Vitamins for the Immune System:

Empower Your Immune System: Vitamins for Optimal Defense

One of the most important things about keeping healthy is having a strong immune system. Some are born with it. They generally don’t fall prey to frequent colds, flu or fevers. But don’t worry, because eating the right foods helps build a better immune system. The role of vitamins is essential to building a strong immune system.

Have you heard of the term antioxidant? Well, these are generally referred to as vitamins. Fruit and vegetables are the primary sources of antioxidants. These help to repair damage to cells caused by free radicals. Doctors suspect that free radicals interfere with your immunity and are also responsible for causing a lot of diseases. If you don’t eat fruits and vegetables, you better start now.

Some of the most important vitamins are:

  • Vitamin C: Vitamin C is very crucial in the formation of white blood cells. These white blood cells help defend our body against infections and toxins. Vitamin C is also responsible for the protein interferon, which protects our body from various pathogens like viruses or bacteria. The primary source of this vitamin is citrus fruits like lemon, oranges, etc.
  • Vit E—Vitamin E is very vital. The primary sources of this vitamin are nuts, seeds, and whole grains. This helps in producing B cells. B cells help produce antibodies that fight against bacteria.
  • Vit A—Vitamin A is responsible for maintaining the mucosal barrier in our intestines. It also helps in creating antibodies. Foods like animal liver, milk and coloured fruits are rich in vitamin A.
  • Vit B6—Pyridoxin is another name for vitamin B6. It helps produce hemoglobin, which carries oxygen in R.B.Fruits, vegetables, meat and cereals are rich in vitamin B6.

Health advice for teenagers:

Teenage is the time when boys and girls go through a lot of physiological and mental changes. Maintaining their good health and growth is essential. This is the time when their bones and muscles start to grow strong. It is also the time when teenagers start making their own decisions and taking control of what they eat.

Some get obsessed with their health and they might not eat at all to remain slim. On the other hand, some get obese because they don’t take their health seriously. They need proper counseling about healthy foods and healthy eating habits. Parents should take the initiative and keep track of what their kids are eating. It is always a good idea to keep enough healthy snacks available at home to make sure your teenage kids don’t go for junk food when hungry.

Some tips to remember:

Adolescence is when kids need a lot of energy because it is a growing phase for them. They have a big appetite. Whatever they eat, as a meal or snack, should be rich in nutrient value. Junk foods might taste good, but they have poor nutritional value. Parents should always keep plenty of healthy snacks at home, like fruits and vegetables.

  • Give them a lot of carbohydrates. Carbohydrates are the main source of energy—foods like potatoes, rice, bread, pasta, etc.
  • Ensure that they eat a lot of fruits and vegetables. At least two servings a day.
  • Include dairy products in their diet like milk, yoghurt, cheese, etc. Dairy products have a lot of calcium, which helps build strong bones.
  • Proteins are also necessary. Meat products help build muscles.
  • Limit sugar and fatty foods as much as possible.

Dietary Supplements and Immune Function

The immune system, our body’s protection against disease-inflicting pathogens, contains innate and adaptive responses. Innate responses, the primary line of protection, involve physical boundaries like skin and gut epithelium that save you from pathogen entry. Additionally, leukocytes (white blood cells) like neutrophils, macrophages (cytokine manufacturers), and natural killer cells work to identify and dispose of foreign pathogens. However, unlike the adaptive immune machine, those additives are nonspecific and do not recognize and respond to precise pathogens.

The adaptive immune system includes B lymphocytes (B cells) that produce antibodies, a process called humoral immunity, and T lymphocytes (T cells) that mediate cell-mediated immunity. Both B and T cells are pathogen-specific. The adaptive response takes time to expand but generates immunological reminiscence, permitting a quick and robust immune response upon subsequent exposure to the same pathogen. Vaccinations stimulate the adaptive immune system, resulting in defensive future encounters.

The body’s immune response to pathogens can trigger inflammation, characterised by redness, swelling, warmth, pain, and tissue dysfunction. While irritation facilitates dodging pathogens and provoking recovery, it is also able to cause symptoms and severe pathologies. For instance, activation of CD8 T cells, part of the adaptive immune response, can increase inflammation and lead to pulmonary damage. This process can manifest as acute respiratory distress syndrome (ARDS), which has been observed in some COVID-19 patients.

