Nutrition tips to prevent the common cold

November 25, 2002 in Healthy Eating, Nutrition for Children and Teenagers, Nutrition for Older Adults, Women's Health

Nutrition tips to prevent the common cold

The following text is an excerpt from Leslie Beck's Nutrition Encyclopedia (Prentice Hall Canada, 2001), available at bookstores across the country.

People seem to suffer from colds more often during the winter months. This is probably because the winter temperatures keep people indoors, where they are more likely to come into prolonged contact with other people suffering from cold viruses. As well, the many cold viruses survive better when humidity is low, which is normally during the colder months. It's also possible that cold weather dries out the lining of the nasal passages, making them more susceptible to infection. A cold will usually last from 4 to 10 days and is most contagious when the first symptoms appear, approximately 2 to 3 days after the infection was contacted.

A cold is the common name for a viral infection of the upper respiratory tract, which includes the sinuses, the lining of the nose, the throat and the large airways. There are over 200 different viruses that can cause a cold. Most colds are caused by rhinoviruses, but influenza and other respiratory viruses can also be the culprits. Because these viruses are so widespread and varied, conventional medicine has been unable to cure or prevent the common cold.

Cold viruses can be spread very easily. When someone coughs or sneezes or even talks, viruses are spread through the air. Inhaling the contaminated droplets allows viruses to enter the nose and infect the nasal membranes. Cold viruses can remain infective for several hours outside the body, which means that the viruses can also be spread by direct and indirect contact. Rubbing your nose or eyes after touching an object that has been contaminated with saliva or nasal secretions (door handles, toys, used tissue) will transfer the virus. Even shaking hands with someone who has a cold can expose you to infectious secretions.


  • Sore, scratchy throat; cough
  • Husky voice
  • Sneezing; runny nose
  • Mild feeling of illness
  • Tired and achy
  • Headache
  • Watering eyes

Who's at risk?

  •   Children have more colds more often than adults
  • Women, possibly because of their close contact with children or the effect of their menstrual cycle
  • People who are fatigued, stressed or have allergies of the nose and throat


Prevention strategies

Good personal hygiene will help protect you, your family, and your coworkers from cold viruses:

  • Wash hands thoroughly and frequently
  • Cover your mouth when coughing or sneezing, preferably with a tissue
  • Clean surfaces that you touch with germ-killing disinfectant
  • Avoid rubbing your eyes and nose with dirty hands
  • Eat a nutritious diet
  • Get plenty of sleep
  • Avoid drinking alcohol
  • If possible, avoid crowded places or close contact with people with colds
Vaccines to prevent influenza are readily available. However, because there are so many types of cold viruses, it is impossible to prevent most colds with a vaccine.


Treating your cold with foods and nutrients

Drink plenty of fluids. During a cold, drink at least 8 cups (2 litres) of fluid per day to prevent dehydration and constipation. Hot fluids are most effective for alleviating nasal congestion. Drink hot water, hot tea, soups, and broths. Fluid also helps keep the lining of the respiratory tract moist which can ease the symptoms of a sore throat.

Drinking plenty of fluid each day is also an important way to help prevent the common cold. When you are dehydrated, tiny cracks form in your nasal membranes. These cracks allow virus filled droplets to take up residence and promote infection. Always consume 8 to 12 glasses of fluid daily.

Reach for chicken soup. Research from Mount Sinai Hospital in Miami, Florida suggests that chicken soup may help treat a cold. A compound in the soup called cystine appears to have a decongestant ability. And it's thought that the spicier the soup the better. Hot peppers contain capsacian, a natural compound that has the ability to act as a decongestant.

Get a dose of healthy bacteria. Fermented milk products such as yogurt, kefir and acidophilus milk contain healthy bacteria called lactic acid bacteria that may help to prevent the common cold. Once ingested, these microbes take up residence in the gastrointestinal tract where they exert their health benefits. A number of studies have shown regular consumption of probiotic foods as well as probiotic supplement enhances the activity of the immune system. Recent research suggests that a deficiency of lactic acid bacteria in the intestinal tract of children may be responsible for viral infections of the respiratory tract.

Include one fermented milk product in your daily diet. To supplement, buy a product that contains 1 to 10 billion live cells per dose (capsule). Take 1 to 10 billions viable cells three times daily with food. Children's products are available on the market. These usually contain one-quarter to one-half half the adult dose (250 to 500 billion live cells).

