Why nutrition strengthens the immune system

Regional, seasonal and varied: A balanced diet strengthens the immune system. Get valuable tips from nutritionist Karin Frey and find out which online services you can also use from home and which ones SWICA supports with contributions of up to 900 francs (find out more) per year.

Regional and seasonal

Are we really what we eat? Definitely – says Karin Frey, a nutritionist with Oviva. "If you eat a balanced diet, you absorb all the major nutrients, you live more healthily, and you strengthen your immune system." But what is a balanced diet?

"A balanced diet means that you should incorporate as many regional and seasonal products as possible", says Karin Frey. Your diet should include vegetables, fruit and salads, and carbohydrates (e.g. potatoes, rice, bread or pasta - whole grain for preference). "The third important component is protein. This can be found in fish, meat, eggs and dairy products as well as in tofu and Quorn. The ideal meal should consist of about 50% vegetables and salad, 25% carbohydrates, and 25% protein," says Karin Frey.

People who eat like this are getting all the nutrients they need – both macronutrients (carbohydrates, fats and proteins) and the important micronutrients (iron, selenium and zinc). The antioxidant vitamins A, C, E and beta-carotene, which are particularly important for strengthening the immune system, are also absorbed in this way. "This type of diet is also good for the gut. The gut plays a major role in the immune system because the most important nutrients are absorbed through it."

Karin Frey is a nutritionist with Oviva.

Preserving the vitamins

To ensure that the vitamins in vegetables and fruit are preserved and can actually be absorbed by the body, food should be prepared as freshly and gently as possible. Vegetables, fruit and salad should be washed briefly and preferably not under running water; potatoes should only be chopped up shortly before preparation in order to preserve the micronutrients; and vegetables should be cooked al dente and not for too long. "When cooking, it is also important to use a high-quality oil, such as rapeseed or olive oil," says Karin Frey. And if you can't always get fresh vegetables, you should go for frozen ones. "Vegetables are frozen just a few hours after they have been harvested. So they still contain about 90% of their original vitamins and nutrients."
However, if you want to store fresh products instead, make sure they are well wrapped, protected from direct light, and kept at a maximum of 4°C in the refrigerator or cellar; the ideal combination is high humidity and low temperature. By the way, plastic containers or bags can be used to protect the vitamins in fresh vegetables or salad.

Don't take supplements unless necessary

As long as you vary your diet and take care when preparing your meals, you don't need to take dietary supplements, explains Karin Frey. "Unless you have a deficiency or illness." For example, vitamin D deficiency is not uncommon in winter. Vitamin D is produced by the action of sunlight on the skin. "If you think you have a deficiency of some kind, you can find out if this is the case and take a supplement if necessary."

Which foods contains these important vitamins and micronutrients?

