Ask SciMoms: Do Cold Remedies Work?

various cold remedies including echinacea and cough syrup
Various cold remedies (image from pixabay)

When your child is young and gets a cold, it can be a huge challenge. Not only is there the challenge of having to care for your child, but seeing your child suffer without being able to help can feel heartbreaking. Most over-the-counter medications that offer relief for cold symptoms aren’t indicated for young children. So in an attempt to speed things along or help your child, it is natural to turn to advice and recommendations from friends. But do these cold remedies really work? Are they safe?

In this post, we’ll review some cold remedies we’ve heard of, for both children and adults, and dig to see if there’s any evidence to support them. Please note that none of the SciMoms are medical doctors: you should ALWAYS talk do your doctor if you have questions and the information in the post is not medical advice. We are reporting on the evidence we found for/against various remedies. 

Remedies

Elderberry Syrup or Elderberry Juice

Extracts from elderberry (also known as elder, European elder, or Sambucus) have been growing in popularity as a cold remedy or flu treatment. There have been a small handful of studies examining the efficacy of elderberry extract to prevent colds or the flu. However, the evidence is very preliminary and somewhat shaky. For example, the extract used in this study, which suggests that using elderberry can shorten the duration of a cold, included a large dose of magnesium. In this study, which suggests that elderberry can shorten the duration of the flu, the number of individuals included was very small. 

It is also worth noting that the findings from most studies I found did not support the idea that elderberry can prevent colds or the flu. However, the weak evidence that exists does indicate that it might help shorten the duration of these illnesses.

As with any bioactive substance, there are also potential risks to using elderberry, especially when prepared at home. In 1993, a group of individuals who had drunk elderberry tea got very sick with symptoms that included “nausea, vomiting, abdominal cramps, and weakness”. The NIH’s National Center for Complementary and Integrative Health highlights: “The leaves, stems, raw and unripe berries, and other plant parts of the elder tree contain a toxic substance and, if not properly prepared, may cause nausea, vomiting, and severe diarrhea. Because the substance may also be present in the flower, consuming large amounts of the flower might be harmful; however, no illnesses caused by elder flower have been reported.” 

The bottom line: Preliminary data suggests that elderberry might help with cold and flu symptoms. However, there is little/no data on efficacy or safety in children. Also, elderberry can be toxic, so extracts should not be prepared at home.

Zinc Lozenges

We all know someone who swears by zinc lozenges as a cold remedy. The good news is there are actually many studies on oral zinc supplements and their efficacy, including several meta-analyses. It is VERY important to note that these studies involve oral zinc supplements or zinc lozenges. Zinc nasal sprays are not safe: they are known to cause permanent loss of smell.

Zinc appears to reduce the duration and severity of cold symptoms if taken within 24 hours of onset of symptoms. The NIH’s National Center for Integrative and Complementary Medicine highlights that, although there have been studies in children, it may not be very effective because it needs to be taken frequently and there’s a risk of side effects.

There’s quite a list of potential side effects from zinc supplements, which include drug interactions (particularly with antibiotics), so please make sure you talk with your doctor before taking zinc. The most common side effects are a bitter taste in the mouth, nausea, and diarrhea. There are additional risks when taken for prolonged periods, which include copper deficiency, increased risk for urinary tract infections, and “reduced immune function,” among others. 

The bottom line: Zinc can reduce the duration of a cold if taken right when symptoms begin, but there are potential harmful side-effects. Because of known drug interactions, it is critical to talk to your doctor before taking zinc if you take other medications. 

Vitamin D Supplements

I recently heard about this one from my parents, who are living in Canada. They said that their health adviser suggested taking vitamin D supplements during the winter months to decrease their risk of getting colds. There are quite a few studies examining the impact of vitamin D on various health outcomes, most of which are summarized here. A recent meta-analysis that brings together data from various papers to create a more robust analysis, examined the impact of vitamin D on upper respiratory infections and found a protective effect in people with vitamin D deficiency. This effect was not seen in people who are not vitamin D deficient, so if this is protective it is not protective for everyone. In addition to this meta-analysis, most data regarding vitamin D and colds/flu is mixed and inconclusive.

In the United States, the CDC has found that approximately a quarter of individuals have inadequate, but not deficient, levels of vitamin D, (known as insufficiency). If you have a poor diet and are living a vampiric lifestyle without much exposure to sun, then there’s good reason to talk to your doctor about vitamin D supplementation, beyond upper respiratory infections. However, for the majority of individuals, their vitamin D levels are just fine and supplementation wouldn’t provide much of a benefit. While rare, it’s also possible to get too much vitamin D from so-called “megadoses” of the vitamin, so it’s important to avoid these large doses.

