And you wondered,

And you wondered, Do I have it? First, a quick lesson in biochemistry courtesy of the National Institutes of Health’s Institute on Aging. Genetic mutations, or permanent changes in one or more specific genes, do not always cause disease. But some do, and if you inherit a disease-causing mutation, then you will likely develop the disease. Sickle cell anemia, Huntington’s disease, and cystic fibrosis are examples of inherited genetic disorders. Sometimes, a genetic variant can occur whereby changes in a gene can lead to a disease, but not always. More often, the variant simply increases or decreases one’s risk of developing a certain disease or condition. If a variant is known to increase risk but not necessarily trigger disease, it’s called a genetic risk factor. 40 To be clear, scientists have not identified a specific gene that causes Alzheimer’s disease. But one genetic risk factor that appears to increase one’s risk of developing the disease is associated with the apolipoprotein E (ApoE) gene on chromosome 19. It encodes the instructions for making a protein that helps transport cholesterol and other types of fat in the bloodstream. It comes in several different forms, or alleles. The three main forms are ApoE ε2, ApoE ε3, and ApoE ε4. ApoE ε2 is relatively rare, but if you inherit this allele, you’re more likely to develop Alzheimer’s disease later in life. ApoE ε3 is the most common allele, but it’s believed to neither increase nor decrease your risk. ApoE ε4, however, is the one typically mentioned in the media and feared the most. In the general population, it’s present in about 25 to 30 percent of people, and about 40 percent of all people with Alzheimer’s carry this allele. So again, you’re probably wondering if you carry this risk factor and what it can mean for you and your future. Unfortunately, we don’t know how this allele increases one’s risk for Alzheimer’s disease. The mechanism is poorly understood. People who are born with the ApoE ε4 allele are more likely to develop the disease at an earlier age than those who do not carry it. It’s important to remember that inheriting an ApoE ε4 allele does not mean that your fate is sealed. You won’t necessarily be stricken with Alzheimer’s. Some people whose DNA contains the ApoE ε4 allele never suffer from any cognitive decline. And there are plenty of people who develop Alzheimer’s but who lack any of these genetic risk factors. A simple DNA screening test can determine if you have this gene, but even if you do, there’s something you can do about it. My protocol is all about taking charge of your brain’s destiny, despite your DNA. I can’t reiterate this enough: The fate of your health—and peace of mind, as the next chapter shows—is largely in your hands. CHAPTER 6 Brain Drain How Gluten Robs You and Your Children’s Peace of Mind As a rule, what is out of sight disturbs men’s minds more seriously than what they see. —JULIUS CAESAR IF SUGARS AND GLUTEN-FILLED CARBS, including your daily whole-grain breads and favorite comfort foods, are slowly impinging on your brain’s long-term health and functionality, what else can these ingredients do on a more short-term basis? Can they trigger changes in behavior, seize control of focus and concentration, and underlie some tic disorders and mood conditions like depression? Can they be the culprit in chronic headaches and even migraines? Yes, they can. The facts of “grain brain” go far beyond just hampering neurogenesis and increasing your risk for cognitive challenges that will progress stealthily over time. As I’ve already hinted at throughout the previous chapters, a diet heavy in inflammatory carbs and low in healthy fats messes with the mind in more ways than one—affecting risk not just for dementia but for common neurological ailments such as ADHD, anxiety disorder, Tourette’s syndrome, mental illness, migraines, and even autism. Up until now, I’ve focused primarily on cognitive decline and dementia. Now, let’s turn to gluten’s destructive effects on the brain from the perspective of these common behavioral and psychological disorders. I’ll start with the afflictions that are often diagnosed in young children, and then move on to cover a wider array of issues that are found in people of every age. One thing will be clear: The removal of gluten from the diet and the adoption of a grain-brain-free way of life is often the surest ticket to relief for these brain ailments that plague millions, and this simple “prescription” can often trump drug therapy. GLUTEN’S ROLE IN BEHAVIORAL AND MOVEMENT DISORDERS I first saw Stuart when he had just turned four years old. He was brought to my center by his mother, Nancy, whom I had known for several years; she was a physical therapist who had treated many of our patients. Nancy began by describing her concerns about Stuart and reported that although she really hadn’t noticed anything wrong with her son, his preschool teacher felt he was unusually “active” and felt it would be a good idea to have him evaluated. I was not the first doctor to see him because of this concern. The week before visiting us, Stuart’s mom had taken him to their pediatrician, who proclaimed that Stuart “was ADHD” and had written a prescription for Ritalin. Nancy was rightfully concerned about placing her son on the drug, and this prompted her to look into other options. She began by explaining that her son had frequent anger outbursts and that he “shook uncontrollably when frustrated.” She described how the preschool teacher complained that Stuart was unable to “stay on task,” making me wonder exactly what tasks require