Common cold: Strengthening the immune system

How micronutrients strengthen the immune system

The viruses which cause an flu-like infection or common cold enter the body through the mouth or nose and trigger the typical symptoms: Coughing, runny nose, hoarseness, headaches, sore throat and aching limbs. Certain types of micronutrients can help strengthen the immune system. This helps the immune system defend against viruses and bacteria more effectively. Find out which types of micronutrients support the body's own defenses and how best to use them in the context of micronutrient medicine. 

Woman suffering from a cold, sitting in bed holding tissues
Coughing, runny nose, sore throat, and hoarseness are all typical symptoms of a common cold triggered by viruses. Image: KatarzynaBialasiewicz/iStock/Thinkstock

Causes and Symptoms

The common cold is an infectious disease, which in most cases is triggered by viruses. There are more than 200 different types of common cold viruses. The most common are the rhinoviruses. They infect the respiratory tract: These viruses enter the body through the mouth or nose and cause the typical symptoms such as coughing, sore throat, runny nose, and hoarseness. Pressure in the ears, fever, and watery eyes are all symptoms related to the common cold.

Contrary to what the name suggests, the cause of the common cold is not cold weather though it is a contributory factor. Studies have shown that the immune system works less effectively at cold temperatures, leading to a weakening of the body's defenses.  

Due to the fact that the symptoms of the common cold and flu are similar, a common cold is also known as an flu-like infection. Unlike real flu, a flu-like infection is not triggered by the flu virus and its effects are generally much milder.

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Aim of the treatment

What is the standard treatment for a common cold?

The body can recover unaided from a flu-like infection: Immune cells search for and neutralize pathogens like the common cold virus.

This is why the classic treatment for a common cold focuses mainly on relieving the symptoms. Nasal sprayscontaining an anti-swelling agent help treat the nasal symptoms of a common cold. Expectorants expectorants make it easier to cough up the mucus. Headaches and fever are treated using medications which, for example, contain the active pharmaceutical ingredient paracetamol.


Antibiotics are not suitable for viruses which cause the common cold. Antibiotics can be used to treat bacterial infections, but not flu or the common cold. With one exception: When viral infections weaken the immune system, it is easier for bacteria to enter the body. In the event of a secondary bacterial infection (known as a superinfection) antibiotics will be administered.

The aims of micronutrient medicine

Micronutrients are an excellent way to prevent and treat the common cold. With the help of vitamins and trace elements, the aim is to strengthen the immune system and help improve the body's ability to defend against pathogens. Mustard oils likely have a direct antiviral effect.

Micronutritionists will most commonly recommend a micronutrient compound which contains all the important vitamins and minerals for the immune system, such as vitamin C, vitamin D, and zinc. Substances which help remove mucus and reduce inflammation with natural enzymes are recommended for the treatment of the common cold: They help reduce the symptoms.

Prevention: A strong and well-functioning immune system also works preventively as it helps defend against pathogens from the outset.  

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Treatment using micronutrients

Vitamin C controls the immune system defenses

How vitamin C works

Vitamin C helps the body's defenses by protecting the immune cell membranes and thereby increasing their longevity. Additionally, vitamin C controls the body's defensive reactions toward pathogens. One of its roles is to ensure that certain chemical messenger substances are released. These attract the immune cells to the location of the inflammation to neutralize the pathogen - for example, to the mucous membrane in the throat.

Vitamin C: Dosage and recommended use of treatment of the common cold:

Vitamin C in capsular form and in a lemon
Taking vitamin C strengthens the immune system and supports the body's own defenses. Image: KMNPhoto/iStock/Thinkstock

For the common cold, it is recommended to take between 1,000 and 6,000 mg of vitamin C through food, tablets, capsules, or powder for five to seven days. The total amount should be split into several portions (e.g., 2 x 3 grams).  Some micronutritionists administer vitamin C directly into the vein (infusion): Between 7.5 and 30 milligrams of vitamin C dissolved in saline solution is advisable two to four times a week.

