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Vitamins, Herbs, & Foods that Fight Colds: Is Food Really Medicine?

I pride myself on having a strong immune system. That is, until the year 2020. I’ve caught two colds already and a stomach bug (hello #momlife). Catching a cold is a little like being pregnant — you get lots of advice. My husband prescribed zinc lozenges and powdered vitamin C concoctions. Others told me drink lots of fluids. And then who’s not saying you should drink bone broth for some reason or another?

Sidebar: Have you tried Brodo though?! It’s ridiculously good.

Last week, when I had a stuffy nose, sore throat, and was just kind of feeling meh, what sounded really good to me was chicken soup. (I made the Flu-Fighter Chicken and Rice Stew from Run Fast. Eat Slow., halved the garlic and squeezed in lots of extra lemon juice at the end — totally hit the spot).

All of this got me thinking, when it comes to the common cold, what does the evidence say about food as medicine?

Vitamin C
Ever loaded up on vitamin C or drank lots of orange juice to thwart a cold? When it comes to this recommendation, the science is a bit nuanced.

In 2013, researchers evaluated the evidence on vitamin C and colds, looking at 29 studies that included 11,000 people. Conclusions of this evaluation were:
• Taking at least 200 mg vitamin C did not decrease the number of colds that developed, however in extremely active people (marathon runners, skiers and troops based in subarctic climates), routine supplementation of 250–1,000 mg vitamin C did reduce the incidence of colds by 50%.
• In those who regularly supplemented with at least 200 mg vitamin C, length of colds was reduced (by 8% in adults compared with 14% in children). Severity of colds was decreased as well.
• Supplementing with vitamin C after the onset of a cold did not lessen the severity or decrease the duration of colds.

So, while prophylactically taking vitamin C won’t necessarily reduce the number of colds you get, it may reduce the duration and severity of a cold if you do catch one. But, if you’re very, very active or are exposed to extremely cold weather, taking at least 200 mg of vitamin C on a regular basis may prevent you from getting a cold.

High intakes of vitamin C have been associated with diarrhea, nausea, and stomach cramps, so avoid taking more than 2,000 mg/day. As a reference, the recommended daily intake vitamin C for women is 75 mg and for men, it’s 90 mg. Consuming five servings of fruits and vegetables a day, on average will provide more than 200 mg vitamin C. Some of the best sources of vitamin C:
• Red pepper
• Orange
• Kiwi
• Broccoli
• Strawberries
• Brussels sprouts
• Cantaloupe
• Cabbage
• Cauliflower

Zinc Lozenges
Much of the research on use of zinc lozenges to treat the common cold is conflicting. Of ten studies, five found that zinc lozenges reduced the duration of the common cold, while five other studies found no difference in severity or duration of colds with taking zinc lozenges.

If you’re thinking about trying zinc lozenges, here’s what you need to know. When taken within 24 hours of the onset of a cold, zinc lozenges may reduce the amount of time you’re sick, however it’s not a guarantee, as more research is needed. Taking zinc lozenges as directed by product instructions (every 2–3 hours during waking hours) often results in consuming very high amounts of zinc. While in the short-term, no harmful side effects have been observed, if you do choose to take zinc lozenges, do not take longer than 5 days. Long-term implications of consuming excessive amounts of zinc include copper deficiency and interactions with certain drugs.

Bone Broth & Chicken Soup
During pregnancy, I sipped on bone broth like it was my job. Why? It’s a rich source of collagen, which is a concentrated source of the amino acid glycine. Glycine needs increase during pregnancy, as it helps support growth and development of baby, as well as mom’s stretching skin, growing uterus and placenta.

A quick clarification before I continue: I mention chicken soup and bone broth here, since both are commonly recommended for healing purposes. It turns out they’re more similar than you may think. The base of chicken soup is stock, which is essentially bone broth. Typically, broth is thinner, because it’s made with more meat, versus stock and bone broth, which are more viscous (due to the collagen content from cooking bones stripped of their meat in liquid for long periods of time).

Ok to the point — does sipping on bone broth or chicken soup help when you have a cold?

One study on chicken soup came to some promising conclusions. Researchers found that chicken soup may contain substances with beneficial medicinal effects, and might alleviate symptoms of upper respiratory infections through the soup’s anti-inflammatory properties.

While there isn’t a ton of evidence out there other than this one study saying that chicken soup and bone broth are useful when you have a cold, my thinking is why not? Variations on chicken soup have been made for generations in many different cultures for the purpose of healing, and I think our elders were onto something. Consuming bone broth or chicken soup, if anything, provide protein and micronutrients in an easy to eat form, which in my book is super important when you might not feel up to eating much. And, they’re a source of fluids, which brings me to my next topic.

Hydration
We’ve all heard this one before when we’ve had a cold: “Drink lots of extra fluids.” But does it help?

In 2011, researchers reviewed the evidence to date, and concluded that there is not evidence for or against recommending people increase fluid intake when they have an acute respiratory infection. But, if you have a fever or a stomach bug (with vomiting or diarrhea), your fluid needs will absolutely increase. Theoretically, fluids (especially hot fluids) help break down congestion, and heat may also help relax the airways.

Bottom line: listen to your body. If hot tea or soup is soothing, go for it. While fluid needs may not necessarily increase when you have a cold, you may also not be drinking as much as usual because you’re not feeling well. No need to overdo it though, just be mindful of hydration.

Honey
Many cough drops contain honey, and honey is commonly added to tea. (I am not a tea drinker, but find hot water, honey and lemon to be really soothing for a sore throat).

If you’re trying to stop a cold-induced cough in its tracks, there’s some evidence that a Tablespoon of honey might help, especially in children. But, if your child is under the age of one year, don’t ever offer them honey, as it may increase their risk of developing infant botulism.

Echinacea
Echinacea is an ingredient in many supplements marketed for colds. Growing up, my family used to swear by the cold-fighting power of a few drops of the herb mixed into OJ.

Exactly how effective is Echinacea for treating colds? In 2014, researchers reviewed the evidence from 24 studies involving over 4,000 participants regarding the effectiveness of Echinacea for preventing and treating colds. The verdict? While some Echinacea products may be effective at treating colds, overall the evidence is weak. In terms of preventing colds, Echinacea may provide a slight beneficial effect, but like the evidence for treating colds, the evidence found was weak at best.

The Takeaway
Like everything in nutrition, the science on preventing and treating colds is continually evolving. I’ll continue to watch the research on this topic — stay tuned. In the meantime, what’s your favorite cold remedy?

Jackie Ballou Erdos, MS, RD, CSSD, CDN