Your body is constantly exposed to pathogens like viruses and bacteria. A well-functioning immune system helps prevent infections and supports recovery when illness occurs. Here’s a walkthrough of nutrients that contribute to maintaining a balanced immune system and support optimal conditions for an effective immune response.
The immune system is a complex network of cells, processes, and signaling molecules that protects the body against pathogens. For it to function effectively, it needs balance. Maintaining that balance is essential for a proper and timely immune response.
Several lifestyle factors influence immune function: a healthy, varied diet that provides sufficient micronutrients such as vitamins and minerals; regular physical activity; adequate sleep; stress management; and basic hygiene practices like frequent handwashing to reduce exposure to pathogens.
For some, consistently meeting these requirements can be challenging. This is particularly true for older adults, where insufficient intake of key micronutrients is relatively common due to reduced appetite and less dietary variety. At the same time, immune responsiveness tends to decline with age [1].
Just like we do not always manage to eat a healthy, varied diet, we may also fall short on exercise – and from time-to-time experience stress. When we are stressed, our immune system’s ability to fight off antigens is reduced. In such cases, targeted supplementation with specific vitamins, minerals, and selected botanicals may help support immune function and resilience.
Vitamins can help keep our immune system healthy and strong
Vitamins A, C, and D are among the most important vitamins for immune health. Vitamin A plays a major role in the immune system, including the innate immune response, cell-mediated immunity, and adaptive immune responses. Studies have shown that vitamin A deficiency is associated with impaired immune function and dysregulated inflammatory signaling, including increased pro-inflammatory mediators, which can compromise effective immune responses [2–4]. A natural source of vitamin A is carotenes, especially β-carotenes, which in the intestine is broken down to vitamin A. The palm fruit is very rich in β-carotenes with up to 300 times more than carrot, leafy vegetables and tomato.
Vitamin C (ascorbic acid), is an essential micronutrient that cannot be synthesized by humans. As an antioxidant, it helps protect cells from damage caused by free radicals. Vitamin C contributes to immune defense by supporting various cellular functions of both the innate and adaptive immune system. Studies have shown that regular vitamin C supplementation may reduce the duration and severity of upper respiratory tract infections such as the common cold [5-8].
Since the body stores only limited amounts of vitamin C, it is advisable to obtain it daily from the diet and, if needed, from supplements. Ascorbic acid is available in several forms. When vitamin C is incorporated into foods, its stability can be an issue, and it may react with other ingredients, leading to significant degradation. In such cases, it may be relevant to consider microencapsulated vitamin C, where a protective barrier surrounds the vitamin. This barrier is robust enough to withstand processing and can help prevent interactions with other ingredients.
It is also worth noting that the body can only absorb vitamin C efficiently up to a certain point; fractional absorption decreases at higher doses and excess vitamin C is excreted. For this reason, sustained-release formulations is a good solution to help maximize the absorption of vitamin C, as they can deliver vitamin C gradually over time.
Vitamin D is essential for immune function. Studies have shown that vitamin D–metabolizing enzymes and vitamin D receptors (VDR) are expressed in many cell types, including immune cells such as antigen-presenting cells, T cells, B cells, and monocytes, all of which play important roles in host defense against pathogens [9–11]. Evidence from human studies, including clinical trials and systematic reviews, suggests that vitamin D supplementation can modulate immune function [12–13] and may reduce the risk of acute respiratory tract infections, particularly in individuals with vitamin D deficiency [14]. Vitamin D deficiency, potentially through reduced vitamin D/VDR signalling, may increase susceptibility to infection partly by weakening epithelial barrier function [15]. However, recent evidence indicates that effects on infection-related outcomes are modest and heterogeneous [16].