undivided focus in a four-year-old. Stuart’s past medical history was revealing. He had suffered lots of ear infections and had been on countless rounds of antibiotics. At the time I evaluated him, he was on a six-month course of prophylactic antibiotics in hopes of reducing his risk for continued ear infections. But beyond the ear problems, Stuart persistently complained of joint pain, so much so that he was now also taking Naprosyn, a powerful anti-inflammatory, on a regular basis. I assumed Stuart hadn’t been breast-fed and learned that my assumption was correct. Three things of importance were noted during his examination. First, he was a mouth-breather, a sure indication of ongoing inflammation in the nasal passages. Second, his face demonstrated classic “allergic shiners,” dark circles under the eyes that correlate with allergies. And third, he was indeed very active. He couldn’t sit still for more than ten seconds, getting up to explore every inch of the exam room and tearing up the crinkly paper that adorns most doctors’ examination tables. Our laboratory evaluation wasn’t extensive. We did a simple test for gluten sensitivity that measures the level of antibodies against gliadin, one of the wheat proteins. Not surprisingly, Stuart’s level was 300 percent higher than the level considered normal by the laboratory. Rather than reach for a drug to treat symptoms, we decided instead to target the cause of this child’s issues, namely inflammation. Inflammation was playing a central role in virtually everything going on in this young boy’s physiology, including his ear problems, joint issues, and inability to compose himself. I explained to Nancy that we had to go gluten-free. And to help rebuild a healthy gut after his extensive antibiotic exposure, we needed to add some beneficial bacteria, probiotics, to his regimen. Finally, the omega-3 fat DHA was added to the list. What happened next couldn’t have been scripted any better. After two and a half weeks, Stuart’s parents received a phone call from his preschool teacher thanking them for deciding to put him on medication as he had “vastly improved” in his demeanor. And his parents noted that he had become calm, more interactive, and was sleeping better. But his transformation wasn’t due to medication. It was purely through diet that he was able to realize “vast” improvements in his health and attitude. I received a note from Nancy two and a half years later stating: “We have been able to start him in school as the youngest student in the class. He has been able to excel in reading and math, and we do not anticipate any further problems with him being hyperactive. He has been growing so fast that he is one of the tallest kids in his class.” Attention deficit hyperactivity disorder (ADHD) is one of the most frequent diagnoses offered in the pediatrician’s office. Parents of hyperactive children are led to believe that their children have some form of a disease that will limit their ability to learn. The medical establishment too often convinces parents that medication is the best “quick fix.” The whole notion that ADHD is a specific disease easily remedied by a pill is convenient but alarming. In several schools throughout the United States as many as 25 percent of students are routinely receiving powerful, mind-altering medications, the long-term consequences of which have never been studied! Although the American Psychiatric Association states in its Diagnostic and Statistical Manual of Mental Disorders that 3 to 7 percent of school-aged children have ADHD, studies have estimated higher rates in community samples, and data from surveys of parents collected by the Centers for Disease Control and Prevention paint a different picture. 1 According to new data from the CDC that came out in March 2013, nearly one in five high school–age boys in the United States and 11 percent of school-age children overall have been diagnosed with ADHD. That translates to an estimated 6.4 million children ages four through seventeen, reflecting a 16 percent increase since 2007 and a 53 percent rise in the past decade. 2 As reported by the New York Times, “About two-thirds of those with a current diagnosis receive prescriptions for stimulants like Ritalin or Adderall, which can drastically improve the lives of those with ADHD but can also lead to addiction, anxiety, and occasionally psychosis.” 3 This has prompted the American Psychiatric Association to consider changing its definition of ADHD so more people are diagnosed… and treated with drugs. Dr. Thomas R. Frieden, the director of the CDC, has said that the rising rates of stimulant prescriptions among children are like the overuse of pain medications and antibiotics in adults, and I agree. In the words of Dr. Jerome Groopman, a professor of medicine at Harvard Medical School and the author of How Doctors Think, who was interviewed for the Times, “There’s a tremendous push where if the kid’s behavior is thought to be quote-unquote abnormal—if they’re not sitting quietly at their desk—that’s pathological, instead of just childhood.” 