The All-Natural Supplement That Keeps Colds At Bay

Reach for this popular (and effective!) supplement so you won’t have to reach for the tissues this season. (Tetra Images/Getty Images)

Call it the battle of the bugs: On one side, the good guys, probiotics — beneficial bacteria in the gut that help support your immune system. On the other, germs like the flu and common cold — foreign invaders trying to break through your body’s defenses.

Want to give the good guys a hand? Pick up a probiotic supplement. In a new University of Florida study, stressed college students were less likely to come down with the cold or flu when they popped a probiotic versus a placebo.

The experiment took place during one of the most stressful periods of the year for young academics: fall semester finals. Researchers assigned 581 undergrads to receive one of three different strains of probiotic supplements, or a sugar pill. The students took one capsule per day for six weeks, from the month before finals through the week after exams.

Why seek out stressed scholars? Probiotics have been shown to shorten the duration of respiratory infections in otherwise healthy people by about a day, according to a 2014 literature analysis. But the researchers wanted to see if the supplements could keep people from catching a cold in the first place — and to do that, you need to find folks who are likely to get sick.

Related: 5 Uncommon Tips To Beat A Cold Or The Flu

“We know that a certain percentage of college students are going to become ill during fall finals,” says study author Bobbi Langkamp-Henken, PhD, RD, head of the Henken Laboratory at the University of Florida. “They likely get sick because they are stressed, stay up all night studying, eat junk food, and live and study in close proximity with other students who have a cold or the flu.”

Sure enough, 37 percent of the placebo group spent at least one day suffering from cold or flu symptoms. But only 24 percent of those taking the probiotic B. bifidum became sick — a significant difference. Students who took B. bifidum also reported fewer cold/flu episodes than the placebo group. And when they did catch a bug, it didn’t last as long — an average of 1.8 days versus 2.4 days.

The small intestine has more immune cells than any other organ in the body, Langkamp-Henken explains. Although experts are still unsure of the details, “the probiotics or good bacteria likely communicate with the immune cells through the small intestine.”

Related: 7 Germaphobe Habits Everyone Should Follow

Not all probiotic supplements are created equal, however. After accounting for factors like sleep and stress, the strain B. infantis was also shown to be effective, but the third probiotic (L. helveticus) was not — a result that surprised the researchers. “I really thought that all three probiotics would be equally beneficial,” Langkamp-Henken tells Yahoo Health. “This just drives home the point that the health benefits of probiotics are genus-, species-, and likely strain-specific.” More research is needed to learn which specific probiotics work best for different ailments, she adds.

Frazzled freshmen aren’t the only people who could benefit from a little immunity TLC. With cold and flu season in full swing, consider these research-supported supplements to keep your body’s defense system strong:

Prebiotics

Prebiotics are specific types of carbohydrates that provide food for our healthy gut bacteria. In a 2011 study by Langkamp-Henken and colleagues, taking a prebiotic supplement reduced the intensity of cold and flu symptoms in college students. A 5-gram dose of prebiotics also reduced the number of days spent with a cold or flu by 40 percent, compared to a placebo. Research shows that prebiotics can significantly increase the number of healthy bacteria in the gut.

Zinc

Zinc lozenges are one of the most popular natural cold remedies, and for good reason: A 2011 Cochrane review of 13 studies found that zinc supplements effectively shorten the duration of colds. A similar analysis from the University of Finland calculated that zinc can reduce the length of a cold by 42 percent on average. Tip: Be sure to take zinc within 24 hours of the onset of symptoms.

Garlic

Only one study has assessed the effect of garlic supplementation on colds, but with promising results. Compared with participants who were given a placebo, the group taking a commercially available garlic supplement (Allicin Max) experienced milder cold symptoms. Their symptoms also lasted only about a day and a half, on average, versus five days for the placebo group.

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