Vitamins A, C and D are vital for immune health, but vitamins B and E also play an important role in keeping the immune system strong. Vitamin B complex is composed of eight vitamins B: B-1 (thiamine), B-2 (riboflavin), B-3 (niacin), B-5 (pantothenic acid), B-6 (pyridoxine), B-7 (biotin), B-9 (folic acid) and B-12 (cobalamin). All of these are essential and important for our immune system. Research has shown that deficiencies in several B vitamins – particularly vitamin B6, B9, and vitamin B12 – can impair immune cell function (including T-cell responses) and thereby weaken immune defenses [17-21].
Vitamin E refers to a family of eight fat-soluble compounds (four tocopherols and four tocotrienols) [22]. Vitamin E is an essential micronutrient, and human vitamin E requirements are defined specifically in terms of α-tocopherol [22]. Vitamin E functions as a fat-soluble (lipid-phase) antioxidant and is also involved in immune function [22]. Clinically overt deficiency is rare in healthy individuals but can occur in conditions that impair intestinal fat absorption and may be associated with impaired immune response [22]. Evidence from human studies show that vitamin E supplementation reduces respiratory tract infection risk in older adults is mixed [23–24]. In older adults, some randomized trials have reported improvements in selected measures of cell-mediated immunity [25, 26]. Reviews suggest that vitamin E supplementation above recommended levels may improve aspects of age-associated declines in cellular immunity [27, 28]. A natural source of vitamin E can be obtained from the palm fruit, which consists of the full spectrum of tocotrienol isomers and α-tocopherols.
Minerals important for immune health
Besides vitamins, there are several minerals which are essential for immune health. This is the case with zinc [29, 30] which is required for the development and function of immune cells and plays an important role in inflammatory signalling and immune regulation [31]. For specifically the common cold, meta-analyses suggest that appropriately dosed zinc lozenges may shorten symptom duration [32, 33].
Just like zinc, selenium is an essential trace mineral for immune function [34,35]. Human studies indicate that selenium supplementation can modulate immune parameters, particularly aspects of cellular immunity (e.g., T-cell responses and NK-cell function) [36,37]. In animal models of influenza, selenium deficiency has been associated with increased pathology [38, 39], suggesting that nutritional deprivation may be a factor that increases susceptibility to influenza infection.
Magnesium is an essential micronutrient and a cofactor for more than 300 enzyme systems in the body [40]. It is closely linked to immune function and influences both innate and adaptive immune responses [41].
Similarly, iron is essential for both innate and adaptive immune responses [42]. Recent evidence suggests that iron deficiency and low serum iron (hypoferremia) not only contribute to anaemia but may also impair adaptive immunity and reduce vaccine-induced immune responses [43,44]. For supplementation, ferrous fumarate and ferrous sulphate are commonly used sources of iron. Iron is notorious for its poor taste, but that issue can be solved using microencapsulated types for superior taste and odour masking. New micro-encapsulated iron complex enables formulation of stable, chewable iron supplements and other oral dosage formulations >.
Generally, minerals used in industry are available in various chemical forms (e.g., citrates, gluconates, glycinate, lactates), and the choice of form depends on the end application. Chelated minerals, minerals bound to ligands such as amino acids or organic acids, are often preferred in nutrition because they tend to be more bioavailable. Their chelated structure can help keep the mineral soluble and stable during transit through the stomach and small intestine, where absorption into the bloodstream occurs. Research suggests that certain chelated mineral forms may be more bioavailable and, in some settings, achieve similar outcomes at lower elemental doses than non-chelated forms [45].
The purity of minerals is another important issue to keep in mind in order to make sure that the end product meets European Regulation (231/2012 & 1881/2006) and the ICH and USP elemental impurity guidelines for heavy metal content in food supplements.
Botanical extracts for immune health
There is a long tradition for using botanicals to support immune health. Plant material such as rosehip (Rosa canina L.), acerola (Malpighia glabra L.), blackcurrant (Ribes nigrum L.) and sea buckthorn (Hippophae rhamnoides L.) are all naturally rich sources of Vitamin C [46, 47], which contributes to normal immune function.
