Garlic, citrus fruits, bell peppers, turmeric, fermented foods, mushrooms, leafy greens and fatty fish provide vitamins, minerals and bioactive compounds that researchers have studied for roles in immune function.
By yourNEWS Media Newsroom.
A varied diet containing vegetables, fruits, fermented foods and nutrient-rich sources of protein may help provide the vitamins, minerals and other compounds the immune system needs to function normally, according to a report examining eight alternatives to ginger.
The foods highlighted were garlic, citrus fruits, bell peppers, turmeric, fermented foods, mushrooms, leafy greens and fatty fish.
Ginger remains widely used for its flavor and potential health benefits, but its strong taste can make it difficult for some people to consume regularly. The alternatives examined in the report offer different combinations of vitamin C, vitamin A precursors, vitamin D, omega-3 fatty acids, probiotics and plant compounds that have been investigated for their effects on inflammation and immune activity.
None should be regarded as a treatment for infection or a substitute for medical care. Rather, researchers have examined how their nutrients may contribute to normal immune-system function as part of an overall diet.
Garlic is notable for sulfur-containing compounds including allicin.
Laboratory and other research has investigated garlic compounds in connection with influenza A and B, rhinovirus and viral pneumonia. Proposed mechanisms include interference with viral attachment and replication as well as effects on inflammatory responses.
Some studies have also examined whether garlic consumption can reduce the duration or severity of common cold symptoms. Garlic may be consumed raw, cooked or in supplemental preparations, although its composition can vary depending on preparation.
Citrus fruits provide another familiar group of immune-related nutrients, particularly vitamin C and folate.
Vitamin C contributes to normal immune function and has been studied for whether regular intake can modestly shorten or lessen cold symptoms. Citrus fruits also contain flavonoids, including hesperidin.
Research involving orange juice has associated hesperidin and other compounds with changes in inflammatory markers, including C-reactive protein.
Oranges, grapefruits, lemons, limes, tangerines, clementines and mandarins can all contribute vitamin C while supplying additional plant compounds.
Bell peppers can provide even more vitamin C per serving than many citrus fruits.
Yellow, orange and red peppers are particularly rich in the vitamin, with red bell peppers containing nearly three times as much vitamin C as oranges in some comparisons.
Bell peppers also contain beta-carotene, which the body can convert to vitamin A.
Vitamin A contributes to the maintenance of skin and mucosal tissues, including the linings of the nose and throat. Those surfaces form part of the body’s physical barrier against infectious organisms.
Turmeric offers a different class of compounds.
Its best-known constituent is curcumin, which has been studied for anti-inflammatory activity and possible effects on immune signaling.
Researchers have investigated whether curcumin can influence viral replication and the activity of B cells and T cells, two components of the adaptive immune system.
One study cited in the report found that people taking curcumin supplements alongside COVID-19 vaccination produced higher antibody responses.
Curcumin has also been investigated beyond immune health. A 2025 report published by Brighteon.com discussed research suggesting turmeric or curcumin supplementation could improve some measures of memory, particularly among older adults, with increases reported as high as 30% in certain study populations.
Those findings depend on the study design, dosage and population and should not be interpreted as establishing the same effect for everyone consuming turmeric as a food.
Fermented foods may support immune function through their relationship with the intestinal microbiome.
Yogurt, kefir, kimchi, miso, sauerkraut and kombucha contain microorganisms or fermentation products that can interact with the gut environment.
Because a substantial portion of immune activity occurs in and around the gastrointestinal tract, researchers have studied whether probiotics and fermented foods can strengthen the intestinal barrier, influence inflammatory responses and affect immune-cell activity.
Research cited in the report has examined probiotic strains found in yogurt and kimchi in connection with influenza and rotavirus.
Kefir has also been studied for possible effects on antibody production and inflammatory responses during illness.
A 2026 study reported that fermented cabbage reduced intestinal-barrier damage by approximately 40% under the conditions examined, outperforming both raw cabbage and probiotic supplements.
Other recent research has emphasized how fermentation changes food itself. Microorganisms can transform proteins, carbohydrates and fibers into additional compounds, including bioactive peptides.
Reviews of observational studies have also found associations between fermented-food intake, immune markers and lower mortality. Such findings demonstrate relationships rather than proving that fermented foods alone produced the outcomes.
Mushrooms provide another collection of compounds that researchers have examined for immune effects.
Shiitake and other varieties contain beta-glucans, complex carbohydrates that can interact with immune cells.
Research has explored whether mushroom beta-glucans can influence natural killer cells and T cells, both of which participate in immune defense.
Certain mushroom compounds have also been studied in laboratory settings for their ability to interfere with viral attachment or replication.
Mushrooms additionally contain nutrients including selenium and vitamin B6, which participate in processes involved in antibody production and immune-cell function.
A February 2026 report included shiitake mushrooms among foods being investigated for antiviral properties associated with interference in viral replication.
Researchers have also explored beta-glucans in cancer immunology. Work led by Associate Professor Frederick Sheedy of Trinity’s School of Biochemistry and Immunology and Professor Helen Roche of University College Dublin’s School of Public Health examined whether yeast-derived beta-glucan could strengthen antitumor immune responses.
Leafy green vegetables contribute a broad range of nutrients required for normal immune activity.
Spinach, kale, Swiss chard, collard greens and arugula supply vitamins A, C and E along with folate and iron.
Those nutrients participate in cellular growth and repair, antioxidant protection, immune-cell activity and the transport of oxygen to tissues.
Preparation can influence how efficiently the body absorbs certain compounds. Light cooking may make some nutrients more bioavailable while still preserving much of the nutritional content.
Fatty fish bring another set of nutrients into the immune-health discussion.
Salmon, sardines, mackerel, trout and herring contain omega-3 fatty acids and, in varying amounts, vitamin D.
Omega-3 fatty acids participate in the regulation of inflammatory processes. Inflammation is an important part of the body’s response to infection, but excessive or poorly controlled inflammation can damage tissues.
Vitamin D also influences immune-cell activity and has been extensively studied in connection with immune regulation.
A 2008 study by Tiago Silva Alexandre and colleagues using data from the English Longitudinal Study of Ageing reported that participants with low vitamin D levels alone had a 91% higher risk of mortality in the population examined.
That observational result does not establish that low vitamin D itself caused the higher mortality risk, but it illustrates why vitamin D status has remained an area of sustained research.
The eight foods highlighted in the report do not work through a single mechanism.
Garlic contributes sulfur compounds, citrus and peppers provide vitamin C, turmeric supplies curcumin, fermented foods interact with the gut microbiome, mushrooms contain beta-glucans, leafy greens provide multiple vitamins and minerals, and fatty fish supply omega-3 fats and vitamin D.
Taken together, they demonstrate why dietary variety matters when considering nutrition and immune function.
No individual food can prevent or cure common viral illnesses on its own, and people with infections or significant medical concerns should rely on appropriate medical care rather than food as a substitute for treatment.
As part of an overall balanced diet, however, these foods can supply many of the nutrients and compounds the body uses to maintain normal immune defenses, offering multiple options for people who do not regularly eat ginger.
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