Nutrition Meets Food Science

Immunity Boosting Nutraceuticals- Current Trends and Challenges

Almost 2500 years back, Hippocrates established the relation between the food and its positive impact on health. The science of herbs, conventional food and nutrients in favour of health and disease management, is well-practised since ancient times. In modern times, with increased prevalence of chronic diseases, viral infections and risk of weak immunity, nutraceuticals are drawing attention more than ever.

Nutraceutical is a well- recognised term across the globe that serves health benefits like bridging the nutritional gap, controlling the deficiency disorders and management of physiological conditions. FSSAI defines nutraceutical as a food or food related component that intends for health benefits even in treatment and prevention of aliments.

In the fast-paced life of urbanisation, consumers are concerned about their health and better quality of life. In spite of advancements in health sector, the prevalence of viral disease and the associated morbidity rate is still the leading cause of health concerns across the globe. Moreover, consumption of processed food, Indian practice of prolonged cooking reduces nutritional value of food, complemented with the sedentary lifestyle, erratic diet pattern and elevated stress levels, the heed for nutraceuticals has increased many folds for protecting and strengthening immunity.

The immune system is a delicate and complex host defence system that comprises of different components like protein structures, physical and biochemical barriers, specialized cells and the associated mechanisms. It has distinct features of- discriminating between self and foreign antigens, managing infections through innate and adaptive immunity and a unique feature to retain memory of previous infections through protective specialized cells known as antibodies. This, in turn, protects an individual from recurrent infection with less severity and, limits the spread of infection.

A well-functioning immune system plays pivotal role in the maintenance of ordinary physiological and immunological functions as well as internal environment.

Trends:  Field of science and technology is evolving around novel nutraceuticals involving widely studied nutrients and bioactive compounds which are known to impact the immunity system. These not only exhibit the properties like immune modulation and immune stimulation but also anti-inflammatory, antioxidant and antimicrobial effect as well.

  1.  Antioxidants– Reactive oxygen species (ROS) are harmful compounds, which are produced in the body by highly active lymphocytes as a normal function or with exposure to toxins, UV radiations, ozone and even stress. These radicals can cause oxidant-mediated tissue injury which is hazardous for immunity. In response to ROS, organisms have an antioxidant defence system to prevent the formation or spread of these compounds and associated complications of oxidative stress. Few nutrients that support this mechanism

Selenium– It is an integral part of enzymes like catalase and glutathione peroxidase, which participates in antioxidant defence system. Studies have shown the association between selenium deficiency and impairment of various components of immune system and microbicidal activity of phagocytes. Consumption of selenium rich foods like seafood, mushrooms, cashews, sunflower seeds and supplements helps boosting cell-mediated immunity and protection against oxidative damage.

Vitamin C (Ascorbic acid)- A strong antioxidant, vitamin C is majorly present in leucocytes and its reduced plasma levels is associated with reduced immune functions. It protects lipid membranes against oxidative damage. It exerts immune-stimulatory effects by prostaglandin synthesis and cytokine production. It has also shown in strengthening immunity against cold, flu and respiratory infections.

Vitamin E- An important chain-breaking antioxidant that plays a crucial role in maintaining the integrity of plasma membranes. Deficient state of vitamin E in the body has been associated with suppressed antibodies production and T cells proliferation, resulting in increased instances of infection. Intake of rich sources like nut, nut butter, seeds, wheat germ oil and supplements provide optimum vitamin E.

– Carotenoids– An important antioxidant, it mediates cell-mediated and humoral cell action in response to ROS and oxidative damage. It also exhibits immunomodulatory activities by increasing the population of lymphocytes, activity of cytokines and tumour necrosis factor (TNF).

  1. Phytochemicals– These are naturally occurring molecules which play an imperative role in modulating favourable immune responses through activities like antioxidants, anti-inflammatory, immunomodulatory action and mainly found in fruits, vegetables and medicinal plants.
Compounds Sources Mechanism in immunity
Flavonoid compounds
Quercetin Apple, onions, dark cherries, blue berries, cherry tomatoes Enhance immunity status and IgM levels. Antioxidant and anti-allergic properties. Suppress inflammation.
Epicatechin gallate Green tea Immunomodulatory effect. Anti-pathogenic. Regulation of T cells activation, differentiation, and proliferation.
Hesperidin Citrus fruits Improvement of humoral and mucosal immunity
Non-flavonoid compounds
Resveratrol Grapes, peanuts, cranberries Antioxidant, anti-inflammatory action
Phenolic acids
Caffeic acid Echinacea Activation of cells, enhanced humoral immunity, activity of NK and Cytotoxic T lymphocyte cells.
Ferulic acid Whole grains like oats, rye Augmented IFN-γ production and proliferation of lymphocyte
Gallic acid Berries, banana, walnuts, cashew Enhance the phagocytosis and lysosomal volume. Inhibits the production of ROS, inflammatory cytokines
Lycopene Tomato Antioxidant. Prevent oxidative damage, inhibits ROS production and induces apoptotic cell death
Ursolic acid Tulsi Stimulates intracellular killing activity of macrophages

  1. Omega 3 fatty acids– Omega 3 polyunsaturated fatty acids like α-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are known for their anti-inflammatory and immunomodulation effects. These fatty acids are well-documented for their role in suppressing inflammation mainly be reducing the secretion of IL-1β, TNF-α, and IL-6. It also modulates immunity system by-

– Potentiating phagocytic activity- It reduces the production and secretion of cytokines and improves phagocytic activity against pathogens and apoptotic cells

– Action on neutrophils- Neutrophils are the first cells to be transported to the site of inflammation and it plays an important role in removal of pathogens. Omega 3 fatty acids helps in this process through various mechanisms including neutrophil migration, phagocytosis, regulated production of reactive oxygen species and cytokines.

