The arrival of winter brings with it the threat of colds. Although the common cold isn’t fatal and doesn’t typically progress to more serious problems, like pneumonia, they’re inconvenient and a productivity destroyer. If you’ve ever tried to sleep at night with a stuffy nose, you know how hard it can be! You toss and turn, struggling to breathe, and then feel completely wiped out the next day.
At one time, it was popular to pop vitamin C supplements at the first sign of a cold, thanks to Linus Pauling, but you might be better off adding more zinc to your diet for cold prevention. Here’s why.
What is Zinc?
Zinc is a mineral involved in numerous chemical reactions your body carries out every minute. Every cell in your body needs zinc in some capacity. For example, zinc plays a vital role in vision, hearing, growth, fertility, and wound healing. Also important is its role in immune function. According to the textbook Nutritional Medicine, zinc has anti-vital properties that may help fight the common cold virus.
Does science support this idea? In a study carried out at Wayne State University School of Medicine and the University of Ann Arbor, researchers gave 24 middle-aged and older men and women 15 milligrams of zinc gluconate before breakfast and two 15 milligram capsules at bedtime. Over the course of the year-long study, researchers monitored them for signs of infection. The results were significant. The control group that didn’t supplement with zinc experienced 35 infections over the course of the study. The zinc gluconate group? Only seven.
Another interesting point was the group who supplemented with zinc had fewer markers of inflammation and oxidative stress, indicators of immune dysfunction. Also interesting is the fact that the study participants were not zinc deficient. Even though they weren’t suffering from a known zinc deficiency, they seemed to benefit from getting more zinc.
Sources of Zinc
Foods rich in zinc are heavily skewed towards animal-based sources with beef, lamb, turkey, seafood, and shrimp topping the list. Other good sources are dried beans, peas, and lentils. If you eat a vegetarian or vegan diet, you’re at greater risk for zinc deficiency, especially if you don’t eat legumes. Age is also a risk factor for zinc deficiency.
After the age of 65, the incidence of zinc deficiency goes up. Some research suggests the decline in zinc levels with age may partially explain why older people are at higher risk for both infections, due to sluggish immune function and inflammation due to a dysregulated immune system.
Zinc helps your immune system target the “bad guys” without attacking normal tissue. Research even shows zinc status affects the response to vaccines, like the influenza vaccine. In the elderly, low zinc levels are linked with deteriorating mental status and obesity, showing zinc is essential for mental and physical health.
As you can see, it’s important to get enough zinc no matter what your age. Surprisingly, eating a healthy, fiber-rich diet can reduce the absorption of zinc and lead to low zinc levels. Compounds called phytates in soy and whole grains form complexes with zinc and blocks its absorption – another reason why vegetarians are at greater risk for deficiency. Milk, cheese, and even fiber-rich fruits and vegetables reduce zinc absorption.
Some medications can lead to imbalances in zinc levels too. Examples are aspirin, diuretics, medications that suppress production of stomach acid, steroids, aspirin, some types of blood pressure medications, and some antibiotics. What’s also concerning is the fact that calcium and zinc compete for uptake by the intestinal tract. If you take a calcium supplement, like many women do, you may not be absorbing adequate amounts of zinc from your diet due to competition.
How do you know if you’re zinc deficient? Unlike some vitamins and minerals like iron, vitamin D, and vitamin B12 you can easily check with a blood test, there isn’t a reliable test for zinc deficiency unless you’re severely deficient. Plus, you would likely only have symptoms if you have very low zinc levels. Signs and symptoms if your level is very low might include slow wound healing, increased susceptibility to infection, depression, itchy skin, reduced taste sensation, hair loss, dry skin, and worsening of skin conditions such as acne and eczema.
Back to the Issue of Cold Prevention
According to the Cochrane Database, a database built around evidence-based medicine, taking a zinc supplement may reduce the risk of catching a cold and shorten the duration of cold symptoms by 24 hours, on average, if you take it as soon as you develop symptoms. On the other hand, taking zinc supplements, especially at high doses has side effects, including nausea and diarrhea. Plus, you would need to take a zinc supplement that contains copper since zinc can block the absorption of copper leading to a copper deficiency.
A better approach to cold prevention, and health, in general, is to make sure you’re getting enough zinc in your diet by eating more zinc-rich foods. If you eat a vegetarian or vegan diet, you’re at higher risk for zinc deficiency and should talk to your doctor or see a nutritionist to optimize the amount of zinc you’re consuming. One form of zinc you definitely don’t want to take are zinc nasal preparations marketed for cold treatment. In rare cases, these preparations can lead to a permanent loss of the ability to smell. Steer clear of them.
The Bottom Line
Cold season is a good time to increase the amount of zinc you’re getting in your diet. As mentioned, seafood and meat are excellent sources as are legumes. Whole grain foods, dairy products, seeds, wheat bran, and wheat germ also contain respectable amounts of zinc. Make sure you’re getting enough of these foods.
Nutritional Medicine. Alan R. Gaby. M.D. 2011.
Smart Publications. “Zinc–The Essential Mineral That Helps Protect Against Colds and Flu”
Pathobiol Aging Age Relat Dis. 2015; 5: 10.3402/pba.v5.25592. Published online 2015 Feb 5. doi: 10.3402/pba.v5.25592.
Cochrane Database. “Zinc for the common cold”
PLoS One. 2015; 10(1): e0117257.Published online 2015 Jan 30. doi: 10.1371/journal.pone.0117257