Treatment should begin within the first 24 hours after the onset of the symptoms of the common cold.


Due to the fact that vitamin C is heat-sensitive, when drinking, for example, a hot lemon drink, make sure you don't leave it for too long in the hot water. It is better to choose a vitamin C supplement which does not need to be dissolved in hot water.

Zinc develops immune cells

How zinc works

Zinc supports the body's own defenses on many levels and ensures that the defensive processes are working. It also protects tissue from damage caused by inflammation. A zinc deficiency means that the immune cells are less active, making it easier for viruses and bacteria to enter the body. 

  • Better Cures: Zinc - at a dosage of 75 milligrams per day -triples the chance of recovering on, for instance, day five of the common cold.
  • Faster Recovery: The duration of an illness can be shortened from ten days to six or seven.
  • Milder Symptoms: A study has shown that zinc is able to reduce the symptoms of the common cold, such as fever and a general feeling of being unwell, in children with respiratory infections. However, the study only showed this effect in boys, not girls.

At low doses, zinc can also prevent the common cold from developing.  

Zinc: Dosage and recommended use of treatment of the common cold:

Treatment should begin within the first 24 hours after the appearance of the symptoms of the common cold using between 75 and 100 milligrams of zinc per day. To treat the common cold, it is also recommended to take 10 milligrams of zinc per day in the form of lozenges or effervescent tablets for a period of between 5 and 7 days. During the studies, the children received a dosage of 30 milligrams per day.

Ideally, zinc should be taken as a preventative measure (5 to 15 milligrams per day).


Zinc lozenges are especially recommendable when suffering from the common cold: Sucking of the lozenge allows the zinc to be delivered directly to the focus of the inflammation, the mucous membrane of the throat. The sucking motion also increases hydration of the mucous membranes. Hydrated and wet mucous membranes can better fulfill their function of acting as a protective barrier and make it more difficult for viruses to enter the body

Instructions if taking other medication or if suffering from kidney disease

Zinc can reduce the effectiveness of certain types of antibiotics containing the active substance tetracycline. If you have to take antibiotics to treat a bacterial infection, make sure to have a break of two hours after taking zinc before taking the antibiotics or four to six hours before taking zinc after antibiotics.

Medication for osteoporosis (bisphosphonate) will be chemically bound to zinc, which in turn makes the medication ineffective. These include Alendronate or Clodronate. Between doses there should be a period of at least two hours.

Zinc supplements should not be taken if kidney function is impaired. Weakened kidneys are not able to fully excrete zinc causing the zinc levels in the blood to increase.

Vitamin D activates immune cells

Illustration of various viruses
Vitamin D can help the body destroy pathogens and protect against illnesses of the respiratory tract. Image: Rost-9D/iStock/Thinkstock

Vitamin D (colecalciferol) plays an important role for the immune system. It is necessary to change certain types of precursor cells into scavenger cells, called macrophages. Scavenger cells track down pathogens in the body and destroy them. Vitamin D also ensures that T cells destroy bacteria and viruses. Firstly, T cells must be awoken from a dormant state. Vitamin D destroys large amounts of pathogens which means that the viruses which trigger the common cold find it more difficult to spread throughout the body.

There is evidence that severe respiratory infections are connected to low vitamin D levels. A study shows that half of the children that had to visit a hospital due to a respiratory infection showed a vitamin D deficiency. The children with vitamin D deficiency were also at a higher risk of requiring intensive medical care or artificial respiration.

Vitamin D: Dosage recommendation to treat the common cold:

Studies have shown that taking vitamins can prevent respiratory infection, like the ones caused when suffering from the common cold. This applies in particular to those who are more prone to infection. 4,000 IU (International Units) have been shown to be a successful dosage.

In the case of frequent infections, the vitamin D level in the blood should be controlled and a deficiency consistently treated.