Echinacea preparations (mainly E. purpurea) are widely used for immune support and have been studied in respiratory infections. Some extracts show antiviral activity [48], but evidence for treating an established common cold is mixed [49]. Trials and meta-analyses suggest that certain standardized E. purpurea products may reduce the incidence and duration of upper respiratory tract infections [50] and reduce antibiotic use in children [51,52], although product heterogeneity limits conclusions [50-52]. In adults, higher-dose formulations improved viral clearance without significantly shortening recovery time [53]. An exploratory study during the COVID-19 pandemic also suggested fewer viral detections and lower viral load, but placebo-controlled confirmation is needed [54].
Many plant extracts are rich in flavonoids, which are a class of polyphenolic plant metabolites. Anthocyanins are coloured pigments that belong to the flavonoid family. Flavonoids have antioxidant properties that may help counteract free radicals and thereby reduce oxidative stress. In addition, anthocyanins have shown potential antimicrobial activity and have been associated with various health benefits [55].
Black elderberry (Sambucus nigra) has a long history of use in traditional medicine to treat infections and is now being studied more systematically. Elderberries are rich in anthocyanins and other polyphenols, and they also contain vitamins (A, B1, B2, B6, folate, C and E) and minerals/trace elements (e.g. K, Ca, Mg, Fe, Zn and Cu). These constituents may contribute to immune function. In vitro studies have reported antibacterial and antiviral activity for elderberry extracts [56]. However, the evidence is mixed. In a randomised study of air travellers, black elderberry extract was associated with a shorter cold duration and reduced symptom severity [57]. Similarly, two reviews concluded that elderberry may reduce the duration and severity of common cold and influenza symptoms [58, 59], and a 2019 meta-analysis reported fewer upper respiratory symptoms [60]. However, a randomised controlled trial in PCR-confirmed influenza found no benefit compared with placebo [61].
Propolis (“bee glue”) is a resinous substance that honeybees use to seal and protect the hive [62, 63]. Its chemical composition is complex and varies by botanical and geographic origin; reviews report more than 600 identified constituents, with polyphenols (e.g., flavonoids, phenolic acids, and their esters) among the key bioactive groups [62, 63]. Experimental and review evidence indicates propolis has antimicrobial (including antibacterial and antifungal) and anti-inflammatory activities [64, 65]. In humans, recent meta-analyses of randomized controlled trials suggest propolis supplementation can reduce inflammatory markers such as CRP (C-reactive protein), IL-6, and TNF-α, and in some analyses may increase anti-inflammatory cytokines (e.g., IL-10), supporting a potential immunomodulatory effect [66, 67]. Clinical evidence in acute infections remains limited; a randomized, double-blind, placebo-controlled trial in hospitalized COVID-19 patients reported no significant reduction in length of hospital stay but was associated with fewer secondary infections [68].
Chaga (Inonotus obliquus) is a birch-associated white-rot fungus long used in traditional medicine. Its extracts contain bioactive polysaccharides (including β-glucans), phenolics, and triterpenoids, and preclinical studies report antioxidant, anti-inflammatory, and immunomodulatory activities [69, 70, 71]. Recent experimental evidence suggests that purified chaga polysaccharides can activate innate immune cells via pattern-recognition receptors such as Toll-like receptors TLR2 and TLR4, supporting chaga’s potential as a nutraceutical ingredient [72].
When formulating supplements with botanical extracts, it is important to consider sourcing from suppliers guaranteeing full traceability from field to final packaging and accurate quantification of bioactive compounds. It is also advisable to choose extracts from botanical species certified by DNA barcoding analysis.
Digestive health & the immune system
A substantial part of our immune system is actually in our gastrointestinal tract. It is estimated that approx. 70% of the cells contributing to the immune system are found in the gut where microbiota plays a fundamental role in the induction, training and function of the host immune system. It is therefore very important to keep the gut healthy for proper functioning of the immune system. A way to strengthen the gut and enhance overall health is to take prebiotics such as inulin and oligofructose and probiotics such as live bacteria and yeast.
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