Nutritional Support for Immune Function

Adequate intake of several vitamins and minerals, including vitamin A, vitamin C, vitamin D, vitamin E, selenium, and zinc, is crucial for proper immune function. Clinical deficiencies of these nutrients weaken immunity, increasing susceptibility to infections. Other ingredients, such as botanicals and probiotics, whether consumed through food or dietary supplements, while not essential for the body, may influence immune function.

Measuring the impact of dietary supplement ingredients on the immune system is challenging due to its complexity, involving a network of organs, tissues, and cells. A single, straightforward measure of immune system function and disease resistance does not exist. Immune function can be indirectly assessed by examining an individual’s risk and severity of infectious diseases.

Impact of Dietary Supplements on Infectious Diseases

This fact sheet summarizes the effects of various dietary supplement ingredients on immune function and the risk of selected infectious diseases, including the common cold, influenza and other respiratory tract infections, infectious diarrhea, and HIV infection. These diseases are caused by a diverse range of pathogens. For example, the common cold is caused by a variety of respiratory viruses, most commonly rhinoviruses but also coronaviruses, adenoviruses, and other virus serotypes.

Dietary supplement ingredients within each category are presented alphabetically. In some cases, the cited research involves intravenous, enteral, or parenteral administration. Dietary ingredients administered through these routes are not classified as dietary supplements, but the information is included for completeness.

Minerals and Vitamins: Immune System Essentials

Empower Your Immune System: Vitamins for Optimal Defense

A balanced and diverse diet is crucial for maintaining typical fitness and a strong immune system. Obtaining adequate quantities of nutrients and minerals is likewise important for optimal fitness. Deficiencies in certain nutrients and minerals, along with vitamins A, B6, B12, C, D, E, and K; folate; and copper, iodine, iron, magnesium, selenium, and zinc, will have damaging consequences for immune characteristics.

Examples of Vitamins and Their Impact on Immune Function

  • Folate deficiency can impair the features of the thymus and spleen, leading to reduced levels of T lymphocytes. Additionally, vitamin B12 deficiency can decrease the phagocytic capacity of neutrophils, which might be important for engulfing and destroying pathogens.
  • Vitamin A deficiency is related to an increased susceptibility to infections, altered immune responses, and a weakened capability of epithelial tissue to act as a barrier against pathogens.
  • Vitamin E deficiency can impair both humoral and cell-mediated immunity and is related to decreased natural killer mobile pastime.

Examples of Mineral Impacts on Immune Function

  • Copper deficiency is related to altered immune responses and an extended hazard of infections, mainly in toddlers and older adults.
  • Low magnesium levels are associated with decreased immune cell activity, increased oxidative stress, and enhanced inflammation, including elevated levels of certain inflammatory cytokines, such as interleukin-6.
  • Selenium deficiency can adversely affect immune responses and potentially influence the virulence of viruses.

Vitamin A: Its Importance, Efficacy, and Safety

Vitamin A is a crucial nutrient that plays a vital role in imagination and prescient, increased, and immune characteristics. It is located in both the preformed and provitamin A bureaucracies. Preformed nutrition A is located in animal resources, inclusive of dairy products, eggs, fish, and organ meats. Provitamin A carotenoids, which the body can convert to diet A, are observed in plant meals along with leafy, inexperienced veggies, orange and yellow greens, tomato merchandise, fruits, and a few vegetable oils.

The Recommended Dietary Allowance (RDA) for Nutrition A varies depending on age. Infants and youngsters want 300 to at least 1,200 mcg of retinol activity equivalents (RAE) per day, while adults want 700 to at least 1,300 mcg of RAE per day. Pregnant and lactating girls want higher quantities of vitamin A.

Vitamin A deficiency is a commonplace hassle in lots of low- and middle-income international locations. It can lead to a number of health troubles, such as blindness, diarrhea, and respiratory infections. Children are mainly vulnerable to diet A deficiency, as they have higher diet A needs than adults.

Vitamin A supplementation can help protect children from vitamin A deficiency and its related health problems. The World Health Organization (WHO) recommends that each child younger than 5 years of age in populations with an excessive chance of vitamin A deficiency get vitamin A supplements every 6 months.

Diarrhea in children

Vitamin A deficiency can increase the risk of diarrhea in children. Vitamin A supplementation has been proven to lessen the chance of diarrhea in children in low- and middle-profit international locations. However, it does not seem to benefit very young toddlers.

A 2011 systematic review found that diet A supplementation decreased the chance of diarrhea by 15% and the hazard of death due to diarrhea by 28%. A 2017 Cochrane evaluation determined similar consequences.

