Nutrition Fact Vs. Fiction: Preventing Colds

by Amy Scheuerman

Some cute polar bears claim that zinc can cure your cold, a school teacher endorses vitamin C–heck, even The New York Times has entered the fray with a Well article on the preventative powers of garlic.

With cold season rushing over us and a sniffle in every classroom, it’s important to separate scientifically valid health claims from products that are a waste of money, or even worse, have associated health risks.  Here we’ll look at four of the most well known alternative techniques for preventing and alleviating colds and see if their claims live up to the research.

Vitamin C
Vitamin C, whether you’re getting it from your morning OJ, supplements, or an Emer-gen-C packet poured into a glass of water, is the subject of some of the oldest cold preventing and curing lore.  Everyone knows that vitamin C is supposed to boost your immune system and keep you healthy.

But the evidence is precarious.  While the evidence for the preventative powers of vitamin C is limited there are quite a few studies that show a decrease in symptom severity when vitamin C supplementation is used.  Then again, there are quote a few studies that show no effect.

Dr. Jeffery Blumberg, PhD, senior scientist at the Jean Meyer Human Nutrition Research Center (HNRC) warns not to be overly optimistic about the curative powers of vitamin C.  “Vitamin C may contribute partly to reducing the severity of cold symptoms,” he says, “nonetheless, these studies do not demonstrate a reduction in the duration of the cold.”

Dr. Blumberg also mentioned that there are a lot of mixed data on vitamin C and the research is hardly unequivocal when it comes to endorsing the vitamin as a cold stopper or shortener.

The bottom line: Vitamin C supplements don’t pan out.  Instead of taking an expensive vitamin pill, you may just want to eat two to three servings of fruits and veggies a day.  Dr. Blumberg points out that by just following the Dietary Guidelines for Americans you could get “intakes [of] 250-500 mg (or more) vitamin C daily.”

Echinacea
Something about echinacea inspires almost religious faith in many scientifically minded people.  They believe it can cure colds and that with the addition of goldenseal root can cure allergies as well.

But, as one of the newest players in the immune-boosting field there’s less research on it than there is on vitamin C and what research there is tends to be poor quality.  There are three species of echinacea available for medical use and the plant parts used and extraction methods differ by institute and researcher.  Given this, it’s unsurprising that a lot of the research gives conflicting results and no dosage recommendations.

The bottom line: For now, especially given the unregulated nature of the product, skip the green pills and look elsewhere for your health elixir.  There are cheaper and more effective methods.

Zinc
While not as well known as vitamin C, zinc is one of the more venerable cold alleviating supplements.  Think of those zinc infused cold lozenges that taste so terrible but have such impressive health claims on the package.  And those health claims seem to be substantiated.  While zinc doesn’t seem to stop you from getting a cold in the first place, most of the research shows it to shorten the duration of a cold.

However, it’s important to use caution when taking zinc supplements.  Dr. Diane McKay, PhD at the HNRC warns that the symptoms of zinc poisoning can seem insidiously similar to common cold symptoms.  “Taking too much zinc over a short period of time might depress your sense of taste, and cause other symptoms including stomach pain, nausea, vomiting, headaches, and loss of appetite.”

These symptoms are just the warm up, long term zinc overdoses can do even worse things, “Within just a few weeks excess zinc can also impair your immune system, lower your “good” HDL cholesterol, and interfere with the absorption of other essential minerals like copper and iron,” says Dr. McKay.

The bottom line: Zinc is proven but risky.  If you’re going to use zinc, take a zinc gluconate supplement the moment you feel that twinge at the back of your throat; studies show that it needs to be taken early or it won’t be effective.  And for God’s sake, don’t take it for more than five days!

Garlic
Garlic is probably the most august cold prevention technique of them all.  Whose grandmother hasn’t given them chicken soup with garlic?  There are even people who swear by eating two cloves of raw garlic a day to stop colds before they start.  Can such an ancient remedy stand up to scientific testing?

Apparently, it can.

According to research done in the UK, garlic seems to have a preventative effect on colds.  Maybe it’s because no one wants to invade your personal space if you’ve been chowing down on something from the allium family, but the research shows that those who take garlic or a garlic supplement get fewer colds than those who take a placebo.

Also, people who take garlic and still get colds tend to have shorter and less severe colds.

The bottom line: According to limited research, garlic is the real deal.  It can both prevent colds and shorten them.  Also, it’s cheap in its whole food form and it tastes great.  Plus, you can’t OD on garlic, so eat all you want.

General Tips to Avoid Colds
You already know how to stay healthy, now you just need to put that knowledge into practice.  Get lots of sleep, eat a balanced diet with lots of fruits and vegetables, keep well hydrated, and avoid people who are already sick.  If you’re worried about the flu more than the common cold you should look into getting a flu shot.

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