Vitamin A is fat-soluble and is essential for good eyesight. It also protects the skin, hair and nails. It is mainly found in offal (e.g. liver) as well as in butter, cheese, milk, eels and tuna. It is also present in yellow-orange-red and green fruit.
Vitamin B1 is also known as thiamine and is good for the heart, brain and nerves. It helps the body to release the energy from fats, carbohydrates and proteins. Yeast, meat, cereals and peas are examples of vitamin B1 suppliers.
Vitamin B2 is responsible for preserving the mucous membranes and helps the body to utilise fat, protein and carbohydrates. Various dairy products, whole grains and linseed contain this vitamin, which is also known as riboflavin.
Niacin boosts the healing power of the skin, helps with tiredness and concentration problems and has a positive influence on the nervous system. Meat, fish, peanuts and dried porcini mushrooms are rich in niacin.
Vitamin B5 is useful in stressful situations because it is involved in the formation of the anti-stress hormone cortisol. It also contributes to fitness, reduces fatigue and exhaustion and promotes the energy metabolism. The good news is that vitamin B5 is found in a wide variety of foods, including meat, fish, eggs, potatoes, dairy products, vegetables and fruit. Vitamin B5 deficiency is therefore very rare.
Vitamin B6 is important for the production of red blood cells. It contributes, among other things, to normal metabolic functioning and to the supply of energy to the muscles during exercise. Vitamin B6 is found in many foods, but is particularly abundant in soya beans, brown rice, millet, fish and bananas.
Vitamin B7 is also known as biotin, vitamin H or vitamin I. It is a building block for cells and hormones and has an influence on the preservation of skin, hair and nails. This vitamin with its many names can be found in numerous foodstuffs including oat flakes, whole grain products, brown rice, eggs, liver, whey, green beans and spinach.
Folic acid is involved in cell formation, cell division and the formation of red blood cells in the bone marrow. Folic acid is found in nuts, but also in fennel, endive, eggs, green vegetables, various types of fruit, and wholemeal and dairy products.
Vitamin B12 is necessary for the entire nervous system, for blood formation in the bone marrow and for brain metabolism. It contributes to our mental wellbeing. Significant amounts of this vitamin are only found in meat, fish and cheese.
Vitamin C is essential for strengthening the immune system. In fact, it strengthens not only the immune system, but also the skin, connective tissues and blood vessels. It is necessary, among other things, for healthy gums and nerves and good sleep. Vitamin C is abundant in fruits and vegetables.
Vitamin D strengthens the bones, is good for the nerves, and helps us to feel relaxed and optimistic. It is only found in a few foodstuffs, including fish and egg yolk. It is mainly made in the skin from exposure to sunlight.
Vitamin E protects cells from destruction by free radicals. It prevents inflammation and aging processes. Anyone who cooks with vegetable oils or fats (derived from wheat germ, sunflower or soya oil for example), or uses wholegrain flakes in his muesli, or snacks on nuts is supplying his body with vitamin E.
Vitamin K encourages blood clotting and is responsible for keeping our bones strong. Poultry is a good source of vitamin K, which is also found in wheat germ, crispbread, curd cheese, butter and calf's liver.
Iron is responsible for transporting oxygen in the blood and ensures that the muscles and liver function normally. Iron is mainly found in meat and offal, fish, seafood and poultry, but also in oatmeal, tofu and millet.
Omega-3 fatty acids play an important role in cognitive processes (e.g. learning), as well as in the development of eyesight. Cold-water fish such as anchovies, herring, mackerel, sardines and salmon are particularly rich in valuable omega-3 fatty acids.
Selenium is vital for keeping the hair and nails strong and healthy. It also contributes to the normal functioning of the immune system and protects the cells from oxidative stress. Selenium is mainly found in animal products such as meat, eggs and seafood. The following non-meat products are also good sources of selenium: Brazil nuts, asparagus, mushrooms, pulses, brassicas (e.g. cabbage) and onions.
Zinc promotes muscle formation and healing processes in the body. It also strengthens the immune system, improves the complexion and can reverse hair loss. Zinc is found in meat, fish and seafood as well as in oats, cheese, lentils, nuts, peas, millet and wheat bran.

In summary, the following are particularly important for the immune system

  • Iron, selenium, zinc, copper, magnesium and vitamins. Supplements are often recommended for vitamin D deficiency.
  • Carbohydrates and fibre (e.g. wholemeal products, rice and potatoes) have a stabilising effect on the immune system.
  • Amino acids, which are found in meat, fish, eggs and dairy products, are important for the immune system.
  • The gut plays a major role in the immune system. A fully functional digestive system and the presence of healthy gut flora make a significant contribution to good health. Probiotic foods containing lactic acid bacteria (e.g. yoghurt combined with prebiotic ingredients such as linseed, wheat bran and chicory) are recommended.

SWICA supports you with exclusive services and benefits

Nutritional advice for SWICA customers

Perhaps you'd like to lose a few pounds, or eat more healthily and more consciously? Or maybe you have some general questions about nutrition? SWICA's customers can access free nutritional advice from specialists at the santé24 telemedicine service. Call santé24 to arrange an appointment.