In very young infants, however, limited evidence suggests that vitamin A supplementation does not affect diarrhea morbidity or mortality.

HIV infection

HIV infection can increase the risk of vitamin A deficiency. Vitamin A supplementation has been shown to have some mixed effects on HIV disease outcomes in children and adults.

Children benefit from vitamin A supplementation in terms of mortality risk reduction. Research indicates a 45% decrease in all-cause mortality risk in children with vitamin A supplementation. However, its impact on diarrhea or respiratory infections remains inconsistent.

Limited Effects on Adults with HIV

In adults with HIV infection, vitamin A supplementation doesn’t significantly affect viral load, CD4+ T-cell counts, or mortality.

Vitamin A and Measles in Children

Severe measles risk is linked to vitamin A deficiency, and supplementation reduces measles risk in deficient children. The impact on measles-related mortality, though, is unclear. A 2013 WHO analysis reported a 26% decrease, but conflicting studies found no conclusive effect.

Vitamin A and Respiratory Infections in Children

Vitamin A deficiency correlates with recurrent respiratory infections in children. However, its effects on pneumonia and respiratory infection risk and severity vary. Some studies note reduced hospital stays and symptoms, while others show no clear preventive effect.

Safety Considerations

Adhering to recommended doses ensures vitamin A safety. Exceeding tolerable upper intake levels (600–2,800 mcg/day for children, 3,000 mcg/day for adults) can result in serious health issues, including headaches, blurred vision, nausea, and, in severe cases, increased intracranial pressure leading to coma. High doses may also cause dry skin, muscle pain, fatigue, depression, abnormal liver function, and birth defects.

Beta-carotene, a safer provitamin A carotenoid, lacks these side effects, even at high doses, but can cause skin discoloration. In conclusion, while vitamin A is vital for health, deficiency remains a concern in low- and middle-income countries.

Vitamin C: Essential for Immune Health

Empower Your Immune System: Vitamins for Optimal Defense

Vitamin C, also known as ascorbic acid, is an indispensable nutrient crucial for various bodily functions, particularly immune system support. Abundant in a diverse range of fruits and vegetables like citrus fruits, tomatoes, potatoes, bell peppers, kiwifruit, broccoli, strawberries, Brussels sprouts, and cantaloupe, its significance in maintaining health cannot be overstated.

Recommended Daily Allowance (RDA) of Vitamin C

The recommended daily intake of vitamin C varies based on age and gender.

  • Infants: 40–50 mg
  • Children: 15-115 mg
  • Adults: 75–120 mg
  • Pregnant or lactating women: 90–120 mg
  • Smokers require an additional 35 mg of vitamin C daily due to heightened oxidative stress from smoking.

Vitamin C’s Crucial Role in Immune Function

Functioning as a potent antioxidant, vitamin C shields cells from free radical damage and plays a pivotal role in various immune system processes.

  • Maintaining Epithelial Integrity: Vitamin C contributes to the integrity of epithelial barriers, forming protective linings in organs and tissues to ward off pathogens.
  • Enhancing Immune Cell Differentiation and Proliferation: Vitamin C supports the differentiation and proliferation of B and T cells, crucial components of the immune system.
  • Enhancing Phagocytosis: Vitamin C boosts the capability of phagocytes, immune cells that engulf and neutralize pathogens.
  • Normalizing Cytokine Production: Regulating immune responses, vitamin C ensures balanced cytokine production.
  • Decreasing Histamine Levels: Vitamin C helps manage histamine levels, reducing the severity of allergic reactions.
  • Inhibiting Viral Replication: Some studies propose antiviral properties in vitamin C, potentially impeding viral replication.

Vitamin C Deficiency and Immune Function

Vitamin C deficiency can impair immune function and increase susceptibility to infections. Symptoms of vitamin C deficiency include fatigue, weakness, easy bruising, bleeding gums, and impaired wound healing.

Vitamin C and the Common Cold

While vitamin C supplementation does not prevent the common cold, it may reduce the duration and severity of symptoms. One study found that regular vitamin C supplementation shortened the duration of colds by 8% in adults and 14% in children.

Vitamin C and Sepsis

Sepsis is a life-threatening condition that occurs when the body’s response to an infection injures its own tissues and organs. Some research suggests that high-dose intravenous vitamin C may be beneficial in treating sepsis, but the evidence is mixed and further research is needed.

