Approximately twenty million Americans visit a chiropractor each year, according to the American Chiropractic Association, making it the largest alternative medicine profession. But if those people were aware of these five facts about chiropractic, I wonder if they'd still be so keen to get their spines manipulated. If you haven't tried chiropractic, these facts might banish any desire to do so.

1. Chiropractic doesn't work. Thousands upon thousands of studies have placed chiropractic under the microscope, examining its effectiveness in treating conditions such as back pain, neck pain, infant colic, headache, and scoliosis. Some studies have found positive results, but many more have shown no effect whatsoever. When the jumble of mixed data is grouped together and examined, only one conclusion is warranted: "these data fail to demonstrate convincingly that spinal manipulation is an effective intervention for any condition."

2. There's a genuine risk of stroke. While spinal manipulation at the hands of a trained chiropractor is generally safe, there's a boatload of evidence to suggest that you should never let a chiropractor touch your neck. The primary vertebral artery, which supplies blood to the brain, is located at the crest of your neck just below your skull. Abrupt manipulations of the cervical vertebrae in the neck, can, and have, caused the artery to rupture, resulting in stroke, coma, or even death. As one would expect, the American Chiropractic Association denies the existence of these events.

3. Chiropractic's most fundamental theory is bunk. Chiropractic was founded on the idea that correcting misaligned vertebrae in the spine -- called subluxations -- could cure all forms of disease. "A subluxated vertebra ... is the cause of 95 percent of all diseases ... The other five percent is caused by displaced joints other than those of the vertebral column," D.D. Palmer, the creator of chiropractic, wrote. Most modern day chiropractors now admit that this is totally wrong.

In 2009, four curious chiropractors reviewed all available evidence on the topic and concluded, "No supportive evidence is found for the chiropractic subluxation being associated with any disease process or of creating suboptimal health conditions requiring intervention. Regardless of popular appeal, this leaves the subluxation construct in the realm of unsupported speculation."

4. Chiropractic's founder was probably crazy. D.D. Palmer created chiropractic back in the late 1800s, but if you asked him, he would say that he got the idea from a medical physician named Dr. Jim Atkinson. As humble as it is for Mr. Palmer to share credit, it's also a little strange, especially considering Jim Atkinson was dead, and according to Palmer, relayed the instructions for chiropractic from beyond the grave. According to B.J. Palmer, D.D.'s son, "Father often attended the annual Mississippi Valley Spiritualists Camp Meeting where he first claimed to receive messages from Dr. Jim Atkinson on the principles of chiropractic."

5. Chiropractic hurts. Simply put, spinal manipulation usually doesn't feel good. "It often involves a high velocity thrust, a technique in which the joints are adjusted rapidly, often accompanied by popping sounds," described Edzard Ernst, a Professor of Complementary Medicine at the University of Pennsylvania. These disconcerting sounds are often harbingers of adverse side effects. Thirty to 61 percent of patients generally experience pain, numbness, stiffness, dizziness, tingling and headaches, which can persist for up to 48 hours after their appointment. These generally mild pains might be worth the discomfort if chiropractic actually worked in the long term. But it doesn't.

(Image: AP)