4 So what does it mean when our definition of childhood gets trampled by fuzzy diagnoses like ADHD? Aside from the dramatic rise in the use of medications to treat ADHD over the past decade, the use of antianxiety drugs soared between 2001 and 2010: In children up to age nineteen, the use of antianxiety medication increased 45 percent in females and 37 percent in males. According to a report by Express Scripts called “America’s State of Mind,” the overall number of Americans taking mental health drugs to treat psychological and behavioral disorders has substantially increased since 2001. In 2010, the most recent data indicated that more than one in five adults was on at least one medication, up 22 percent from ten years earlier. Interestingly, women are far more likely to take a drug for a mental health condition than men. More than a quarter of the adult female population was on these drugs in 2010, as compared to just 15 percent of men. 5 (Harvard researchers theorize that this could be due to hormonal changes in women that are linked to puberty, pregnancy, and menopause. Although depression can affect men and women equally, women are typically more likely to seek medical help.) Percent of population using mental health medications 2001 vs. 2010 Eleven percent of Americans over age twelve take antidepressants, but the percentage skyrockets when you look at the number of women in their forties and fifties who have been prescribed antidepressants—a whopping 23 percent. Given the soaring rates of mental and behavioral disorders for which powerful drugs are increasingly used, why isn’t anyone drawing attention to the underlying reasons for this trend? And how can we propose solutions that don’t entail hazardous pharmaceuticals? At the root of the problem? That sticky wheat protein, gluten. Although the jury is still out on the connections between gluten sensitivity and behavioral or psychological issues, we do know a few facts: People with celiac disease may be at increased risk for developmental delay, learning difficulties, tic disorders, and ADHD. 6 Depression and anxiety are often severe in patients with gluten sensitivity. 7, 8 This is primarily due to the cytokines that block production of critical brain neurotransmitters like serotonin, which is essential in regulating mood. With the elimination of gluten and often dairy, many patients have been freed from not just their mood disorders but other conditions caused by an overactive immune system, like allergies and arthritis. As many as 45 percent of people with autism spectrum disorders (ASD) have gastrointestinal problems. 9 Although not all gastrointestinal symptoms in ASD result from celiac disease, data shows an increased prevalence of celiac in pediatric cases of autism, compared to the general pediatric population. The good news is that we can reverse many of the symptoms of neurological, psychological, and behavioral disorders just by going gluten-free and adding supplements like DHA and probiotics to our diet. And to illustrate the impact of such a simple, drug-free prescription, consider the story of KJ, whom I met more than a decade ago. She was five years old at the time and had been diagnosed with Tourette’s syndrome, a type of tic spectrum disorder characterized by sudden, repetitive, nonrhythmic movements (motor tics) and verbal utterances that involve discrete muscle groups. Science says that the exact cause of this neurological anomaly is unknown, but we do know that, like many neuropsychiatric disorders, it has genetic roots that can be worsened by environmental factors. I think future research will bear out the truth behind many cases of Tourette’s and show gluten sensitivity at play. At KJ’s initial office visit, her mother explained that in the previous year her daughter had developed involuntary contractions of her neck muscles for unknown reasons. She had received various types of massage therapy, which provided some improvement, but the problem would come and go. It eventually worsened to the point that KJ had aggressive movements in her jaw, face, and neck. She also persistently cleared her throat and produced various grunting noises. Her primary doctor had diagnosed Tourette’s syndrome. When taking her history I noted that three years prior to the onset of her serious neurological symptoms, she’d begun to have bouts of diarrhea and chronic abdominal pain that were still with her. As you might expect, I ran a test for gluten sensitivity and indeed confirmed that this poor child had been living with undiagnosed sensitivity. Two days after starting a gluten-free diet, all of the abnormal movements, throat clearing, grunting sounds, and even abdominal pain had vanished. To this day, KJ is symptom-free and can no longer be considered a person with Tourette’s syndrome. So compelling was her response that I often use this case when lecturing to health care professionals. Warning: Drugs used to treat ADHD have resulted in cases of permanent Tourette’s syndrome. Science has been documenting this since the early 1980s. 10 Now that we have the research to prove the powerful effect of going gluten-free, it’s time we change—no, make—history. Another case I’d like to share brings us back to ADHD. The parents of KM, a sweet nine-year-old girl, brought her to me because of classic signs of ADHD and “poor memory.” What was interesting about her history was that her parents described her difficulties with thinking and focusing as “lasting for days,” after which she would remain “fine” for several days. Academic evaluations indicated she was functioning at a mid-third-grade level. She seemed very composed and engaged, and when I reviewed her various achievement tests, I confirmed that she was indeed functioning at a mid-thirdgrade level, typical for her age. Lab work identified two potential culprits in her challenges—gluten sensitivity and below-normal blood levels of DHA. I prescribed a strict gluten-free diet, 400 milligrams of supplemental DHA daily, and asked her to stop consuming aspartame, or NutraSweet, as she drank several diet sodas a day. Three months later, mom and dad were thrilled with her progress, and even KM was