Safety of Vitamin C

Vitamin C from foods and dietary supplements is safe for most people. The tolerable upper intake level (UL) for vitamin C is 2,000 mg per day for adults. Higher intakes may cause diarrhea, nausea, and abdominal cramps.

Vitamin C is an essential nutrient that plays a crucial role in immune health. While regular vitamin C supplementation may not prevent the common cold, it may reduce the duration and severity of symptoms. Further research is needed to determine the potential benefits of high-dose intravenous vitamin C for treating sepsis.

Vitamin D: Essential for Health, Bone Strength, and Immunity

Vitamin D, a vital nutrient, plays a crucial role in various bodily functions, encompassing bone health, immune function, and calcium absorption.

While most individuals in the United States acquire sufficient vitamin D through diet and sun exposure, certain groups face an increased risk of deficiency. These include individuals with limited sun exposure, dark-skinned individuals, those with obesity, and those with specific medical conditions.

Notably, vitamin D deficiency amplifies the risk of respiratory tract infections such as influenza and pneumonia, exacerbating their severity.

Though vitamin D supplementation shows promise in reducing respiratory tract infection risks, the evidence is mixed, with some studies yielding inconclusive results.

While generally safe at recommended doses, excessive vitamin D intake can lead to toxicity, underscoring the importance of consulting a doctor, especially for those with specific medical conditions.

Key Points to Consider:

  • The recommended daily intake (RDI) of vitamin D for adults ranges from 15 to 20 mcg (600 to 800 IU).
  • Serum 25(OH)D concentration serves as the primary indicator of vitamin D status, with a level of 30 nmol/L (12 ng/mL) or higher considered adequate for bone and overall health in most individuals.
  • Vitamin D deficiency can compromise macrophage function and interleukin-10 production.
  • Recent clinical trials published in 2022 did not demonstrate a reduction in the risk of respiratory tract infections with vitamin D supplementation.

Understanding these nuances is crucial for maintaining optimal health and navigating the complexities of vitamin D supplementation.

Vitamin E and Immune Function

Vitamin E, or alpha-tocopherol, an indispensable nutrient, is present in various foods like nuts, seeds, vegetable oils, and leafy green vegetables. The recommended daily allowance (RDA) spans from 4 to 15 milligrams (mg) for infants and children (depending on age) to 15 to 19 mg for adults, including pregnant and lactating women.

Crucial Role in Immune Function

Functioning as a potent antioxidant, vitamin E is pivotal for immune function. It preserves cell membrane integrity and epithelial barriers, which are crucial in preventing pathogen entry. Additionally, vitamin E boosts antibody production, lymphocyte proliferation, and natural killer cell activity—essential components in the battle against infections. Moreover, it mitigates inflammation by inhibiting pro-inflammatory cytokine production and curbing the body’s inflammatory response.

Impact on Immune Function

Both human and animal studies suggest that vitamin E deficiency compromises humoral and cell-mediated immunity, resulting in reduced natural killer cell activity and heightened susceptibility to infections. Notably, high-dose vitamin E supplements (ranging from 60 to 800 mg/day) over 1 to 8 months show potential for enhancing lymphocyte proliferation, interleukin-2 production, and natural killer cell activity. Furthermore, in adults aged 60 or older, vitamin E supplementation appears to increase antibody titers post-hepatitis B and tetanus vaccinations.

Vitamin E Deficiency

Vitamin E deficiency is rare, primarily affecting individuals with intestinal malabsorption disorders. Research on vitamin E’s ability to improve immune function often utilizes supplemental vitamin E rather than simply ensuring adequate vitamin E status. This approach stems from the belief that higher doses may be necessary to achieve beneficial effects.

Efficacy in Respiratory Tract Infections

Due to vitamin E’s influence on immune function, researchers have investigated its potential to reduce the risk or severity of respiratory tract infections. However, study findings have been inconsistent. Some researchers suggest that variations in study outcomes may be attributed to differences in participants’ baseline vitamin E status and discrepancies in supplementation doses used across studies.

Reduced Rehospitalization Risk in Pneumonia Patients

A study involving 717 elderly Canadians hospitalized with pneumonia found that vitamin E supplementation (dose unspecified) significantly reduced the risk of rehospitalization within 90 days by 63% compared to non-supplement users.

Limited Benefits or Increased Symptom Severity in Other Populations

Clinical trials assessing vitamin E supplementation’s effects on respiratory tract infections in infants, young children, and older adults have yielded mixed results.

