The common cold is an infection of your nose and throat caused by viruses. We typically catch between two and four colds a year.
Symptoms of the common cold, which usually appear one to three days after being exposed to a cold virus, include:
- Runny nose
- Nasal congestion
- Sore or itchy throat
- Watery eyes
- Mild headache
- Mild fatigue or body aches
- Fever less than 102 degrees
Here is a look at eleven of the more popular natural remedies for the prevention and treatment of the common cold. In addition to these remedies, certain foods may also help to boost the immune system and additional remedies may be recommended for cough relief and post-nasal drip.
1) Zinc Lozenges
Zinc is an essential mineral that is required by more than 300 enzymes in our bodies. It’s found naturally in foods such as meat, liver, seafood and eggs. The full recommended daily allowance (RDA) is 12 mg for women and 15 mg for men, an amount found in a typical multivitamin.
Zinc lozenges are often found in health stores, online and in some drug stores marketed as cold remedies. A number of studies have found that zinc helped to reduce the duration of cold symptoms, especially if people started taking it within 24 hours after the appearance of cold symptoms. Zinc also reduced the severity of symptoms and decreased the duration of symptoms by three to four days. The problem is that many of these zinc studies have had flaws, so better-quality studies are needed. Zinc lozenges may work by blocking the replication of the cold virus (preventing it from spreading) or by impairing the ability of the cold virus to enter cells in nose and throat.
The zinc lozenges used in the studies contained a minimum of 13.3 mg of elemental zinc. The lozenges were taken every two hours during the day, starting immediately after the onset of cold symptoms. The studies that found zinc to be ineffective may have used a dose of zinc that was too low or have had taste-enhancing compounds known to decrease the effectiveness of zinc, such as citric acid (found in citrus fruit), tartaric acid, sorbitol or mannitol.
Zinc lozenges usually contain either zinc gluconate or zinc acetate, providing 3.3 mg of elemental zinc in each lozenge. It's typically recommended that people take one lozenge every two to four hours during the day for a maximum of six to 12 lozenges a day.
Side effects of zinc may include nausea and an unpleasant taste in the mouth. Zinc lozenges are not recommended for the prevention of colds or for long-term use, because zinc supplements in excess of 15 mg per day may interfere with the absorption of the mineral copper and result in a copper deficiency.
More about zinc for colds.
2) Vitamin D
There is some evidence suggesting that people with higher levels of vitamin D may have a reduced risk of catching the common cold. Read more about vitamin D and the common cold.
Astragalus root has long been used in traditional Chinese medicine to strengthen immunity and prevent colds and flu. Studies have found that astragalus has antiviral properties and stimulates the immune system, although there have been no clinical trials examining the effectiveness of astragalus against colds in humans.
Astragalus is also an antioxidant and has been suggested for conditions such as heart disease. It's being investigated as a possible herbal treatment for people with health conditions that weaken their immune systems.
Astragalus can be found in capsule, tea or extract form at health food stores or as a dried root in Chinese herbal shops and some health food stores. The dried root can be difficult to find.
Traditional Chinese medicine practitioners usually recommend taking astragulus to prevent colds and to avoid it if you're already sick. A bowl of soup boiled with astragalus root is often recommended once or more per week throughout the winter to prevent colds.
Astragalus may increase the potency of antiviral medications such as acyclovir or interferon, thereby worsening the potential side effects of these drugs (such as possible kidney failure and other side effects). It could also possibly counteract immune-suppressing drugs such as cyclophosphamide (Cytoxan, Neosar) or corticosteroids. It may lower blood glucose or blood pressure, increasing the effects of blood pressure or diabetes medications.
Garlic is one of the more popular home cures for colds. Many cultures have a home remedy for the cold using garlic, whether it’s chicken soup with lots of garlic, a drink made with raw crushed garlic, or if it just involves eating raw garlic.
The cold-fighting compound in garlic is thought to be allicin, which has demonstrated antibacterial and antifungal properties. Allicin is what gives garlic its distinctive hot flavor. To maximize the amount of allicin, fresh garlic should be chopped or crushed and it should be raw. It’s also available in pill form.
In one study involving 146 people, participants received either a garlic supplement or a placebo for 12 weeks between November and February. People who took garlic reduced the risk of catching a cold by more than half. The study also found that garlic reduced the recovery time in people who caught a cold. More research is needed to corroborate these results.
Garlic does have some possible side effects and safety concerns. Bad breath and body odor are perhaps the most common side effects, however, dizziness, sweating, headache, fever, chills and runny nose have also been reported. Large amounts may irritate the mouth or result in indigestion. Garlic supplements should avoided by people with bleeding disorders, two weeks before or after surgery, or by those taking "blood-thinning" medications such as warfarin (Coumadin) or supplements believed to affect blood clotting such as vitamin E, garlic or ginkgo.
Garlic may also lower blood glucose levels and increase the release of insulin, so it should be used with caution by people taking drugs that lower blood sugar. People with allergies to plants in the lily family (including onion, leeks and chives) should avoid garlic. Pregnant women should avoid garlic in supplement form because it may increase the risk of bleeding. More about garlic for colds.
5) Vitamin C
In 1968, Linus Pauling, PhD, proposed the theory that people had individual requirements for various vitamins and some needed amounts higher than the recommended dietary allowances (RDAs). Pauling proposed that 1,000 mg of vitamin C daily could reduce the incidence of colds for most people. Since then, vitamin C has become a popular cold remedy.
A review by the Cochrane Collaboration examined whether vitamin C taken orally in doses of 200 mg or more a day could reduce the incidence, duration or severity of the common cold. The researchers analyzed 30 previously published studies (involving a total of 11,350 participants) that met their quality criteria. They found that vitamin C didn’t appear to prevent the common cold. There was a slight reduction in the length and severity of cold symptoms. It appeared to markedly reduce the risk of catching a cold in people involved brief, intense physical activity (such as marathon running or skiing), or in those exposed to cold temperatures.
Vitamin C in amounts over 2,000 mg may cause diarrhea, loose stools and gas.
More about vitamin C supplements.
Honey is a popular home remedy for cough and colds in many cultures. A new study in the Archives of Pediatrics and Adolescent Medicine provides the first evidence showing that honey may help to calm children's coughs and help them sleep better. Researchers gave 105 children with colds eith honey, honey-flavored cough medicine or no treatment. All of the children got better, but honey consistently scored best in parents' rating of their children's cough symptoms.
The researchers say that honey may work by coating and soothing an irritated throat and it’s believed to have antioxidant and antibacterial effects. Dark-colored honey, such as the buckwheat honey used in the study, is particularly high in antioxidants.
Honey isn't recommended for infants younger than one year old, because of the risk of botulism. Regular use of honey at night may also promote the development of cavities.
More about honey for coughs.