"In 1983, I was the picture of health. I looked fit, I felt great, and I had no idea that a silent crippler lurked inside me, stealthily damaging my brain, nerves, blood vessels, and in fact nearly every organ in my body.
     Because of my medical training, however, I noticed small signs that something wasn’t right, and I knew enough to be worried even when my doctors dismissed those signs as “nothing to worry about.” I pursued the few clues that my potentially deadly disease left, eventually obtaining a diagnosis of pernicious anemia (an autoimmune form of vitamin B₁₂ deficiency), and as a result I’ll never suffer the terrible symptoms that this disorder can cause.
     Millions of other victims of B₁₂ deficiency—many of them also victims of doctors who mistakenly ruled out B₁₂ deficiency with serum B₁₂ tests or blood smears, or never considered the diagnosis at all—aren’t as lucky. Some are infants and toddlers, left developmentally disabled for life. Some are young adults, mistakenly diagnosed as having multiple sclerosis or told, erroneously, that they are “incurably” infertile. Others are middle-aged men and women, tormented by balance problems, numb hands or feet, or mysterious shooting leg pains so agonizing that they can barely walk. Some are diagnosed with early-onset dementia or pre-Parkinson’s disease in their thirties or forties. Some are people so depressed that they try to kill themselves. Some appear to be full-blown schizophrenics. And still others are seniors living out their days in nursing homes, because their doctors think they have Alzheimer’s disease.
     It’s too late to completely reverse the symptoms of many of these people—but it’s not too late to protect yourself, or the people you love, against a similarly tragic fate. In fact, it’s extraordinarily simple to prevent or completely reverse the symptoms of B₁₂ deficiency if the deficiency is discovered in time. But this condition isn’t like other vitamin deficiencies, and simply taking a standard multivitamin pill won’t always protect you; instead, you need an accurate diagnosis and medical treatment. And getting a diagnosis isn’t always easy, as I know from experience.
     I had no idea that an invisible disease was attacking my body when I went for a pre-employment physical examination back in 1983, when I was just nineteen. The first clue came when the examining physician reviewed my blood tests and commented on my abnormally large red blood cells. (In retrospect, I may owe my life to the fact that this test came back positive. Many people suffer neurological damage decades before their blood tests become abnormal, and by then it’s too late.)
     “What kind of diet do you eat?” the doctor asked when he saw my results. When I said that I didn’t like vegetables, he told me to eat more of them, dismissing my blood abnormality as merely a sign of a diet low in folic acid.
     One month later, another doctor commented again on my large red blood cells, but concluded that my lab results were “insignificant.” Like the first doctor, this physician sent me on my way, unaware that he’d just missed diagnosing a disease that could destroy my brain, cripple my body, or even kill me.
     Two years later, in nursing school, I bought a manual describing laboratory tests and their meanings. In the section on “macrocytosis”—the medical term for unusually large red blood cells—the manual outlined two different problems, folic acid deficiency and B₁₂ deficiency, which could cause this abnormality. Since I loved B₁₂ -rich meat and didn’t like folate-rich vegetables, I could see why my first doctor picked low folic acid as a likely culprit in my case. But I wondered why he’d never considered B₁₂ deficiency as well.
     Thinking to myself, “It can’t hurt to be sure,” I persuaded a doctor at my hospital to order a serum folate and serum B₁₂ level for me. That night, when I mentioned the tests to my parents, my father surprised me by saying that my grandfather had been diagnosed with pernicious anemia—the most well-known, although not the most common, cause of B₁₂ deficiency—back in the 1960s. So I wasn’t completely caught off-guard a few days later when my own B₁₂ test came back low. I started receiving B₁₂ shots, grateful that I’d obtained a diagnosis before I suffered any symptoms.
     But that wasn’t the end of my story. Two years later, when I needed surgery, I mentioned my B₁₂ deficiency to my surgeon. Skeptical because she thought I was “awfully young” to have this problem, she sent me to a hematologist, who dismissed the idea that I had a B₁₂ problem, in spite of my earlier diagnosis and positive findings. (In fact, the hematologist’s chart notes, which I read surreptitiously at a later visit—a nurse’s instinct!—suggested that I was merely a hysterical female, imagining problems that didn’t exist.) I insisted he run tests anyway.