  • Infants and Young Children: A trial conducted in India evaluated the effects of a combination of 200 mg alpha-tocopherol and 100 mg ascorbic acid taken twice daily for five days versus placebo in 174 infants and young children (aged 2-35 months) hospitalized with severe acute lower respiratory tract infections. Supplementation did not affect the time required for illness recovery.
  • Older Adults: A trial involving 652 healthy men and women aged 60 or older compared four different daily treatments for approximately 15 months: 200 mg vitamin E (as alpha-tocopheryl acetate), a multivitamin/mineral supplement (containing 10 mg vitamin E), a combination of multivitamin/mineral and vitamin E, or placebo. Vitamin E supplementation did not reduce the incidence of acute respiratory tract infections throughout the trial. Additionally, vitamin E supplement users experienced longer durations of illness, more severe symptoms (including fever and activity restrictions), and a greater number of symptoms compared to non-supplement users.
  • Nursing Home Residents: A similar trial in 617 nursing home residents aged 65 or older investigated whether daily supplementation with 200 IU vitamin E (91 mg, as dl-alpha-tocopherol) for one year reduced the risk of upper or lower respiratory tract infections. Vitamin E supplementation did not affect the incidence or overall duration of upper or lower respiratory tract infections.

Mixed Results in Smokers

  • The Alpha-Tocopherol, Beta-Carotene Cancer Prevention study, which included 29,133 male smokers aged 50–69 years, compared the effects of 50 mg/day of vitamin E (as dl-alpha-tocopheryl acetate) with or without beta-carotene or a placebo. Vitamin E supplementation for a median of 6.1 years did not affect the risk of hospital-treated pneumonia.
  • Subgroup Analysis: A secondary analysis revealed that vitamin E supplementation reduced the risk of pneumonia by 69% among participants who started smoking at age 21 or older, smoked 5–19 cigarettes per day, and engaged in recreational exercise.

Selenium and Immune Function in HIV Infection

Selenium, an essential trace mineral, plays a pivotal role in various biological processes such as immune function, thyroid hormone metabolism, and antioxidant defense. It is present in diverse foods like Brazil nuts, seafood, meat, poultry, eggs, dairy products, bread, cereals, and other grains. The recommended dietary allowance (RDA) for selenium varies, ranging from 15 to 70 mcg per day for infants and children to 55 to 70 mcg per day for adults.

Selenium’s Impact on Immune Function

Research reveals the critical role of selenium in supporting both the innate and adaptive immune systems. It actively contributes to the maturation and function of T cells, natural killer (NK) cells, and macrophages—integral components of the immune system responsible for combating infections. Furthermore, selenium acts as an antioxidant, shielding cells from damage caused by free radicals.

Selenium Deficiency and HIV Infection

Individuals with HIV face an elevated risk of selenium deficiency due to factors like impaired absorption, increased excretion, and altered metabolism. This deficiency is linked to higher morbidity and mortality rates, along with impaired immune function and increased susceptibility to infections, including tuberculosis.

Selenium Supplementation in HIV Infection

Studies exploring selenium supplementation benefits for people with HIV yield mixed results. Some indicate improved immune function and reduced infection risks, while others find no significant effects. A Cochrane review concludes that the evidence is insufficient to determine whether selenium supplementation impacts hospital admission risk or other outcomes in individuals with HIV.

Safety Considerations

Selenium is generally safe within recommended amounts. Excessive intake may lead to adverse effects like nausea, diarrhea, skin rashes, and nervous system abnormalities. The upper tolerable limit (UL) for selenium is 400 mcg per day for adults, including those who are pregnant or lactating.

While selenium proves crucial for immune function, its supplementation efficacy in people with HIV remains inconclusive. Further research is imperative to ascertain whether selenium supplementation can genuinely enhance health outcomes in this population.

Zinc’s Role in Immune Health and Common Cold Management

Zinc, a vital mineral found in various foods, plays a crucial role in maintaining overall health. From oysters and crab to beef, pork, poultry, beans, nuts, whole grains, and dairy products, zinc is readily available in our daily diets.

The recommended daily allowance (RDA) for zinc varies depending on age. Infants and children require 2–13 mg, depending on age, while adults, including pregnant or lactating women, need 8–12 mg.

