Food as Medicine – Can we Eat to Treat ?

With winter taking its toll on our health, can we rely on food to fight colds and flu? The first most important step is to always consult your doctor. However, in cases where prescription medication is not required, there are some foods and nutrients that can support the immune system in fighting colds and flu.

The desire for self-improvement and the growing access to online healthcare information has fuelled the health trend of self-diagnosis and self-treatment globally. In the UK, health searches online have increased by 13.5%1 and, according to Vitafoods Insights, NMI research shows that more than a quarter of Americans believe functional foods and beverages can be used in place of some medicines.2 The second most desired functional benefi t is immune support.3


We’ve been told to feed a cold and starve a fever, and that chicken soup is the best meal during illness. While there is no known cure for the common cold, we do know that certain natural remedies and even foods can help bring relief from certain symptoms.



Chillies (Capsicum frutescens) are rich in a component called capsaicin, which is responsible for the burning sensation when you eat them. It’s this very same characteristic of chillies that contributes to their role in the management of colds and flu. Eating chillies can cause a runny nose, which thins mucous secretions, potentially helping to relieve mucous congestion. Chillies may also support the immune system.4

The antiviral potential of capsaicin was shown in animal studies, where it offered protection against the herpes simplex virus. Other laboratory studies have shown changes in immune cell activity and increased immune cell production in the presence of capsicum.5

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Uncooked chillies, as well as sweet red peppers, are also among the foods with the highest concentration of vitamin C. Vitamin C is known to help in the fight against flu by supporting the immune system, as well as helping to reduce the severity and possibly also the duration of the common cold.6


Ginger is known to have expectorant properties, helping to expel mucus from the respiratory system. When eaten, ginger’s aromatic properties open your sinuses, an action attributed to constituents called shogaols and gingerols, which also have circulatory stimulant properties.8

Despite its hot taste, ginger has anti-inflammatory properties, which combat the pain-causing inflammation of sore throats, colds and sinus congestion. With ginger’s stimulating effects on blood circulation, it also supports toxin removal and increased oxygen supply to the tissues, further assisting with healing. What’s more, ginger has febrifuge or antipyretic properties – thus helping to bring down fevers.


Garlic is probably the most well-known of all flu-fighting foods. It contains healing components of which the most well-known is allicin, which is also responsible for garlic’s characteristic pungent odour.9

Preliminary research shows that taking a garlic supplement can help prevent and also shorten the duration of a cold.10,11 This is believed to be because of garlic’s antimicrobial, and particularly antiviral, properties.12 Antiviral activity against a variety of well-known influenza, rhinovirus and herpes simplex viruses effects have been linked to garlic compounds, including ajoene, allicin, allyl methyl thiosulfinate and methyl allyl thiosulfinate.13

In addition to garlic’s direct antiviral effects, it is also believed to help fight infections through its stimulating effects on the immune system. Research suggests that garlic oil enhances the production and activity of lymphocytes and other immune cells and factors.14 The garlic constituent allicin appears to increase the phagocytic function of key immune cells such as leukocytes and monocytes.15


The antimicrobial properties of honey are well known in the support of wound healing. It is also believed that raw unadulterated honey has immune-stimulating properties. Interestingly, honey has received some attention because it seems to have a soothing effect on sore throats and may even help reduce coughs. Preliminary research has shown that honey can help to reduce coughing in children by soothing an irritated throat, more effectively than cough medicine.16,17


In addition to the active components found in foods, certain vitamins and minerals are also well known for their immune support benefits.

Vitamin C

A meta-analysis of studies have concluded that vitamin C supplementation reduced the duration and severity of cold and flu symptoms. 18 In fact, the majority of evidence shows that taking high doses of vitamin C orally might decrease the duration of cold symptoms by one to one and a half days.19

Since our immune system is responsible for protecting our bodies against invading viruses and bacteria, it comes as no surprise that vitamin C’s actions are directly focused on the immune cells. According to test results published in Advances in Experimental Medicine and Biology, there is up to 100 times more vitamin C in our white blood cells, compared to the plasma (the fluid component) of our blood.20 Vitamin C has also been shown to increase the numbers and activity of our immune cells, as well as protecting our immune cells against premature degeneration.21


Zinc is known to stimulate the immune system through increasing immune cell production, as well as immune cell activity. Zinc is particularly important for neutrophils (natural killer cells) and T-lymphocyte function.22 Even mild zinc deficiency may adversely affect immune T-cell functions.23

Even though there is limited evidence, zinc has been shown to help fight the common cold. A dose of 9 to 24 mg zinc per day is recommended to help reduce cold duration.24 Select studies show reduced incidence in colds in children and adults.25

The mechanism of action is believed to be through the antimicrobial effects of zinc. As an antiviral agent, zinc helps to reduce viral load and prevents viral absorption to body cells.26 Zinc also shows antibacterial effects by reducing bacterial replication.27

Vitamin D

Epidemiological evidence suggests that vitamin D levels are associated with respiratory function. People with higher levels seem to have greater pulmonary function compared to people with lower levels. It is even believed that vitamin D may be involved in repair of lung tissue.28 Vitamin D may also decrease immune-mediated inflammation in the respiratory system.29 Population- based study results suggest patients with low vitamin D levels are 27 to 55% more likely to have upper respiratory tract infections compared to patients with normal levels.30


Selenium is needed for the proper functioning of neutrophils, macrophages, NK cells, T-lymphocytes, and other immune mechanisms, mainly as a constituent of selenoproteins. 31 Selenium may support immune function through improved T-lymphocyte responsiveness. 32 In human research, selenium supplementation has been shown to increase immune cell activity.33

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These flavourful flu shots are packed with immune-boosting nutrients, antimicrobial properties, and pain-relieving and decongestant effects.

Red hot flu-fighting shot


  • 1 crushed garlic clove
  • 30 ml fresh lemon juice
  • 1 tsp honey
  • ½ tsp lemon zest
  • 1 level tsp finely grated or chopped fresh ginger
  • 1 red chilli, finely chopped


Combine all the ingredients in a small glass and drink it all in one go. If you have a very sore throat, you may want to try the milder version:

Soothing flu shot


  • 1 crushed garlic clove
  • 25 ml fresh orange juice
  • 1 tsp honey
  • 1 tsp finely grated or chopped fresh ginger


Combine all the ingredients in a small glass and drink it all in one go.


It is always best to consult your doctor first to find out if medical treatment is required. However, in cases where medical treatment is not required, it would be wise to indulge in the knowledge and pleasure of immune support foods.

A list of references is available from the Natural Medicine® office. Tel: 021 8801444.


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Food as Medicine – Can we Eat to Treat ?

Andrea du Plessis
About The Author
- Andrea is a registered dietician. Following her initial career as a consulting dietitian, she furthered her studies in the field of sports nutrition with a Master’s degree in Sports Science. As nutrition expert, she has a passion for healthcare through nutrition, natural remedies and an active lifestyle.