If you’re looking for the best vitamins and supplements to boost your immune system, look no further.
Here you’ll learn about some of the most helpful vitamins, minerals and other nutrients for your immune system and why they’re important.
We’ll also look at how the immune system works, what can go wrong, and how to recognise the signs that your immune system needs support.
SUPPLEMENTS TO BOOST THE IMMUNE SYSTEM
Vitamin C is probably the best-known vitamin for your immune system. One reason it’s essential is because it helps the body make collagen, which is vital for strong and healthy skin and internal linings of our body such as the gut wall.
These are part of our immune system as they’re our first line of defence against germs getting in.
Vitamin C may also help to keep our immune cells active and help boost production of antibodies and other immune chemicals.
When it comes to practical benefits for your immune system, studies suggest that taking a vitamin C supplement can reduce duration of colds and could lower your risk of getting a cold, too .
Famed as the ‘sunshine vitamin’, vitamin D is typically associated with bone health. But it’s a vital immune nutrient too.
Our immune cells have ‘receptors’ for vitamin D, which basically means vitamin D can communicate with cells of the immune system and pass on messages.
Vitamin D is thought to help boost immunity where needed, but also regulate the immune system. This means it could also help prevent over-activation that can lead to problems such as allergies and autoimmune disease, such as rheumatoid arthritis, psoriasis and MS.
It also helps produce anti-bacterial chemicals in the body to help keep germs at bay.
Taking a supplement containing vitamin D can be especially important over winter, as our natural vitamin D levels drop due to lack of sunlight on our skin.
How much vitamin D should I take?
Pay attention to how much vitamin D you’re getting in your supplement: many supplements only contain 10 mcg (400 IU), which is rarely enough to keep our vitamin D levels at an optimal level. A more effective daily intake is 25 to 50 mcg per day (1000 to 2000 IU).
This is one vitamin that gets much less attention when it comes to the immune system – but it’s no less important!
Like vitamin C, vitamin A is essential for healthy skin and the linings of the body that stop germs getting through. And like vitamin D, it’s thought to have roles in activating immune cells and helping regulate the immune response too.
It may not be as easy as we think to get enough of this vitamin from our food. True vitamin A is only found in animal foods, especially liver, cod liver oil, butter, eggs and whole milk.
Vegetables and fruit - especially green, orange and yellow colours - are often considered a source of Vitamin A. It is worth noting that they actually contain a chemical (a type of carotenoid) known as beta carotene. Our body can change beta carotene into Vitamin A.
The problem is that some people may not absorb carotenoids very well, and may only convert a very small amount of them to vitamin A .
The reason for poor absorption of carotenoids is unclear but we do know that it is easier to absorb them if you eat them with some form of fat. People following a low fat diet may therefore have poor absorption rates.
Zinc, like vitamin C, is instantly recognisable as an immune-supporting nutrient, and you’ll find it in most immune supplements.
Deficiency in zinc is known to lead to poor immunity and increased risk of infections. It’s thought to be needed for many types of immune cells to develop and to work properly. 
Selenium, copper, iron, folate (folic acid) and vitamin B12 are other minerals and vitamins that can boost the immune system.
OMEGA 3 FATTY ACIDS
The omega-3 fats in oily fish and fish oil supplements could be helpful for immune support in a different way. Research suggests they can have an anti-inflammatory effect .
Because autoimmune diseases and allergies involve excessive inflammation, eating oily fish or taking a good-quality fish oil supplement may help restore balance.
BIOTIC (GUT BACTERIA) SUPPLEMENTS
Our gut contains trillions of bacteria, many of which are known as the ‘friendly’ or 'good' bacteria.
As well as helping to digest our food, they can produce antimicrobial substances against ‘bad’ bacteria and other pathogens such as viruses and fungi.
FYI: "An antimicrobial substance is something that kills microorganisms or stops their growth. For example, antibiotics are antimicrobial."
They may also interact directly with the part of the immune system found in and around the gut (see ‘What is the immune system?’ below), helping to teach it what to react to .
So, a lack of the right gut bacteria – which can happen due to poor diet, stress, antibiotic medication and for many other reasons – may impact our immunity.
This is why a biotic (probiotic) supplement may be helpful. Lactobacillus rhamnosus GG is a strain of ‘friendly’ bacteria that’s been studied for its potential immune-supporting effects.
For example, research suggests Lactobacillus GG can help balance the immune response in infants with allergies, and help relieve inflammation in the gut that can be linked to allergies .
In addition, animal studies have indicated it may help protect against infections such as flu .
WHAT IS THE IMMUNE SYSTEM?
The immune system is a huge network of cells, organs, tissues and chemicals whose main job is protecting us against pathogens – bacteria, viruses and other microbes.
Cells of the immune system come in many different types. Some directly attack and ‘eat’ germs and toxins; some produce chemicals that kill pathogens. Others make antibodies and some help coordinate the actions of other immune cells.
Organs and tissues involved in immunity include the lymph glands, spleen, thymus and bone marrow.
A lot of our immune tissue is found in the gut, too, because this is the main way germs from the outside world can enter the body – it helps to trap and deal with them before they can make us unwell!
THE TWO DIVISIONS OF OUR IMMUNE SYSTEM
There are two main divisions of our immune system – although they’re closely linked.