Zinc’s Impact on Immune Function

Contributing to numerous aspects of cellular metabolism, zinc is essential for the catalytic activity of approximately 100 enzymes and plays a critical role in various body processes, including both the innate and adaptive immune systems.

Zinc’s Antiviral and Anti-inflammatory Properties

Zinc’s antiviral and anti-inflammatory properties, along with its ability to maintain the integrity of tissue barriers, such as the respiratory epithelia, make it a vital nutrient for overall well-being.

Zinc deficiency adversely affects immune function by impairing the formation, activation, and maturation of lymphocytes. Additionally, zinc deficiency decreases the ratios of helper to suppressor T cells, the production of interleukin-2, and the activity of natural killer cells and cytotoxic T cells.

These effects on the immune response likely increase susceptibility to infections and inflammatory diseases, particularly those affecting the lungs. Studies have established associations between low zinc status and a higher risk of viral infections. Individuals with zinc deficiency are more likely to develop diarrhea and respiratory diseases.

Zinc deficiency is also prevalent among people with HIV or hepatitis C and is a risk factor for pneumonia in older adults. Research suggests that zinc supplementation can increase the number of T cells in the blood of older adults residing in nursing homes.

While zinc deficiency is not widespread in the United States, approximately 15% of the U.S. population may consume inadequate amounts of zinc. Older adults are among the groups most at risk for low zinc intake.

Zinc’s Potential Benefits for the Common Cold

Researchers hypothesize 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.

Administration of Zinc Supplements

In studies examining the effects of zinc supplements on the common cold, zinc is typically administered in a tablet or syrup that adheres to the mouth and throat, allowing zinc to come into direct contact with the rhinovirus in those areas.

Results from clinical trials investigating the effects of supplemental zinc on the common cold have been inconsistent. However, overall, supplemental zinc in tablet 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.

One clinical trial demonstrated the beneficial effects of zinc on the common cold. Fifty adults were randomly assigned to receive either a zinc acetate lozenge (13.3 mg zinc) or a placebo every 2–3 wakeful hours within 24 hours of developing the common cold, continuing as long as they had cold symptoms. Compared to the placebo group, zinc lozenges reduced the duration of colds by 3 days and the severity of cold symptoms (cough, nasal discharge, and muscle aches).

Varied Results from Additional Trials

Results from another clinical trial were more mixed. In this study, 273 adults with experimentally induced colds were randomly assigned to receive lozenges containing zinc gluconate (13.3 mg zinc) or zinc acetate (5.0 mg or 11.5 mg zinc) every 2 to 3 hours while awake, for a total of 6 lozenges per day, or placebo, for up to 14 days. Individuals receiving zinc gluconate lozenges experienced illnesses 1 day shorter than those in the placebo group, but the tablets had no effect on symptom severity.

A 2021 systematic review and meta-analysis concluded that zinc appears to reduce the duration of the common cold but has mixed effects on the severity of signs and symptoms. The analysis included 28 clinical trials (including the three described above) with a total of 5,446 participants (mostly adults younger than 65 years) who had a community-acquired viral respiratory tract infection or were inoculated with a rhinovirus.

Herbs for Common Cold and Respiratory Tract Infections

Common colds and respiratory tract infections are prevalent, impacting millions of people annually. While conventional medicines offer relief, some individuals prefer natural approaches. This text explores the potential benefits and safety of various herbs for managing these conditions.


  • Traditional Uses: Ayurvedic, Chinese, and Thai medicine for symptoms of the common cold, influenza, and other respiratory tract infections.
  • Active Constituents: Andrographolide and related diterpene lactones
  • Efficacy: Studies suggest potential for reducing the duration and severity of cold symptoms.
  • Safety: Generally considered safe at typical doses (340–1,200 mg/day) for short periods. Minor side effects reported include nausea, vomiting, and diarrhea.

Note: There is limited evidence and potential interactions with medications.


  • Traditional UsesNorth American and European native cultures use them for wound healing and various ailments.
  • Active Constituents: a complex mixture of terpenes, polysaccharides, and other compounds.
  • Efficacy: mixed results from research. May slightly reduce the risk of developing a cold but does not shorten its duration or severity.
  • Safety: generally considered safe. Minor side effects reported include gastrointestinal upset and skin rash.

Note: There is limited research on efficacy for respiratory infections and potential drug interactions.


