Immune Support Foods

Your immune system protects your body from viruses, bad bacteria, fungi and other nasties. Made up of organs and cells working together to keep you fighting fit, it’s vital that your immune system is doing its best work 24/7/365.

Low immunity doesn’t only open you up to more frequent illnesses, including colds and stomach bugs. It can also make healing after an injury difficult, leave you feeling exhausted and even result in weight gain[i]. People with compromised immune systems may also experience digestive issues such as chronic diarrhea, bloating, reflux and abdominal pain[ii].

There are many ways to build a healthier immune system. You might choose supplements, stress management and avoiding alcohol and nicotine. But perhaps one of the most efficient ways to support your immunity is through diet.

What Causes Compromised Immunity?

Your immune system can be weakened by a variety of factors, including specific medical conditions, medications and medical treatments. Certain lifestyle choices such as smoking and drinking alcohol may have a negative impact on immunity too.

How do my genes, medications and preexisting conditions impact my immune system?

In addition to the more than eighty autoimmune diseases, including lupus, MS and rheumatoid arthritis, there are numerous genetic or acquired immunodeficiencies. These will be diagnosed by a specialist and are usually controlled with medication.

Medical treatment such as chemotherapy, radiation and bone marrow transplantation can significantly reduce the immune system’s effectiveness too. Additionally, some medication, particularly anti-epileptics, negatively affect immune function as a side effect[iii].

Will my immunity get worse as I age?

The immune system’s effectiveness declines with age[iv]. In our older years our immune system becomes less able to distinguish between healthy cells and foreign invaders. We also see a reduction in the effectiveness of invader-busting T-cells and macrophages while white blood cell counts decrease. Antibodies also become less effective, meaning that infections hit harder and are trickier to shift.

How does my lifestyle affect my immune system?

Certain lifestyle choices can have a significant impact on your immune system too[v]:

Smoking: nicotine is not only linked to the development of autoimmune diseases, it’s also seen to affect short and long term immunity[vi]
Drinking alcohol: excessive drinking is strongly linked to immune-related adverse health outcomes, including pneumonia, sepsis and alcoholic liver disease[vii]. Experts underline that immune deficiencies can be caused by both chronic alcohol consumption and binge drinking[viii]
Lack of exercise: studies show that, long term, a sedentary lifestyle can contribute to immune dysfunction[ix]
Poor sleep: quality sleep is vital for a healthy immune system. A lack of sleep leads to changes in our adaptive and innate immunity, resulting in chronic inflammation and susceptibility to illness and infection[x]
High BMI: studies show that along with smoking and the presence of latent cytomegalovirus, being overweight is the most common cause of low immune function[xi]

Can What I Eat Support My Immune System?

Eating well is just as important for a healthy, functional immune system as dodging nicotine and reducing those glasses of vino.

What’s the link between food and immunity?

A good diet supports the immune system. The nutrients we consume are used in the maintenance of all cells, including those that make up the immune system. The various stages of the immune response will rely on different nutrients to properly function, which is why it's especially important to eat a varied diet.

The immune system is also strongly linked to our microbiome [xii]. Studies show that a diet rich in probiotics can aid in the regulation of all-important, body-wide immune cells and intestinal epithelial cells[xiii].

What are the key vitamins and minerals needed for a better immune system?

A well-rounded diet should give you everything you need for good immunity but there are some key nutrients to look out for:

Nutrient	Why It’s Important	How Much?[xiv] (per day)	Ideal Sources
B Vitamins (B6, B12, folate)	Aid in the production of immune cells[xv]	Men: 1.4mg B6, 1.5mg B12, 200µg folate Women: 1.2mg B6, 1.5mg B12, 200µg folate	Meat and poultry, milk, cheese and eggs, leafy greens, broccoli, soya beans, fortified breakfast cereals
Vitamin A	T-cell (white blood cells that target pathogens) support[xvi]	Men: 700µg Women: 600µg	Milk and cheese, oily fish, eggs, liver
Zinc	Aids in the production of immune cells[xvii]	Men: 9.5mg Women: 7mg	Dairy, bread, shellfish, meat, cereals
Selenium	Aids in the production of immune cells. Plays a role in inflammation[xviii]	Men: 75µg Women 60µg	Meat, fish, eggs, Brazil nuts
Copper	Participates in development of immune cells. Plays a role in fighting ‘bad’ bacteria[xix]	Men & women: 1.2mg	Shellfish, nuts, whole grains, organ meats
Iron	Vital for immune cell production. Studies show low levels inhibit immune responses[xx]	Men (& women over 49): 8.7mg Women: 14.8mg	Red meat, pulses, nuts, liver, leafy greens. Vitamin C enhances absorption

Vitamin D is especially significant in immune system support[xxi]. However, vitamin D isn’t present in food, relying on exposure to sunlight and/or supplementation.