The bottom line: Vitamin D supplementation to restore adequate levels may help protect against colds in people with vitamin D deficiency. Data on whether this effect applies to people with vitamin D insufficiency or adequate levels of vitamin D is inconclusive. Data on effects in children is even more limited.

Echinacea

Ten years ago, echinacea was all the rage and was found in every herbal supplement as a guaranteed cold remedy to ward off the flu and shorten colds. To this day, extracts from the flower, which is related to daisies, are often found in teas. However, over the years studies have failed to find any demonstrated benefit for echinacea extracts as a means of preventing or shortening colds. 

Echinacea’s history is an interesting case study on supplements and herbal cold remedies. Often times, a supplement will become wildly popular based on limited data: studies with very few participants, results suggesting a weak impact, or studies that are poorly designed. Subsequent studies with adequate strength and proper design often demonstrate little/no impact. We have seen this story repeat itself with various vitamins, antioxidants, and supplements. This is not to say that FDA approved medications are all effective or free of side-effects. However, the bar set for the approval of drugs provides us with greater protection and more data on the safety and efficacy of treatments. 

The bottom line: There is little evidence supporting any benefit to using echinacea for preventing or shortening colds.

Honey

Honey with warm milk, honey with tea, or honey cough drops can feel really good when you’re hacking up a cough. But what about honey on its own? Is it effective as a cold remedy?

For older children, a recent meta-analysis found that honey can help reduce the frequency of acute coughs. However, the study didn’t examine whether it helps the duration of the cough. Honey performed better than placebo, no treatment, and diphenhydramine (the antihistamine found in Benadryl), but not as well as dextromethorphan, which is a cough suppressant found in cold medication. 

Important note: Honey should NEVER be given to infants. According to the CDC: “Honey can contain the bacteria that causes infant botulism, so do not feed honey to children younger than 12 months. Honey is safe for people 1 year of age and older.” There have been cases of infants getting botulism from honey pacifiers.

The bottom line: Honey can be soothing to the throat and reduce frequency of coughs in children over 1 year of age.

Antibiotics

Antibiotics should never be taken to treat a cold. Colds are caused by viruses, and antibiotics help kill bacteria. Antibiotics will not be effective in treating the symptoms of a cold, preventing a cold, or reducing the duration of a cold.

Over-The-Counter Cough Medicine

A 2014 review of over-the-counter (OTC) cough medicine in treating acute coughs in children and adults found that most studies were not well designed and there was too much variability in the studies to be able to aggregate the data together. The review concluded that assessing the effectiveness of OTC medication is difficult, due to the quality of data. 

The CDC does not recommend the use of OTC medication for children younger than 4, unless indicated by a medical doctor. Studies have shown that, although rare, there can be serious risks taking OTC medication in younger children and infants.

Non-steroidal anti-inflammatory drugs

Non-steroidal anti-inflammatory drugs include ibuprofen (brand name is often Advil), acetaminophen (brand name is often Tylenol), and aspirin, among others. These are often used to reduce fevers and to treat pain. But do they work for colds?

A 2015 review found that there’s no evidence suggesting that these drugs treat runny noses or coughs. However, these drugs did help with other symptoms such as headaches, muscle aches, and ear pain. 

The CDC suggests:

  • “Children younger than 6 months: only give acetaminophen.
  • Children 6 months or older: it is OK to give acetaminophen or ibuprofen.
  • Never give aspirin to children because it can cause Reye’s syndrome, a rare but very serious illness that harms the liver and brain.”

What Cold Remedies are recommended?

So, if OTC cough treatments aren’t recommended for young children or infants and there’s little evidence for most remedies, what can parents do when their young ones get sick

The age-old treatment of “rest and plenty of fluids” is the only real way to get over a cold. A humidifier can help your child feel better, or breathing in steam from a bath or bowl of hot water. As previously mentioned, honey and OTC treatments might help with symptoms if your child is old enough.

Summary

Unfortunately, we don’t have a lot of options besides time to get over a cold. Lots of rest and plenty of fluids are the best means of relieving symptoms. While there’s some evidence to support the use of some herbal remedies, more data is needed to be able to draw clear conclusions. These remedies also carry the risk of side-effects, which are often not studied in children. Most supplements have few, if any, studies for safety or efficacy in children. Supplements contain bioactive ingredients (like medicine) so it is important to use them wisely.
An important note: A cold is different than the flu. None of these remedies replace the flu shot, which is the best means of preventing the flu.