  • Traditional Uses: European folk medicine for various ailments
  • Active Constituents: Anthocyanins, flavonols, and phenolic acids
  • Efficacy: Some studies suggest a potential for reducing the symptoms of respiratory tract infections. May shorten the duration and severity of cold and influenza symptoms.
  • Safety: Elderberry fruit and ripe flowers are considered safe for consumption. Avoid bark, leaves, seeds, and raw or unripe fruit due to potential toxicity.

Note: Recent analyses suggest some supplements are diluted or adulterated. Consult a healthcare professional before use.


  • Traditional Uses: Culinary and medicinal applications across cultures
  • Active constituents: allicin and ajoen (in raw garlic). Aged garlic extract contains lectins and fructo-oligosaccharides.
  • Efficacy: There is limited research on preventing or treating the common cold and influenza. Some evidence suggests potential for reducing symptoms.
  • Safety: generally considered safe as a culinary ingredient. Garlic supplements may cause minor side effects like bad breath and body odor.

Note: potential interactions with medications, including warfarin and antihypertensive drugs.


  • Traditional Uses: Asian and American cultures for various health conditions
  • Active Constituents: Triterpene glycosides, also known as ginsenosides.
  • Efficacy: Some evidence suggests potential for reducing the risk of developing respiratory tract infections. Effects on symptom severity and duration are unclear.
  • Safety: generally considered safe. High doses may cause insomnia, headaches, and hypertension.

Note: There are potential interactions with many medications. Consult a healthcare professional before use.

Tea and Tea Catechins:

  • Traditional Uses: A popular beverage worldwide with potential health benefits.
  • Active Constituents: Catechins, especially epigallocatechin gallate (EGCG).
  • Efficacy: limited and mixed research on preventing or treating respiratory infections. Some studies suggest potential for reducing the risk and severity of symptoms.
  • Safety: Moderate tea consumption is generally safe. Green tea extract may cause liver damage at high doses.

Note: Caffeine content may interact with medications. Consult a healthcare professional for recommended limits.

While some herbs show promising potential for managing common cold and respiratory tract infections, the evidence for their effectiveness is often limited. Consult a healthcare professional to discuss the appropriate use of these herbs and determine their suitability for your individual needs.

Omega-3s: Essential Nutrients for Optimal Health

Empower Your Immune System: Vitamins for Optimal Defense

Omega-3 fatty acids, or omega-3s, represent a class of polyunsaturated fatty acids (PUFAs) present in specific foods like fatty fish and flaxseeds, as well as in dietary supplements like fish oil. These compounds wield significant influence over various bodily functions, including immune response, inflammation regulation, and brain function.

Diverse Types of Omega-3s

Among several omega-3s, the most extensively studied and crucial ones are alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). ALA predominantly exists in plant sources such as flaxseeds, walnuts, and chia seeds, while fatty fish like salmon, sardines, and mackerel are rich sources of EPA and DHA.

Dietary Recommendations

The Food and Nutrition Board (FNB) has established adequate intake (AI) recommendations for omega-3s:

  • ALA: 0.7 to 1.6 g/day for children and teens age 1 and older, and 1.1 to 1.6 g/day for adults, including pregnant and lactating women.
  • EPA and DHA: While recommendations were not established in 2005 due to limited data, most experts advise a daily intake of at least 500 mg of combined EPA and DHA for optimal health.

Health Benefits of Omega-3s

Omega-3s confer a multitude of health advantages, including:

  • Reducing Inflammation: Omega-3s regulate inflammation, a pivotal factor in chronic diseases like heart disease, arthritis, and cancer.
  • Supporting Heart Health: They may lower triglyceride levels, reduce blood pressure, and diminish the risk of abnormal heart rhythms.
  • Enhancing Brain Function: Essential components of brain cell membranes, omega-3s contribute to cognitive function, memory, and mood regulation.
  • Supporting Immune Function: Modulating immune responses, omega-3s may lower the risk of autoimmune diseases.

Omega-3 Deficiency

While rare, omega-3 deficiency can manifest in symptoms such as dry, scaly skin and dermatitis. While most individuals in the United States obtain sufficient ALA, increased EPA and DHA intake could be beneficial for many.

Omega-3s for Specific Conditions

Research has delved into the potential benefits of omega-3s for various health conditions:

  • Acute Respiratory Distress Syndrome (ARDS): While some studies show positive effects, overall evidence remains inconclusive.
  • Respiratory Tract Infections in Infants and Young Children: Omega-3-enriched formulas may reduce the risk, as suggested by some studies.

