Have a cough that just won't go away? You've had it for months (or years) and know it's not a cold. You don't have allergies, asthma, or acid reflux. And you're not a smoker. Could it be that you've got a B12 deficiency? It's highly possible, especially if you're over 60.

That's according to a new study presented at the World Allergy Conference last month.

For this study, Italian scientists looked at 40 patients with an unexplained chronic cough. The scientists had a hunch that sensory neuropathy (or nerve damage) caused their older patients' chronic cough. And what's one of the main causes behind sensory neuropathy? You got it: deficiencies in the vitamin B12.

So, following their hunch, the Italian scientists tested the patients' blood. They found that 25 of the 40 patients with a mysterious chronic cough were deficient in vitamin B12.

According to the lead author of the study Giuseppe Guida, M.D., their older patients were particularly prone to B12 deficiencies. He said, "Generally, you can find these lower levels of vitamins in older people because they can have some problem with their nutrition."

So how does low B12 cause a chronic cough? Well, over time, lack of B12 may cause inflammation of the nerves leading to your airways. It also may cause you to become hyper-sensitive to every little dust particle...

Does just a little bit of dust make you cough?

The Italian scientists wanted to see exactly what made their vitamin B12 deficient patients so prone to coughing. They measured the lung capacity of all 40 patients using a machine called a spirometer. The patients exhaled into the machine to measure their bronchial capacity to get a baseline reading. Then the patients took a histamine "challenge test."

You see, typically, when exposed to histamine, your airway will constrict and cause you to cough. But if you are "hyper-responsive," your airway will constrict at lower doses of histamine. Each of the patients with a B12 deficiency had significantly lower thresholds for histamine response. Translation?

When exposed to even just a tad of histamine, the vitamin B12 deficient group started coughing. Then, the scientists gave them B12 shots. And any guesses what happened?

Yep, their histamine responses improved. Their airways didn't constrict as readily and they didn't start coughing.

Dr. Guida's guardedly optimistic. In his presentation at the World Allergy Congress, he said, "Of course, we need more data to confirm the fact that there is a strong association between these two cofactors [chronic cough and the B12 deficiency]." However, "if this is the case, [this] could be a very easy way to help these people," he said, "especially because they are older and it's a very easy medication to [administer]."

Boosting B12 naturally

Bottom line here, folks? If you've got a mysterious cough that just won't go away (or if you seem to overreact to allergens in your house), ask your doctor for a B12 blood test. Ideally, you should have blood serum levels above 300 pg/mL.

An important warning here for vegans and vegetarians: don't necessarily trust your B12 blood tests. You see, some vegetables contain a nutrient that mimics B12 in the body. So it appears as though you have enough B12 in blood tests; but this analog doesn't perform the same job as B12. In fact, if you're a plant-eater, you can be severely B12 deficient and still look normal in blood tests.

In any case, if blood tests show you're a little low, you'll definitely want to add some grass-fed meat, wild-caught fish, and free-range eggs to your diet. In most cases, your body should have no trouble at all absorbing B12 from these natural sources.

For readers who have a more serious B12 deficiency, I recommend B12 shots. They're not as bad as they sound, I promise! Some people get them once a month and some people as often as two times per week. Your doctor will help you figure out how often you need one. (As always, I recommend finding a natural healthcare practitioner which you can do through associations like the International College of Integrative Medicine at www.icimed.com, the American Association of Naturopathic Physicians at www.naturopathic.org, or the American College for the Advancement of Medicine at www.acam.org.)

If you're not thrilled about getting regular shots in the arm, you can always try sublingual B12 tablets (you put them under your tongue) or low dose mouth sprays. Unfortunately, B12's just not very well absorbed in tablet form. Try this for a few months and see if your levels improve. If they don't, B12 shots are your best alternative.

No matter how you get it, B12's one magic elixir. When your body gets enough, you'll feel more energized and relaxed. And you may just see your mysterious cough disappear!