed to recommend Vitamin D supplementation for the prevention and treatment of COVID However, many professionals within the health and science community argue that supplementing with Vitamin D is generally safe and could possibly help protect individuals from the virus Vitamin D is essential for immune function.
Healthy levels of this vitamin may help lower your risk for respiratory infections. This is because zinc is essential for immune system function. Zinc is needed for immune cell development and communication and plays an important role in inflammatory response.
Zinc also specifically protects tissue barriers in the body and help prevent foreign pathogens from entering Zinc deficiency affects around 2 billion people worldwide and is very common in older adults. Zinc deficiency is relatively rare in North America and in developed countries 17 , Nevertheless, many individuals in the United States have marginal zinc deficiency related to intake or absorption.
Older individuals are generally at an increased risk Numerous studies reveal that zinc supplements may protect against respiratory tract infections like the common cold 19 , In a study in 64 hospitalized children with acute lower respiratory tract infections ALRIs , taking 30 mg of zinc per day decreased the total duration of infection and the duration of the hospital stay by an average of 2 days, compared with a placebo group Supplemental zinc may also help reduce the duration of the common cold Additionally, zinc demonstrates antiviral activity 23 , Taking zinc long term is typically safe for healthy adults, as long as the daily dose is under the set upper limit of 40 mg of elemental zinc Supplementing with zinc may help protect against respiratory tract infections and reduce the duration of these infections.
Vitamin C is perhaps the most popular supplement taken to protect against infection due to its important role in immune health. This vitamin supports the function of various immune cells and enhances their ability to protect against infection. Vitamin C also functions as a powerful antioxidant, protecting against damage induced by oxidative stress, which occurs with the accumulation of reactive molecules known as free radicals.
Oxidative stress can negatively affect immune health and is linked to numerous diseases Supplementing with vitamin C has been shown to reduce the duration and severity of upper respiratory tract infections, including the common cold Additionally, high-dose intravenous vitamin C treatment has been shown to significantly improve symptoms in people with severe infections, including sepsis and acute respiratory distress syndrome ARDS resulting from viral infections Still, other studies have suggested that the role of vitamin C in this setting is still under investigation 32 , The upper limit for vitamin C is 2, mg.
Supplemental daily doses are typically between and 1, mg Vitamin C is vital for immune health. Supplementing with this nutrient may help reduce the duration and severity of upper respiratory tract infections, including the common cold. Black elderberry Sambucus nigra , which has long been used to treat infections, is being researched for its effects on immune health.
In test-tube studies, elderberry extract demonstrates potent antibacterial and antiviral potential against bacterial pathogens responsible for upper respiratory tract infections and strains of the influenza virus 35 , A review of 4 randomized control studies in people found that elderberry supplements significantly reduced upper respiratory symptoms caused by viral infections However, this study is outdated and was sponsored by the elderberry syrup manufacturer, which may have skewed results If so, to what extent?
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Ich bin endlich, ich tue Abbitte, es nicht die richtige Antwort. Wer noch, was vorsagen kann?
Ich bin endlich, ich tue Abbitte, aber es kommt mir nicht ganz heran.