Safety of Omega-3s

Omega-3s are generally safe within recommended amounts. However, high doses of EPA and DHA may increase bleeding time and interact with certain medications.

As essential nutrients, omega-3 fatty acids are pivotal for overall health. Ensuring adequate intake through food sources or supplements offers a spectrum of health benefits, reducing the risk of chronic diseases and fostering overall well-being.


Probiotics are live microorganisms that provide health benefits to the host when consumed in adequate amounts. They include certain bacteria (e.g., Lactobacillus acidophilus, Lactobacillus rhamnosus, and Bifidobacterium longum) and yeasts (e.g., Saccharomyces boulardii). Probiotics are naturally present in some fermented foods, added to some food products, and available as dietary supplements.

Identification and Measurement

Probiotics are identified by their strain, which includes the genus, the species, the subspecies (if applicable), and an alphanumeric strain designation. The units of measure for probiotics are colony-forming units (CFUs), which indicate the number of viable cells. Common amounts used in dietary supplements are 1 x 10⁹ (1 billion CFU; commonly designated as 10⁹ CFU) and 1 x 10¹⁰ (10 billion or 10¹⁰ CFU).

Mechanisms of Action

Probiotics primarily act in the gastrointestinal tract. They may improve immune function in several ways, including by:

  • Enhancing gut barrier function
  • Increasing immunoglobulin production
  • Inhibiting viral replication
  • Enhancing the phagocytic activity of white blood cells


Acute Infectious Diarrhea in Infants and Children

Probiotics may reduce the risk of infectious diarrhea and help manage its symptoms by:

  • Stimulating the immune system
  • Secreting antimicrobial substances
  • Limiting the ability of pathogenic bacteria to colonize, adhere to, and invade the gut by competing for available nutrients and binding sites

Evidence from Clinical Trials

  • Early clinical trials showed some beneficial effects of probiotics on acute infectious diarrhea in infants and children.
  • A Cochrane Review of 63 clinical trials found that single- and multi-strain probiotics shortened the duration of acute infectious diarrhea by about 25 hours.
  • Two strains—LGG and Saccharomyces boulardii—had the strongest evidence of efficacy.
  • However, recent clinical trials have largely failed to show that probiotics benefit children with acute infectious diarrhea.


  • The European Society for Pediatric Gastroenterology, Hepatology, and Nutrition (ESPGHAN) found evidence to support the use of LGG (typically at least 10¹⁰ CFU/day for 5–7 days) and Saccharomyces boulardii (typically 250–750 mg/day [10⁹–10¹⁰ CFU] for 5–7 days) in combination with rehydration for managing acute infectious diarrhea in pediatric patients.
  • However, in 2020, ESPGHAN downgraded its recommendations from strong to weak for the use of LGG and Saccharomyces boulardii in infants and children with acute gastroenteritis.

Common Cold, Influenza, and Other Respiratory Tract Infections

Probiotics may reduce the risk of respiratory tract infections and shorten the duration of illness by:

  • Stimulating the immune system
  • Inhibiting viral replication

Evidence from Clinical Trials

  • Most clinical trials that have examined whether probiotics reduce the risk of respiratory tract infections have had positive findings.
  • Systematic reviews and meta-analyses have also found beneficial effects of probiotics on some outcomes.
  • A Cochrane Review found that probiotics reduced the risk of developing at least one acute upper respiratory tract infection by 47% and shortened the duration of illness by 1.89 days in comparison with placebo.

Challenges in Evaluating Probiotics

  • The effects of probiotics appear to vary by strain.
  • The effects of probiotics may vary by virus.

Ventilator-associated Pneumonia (VAP)

Studies examining whether probiotics reduce the risk of VAP in critically ill patients have had inconsistent findings.

  • Some studies have shown positive results.
  • A 2022 systematic review and meta-analysis found that probiotics reduced the incidence of VAP by 32%, but the effect was not statistically significant in double-blind studies or in studies with a low risk of bias.
  • A 2014 Cochrane Review found that probiotics decreased the incidence of VAP by 30%, but the authors noted that the quality of this evidence was low.


  • Probiotics have a long history of safe use in foods.
  • Side effects, which are usually minor, include gastrointestinal symptoms, such as gas.
  • Potential safety concerns can include systemic infections, especially in people who are immunocompromised.


  • Probiotics are not known to interact with medications.
  • Antibiotic and antifungal medications might decrease the effectiveness of some probiotics.
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