  • healthy diet
  • poor diet and malnutrition
  • weight loss
  • nutrition while pregnant or breastfeeding
  • nutrition in old age
  • nutrition for amateur athletes
  • being underweight
  • nutrition following abdominal surgery (on the oesophagus, stomach, gallbladder, pancreas, liver, intestine with e.g. creation of a stoma, diverticulitis, hemicolectomy, removal of part of the stomach, removal of the gallbladder)
  • nutrition following bariatric surgery (gastric bypass, gastric sleeve, biliopancreatic diversion)
  • nutrition in the case of metabolic illnesses (diabetes, gout, dyslipidaemia (elevated cholesterol levels, high blood pressure), gallstones, kidney stones, pancreatic hypofunction)
  • nutrition in the case of cardiovascular disease
  • nutrition in the case of oncological illnesses (e.g. loss of appetite, impaired sense of taste, weight loss, problems in the digestive tract as a result of therapy (mouth pain, difficulty swallowing, diarrhoea, constipation), nutrition following surgical removal of tumours)
  • nutrition in the case of digestive disorders (flatulence, bloating, reflux, irritable bowel, constipation, diarrhoea, Crohn's disease, ulcerative colitis)
  • nutrition in the case of food allergies or intolerances (e.g. lactose intolerance, coeliac disease etc.)
  • nutrition in the case of lung diseases (e.g. COPD, cystic fibrosis)
  • nutrition in the case of medication-related taste disorders (potentially in cooperation with pharmacist)
  • nutrition in the case of chewing and swallowing problems (e.g. mucositis, ill-fitting prostheses, etc.)
  • nutrition in the case of renal insufficiency (without dialysis)

Phone-based nutritional advice is offered in German, French and English. Appointments are planned and scheduled in advance.

santé24 – your Swiss telemedicine service

Phone +41 44 404 86 86

SWICA-recognised benefits relating to nutrition

Eating a varied and balanced diet makes a crucial contribution to health and wellbeing – which is why SWICA offers its supplementary insurance plan customers up to 900 francs (find out more) per year towards a wide range of services relating to nutrition, including nutritional advice, nutritional apps, TCM, and dietary/nutritional programmes with SWICA-recognised advisors and service providers. These include online, video-streaming and phone-based consultations which can also be accessed from home. Incidentally, supplementary insurance plans always provide valuable additional benefits above and beyond those available under basic insurance. It can be taken out with SWICA at any time, regardless of which insurer currently provides your basic insurance.

How your preventive healthcare contribution breaks down

SWICA covers 90% of the costs under your COMPLETA FORTE supplementary plan, up to 300 francs per calendar year. COMPLETA PRAEVENTA covers an additional 50% of the costs up to 300 francs per year. OPTIMA supplementary insurance covers 90% of the cost exceeding this amount, up to a maximum of 300 francs per calendar year. This can result in prevention contributions of up to 900 francs per year.

Discover offers relating to home-based nutrition

Nutritional advice by app and phone

Nutritional advice can also be provided digitally. You can communicate directly with your nutrition coach and plan your meals using apps and online programmes.

- Betty Bossi
- SalutaCoach

Nutritional advice by phone or video chat

Nutritional advice can easily be provided over the phone or by video chat (e.g. Skype). The following advice centres, for example, provide this service:

- Nutritional advice MonBijou
- Foodteam
- Practice for nutritional advice

Because health is everything

Physical fitness, a balanced diet and wellbeing are important elements in a healthy lifestyle. That's why SWICA supports your personal commitment in all areas of health with annual contributions of up to 1'300 francs* under the COMPLETA FORTE, COMPLETA PRAEVENTA and OPTIMA supplementary insurance plans (*go to detailed information).

Incidentally, supplementary insurance always provides valuable additional benefits above and beyond those available under basic insurance. It can be taken out with SWICA at any time, regardless of which insurer currently provides your basic insurance. .

SWICA is there for you

The SWICA team would be happy to assist you online or by phone if you have questions about benefits or require personal advice. Call free of charge on 0800 80 90 80 or complete the form below:

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For your health at home

SWICA supports you with medical services and advice around the clock and has useful recommendations and products for promoting health and preventing illness. Here you can get valuable tips on staying in shape while at home and working from home. You can also discover the online courses and coaching sessions that SWICA supports.

All coronavirus offers 

Getting medical support and recommendations for symptoms

Staying fit and healthy at home: Tips and offers

Personal training: Why you will reach your goals more quickly

Nutrition: Tips for the immune system and offers for at home

Resilience: Strengthen your mental immune system