- The innate immune system is what we’re born with.
- It includes physical barriers such as the skin and gut wall that stop germs getting in.
- It includes cells that can recognise pathogens such as bacteria and trigger a general immune response.
- The adaptive immune system is the part of our immune system that develops from birth onwards.
- Cells of the adaptive immune system learn and remember specific viruses, bacteria and other pathogens they’re exposed to, so that they can mount a faster response next time and stop us getting ill with the same infection again.
- It’s why, for example, having chicken pox or measles as a child means you’re unlikely to get them again; and it’s how vaccinations work, too.
Another important job of a healthy immune system is to not respond to things that are safe. This includes our body’s own cells, the friendly bacteria that are in our gut, and safe substances in the foods we eat and absorb.
WHAT CAN GO WRONG?
OUR IMMUNE SYSTEM IS UNDERACTIVE
Our immune system can be underactive, so that it doesn’t provide enough protection against viruses, bacteria and other threats.
In this situation we may catch infections such as colds more easily, or be unable to shift a bothersome cough or flu.
If you’re looking for supplements to boost your immune system, it’s usually for this reason – or because you want to strengthen your immune system further against threats.
OUR IMMUNE SYSTEM IS ATTACKING THE WRONG THINGS
The immune system can also mount an attack against the wrong things. This is what’s going on if you have an allergy or certain food intolerances, where it reacts against a substance that should be harmless, such as pollen or food particles.
Autoimmune conditions such as psoriasis and rheumatoid arthritis are also a result of a mistaken immune reaction, where your immune system produces antibodies against your own cells and tissues.
CAUSES OF IMMUNE IMBALANCES
There may be many reasons for either type of immune ‘imbalance’.
Lack of those immune-supporting nutrients in our diet (or from sunlight, in the case of vitamin D!) can be one factor.
This is where a supplement such as a multivitamin and mineral could be especially helpful.
OUR POOR GUT HEALTH IS AFFECTING OUR IMMUNE SYSTEM
Poor gut health could be another factor. If your gut is in less than optimal health, absorption of those immune-boosting vitamins and minerals may be affected.
And in some cases, gaps can open up between the cells of the gut lining, allowing substances to get through that shouldn’t be absorbed.
This is sometimes known as ‘leaky gut’ and is thought to be linked to allergies and autoimmune conditions.
As we’ve seen, an imbalanced gut flora – with not enough of the right ‘friendly’ bacteria – can also throw things off balance.
Both types of imbalance may also be linked to our over-hygienic modern environment. We need a certain level of exposure to bacteria and other germs to keep our immune system active and responding normally.
The modern obsession with anti-bacterial handwashes, sanitisers and cleaning products may be a significant contributing factor.
As part of the research on this theory, it’s been found that people who grow up on a farm – where there is more exposure to dirt – may have a more balanced immune system when they grow up .
Stress can be another trigger for immune problems. Stress may have a direct suppressive effect on the immune system, can affect our digestion and absorption of nutrients, and may also lead to other habits that can affect immunity, such as a poor diet or lack of exercise.
 Wintergerst ES, Maggini S, Hornig DH. Immune-enhancing role of vitamin C and zinc and effect on clinical conditions. Ann Nutr Metab. 2006;50(2):85-94.
 Johnston CS, Barkyoumb GM, Schumacher SS. Vitamin C supplementation slightly improves physical activity levels and reduces cold incidence in men with marginal vitamin C status: a randomized controlled trial. Nutrients. 2014 Jul 9;6(7):2572-83.
 Aranow C. Vitamin D and the immune system. J Investig Med. 2011 Aug;59(6):881-6.
 Raverdeau M, Mills KH. Modulation of T cell and innate immune responses by retinoic Acid. J Immunol. 2014 Apr 1;192(7):2953-8.
 Hickenbottom SJ et al. Variability in conversion of beta-carotene to vitamin A in men as measured by using a double-tracer study design. Am J Clin Nutr. 2002 May;75(5):900-7.
 Prasad AS. Zinc in human health: effect of zinc on immune cells. Mol Med. 2008 May-Jun;14(5-6):353-7.
 Shankar AH, Prasad AS. Zinc and immune function: the biological basis of altered resistance to infection. Am J Clin Nutr. 1998 Aug;68(2 Suppl):447S-463S.
 Calder PC et al. Marine omega-3 fatty acids and inflammatory processes: Effects, mechanisms and clinical relevance. Biochim Biophys Acta. 2015 Apr;1851(4):469-84.
 Ferreira CM et al. The central role of the gut microbiota in chronic inflammatory diseases. J Immunol Res. 2014;2014:689492.
 Fong FL et al. Mechanism of Action of Probiotic Bacteria on Intestinal and Systemic Immunities and Antigen-Presenting Cells. Int Rev Immunol. 2016 May 3;35(3):179-88.
 Kawase M et al. Oral administration of lactobacilli from human intestinal tract protects mice against influenza virus infection. Lett Appl Microbiol. 2010 Jul;51(1):6-10.
 ScienceDaily. (2012). Growing up on a farm directly affects regulation of the immune system, study finds. [online] Available at: https://www.sciencedaily.com/releases/2012/02/120208132549.htm [Accessed 26 Apr. 2018].