     The hematologist had changed his mind by the time his office called me, a week later, asking me to come in “right away.” By then, the tests he’d ordered had revealed that I indeed had juvenile pernicious anemia. In fact, he exclaimed exuberantly, I was the youngest patient he’d ever seen with pernicious anemia in his twenty years of practice. I felt like a rare freak of nature. This time around, the doctor was friendly and informative—and, I sensed, secretly relieved that I’d insisted he verify my earlier diagnosis. He certainly wouldn’t have detected my problem on his own, even with all of the information I’d given him on my first visit, because that surreptitous glance at my chart showed that his suspected diagnoses didn’t even include B₁₂ deficiency.
     In short, although I’d virtually handed this doctor my diagnosis, he nearly missed it. If I’d come to him without the benefit of my nursing training or without already knowing that I had a history of B₁₂ deficiency, his failure could have injured or killed me—because, if I had passively accepted his initial opinion, I would have stopped receiving the B₁₂ shots that saved my body from the ravages of pernicious anemia. And yet, in a way, I’m thankful to him.
     Why? Because his disbelief led me to ponder an important question: How many other people suffer or die, because their doctors don’t consider the simple diagnosis of B₁₂ deficiency? I was lucky, because I had enlarged red blood cells—the easiest-to-spot sign of the problem—and a family history of pernicious anemia. Yet despite these red flags, this doctor, as well as others, missed the correct diagnosis. Unlike me, a third of people with B₁₂ deficiency never develop either large red blood cells or anemia, meaning that their disease is invisible to routine blood tests. In addition, most have no known family history of B₁₂ deficiency. I wondered: Were doctors misdiagnosing such patients on a regular basis?
     My curiosity developed, over time, into nearly two decades of research on the scope of B₁₂ deficiency. I became an expert, reading every textbook and journal article I could get my hands on, and making connections with both clinical doctors specializing in B₁₂ deficiency and scientists involved in B₁₂ research. My husband Jeffrey, an emergency medicine physician, also conducted research to determine the percentage of B₁₂ -deficient patients seen in his emergency department. What we learned about the prevalence of B₁₂ deficiency, the havoc it wreaks on the entire body, and the number of undiagnosed cases, is alarming.
     B₁₂ deficiency is very common—not just in seniors and middle-aged people, but even in teens, children, and infants. As many as 20 percent of people over sixty (and, according to one new study, 40 percent of seniors with severe mental or physical problems) are suffering, most of them unknowingly, from its ravages. Thousands of young children, teens, and young adults have borderline B₁₂ levels, below what’s considered necessary to keep their brains functioning optimally. And millions of people labeled as having Alzheimer’s, multiple sclerosis, early-stage Parkinson’s disease, autism, learning disability, depression, bipolar disorder, vision loss, schizophrenia, diabetic neuropathy, and other severe and often incurable disorders could actually be victims of the easily diagnosable, treatable, and (in its early stages) completely curable problem of B₁₂ deficiency.
     Initially I was tremendously excited by the extensive research proving that B₁₂ deficiency plays a role in so many seemingly hopeless problems. That’s because this is a problem that’s simple to fix. It’s an inexpensive problem as well, with treatment costing only a few dollars a month—pocket change, compared to the expense of other medical conditions. Thus, diagnosing and treating patients with B₁₂ deficiency could both reduce the pain and suffering of these patients and cut medical care costs—a win-win situation, in my opinion.
     My excitement was short-lived, however, because most of the doctors I worked with didn’t care about an epidemic of undiagnosed B₁₂ deficiency. They didn’t care that the serum-B₁₂ test available to diagnose the problem frequently was inaccurate and misleading. They didn’t care about the growing number of journal articles warning about the high costs, both to patients and to society, of doctors’ rampant failure to identify this problem. Indeed, they accused me of “playing doctor,” and balked at ordering accurate B₁₂ tests, even for patients with clear signs and symptoms of the disorder. Eventually, I was told, in no uncertain terms, to drop the subject or lose my job.
