How can diet boost your immune system? Part 1.
Category: Nutrition

How can diet boost your immune system? Part 1.

How diet can boost your immune system- what to eat to stay safe!

From Turner Swim’s Managing Director Andrew: “Turner Swim’s resident nutritionist Magda has put together this blog below to help with the Coronavirus times we are currently living in. We hope you stay safe, eat well and look forward to being the other side of this strange time.”

By Magda: It has been proven by the World Health Organisation that people with a stronger immune system are less likely to catch any types of virus or infection.

So, what we can do to strengthen it? The answer is simple- an immunity diet!

According to Harvard University research a nutritious diet, full of vitamins can strengthen the body’s immune system. To quickly deal with the infection, you need to strengthen those areas of the body where immune cells are produced. One of them is the intestines which are responsible for absorbing most if the nutrients and water from what we eat and drink.

Therefore, the best ally in overcoming bacteria and viruses is a strengthening immunity diet.

The immune system plays a role of a protective shield for our body. For the immune system to perform at its highest speed, you need to take care not only of your physical activity or good sleep, but also about a balanced diet.

So, what to eat to strengthen your immunity during those difficult times? The three main ingredients that have beneficial properties for immunity are vitamins, minerals and fatty acids such as:

  • Vitamins: C, A (beta carotene), E, D3
  • Minerals: Zinc
  • Fatty acids: Omega 3.

Moreover, it has been proven by WHO that many Prebiotics and probiotics as well as several spices have also a positive impact on our digestive system which boosts our immunity. So How exactly those mentioned above affect our body and most importantly in what products can we find them?


Vitamin C

Vitamin C is an antioxidant which neutralizes free radicals, strengthens the immune system. To provide the right amount of this vitamin

Vitamin C examples photo

Photo above: Examples of vitamin C

you should eat 5 portions of vegetables and fruit, which is its rich source. However, it should be remembered that processes such as cooking reduce its content, which is why we should try to eat raw fruits and vegetables whenever possible.

For adults, the recommended daily amount for vitamin C is 65 to 90 milligrams (mg) a day, and the upper limit is 2,000 mg a day. So how much fruits and vegetable should I be eating to meet my Recommended Daily Intake (RDI)? Have a quick look on the table below to find out!

Where is Vitamin C found?
Food Vitamin C per 100 g Serving Recommended Daily Intake in percentage
Cauliflower 46 mg 51%
Orange 59 mg 65%
Strawberries 59 mg 65%
Papaya 62 mg 69%
Brussels Sprouts 75 mg 83%
Broccoli 81 mg 90%
Kiwi 93 mg 103%
Kale 120 mg 133%
Parsley 133 mg 147%
Red Chilli pepper 144 mg 160%
Bell pepper 184 mg 204%
Green chilli pepper 242 mg 269%

As you can see as much as 1.5 orange or ¼ of green chilli pepper can meet your recommended daily intake. So, it is not as hard is it?


Vitamin A + B-carotene

As vitamin A affects the number of cells of the immune system, increasing their number thereby strengthens immunity. A rich source of vitamin A is dairy products, butter, margarine as well as liver, eggs, fish, carrots, peppers, spinach and chives.

Vitamin A + B-carotene

Examples of Vitamin A + B-carotene


B-carotene is a vitamin A provitamin, an antioxidant, stimulates immune cells. A rich source of b-carotene is yellow and orange vegetables and fruits, i.e. red, yellow peppers, carrots, apricots, peaches as well as dark green vegetables (spinach, broccoli) and nuts.

The recommended daily Intake for vitamin A is 900 mcg and 700 mcg per day for men and women, respectively. You can easily meet your requirements for vitamin A by regularly eating some of the foods listed below. Many foods also contain added vitamin A, including cereals, margarine and dairy products.

Where is Vitamin A found?
Food Vitamin A per 100 g Serving Daily Recommended Intake in percentage
Carrots (cooked) 852 mcg  95%
Red bell pepper 157 mcg 17%
Apricots 96 mcg 11%
Grapefruit 58 mcg 6%
Sweet Potatoes 1,043 mcg 116%
Spinach 469 mcg 52%
Kale 681 mcg 62%
Butter 687 mcg 76%
Eggs 149 mcg 17%
Cod Liver Oil 30.000mcg 3,333 %
Salmon 149 mcg 17%
Cheddar 241 mcg 27%


Vitamin E

Foods contraining Vitamin E

Examples of foods containing vitamin E

It is an antioxidant and immunostimulatory. It protects the body against free radicals (responsible for ageing processes).

This vitamin also blocks prostaglandins (tissue hormones) that weaken your immune defence. The Recommended Daily Intake for vitamin E is 15 milligrams (22.5 IU) a day. The perfect meal to meet those requirements could be shrimp’s pasta with olive oil and spinach. Look on the table below to find out top food highest in Vitamin E.

Where is Vitamin E found?
Food Vitamin E per 100 g Serving Daily Recommended Intake in percentage
Sunflower Seeds 26.1 mg 174%
Almond 25.6 mg  171%
Avocado 2.1 mg 14%
Spinach 2.1 mg 14%
Butternut Squash 1.3 mg 9%
Kiwi 1.5 mg 10%
Broccoli 1.5 mg 10%
Trout 2.8 mg 19%
Olive Oil 14.4 mg 96%
Shrimp 2.2 mg 15%



Omega 3 fatty acids are polyunsaturated fatty acids with a broad action, including strengthening the immune system by

Omega-3 Photo

Examples of foods that are good sources of omega-3

stimulating white blood cells. Studies have shown the impact of linseed oil intake to strengthen immunity. In addition to the linseed oil, omega-3 fatty acids are also present in fatty fish (salmon, herring), crustaceans, tofu, almonds and walnuts. The inclusion of omega-3 fatty acids in the diet helps to increase the activity of phagocytes (white blood cells that destroy bacteria).

Health organizations recommend a minimum of 250–500 mg of omega-3s per day for healthy adults. To meet those guidelines, it is recommended to consume 2 portions of fish per week, oily fish is best. A portion for adults equals the thickness and size of the palm of the hand or 140g in weight of fresh fish or 1 small can of tinned fish.

Here is a list of 10 foods that are very high in omega 3.

Where is Omega 3 found?
Food Omega 3 per 100 g Serving
Mackerel 5,134 mg
Salmon 2,260 mg
Cod Liver Oil 20,682 mg
Herring 2,366 mg
Oyster 435 mg
Sardines 1,480 mg
Anchovies 2,113 mg
Flax seeds 20,350 mg
Chia seeds 18,261 mg
Walnuts 9,259 mg

We hope that you are able to use this blog well and eat a balanced diet. If you would like more advice please just let us know at

Look out for Magda’s part 2 blog due out 6 April, with further nutritional advice and her own recipes in too!


About the blog’s author Magda

Magda has a Masters in Sports and Exercise Nutrition from the University of Westminster and is also a fully qualified level 2 swimming coach. Magda is available for one-to-one adult swimming lessons in Turner Swim at Le Meridien Piccadilly on weekday mornings. Once the coronavirus outbreak is over, click here to book a swimming lesson with Magda.



  1. Health, H.S. of P. (2009). Vitamins and Minerals Available from [Accessed 2019].
  2. Hoflund et al. (2017). The Intersection of Food and Public Health, 1st ed.Public Administration for Public Health. Milton: Routledge Ltd. Available from
  3. National Health Services, (NHS) (2017). Vitamins and minerals<br>[]. National Health Services. Available from
  4. World Health Organization, (WHO) (2004). Vitamin and mineral requirements in human nutrition. Geneva: World Health Organization. Available from

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