Vitamins for Immune Health: Which Nutrients Matter Most for Immune Support

Understanding immune health

The immune system is a complex network of organs, tissues, cells, and biochemical messengers, and several vitamins and minerals make it possible for this network to function properly. These nutrients act as antioxidants, protecting cells from free radicals and environmental stress.

• They can be signaling molecules that tell immune cells where to go.
• They can be cofactors, which are vital helper molecules that join enzymes to activate cells.
• Together with other factors, these essential nutrients help maintain a balanced, resilient immune system.

The best way to acquire these vitamins and minerals is through a varied diet of whole foods. However, consistently meeting the daily recommended amounts of these nutrients can be difficult. Beyond our busy lifestyles, studies show that the nutrient density of whole foods is also declining due to environmental factors, soil depletion, and modern farming practices.^1,2

According to the National Health and Nutrition Examination Survey (NHANES), a substantial number of Americans fall below the Estimated Average Requirement (EAR) for several key vitamins. Vitamins D and E are the most common shortfalls—95% and 84% of adults have an estimated intake below recommended levels. Additionally, almost half of those surveyed weren’t getting recommended levels of vitamins A and C.⁴ In the case of nutrient gaps, supplements can be a helpful addition to a healthy diet.

Vitamins for immune support

Your body absorbs important nutrients from your food and supplements to maintain normal immune function. Here are some of the most important vitamins for immune support.

Fat-soluble vitamins

Fat-soluble vitamins dissolve in fats and oils, allowing them to be absorbed alongside dietary fats. They are stored in the body’s liver and fatty tissues.

Vitamin A
The skin and the mucous membranes of the lungs, nose, and other areas are the body’s first line of defense. Vitamin A plays a role in maintaining those barriers, while also supporting the differentiation of immune cells—the process in which immature cells become specialized for a specific job.³

Good sources: Carrots, oranges, sweet potatoes, dark leafy greens, liver, and dairy.⁵

Vitamin D
Vitamin D supports first responder immune cells’ ability to multiply. It also plays a role in keeping the immune system in balance.⁶

Good sources: Primarily sunlight, but can be obtained from oily fish or fortified foods.

Vitamin E
Vitamin E is an antioxidant that supports the integrity of cell membranes, as well as cell signaling and division.⁷

Good sources: Plant-based oils (corn, olive, palm), nuts (almonds, hazelnuts), and seeds.⁸

Water-soluble vitamins

Water-soluble vitamins dissolve in water and are absorbed directly into the bloodstream. Because they’re not stored in the body’s tissues for long-term use, any excess is soon flushed out in urine. This means they must be replenished daily through your diet to maintain healthy levels.

Vitamin C
Vitamin C is a key vitamin to help support immune system resilience. An antioxidant and coenzyme, vitamin C helps protect cells and maintain barriers like the skin. It also supports immune health.

Good sources: Citrus fruits (oranges, grapefruit), red peppers, broccoli, and kale.⁹

B vitamins
B-complex vitamins, particularly B6, B9​ (folate), and B12, support cellular processes involved in energy metabolism. This supports cellular function and the rapid multiplication of immune cells as part of normal immune function.¹⁰

Good sources: Poultry, fish, liver, eggs, whole grains, dairy products, legumes, and fortified cereals.⁵

Essential minerals

Many people consider the link between the immune system and vitamins, but they should also pay attention to several key minerals.

Zinc
Zinc is often called the “gatekeeper” of immune function. As a key signaling molecule, it supports many aspects of the immune system, from the maintenance of skin integrity to the formation of memory cells. It’s also a building block of cells themselves.¹¹

Good sources: Meat, fish, and soybeans.¹²

Iron
Iron plays an important role in the development and proliferation of immune cells and supports immune balance.¹³

Good sources: Cereals (especially fortified bread) and meats.¹⁴

Selenium
Selenium is integrated into selenoproteins, which play critical roles in antioxidant defense and maintaining immune balance.¹⁵

Good sources: Brazil nuts, fish, meat, poultry, cereals, and grains.¹⁶

How vitamins support your immune system

Beyond focusing on which vitamins help immune system function, you should also be aware of the amount and the form of the nutrients you’re getting.

For example, iron and zinc tend to have greater bioavailability if ingested from animal rather than plant sources.¹⁷ While absorption depends on individual factors, vegetarians and vegans are more likely to fall short of the recommended intake of these minerals and may be good candidates for supplementation.¹⁸ If using supplements, it’s important to know that these nutrients also come in different forms with varying degrees of bioavailability.

Absorption can also be affected by other nutrients. Fat-soluble vitamins like A and D require dietary fats for optimal absorption, making it important to pair them with healthy fats from oils, avocados, fish, and nuts.¹⁹ Certain other nutrients can compete for absorption. For example, high-dose supplementation of copper and zinc may inhibit iron uptake, while iron can inhibit copper absorption.²⁰ These nutrients should be taken separately if possible.

Tips for maintaining a healthy immune system

In addition to paying attention to minerals and vitamins for immune health, consider adding pro- and prebiotics to your diet. Probiotics are typically found in fermented foods like sauerkraut, yogurt, and cottage cheese, as well as drinks like kefir and kombucha (just make sure to buy the kind with “live cultures”). Probiotics introduce helpful bacteria into your gut, the center of much immune activity. Prebiotics are plant fibers that gut bacteria ferment, essentially feeding the microbiome and supporting immune function.²¹

Combining a nutrient-rich diet of whole foods, prebiotics, and probiotics with regular exercise, adequate sleep, and stress management is the formula for a healthy immune system. At the same time, avoid the trappings of the Western Diet. Saturated fats, refined sugar, and ultraprocessed foods have been linked to changes in microbiome balance.²²

While whole foods are the best source of vitamins for immune system support, supplements can help fill nutrient gaps.

How foundational nutrition supplements work

Instead of relying on many individual supplements, keeping track of dosages, and maximizing bioavailability, many people turn to a foundational nutrition supplement for more convenient support.

AG1 combines over 75 vitamins, minerals, and whole-food-sourced ingredients to help fill common nutrient gaps and support whole-body health, including immune health. With prebiotics and probiotics that promote a healthy gut and support immune defense, AG1 Next Gen is a clinically studied formula that helps fill common nutrient gaps in one daily scoop.*

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