     Their attitude didn’t stem simply from the fact that I am a nurse, rather than a physician (although that didn’t help). My husband encountered a similar level of apathy, even when he showed his colleagues study data revealing that large numbers of his own facility’s patients suffered from undetected B₁₂ deficiency. Later I learned that other physicians had encountered the same negative response from their own colleagues.
     Faced with an impenetrable wall of apathy and eventually outright hostility, I slowly and quietly gave up. What else could I do? Those with the ability to diagnose and fight this disease chose instead to ignore it. Noted physicians had fought the battle to bring the B₁₂ -deficiency epidemic to light, and had lost. What chance did I have of making a difference?
     My silent surrender lasted until the day I was asked to discharge a patient who’d been labeled by the preceding shift as a “frequent flyer,” a “drug-seeker,” and a patient who “did not want to go home.” When I examined this woman and reviewed her laboratory results and medical history, I saw painfully obvious indications of B₁₂ deficiency—evidence that even a first-year medical student should be able to recognize. I also noted the complete absence of any effort by her doctors to test her accurately for this problem during her previous hospital admissions, or even to recommend such testing to her family physician. This sad and frightened woman had suffered for years from crippling and seemingly mysterious symptoms, every one of which could be explained by B₁₂ deficiency, and yet no one had correctly evaluated her for the disorder. Instead, they’d simply labeled her as nuts.
     She wasn’t the first patient I’d seen dismissed by doctors who overlooked the signs and symptoms of B₁₂ deficiency. In fact, she was only the latest in a long line of patients written off as hopeless by medical professionals who’d failed to diagnose a life-threatening, and very common, medical problem. Indeed, I’d seen far worse cases, including patients who were on the verge of death, or in a permanent state of dementia, as a result of undiagnosed B₁₂ deficiency. Each case broke my heart. But this time, as I wrote up the discharge papers for this woman who’d received no real help and no real treatment—only a condescending response from her doctors and nurses, a large hospital bill, and a possible death sentence—my anger hit critical mass.
     I knew that my own health and life had hung in the balance years earlier, when doctors told me that my troubling lab test findings were “insignificant.” Now, on a regular basis, I was watching other patients being sentenced to death or disability by the doctors they trusted. I knew that many of these patients would wind up back in our hospital some day with strokes, dementia, depression, fall-caused fractures, the need for blood transfusions, and other problems stemming from undiagnosed B₁₂ deficiency.
     I could no longer stand by and be a silent accomplice to an epidemic of apathy and non-diagnosis that is leaving millions of young and old patients crippled or dead. As a medical professional, I’d long since come to terms with the daily tragedy of lives ruined by diseases that can’t be prevented or cured. But I could not come to terms with the continuing parade of lives ruined by the failure to detect and treat a simple-to-identify, simple-to-treat, simple-to-cure disorder. Neither could my husband, a physician who finds it reprehensible to refuse a patient the couple of tests that could prevent nearly every case of disability or death due to B₁₂ deficiency.
     This book was born out of our frustration and anger over these lost lives. But it was also born out of hope—the hope that we can help many current and potential victims of B₁₂ deficiency by putting this information in the hands of sufferers and their families, as well as in the hands of concerned medical professionals.
    If you are a medical consumer, this book will empower you to protect yourself and your family members, by helping you to identify loved ones at risk for B₁₂ deficiency, and to obtain a real diagnosis and real treatment before it’s too late. And if you are a medical professional, we hope you will examine the compelling body of research reviewed in this book and make complete B₁₂ screening (not just often-inaccurate serum B₁₂ levels and blood smears) part of your standard practice. The hundreds of studies we cite, published in major and respected medical journals, prove that few diseases are more prevalent, simple to diagnose, and easy to treat than B₁₂ deficiency—and few carry such a high, yet entirely preventable, risk of deadly disease or infirmity.
     Above all, the message of this book is that the suffering caused by B₁₂ deficiency, an “invisible” problem so pervasive that it touches the lives of nearly every family in America, is unnecessary. We can stop this cruel disorder in its tracks, before it destroys more lives. I dodged the bullet of B₁₂ deficiency, and so can its other potential victims—but only if patients and doctors alike open their eyes to the scope of this hidden epidemic."