Boost your vitamin C. So far over 60 studies have examined the effects of large doses of vitamin C on the common cold. While vitamin C supplements do not appear to prevent a cold, they do appear to reduce the duration and severity of symptoms. Studies have tested doses of 1000 milligrams and higher, more than 10 times the recommended daily intake. The greatest benefit is seem when a daily dose of 2000 milligrams (2 grams) or more is taken. Children, people under physical stress, and people with low dietary intakes of vitamin C tend to respond better to the nutrient.

Vitamin C promotes the body's production of interferon, a natural antiviral agent that fights infection. Vitamin C also has a slight antihistaminic effect. To treat a cold, take 1000 milligrams of time-released vitamin C twice daily. High doses of vitamin C can cause diarrhea, but this side effect resolves after continued use. You may have to build up to 2000 milligrams per day. Once your cold symptoms have subsided, return to a typical supplemental dose of 500 milligrams per day.

There is some concern that vitamin C supplements can cause kidney stones even though no studies have found this to be the case. Individuals with a history of kidney stones or kidney failure should restrict their intake to 100 milligrams per day.

Consider more vitamin E. Vitamin E does not treat a cold, but it may play a role in preventing one. Research in healthy older adults determined that a daily vitamin E supplement taken for one month improved the responsiveness of the immune system. Vitamin E appears to help certain white blood cells, called natural killer cells, fight infection. Vitamin E rich foods include wheat germ, nuts, seeds, vegetable oils, whole grains and leafy green vegetables. To supplement take 100 to 800 international units (IU) of natural source vitamin E. Buy a 'mixed' vitamin E supplement if possible. The daily upper limit is 1000 IU.

Go for zinc. Studies support the use of zinc lozenges to reduce the duration of cold symptoms. Compared to cold suffers taking placebo pills, those taking zinc gluconate or zinc acetate lozenges experienced faster recovery from coughing, sore throat, runny nose and headache. However, not all studies have found zinc lozenges to be effective. It has been suggested that this may be due to the chemical form of zinc used or the addition of certain flavouring agents that may interfere with zinc's activity.

When zinc lozenges are dissolved in the mouth, the zinc is released and attaches to cold viruses. By doing so, cold viruses are unable bind to cells in the mouth and throat and cannot cause infection. To treat a cold, take one zinc lozenge made of zinc gluconate or zinc acetate every two hours, for a total of five per day. More is not better since taking high doses of zinc can cause toxic effects. Once your cold symptoms have disappeared discontinue use of zinc lozenges.

It is important to ensure your daily diet contains zinc rich foods since the mineral is vital to a healthy immune system. Zinc rich foods include oysters, seafood, red meat, poultry, yogurt, wheat bran, wheat germ, whole grains, and enriched breakfast cereals. Your diet and a multivitamin and mineral supplement will provide all the zinc you need to stay healthy.

The herbal route

Echinacea. Many studies in the laboratory have shown the ability of echinacea to enhance the body's production of white blood cells that fight infection. Despite the positive results in the lab, clinical trials in adults taking echinacea to treat a cold or flu have not conclusively shown that the herb is effective, perhaps because so many different brands were used. However, a recent review of 16 studies conducted in 3396 participants found that most studies report a positive effect.

To ensure quality, buy a product that's standardized to contain 4 percent echinacosides (Echinacea angustifolia) and 0.7 percent flavonoids (Echinacea pupurea), two of the herbs active ingredients. Take a total of 900 milligrams three to four times daily. For fluid extracts (1:1) take 0.25 - 1.0 mL three times daily. For tinctures (1:5) take 1-2 mL three times daily. For teas take 125-250 ml three to four times daily. Take until symptoms are relieved then continue taking two to three times daily for one week. Don't use echinacea if you are allergic to plants in Asteracease/Compositae family (ragweed, daisy, marigold, and chrysanthemums).

Garlic (Allium Sativum). The sulfur compounds garlic have been shown to stimulate the body's immune system making garlic a potential agent in the prevention of colds. A number of studies have focused on the specific sulfur compounds in aged garlic extract, a special supplement that is aged for up to 20 months. Whether garlic actually heals to treat a cold, remains to be proven by clinical studies. However, the herb does have along history of use in the treatment of infection.

Use one-half to one clove each day in cooking. To supplement, buy a product made with aged garlic extract. Take two to six capsules a day in divided doses. Aged garlic extract is odourless and is less irritating to the gastrointestinal tract than other forms of garlic supplements (e.g. garlic oil capsules, garlic powder tablets).

All research on this web site is the property of Leslie Beck Nutrition Consulting Inc. and is protected by copyright. Keep in mind that research on these matters continues daily and is subject to change. The information presented is not intended as a substitute for medical treatment. It is intended to provide ongoing support of your healthy lifestyle practices.