smiling ear to ear. New academic testing had her math calculation skills at the early fifth-grade level, overall academic skills at the mid-fourth-grade level, and story recall ability at the mid-eighth-grade level. To quote a letter I received from her mother: [KM] is completing third grade this year. Prior to removing gluten from her diet, academics, especially math, were difficult. As you can see, she is now soaring in math. Based upon this test, entering the fourth grade next year she would be at the top of her class. The teacher indicated if she skipped fourth grade and went to fifth grade, she would be in the middle of the class. What an accomplishment! Stories like this are commonplace in my practice. I’ve known about the “achievement effect” from going gluten-free for a long time, but thankfully the scientific proof is finally catching up to the anecdotal evidence. One study that really stood out for me was published in 2006; it documented a very revealing “before” and “after” story of people with ADHD who went gluten-free for six months. What I love about this particular study is that it examined a broad spectrum of individuals—from the age of three to fifty-seven years—and it employed a well-respected behavioral scale for ADHD called the Conner Scale Hypescheme. After six months, the improvements were significant: 11 “No close attention to details” was reduced by 36 percent. “Difficulty sustaining attention” was reduced by 12 percent. “Fails to finish work” diminished by 30 percent. “Easily distracted” diminished by 46 percent. “Often blurts out answers and quotes” diminished by 11 percent. The overall “average score” for those studied was lowered by 27 percent. My hope is that more people will join my crusade and take action to make us all healthier—and smarter. HOW C-SECTIONS INCREASE RISK OF ADHD Babies who are born via Cesarean section have a higher risk of developing ADHD, but why? Understanding the links in the chain give credence to the importance of healthy gut bacteria to sustain intestinal health and overall wellness. When a baby passes through the birth canal naturally, billions of healthy bacteria wash over the child, thereby inoculating the newborn with appropriate probiotics whose pro-health effects remain for life. If a child is born via C-section, however, he or she misses out on this shower of sorts, and this sets the stage for bowel inflammation and, therefore, an increased risk of sensitivity to gluten and ADHD later in life. 12 New research is also giving moms another reason to breast-feed, as babies who are regularly breast-fed when they are first introduced to foods containing gluten have been shown to cut their risk of developing celiac disease by 52 percent, compared with those who are not being breast-fed. 13 One of the reasons for this might be that breast-feeding cuts the number of gastrointestinal infections, lowering the risk of a compromised lining of the bowel. It may also curb the immune response to gluten. CAN AUTISM BE TREATED WITH A GLUTEN-FREE DIET? I get a lot of questions about the possible relationship between gluten and autism. As many as 1 in 150 children born today will develop a form of the condition across a wide spectrum; in 2013, a new government report indicated that 1 in 50 school-age children today—or about a million children— have been diagnosed with some sort of autism. 14 A neurological disorder that usually appears by the time a child is three years old, autism affects the development of social and communication skills. Scientists are trying to figure out the exact causes of autism, which is likely rooted in both genetic and environmental origins. A number of risk factors are being studied, including genetic, infectious, metabolic, nutritional, and environmental, but less than 10 to 12 percent of cases have specific causes that can be identified. We know there is no magic-bullet cure for autism, just as there isn’t for schizophrenia or bipolar disorder. These brain maladies are uniquely different, but they all share one underlying characteristic: inflammation, some of which could simply be the result of sensitivity to dietary choices. While it remains a topic of debate, some people who suffer from autism respond positively to the removal of gluten, sugar, and sometimes dairy from their diets. In one particularly dramatic case, a five-year-old diagnosed with severe autism was also found to have serious celiac disease that prevented him from absorbing nutrients. His autistic symptoms abated once he went gluten-free, prompting his doctors to recommend that all children with neurodevelopmental problems be assessed for nutritional deficiencies and malabsorption syndromes like celiac. In some cases, nutritional deficiencies that affect the nervous system may be the root cause of developmental delays that mirror autism. 15 I’ll admit that we lack the kind of gold-standard scientific research that we need to draw any conclusive connections, but it’s worth taking a sweeping view of the topic and considering some logical inferences. Let me begin by pointing out a parallel trend in the rise of autism and celiac disease. That is not to say the two are categorically linked, but it’s interesting to note a similar pattern in sheer numbers. What these two conditions do indeed have in common, however, is the same fundamental feature: inflammation. As much as celiac is an inflammatory disorder of the gut, autism is an inflammatory disorder of the brain. It’s well documented that autistic individuals have a higher level of inflammatory cytokines in their system. For this reason alone, it’s worthwhile to ponder the effectiveness of reducing all antibody–antigen interactions in the body, including those involving gluten. One study from the United Kingdom published in 1999 showed that when twenty-two autistic children on a gluten-free diet were monitored over a five-month period, a number of behavioral improvements were recorded. Most alarming, when the children accidentally ingested gluten after they’d started their gluten-free diet, “the speed with which behavior changed as a result… was dramatic and noticed by many parents.” 