Support your immune system with good nutrition

How our bodies fight off diseases has gained more attention recently since the unprecedented global pandemic hit. The immune system is the intricate mechanism your body uses to fight off diseases and foreign invaders. Your diet and lifestyle can greatly affect your immune system, Jessica Pieterse tells us how.

Vitamin D

Vitamin D has always been a large role player in immune health. Receptors of vitamin D have been identified on several immune cells; in addition, they regulate the immune system by suppressing the pro-inflammatory molecules.

To improve your vitamin D levels, spend 15-20 minutes daily in the sun with as much skin exposed as possible. It must be from direct sun exposure and not through any windows. To get as much vitamin D, avoid applying sun cream, however, being sun smart is just as important. Eat more foods that contain vitamin D, such as liver, mushrooms, whole eggs, salmon, mackerel, and cod liver oil. Take a supplement if you know you are deficient. It is best if your health practitioner monitors your vitamin D levels annually and regulates your supplementation.

Gut bacteria

We have billions of bacteria making their home in our gut. Gut bacteria can be helpful or harmful depending on the type of bacteria. If a person has a healthy balance of the good bacteria, it can be vital in supporting immune health. Good bacteria fight harmful foreign substances that enter the body by detoxifying them and easing their elimination. Bacteria can also stimulate immune cells and affect gut lining integrity.

Ways to improve your gut bacteria balance is to take a good quality probiotic supplement, increasing prebiotic fibres, adopting a balanced healthy diet, reducing stress and improving sleep.

Good quality probiotic supplements contain several different strains of bacteria, have high doses of bacteria (at least 1 billion CFUs) and are stored in the refrigerator to keep bacteria alive. Take probiotics on an empty stomach so the bacteria are released further down the gut system and not in the stomach.

Most fruit, vegetables and wholegrains (barley, brown rice, oats) are sources of prebiotic fibres. Eating more of these foods will improve your gut bacteria balance. People suffering with IBS, be cautious. Some prebiotic fibres can worsen IBS symptoms so it’s best to seek individualised advice from your health practitioner.

Antioxidants, vitamins and minerals

Many supplements marketed to improve your immune system will contain a variety of vitamins, minerals and antioxidants. Antioxidants help by reducing oxidative stress. Eat more cocoa, red grapes, berries, herbal teas, turmeric, olive oil and pomegranates to boost your antioxidant intake.

The main vitamins and minerals that support your immune system are vitamin A, C, E, D, selenium and zinc. They each play a unique role. One vitamin or mineral is not a magic pill for avoiding getting sick. To clean your house, you can’t just use a broom; you also need a mop, cloth, water, and a bucket to do a good thorough job. Your immune system is the same. Many different vitamins, minerals and substances are needed to protect your body. They all play a part in the big picture.

Eat more beans, chickpeas, lentils, salmon, pilchards, fish, oysters, nuts, seeds, sweet peppers, strawberries and orange fruit and vegetables to improve your intake of these key nutrients.


Being active can improve your immune system. It is interesting to note that very high amounts of exercise can potentially strain your immune system and have the opposite effect. That is why it is common to hear of many Comrades runners getting sick right before the race as they are extensively exercising at that point.

Aim for 30-45 minutes of exercise 3-4 times a week of varying intensities as a gauge. Exercise that lowers stress levels will have further beneficial impacts.


Most people are told when they are sick to sleep more. This is not just an old wife’s tale but is correct. While you sleep, your body releases certain immune and inflammation molecules which affect your immune health.

Aim to improve how long you sleep and the quality of your sleep. Make these changes to improve your sleep.

  • Avoid digital devices an hour before sleeping.
  • Make your room dark and cool enough.
  • Avoid drinking liquids too late at night.
  • Reduce your caffeine intake.
  • Be more active.

Do a relaxing activity before sleep like reading, deep breathing, prayer or mediation.


Jessica Pieterse is a registered dietitian and owner of Dish Up Dietitians. She practices in Edenvale, Johannesburg and has a special interest in women’s health and gut health.

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