From orange juice and chicken soup to zinc lozenges and garlic supplements, home remedies for the common cold are abundant.

But how effective are they in reality? Can these remedies truly alleviate symptoms, or are they simply comfort foods with no medical backing?

The Mechanics of Fighting a Cold

The common cold, caused by roughly 200 different viruses, is a universal experience. When a virus invades the body, it encounters two layers of defense: the innate immune system, which attempts to expel the intruder, and the adaptive immune system, which specifically targets pathogens the body has encountered before. However, the common cold virus constantly mutates, eluding the memory cells of the adaptive system, which is why it recurs multiple times a year.

While lifestyle and diet undeniably influence the immune system, the question remains whether popular remedies can actually enhance immunity to ward off a cold. Some remedies are also widely promoted for their ability to bolster immunity during more severe outbreaks, such as the coronavirus pandemic. But what does the evidence say?

Garlic and Other Supplements

Garlic has long been touted for its health benefits, including its potential to combat colds. A study involving 146 adults found that those taking a daily garlic supplement for 12 weeks during winter experienced fewer colds and shorter periods of illness compared to those given a placebo. Garlic's potential to strengthen the immune response suggests it may help prevent colds rather than cure them.

Other supplements can also play a role. A multivitamin containing a range of nutrients like vitamins A, C, D, and zinc was found to reduce both the frequency and severity of cold symptoms in a study conducted over two winters. However, experts caution that supplements are only effective if there is an existing deficiency in essential nutrients. For individuals with a balanced diet, adding supplements may not significantly enhance immune efficiency.

Does Vitamin C Work?

Vitamin C is a common go-to remedy for colds, with evidence suggesting it can slightly reduce the severity of symptoms such as runny nose and sore throat. A review from 2023 found that vitamin C supplements decreased the severity of cold symptoms by about 15% and had a more pronounced effect on severe cases. However, regular dietary sources like orange juice may not provide sufficient vitamin C to replicate these effects, as they typically contain lower doses than supplements.

The Role of Zinc

Zinc lozenges have also been studied extensively, with evidence showing they can reduce the duration of cold symptoms, such as sneezing and coughing, by up to a third. To be effective, these lozenges need to dissolve slowly in the mouth, delivering the zinc directly to the throat region. However, the dose and duration of treatment matter; some studies indicate that lower doses or shorter treatment periods may not yield significant results.

Placebo Effects and Comfort Foods

For remedies like chicken soup, the scientific evidence is limited. However, the psychological comfort they provide should not be underestimated. The placebo effect—where a belief in a remedy’s efficacy can lead to improved symptoms—plays a significant role in the perceived effectiveness of many home remedies. Studies show that people who believe in the healing power of certain foods or supplements, such as echinacea, often report milder symptoms, even if the actual substance has no direct medicinal effect.

Similarly, childhood associations with comforting foods, such as chicken soup prepared by a parent, can enhance the placebo effect, creating a sense of care and well-being that alleviates symptoms.

Genes and Individual Differences

The susceptibility to colds and the severity of symptoms are also influenced by genetic factors. Some individuals are genetically predisposed to respond more strongly to certain viruses, while others may experience only mild symptoms or none at all. This genetic variability means that remedies effective for one person may not work for another.

The Verdict

For those with a healthy immune system, home remedies like chicken soup or orange juice are unlikely to cure a cold but can provide comfort and potentially ease symptoms through the placebo effect. Supplements like zinc lozenges or garlic may offer some benefit, particularly if taken early in the illness. However, the most important factors in combating colds remain overall immune health, lifestyle habits, and genetics. While remedies may provide short-term relief, their effectiveness varies from person to person, making them a supportive, rather than definitive, solution for winter illnesses.