Supporting immunity: what really helps
When more and more people around you are catching colds, many look for ways to boost immunity. However, immunity cannot be boosted with a single tablet. The immune system works best when the body gets what it needs every day.
In this article you will learn which habits matter most for the immune system, which nutrients it needs and when supplements are genuinely useful.
In brief. Enough sleep, physical activity and hand hygiene are the foundation of immunity.12 Vitamins and minerals contribute to the normal function of the immune system.3 A supplement is most useful when you get too little of a particular nutrient.
First things first: daily habits
Sleep
In one study, 164 healthy adults were given nasal drops containing a cold virus. Those who had previously slept less than 6 hours a night were about 4 times more likely to fall ill than those who slept more than 7 hours.1
What this means for you. If you often get ill, start by looking at your sleep. Sleeping a regular 7 hours or more is a simple first step.
Physical activity
Adults are recommended to do at least 150–300 minutes of moderate-intensity physical activity per week.4 For example, that is 30 minutes of brisk walking 5 days a week.
Hand hygiene
Washing your hands with soap and water is one of the simplest ways to reduce the spread of infections.2 Wash your hands when you get home, before eating and after sneezing.
Vaccination
Vaccines offer the most effective protection against some infections, for example influenza.5 Ask your doctor whether a vaccine is suitable for you.
Which nutrients does the immune system need?
The following vitamins and minerals contribute to the normal function of the immune system:3
| Nutrient | Where to find it | Who is more likely to lack it |
|---|---|---|
| Vitamin D | Oily fish, eggs, sunlight | Many people from October to March.6 |
| Vitamin C | Peppers, citrus fruits, cabbages, berries | People who eat few fruits and vegetables. |
| Zinc | Meat, cheese, legumes, pumpkin seeds | Vegetarians and vegans.7 |
| Selenium | Fish, eggs, Brazil nuts | People who eat few animal products. |
| Vitamin B12, folate, iron | Meat, leafy green vegetables, legumes | Vegans (B12), women (iron). |
Vitamins A and B6 and copper also contribute to the normal function of the immune system.3 A varied diet usually provides enough of them.
When are supplements genuinely useful?
- Vitamin D – for many adults from October to March.6
- Vitamin C – if you eat few fruits and vegetables.
- Zinc or selenium – if your diet is restricted, for example if you do not eat animal products.
More is not better. It is not recommended to take more than 25 mg of zinc per day from all sources, or more than 255 µg of selenium.78 If you take multivitamins as well as individual supplements, add up the amounts.
Example. Your multivitamin contains 15 mg of zinc, and you also take a zinc and copper capsule with 15 mg. Together that is already 30 mg – more than the safe limit.
Selected products containing nutrients needed for immunity
Commercial information. These are products available in our shop. This is not an effectiveness ranking. Before buying, check the composition and instructions for use on the product page.
D1000 Daily Vitamin D Oral Spray - 15 ml - BetterYou
Oral spray with 25 µg (1000 IU) of vitamin D3 per spray, mint flavour. Contains xylitol, which may have a laxative effect in larger amounts.9
Vitamin C-1000 with 100mg Bioflavonoids - 100 vcaps - NOW Foods
Each capsule contains 1000 mg of vitamin C, 100 mg of citrus bioflavonoids and 25 mg of rutin powder. Take 1 capsule per day. If you have a sensitive stomach, take it with food.10
Zinc + Copper, 15mg + 1mg - 60 vegan caps - Osavi
Each capsule contains 15 mg of zinc and 1 mg of copper; take 1 capsule per day after a meal. If you take multivitamins containing zinc, add up the amounts.11
Selenium, 100mcg - 100 tablets - NOW Foods
Selenium in the form of L-selenomethionine, 100 µg per tablet. The manufacturer recommends 1 tablet 1–2 times a day with food. You also get selenium from food and multivitamins, so one tablet is usually enough.12
Frequently asked questions
Can immunity be boosted within a few days?
No. The immune system depends on long-term habits: sleep, diet and physical activity. A supplement will not boost immunity within a few days. It is useful if you get too little of a particular nutrient.
Do probiotics support immunity?
Study results are mixed and depend on the specific bacterial strains. Read more about this in the article Probiotics and friendly bacteria.
When should I see a doctor?
If you fall ill very often, or infections drag on or keep coming back, talk to your doctor. If you have difficulty breathing or your condition suddenly worsens, call 112.
Scientific references
- Prather AA, Janicki-Deverts D, Hall MH, Cohen S. Behaviorally assessed sleep and susceptibility to the common cold. Sleep. 2015;38(9):1353–1359. doi:10.5665/sleep.4968
- Pasaulio sveikatos organizacija (WHO). Hand hygiene: why, how and when? who.int
- Komisijos reglamentas (ES) Nr. 432/2012, kuriuo nustatomas leidžiamų teiginių apie maisto produktų sveikatingumą sąrašas (konsoliduota redakcija). EUR-Lex
- Pasaulio sveikatos organizacija (WHO). Physical activity. Fact sheet. who.int
- Pasaulio sveikatos organizacija (WHO). Influenza (seasonal). Fact sheet. who.int
- NHS. Vitamin D. nhs.uk
- NIH Office of Dietary Supplements. Zinc – Fact Sheet for Health Professionals. ods.od.nih.gov; Scientific Committee on Food, EFSA. Tolerable upper intake levels for vitamins and minerals. 2006. efsa.europa.eu
- EFSA NDA Panel. Scientific opinion on the tolerable upper intake level for selenium. EFSA Journal. 2023;21(1):7704. doi:10.2903/j.efsa.2023.7704
- BetterYou. D1000 Daily Vitamin D Oral Spray, 15 ml. Product label.
- NOW Foods. Vitamin C-1000 with 100 mg Bioflavonoids, 100 capsules. Product label.
- Osavi. Zinc + Copper, 15 mg + 1 mg, 60 capsules. Product label.
- NOW Foods. Selenium, 100 mcg, 100 tablets. Product label.
Disclaimer. This article is for information purposes only and does not replace advice from a doctor or pharmacist. Food supplements are not intended to treat or prevent diseases and are not a substitute for a varied diet and a healthy lifestyle. Before taking supplements, especially during pregnancy or breastfeeding, if you have a chronic condition or if you are taking medicines, consult a healthcare professional.
