Our immune system is vital for defending the body against infections, promoting recovery from illness, preventing autoimmune diseases, and maintaining overall health and well-being.
That’s why we’re going to share with you the best supplements to strengthen your immune system according to scientific literature. Keep reading!
Zinc is a vital mineral that supports the immune system. It helps the body defend itself against infections and plays a crucial role in overall immune health.
The scientific literature on zinc in this area is vast, with hundreds of studies showing its benefits against flu and infections.
For example, several meta-analyses have shown that zinc supplementation was able to significantly reduce the duration of colds, with the effect being more prevalent in adults. High doses (>75mg daily in divided doses) are more effective than lower doses. [3][4]
Virtually all studies show the same results, surprisingly, zinc in some studies was able to reduce the duration of flu/infections by more than half. [5][6][7]
As for flu prevention, studies show that zinc supplementation can prevent the common flu up to 45% in children under 10 years of age, but not in adults. [8]
Vitamin C needs no introduction, it is one of the most popular supplements for fighting infections and flu due to its antioxidant power and ability to support the immune system.
There are hundreds of studies evaluating the effectiveness of vitamin C against respiratory infections or common colds, and most of these studies show promising results.
For example, according to a meta-analysis of 10 controlled studies, vitamin C supplementation was able to improve symptoms of the common cold, as well as reduce recovery time. [1]
Furthermore, in another meta-analysis of 10 controlled studies different from those mentioned above, vitamin C supplementation was again shown to reduce the severity of influenza by an average of 15%. The effects were more prevalent in people with more severe symptoms. [2]
Vitamin C is not only able to improve flu symptoms, but also reduce the likelihood of catching the flu, according to some studies in a meta-analysis. However, this effect is only prevalent in people who practice high-intensity physical exercise. The reduction in the incidence of flu can go up to 18%. [3]
These results confirm that vitamin C supplements can significantly affect the immune system, especially in people who do not consume sufficient amounts of this vitamin through their diet.
Did you know that the bacteria in our intestines have a huge impact on our immune system? The effects, according to scientific literature, are impressive.
Probiotics are bacteria that promote a healthy balance in the gut microbiome. They support the immune system, improving gut health and digestion, and potentially reducing the risk of infections and inflammation. [8]
This study analyzed the effect of probiotics in patients with COVID-19 and it was observed that the median time to global resolution of symptoms (elimination of symptoms) was 5 days shorter in the probiotic group than in the placebo group. Showing that probiotics had a significant effect in improving the remission rate. [9]
Certain varieties of probiotics such as Lactobacillus plantarumand Lactobacillus paracasei have shown effectiveness in reducing the likelihood of developing flu, as well as improving recovery time and symptoms. [10]
Probiotics are effective in virtually all studies conducted, showing similar results to those we mentioned above. From symptoms of runny nose, stuffy nose, sneezing, sore throat, hoarseness, cough, headache and feeling tired. [11][12][13][14][15][16][17]
It is known for its medicinal properties, particularly for strengthening the immune system and relieving the symptoms of colds and flu. Echinacea has a direct impact on the immune system, being immunostimulant and immunoregulatory. [24] [25]
According to 2 meta-analyses, echinacea is effective in preventing symptoms and reducing the incidence and duration of the common cold. [18] [19]
Even in patients with COVID-19, echinacea supplementation showed antiviral effects and reduced the risk of acute respiratory viral infections. [24]
Echinacea appears to have a prophylactic (preventive) effect on flu and infections [20]. One study showed that echinacea supplementation reduced daily symptoms of respiratory infections by 21%. [21]
Benefits do not appear to exist when supplemented in children. [22][23]
Lactoferrin is one of the components of the body's immune system; it has antimicrobial, anti-inflammatory, antioxidant activity and is part of the body's innate defense [43]. It is present in large quantities in breast milk. Supplementation appears to reduce the risk of respiratory tract infections.
Several studies show that lactoferrin reduces the incidence of flu and respiratory infections when compared to placebo, as well as reducing inflammatory markers [27][29] and improves the immune system in older people [28]. A meta-analysis of 9 controlled studies showed similar results. [31]
In patients with COVID-19, lactoferrin resulted in improved recovery from symptoms and significantly decreased the time to negative COVID-19 test. [30]
Flavonoids are phytochemical compounds/polyphenols present in various plants, fruits and vegetables, with potential applications in medicine, whether as anti-inflammatory, antioxidant or antiviral activity [32]. Some examples of flavonoids are quercetin, luteolin, rutin, apigenin, among others.
Flavonoids have been found to be effective and safe in treating several viral respiratory infections, including the common cold, influenza, and COVID-19, in a meta-analysis of 30 studies [33]. They also have a significant anti-inflammatory effect. In another meta-analysis, flavonoids reduced the incidence of respiratory infections by up to 33%. [35]
One way to get flavonoids into your diet is to incorporate the consumption of red fruits, which are excellent sources of flavonoids [34].
In this controlled study, the effect of consuming an extract of elderberry, a red fruit similar to blackberries, was investigated. Although the number of constipation episodes did not change substantially, those taking elderberry had a significantly shorter duration of constipation and less severe symptoms. [36]
Ginseng, a popular herb in traditional medicine, is often touted for its potential immune health benefits. With active compounds like ginsenosides, it is believed to modulate the immune system, improving its response to infections and diseases. [37]
North American ginseng appears to be more effective than Asian ginseng in shortening the duration of colds or respiratory infections in healthy adults when taken preventively for 8 to 16 weeks. Compared with placebo, ginseng significantly reduced the duration of colds or respiratory infections by 6 days. The number of included studies was small, and the results should be interpreted with caution. [38]
Another meta-analysis showed the same results, that ginseng was found to be effective in reducing the risk in 38% and reducing the duration of acute respiratory illness (ARI) by 3 days, compared to placebo. [39]
Few people know about this medicinal plant, but don't let its lack of popularity fool you.
Pelargonium sidoides is a plant with immense medicinal properties, used for centuries by local populations as a herbal remedy for respiratory and gastrointestinal infections, this plant appears to have antiviral and antimicrobial action. [42]
Two meta-analyses of controlled studies showed that this herb was able to reduce the symptoms of bronchitis (cough, chest pain, phlegm) when compared to placebo. In addition, pelargonium sidoides supplementation showed improvements in subjective well-being, with a greater proportion of people reporting a complete remission of symptoms [40] [41]