– Regulation of inflammation- Omega 3 fats help in synthesis of resolvins and produce metabolites like protectins which regulates the anti-inflammatory effect by targeting the inhibition of NF-κB cells.

  1. Amino acids-These are the structural component of protein and a building block of different immune cells and its components. These are required for synthesis of specific immune cells and regulation of metabolic pathways for immune responses.

Innate level– Amino acids regulate the activation NK cells and macrophages, increased NK cells killing activity, phagocytosis, antioxidant activity and reduced pro- inflammatory adipokines.

Adaptive level– Amino acids regulate the activation of T and B cells, lymphocyte proliferation and production of cytokines and immunoglobulins.

Therefore, it is important to maintain amino acid pool in the body, through intake of high-quality protein like eggs, milk, soybeans and supplements, in case, protein needs remain unmet, for strong immunity.

  1. Probiotics– Probiotics are the live microorganisms that when being administered in appropriate doses, confer a benefit to the health of the host.

– Probiotics compete for nutrients for growth and proliferation and as a reason, inhibits the growth of pathogenic bacteria.

– 70% of the immune cells are localized in the gut associated lymphoid tissues in the gastrointestinal area. Certain probiotic strains have the capability to stick on intestinal epithelial cells that initiate a set of complex reactions to stimulate immunity.

– Probiotics also strengthen the intestinal barrier by increasing the production of goblet cells which reinforce mucus secretion. It also maintains the barrier integrity by increased gene expression in tight junction signalling.

– It produces low molecular weight organic acids like acetic and lactate and antimicrobial compounds like bacteriocins, which inhibit the growth of pathogens.

– Probiotic also modulate the gut microbiome by maintaining the balance of microflora and suppressing the growth of pathogenic bacteria.

  1. Vitamin D-Vitamin D receptors are expressed on immune cells including B cells, T cells and antigen presenting cells. It is an important stimulant of innate immunity which enhances chemotaxis, phagocytosis and transcription of antimicrobial peptides like defensin β2 (DEFB). Vitamin D also plays an important role in B cells homeostasis, regulating mechanisms associated with autoimmune responses and control inflammatory reactions. Prevalence of vitamin D deficiency is high and therefore rich sources like dairy products, eggs, mushrooms and supplements, can ensure optimal supply of vitamin for healthy immunity.

With the advanced technology in the composition, ingredient combination and the delivery format, nutraceuticals, now, are serving an acceptable and innovative carrier for these strong actives.

Challenges: While there are many advantages of technology used in nutraceuticals and extensive studies exploring wide array of actives, there are few challenges that needs the attention.

Acceptability– In the current scenario, immunity has now moved to a category of all-year-round necessity. Therefore, focus must be drawn to a combination of novel ingredient along with conventional actives, to ensure both immediate and long-term strong immunity. This will also help in better familiarity and acceptability among consumers with increased awareness.

Multi-functional application– For the aspect of convenience and because of understanding now that immunity can be affected by various physical, physiological and psychological stressors, emphasis can be given on multi-functional nutraceutical.

Intense research– To understand the safety and efficacy of the nutraceutical, it is crucial to research in less-explored aspects like extraction process, chemical characterization, bioavailability and interaction of single or mix of actives with organ and systems.

Proper documentation– With intense research, its proper documentation becomes equally important. Aspects like pharmacokinetics and pharmacodynamics of actives, interaction with body system and each another, interaction of actives in nutraceuticals with conventional medications, is currently not widely available, especially for botanicals. Proper studies and documentation of the safe use of the product, clinical studies and substantiation should be considered.

To summarize, while immunity is now an important factor of determining our health quotient, nutraceutical holds a promising solution to ensure the well-being when complemented with healthy diet and exercise. And as we set to accept nutraceuticals as an integral part of our lifestyle, more awareness among people, extensive studies on the actives combination, its synergistic mode of action and its documentation is the need of the hour!


  1. Santini A, et al.  Nutraceuticals: opening the debate for a regulatory framework. British Journal of Clinical Pharmacology. 2018. 84(4):659-672.
  2. Nicholson LB. The immune system. Essays Biochemistry. 2016.60(3):275-301.
  3. Li P, Yin YL, Li D, Kim SW, Wu G. Amino acids and immune function. British Journal of Nutrition. 2007 Aug;98(2):237-52.
  4. Galdeano C, et al. Beneficial Effects of Probiotic Consumption on the Immune System. Annual Nutrition Metabolism. 2019. 74:115-124.

Dr Shyam Ramakrishnan

Dr Palaniyamma Durairaj

Dr Swati Shukla

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