Blood test to establish your vitamin D level

We can obtain vitamin D from our diet. However, the majority of our vitamin D is produced by the body itself. The body requires sunlight to produce vitamin D. Especially during the winter months there is not enough sunlight available for the body to produce vitamin D, this makes it easy for a vitamin D deficiency to develop. Depending on the time of year, approximately between 60 and 80 percent of people do not have optimal vitamin D levels.

Therefore, it recommendable to undergo vitamin D level testing. A blood serum is used to determine the calcidiol (25-OH-Vitamin-D) levels, which is the transport agent for vitamin D. A level of less than 20 nanograms per milliliter is considered insufficient. For optimal health-related benefit, micronutritionists recommend a level of between 40 and 60 nanograms per milliliter.

Bromelain and Papain both help strengthen the body's immune defenses.

Tropical fruits
Bromelain and Papain can be obtained from tropical fruits. Both of these enzymes help strengthen the immune system and reduce the risk of illnesses becoming chronic. Image: billberryphotography/iStock/Thinkstock

How they work: Bromelain reduces mucus levels.

Bromelain is an enzyme that comes from pineapple. Papain, on the other hand, comes from the skin of the papaya. Both enzymes are involved in the control of the immune system: They help boost immune reactions if they are too weak. the symptoms of a flu-like infection subside more quickly, while the risk of the conditions becoming chronic, such as chronic bronchitis, is also reduced.

Both enzymes also help reduce swelling of the nasal mucous membrane and help remove built up mucus. This helps clear up a blocked nose. A high-quality comparative study found that children with a sinusitis recovered more quickly when given bromelain. Papain has pain-reducing and anti-inflammatory properties when used to treat symptoms of the common cold, such as a blocked nose and headache.

Bromelain: Dosage and recommended use of treatment of the common cold:

A dosage of between 500 and 2,700 milligrams of bromelain per day and 540 to 1,000 milligrams of Papain per day is recommended for the treatment of the common cold. The doses of these substances should be spread throughout the day and between meals: at least one hour before and two hours after eating. Ensure the highest possible enzyme activity per capsule or tablet. This is listed in FIP units. At least 1,000 FIP per tablet or capsule is recommended.


Ensure the highest possible enzyme activity per capsule or tablet. This is listed in FIP units. At least 1,000 FIP per tablet or capsule is recommended.

Instruction if taking antibiotics or during pregnancy

If you are required to take antibiotics to treat a bacterial infection, avoid taking bromelain. Concomitant use influences the effectiveness of the antibiotics.

There is currently not enough suitable study literature dealing with the use of bromelian during pregnancy or when breastfeeding. Talk to your doctor beforehand.

N-acetyl cysteine helps remove mucus.

How it works:

Woman coughing during a medical examination
N-acetyl cysteine promotes the clearance of mucus and aids the mucous membranes with their self-cleaning process. Image: AlexRaths/iStock/Thinkstock

N-acetyl cysteine helps the body remove mucus and is used, for example in the treatment of bronchitis. A study carried out with small children who had been admitted to the hospital suffering from viral bronchitis was able to show that the children who had been administered N-acetyl cysteine had less severe symptoms and were able to be discharged from the hospital earlier. N-acetyl cysteine also helps thin the mucus and thereby aids the self-cleaning function of the mucous membrane. This helps the mucus to be expelled via the nose.

N-Acetyl Cysteine: Dosage and recommended use of treatment of a common cold:

It is recommended to take between 200 and 400 milligrams of N-acetyl cysteine per day to treat the common cold, such as in capsules.

High doses may trigger nausea and stomach discomfort in more sensitive people.

Instructions if taking cough medicine and during pregnancy

Medication which suppresses the cough reflex (antitussives) should not be taken together with the expectorant N-acetyl cysteine This can cause a mucus build-up in the lungs as the mucus is unable to be coughed up.

Consult with your doctor before taking N-acetyl cysteine when pregnant or breastfeeding. There is currently not enough suitable study literature regarding the application of the substance.