Which foods should I eat for immune system support?

Immune system-supporting superfoods include[xxii]:

Mushrooms: containing selenium and B6 as well as immune cell-supporting β‐d‐glucan
Kiwi: for anti-inflammatory vitamin C and polyphenols
Almonds: containing antioxidant vitamin E and T-cell support
Broccoli: providing B vits and anti-inflammatory sulforaphane
Garlic: for immune cell stimulation
Onions: antioxidant, antibacterial, antifungal and antiviral properties[xxiii]
Ginger: with gingerol for antioxidant, analgesic and anti-inflammatory action[xxiv]
Turmeric: contains immune cell modulating curcumin

The Easy Immune System Diet

Knowing which nutrients and foods support the immune system is one thing. Incorporating them into your daily diet is another...

Eating in: diet plans for an improved immune system

An immune system supportive diet doesn’t have to mean slaving over a hot stove. Eating for immunity is as simple as getting your five-a-day. This might mean snacking on fruit, inserting a smoothie bowl into your morning routine or adding a side salad to your evening meal. Diversity is key, so opt for a wide range of different fruits and veggies to maximise nutrient load. Frozen fruit and veg is particularly convenient while also holding onto vitamins better than fresh ingredients.

Wherever possible choose ingredients that support gut health. Key for immunity, probiotic foods such as yoghurt, kefir, kimchi, miso, and even some cheeses, are easy to eat alone or as part of a healthy meal. Meanwhile, prebiotics, which feed good bacteria, are found in many simple, easy to use ingredients. Good prebiotic choices include wholemeal bread, pasta and rice, beans, lentils and flaxseeds.

Eating out: ultra-processed foods and the immune system

Ultra-processed foods are the enemy of immunity[xxv]. Low on whole foods and high in synthetic ingredients, UPFs have been linked to immune dysregulation diseases such as inflammatory bowel disease[xxvi]. There’s also emerging evidence that UPFs could increase the risk of autoimmune diseases[xxvii].

Limiting your intake of these UPFs, often found in fast foods and convenience foods, is sensible. Choosing small, local restaurants over big-name chains is one easy way to bank on healthier dining. And if you can’t resist a drive-thru? Make it a one-off, not a regular habit.

Three more easy tips for better immunity

Drinking more water: your water intake supports the immune system[xxviii]. It’s also important for gut health, which plays a vital role in immunity. Not big on jus de tap? Herbal teas, low-sugar squashes, milks and no-added sugar juices count too
Taking vitamin supplements: a daily vitamin supplement is an easy, affordable way to assure your intake of important nutrients. However, supplementation should not be considered an alternative to a healthy diet

Supplementing with probiotics: a high quality immunity-targeting probiotic supplement, like Precision Biotics’ Daily Immune Support is ideal for immune system-friendly gut health.

References:

[i] https://www.tcd.ie/news_events/articles/immune-system-plays-major-role-in-regulation-of-body-weight/

[ii] https://pmc.ncbi.nlm.nih.gov/articles/PMC3150032/

[iii] https://www.immunodeficiencyuk.org/immunodeficiency/secondary-immunodeficiency/#:~:text=There%20are%20many%20potential%20causes,problem%20in%20its%20own%20right.

[iv] https://www.immunodeficiencyuk.org/wp-content/uploads/2023/02/IUK_booklet29_Ageing_AW.pdf

[v] https://www.cdc.gov/healthy-weight-growth/about/enhancing-immunity.html#:~:text=You%20can%20also%20strengthen%20your,and%20avoid%20excessive%20alcohol%20use.

[vi] https://www.pasteur.fr/en/press-area/press-documents/smoking-has-long-term-effects-immune-system?language=fr

[vii] https://pmc.ncbi.nlm.nih.gov/articles/PMC4590612/

[viii] https://pmc.ncbi.nlm.nih.gov/articles/PMC4590612/

[ix] https://pmc.ncbi.nlm.nih.gov/articles/PMC7362590/

[x] https://pmc.ncbi.nlm.nih.gov/articles/PMC8602722/

[xi] https://www.pasteur.fr/en/press-area/press-documents/smoking-has-long-term-effects-immune-system?language=fr