Beta-glucan helps jump start the immune system.

How it works:

Fresh and dried yeast on a wooden board
Beta-glucans, which are extracted from yeast, trigger the defense reaction against viruses which cause the common cold. They can also have an overall positive effect on the patient's condition. Image: jirkaejc/iStock/Thinkstock

Beta-glucan comes from yeast and is an indigestible substance which activates the immune system and thereby sets the defensive reactions against cold viruses in the mucous membranes in motion. Beta-glucan affects the body's immune cells and also helps with the development of antibodies. It activates the natural killer and scavenger cells which effectively kill and remove virus-infected cells.

Studies have shown that the intake of beta-glucan from yeast has beneficial effects on the overall condition of those suffering from the common cold. Further tests have shown that test groups who had been taking beta-glucan from yeast had less common cold symptoms and felt generally more fit and better than those people who had been given a placebo. Beta-glucan can also help with common-cold related sleep problems.

Beta-Glucan: Dosage and Recommended Use

To treat the common cold, 250 milligrams of beta-glucan per day in capsule form is recommended. Beta-glucan has been shown to be very well-tolerated by the body.

Nasturtium and horseradish act like natural antibiotics:

How it works:

Mustard oils are plant substances which are found in nasturtium and horseradish. They have an anti-bacterial effect. They are particularly effective in the treatment of urinary and respiratory tract infections. They can also help stop the development of secondary bacterial infections: They are, in a sense, plant-based antibiotics. Studies show that they work in an effective and safe way against germs. The advantage of the active ingredients in nasturtium and horseradish is that, in contrast to antibiotics, bacteria develop resistance against them.

Along with their antibacterial effects, there is evidence that mustard oils also help against viruses which cause the common cold. In the field of phytomedicine (phyto=substances from plants), nasturtium and horseradish have long been used in the treatment and prevention of the common cold.

Nasturtium and Horseradish Dosage and recommended use of treatment of the common cold:

To treat the common cold, 2,500 milligrams of nasturtium and 500 milligrams of horseradish extract per day should be used. These can be taken in capsule form. The intake of these substances should be spread throughout the day and after meals.

Mustard oils are most effective when administered in a sufficient dosage by the first signs of the symptoms of the common cold.

Instructions during pregnancy or when breastfeeding

As there is currently insufficient study literature available on the use of nasturtium and horseradish during pregnancy and while breastfeeding, please consult your doctor beforehand. It is not known if mustard oils pass into breast milk.

Dosage overview

Vitamin C200 to 500 milligrams (mg) per day
Vitamin D31,000 to 4,000 International Units (IU) per day
Trace Elements
Zinc 20 to 25 milligrams per day
Other Substances
Bromelain500 to 2,700 milligrams per day 
Papain540 to 1,000 milligrams per day
N-acetyl cysteine200 to 400 milligrams per day 
Beta-Glucan250 milligrams per day 
Nasturtium 2,500 milligrams per day
Horseradish500 milligrams per day

Recommended Laboratory Tests

Recommended laboratory tests for frequent colds

Normal Values
Vitamin D (Serum)40 to 60 nanograms per milliliter (ng/ml)
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During a common cold or a flu-like infection, viruses infect the respiratory tract resulting in symptoms such as a blocked nose, coughing, sore throat, or fever.

Micronutrient medicine uses vitamins C and D and trace elements such as zinc along with beta-glucan to activate the immune system. An active immune system enables effective defense against the viruses which cause the common cold. Nasturtium and horseradish extract have a direct antibacterial and antiviral effect. Bromelain, papain, and N-acetyl cysteine help the body remove mucus and relieve a blocked nose. They also relieve the unpleasant symptoms of the common cold.

Also, vitamins C and D and the trace element zinc are recommended as a preventative treatment: This helps reduce the frequency of common cold and flu-like infections.

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Study and Source Index

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