16 The study also noted that it took at least three months for the children to show an improvement in their behavior. For any parent regulating a child’s diet, it’s important to not lose hope early on if behavioral changes don’t occur right away. Stay the course for three to six months before expecting any noticeable improvement. Some experts have questioned whether or not gluten-containing foods and milk proteins can impart morphine-like compounds (exorphins) that stimulate various receptors in the brain and raise the risk not just for autism but for schizophrenia as well. 17 More research is needed to flesh out these theories, but we can potentially reduce the risks of developing these conditions and better manage them. Despite the lack of research, it is clear that the immune system plays a role in the development of autism, and that the same immune system connects gluten sensitivity to the brain. There’s also something to be said for the “layering effect,” where one biological issue ushers in another down a chain of events. If a child is sensitive to gluten, for instance, the immune response in the gut can lead to behavioral and psychological symptoms, and in autism this can lead to an “exacerbation of effects,” as one team of researchers put it. 18 DOWN AND OUT It’s a heartbreaking fact: Depression is the leading cause of disability worldwide. It’s also the fourth leading contributor to the global burden of disease. The World Health Organization has estimated that by the year 2020, depression will become the second largest cause of suffering—next only to heart disease. In many developed countries, such as the United States, depression is already among the top causes of mortality. 19 What’s even more disquieting is the white elephant sitting in the medicine cabinets of many depressed people: the bottles of so-called antidepressants. Drugs like Prozac, Paxil, Zoloft, and countless others are by far the most common treatments for depression in the United States, despite the fact that they have been shown in many cases to be no more effective than a placebo and in some cases can be exceedingly dangerous and even lead to suicides. New science is starting to show just how murderous these drugs can be. To wit: When researchers in Boston looked at more than 136,000 women between the ages of fifty and seventy-nine, they discovered an undeniable link between those who were using antidepressants and their risk for strokes and death in general. Women on antidepressants were 45 percent more likely to experience strokes and had a 32 percent higher risk of death from all causes. 20 The findings, published in the Archives of Internal Medicine, came out of the Women’s Health Initiative, a major public health investigation focusing on women in the United States. And it didn’t matter whether people were using newer forms of antidepressants, known as selective serotonin reuptake inhibitors (SSRIs), or older forms known as tricyclic antidepressants, such as Elavil. SSRIs are typically used as antidepressants, but they can be prescribed to treat anxiety disorders and some personality disorders. They work by preventing the brain from reabsorbing the neurotransmitter serotonin. By changing the balance of serotonin in the brain, neurons send and receive chemical messages better, which in turn boosts mood. Unsettling studies have reached a tipping point, and some Big Pharma companies are backing away from antidepressant drug development (though they still make a lot of money in this department—to the tune of nearly 15 billion dollars a year). As recently reported in the Journal of the American Medical Association, “The magnitude of benefit of antidepressant medication compared with placebo increases with severity of depression symptoms and may be minimal or nonexistent, on average, in patients with mild or moderate symptoms.” 21 This isn’t to say that certain medications aren’t helpful in some severe cases, but the implications are huge. Let’s briefly review some other intriguing findings that will inspire anyone thinking of taking an antidepressant to try another route to happiness. Low Mood and Low Cholesterol I’ve already made my case for cholesterol in nourishing the brain’s health. As it turns out, innumerable studies have demonstrated that depression runs much higher in people who have low cholesterol. 22 And people who start taking cholesterol-lowering medication (i.e., statins) can become much more depressed. 23 I’ve witnessed this myself in my own practice. It’s unclear if the depression is a direct result of the drug itself, or if it simply reflects a consequence of a lowered cholesterol level, which is the explanation I favor. Studies dating back more than a decade show a connection between low total cholesterol and depression, not to mention impulsive behaviors including suicide and violence. Dr. James M. Greenblatt, a dually certified child and adult psychiatrist and author of The Breakthrough Depression Solution, wrote a beautiful article for Psychology Today in 2011 in which he summarized the evidence. 24 In 1993, elderly men with low cholesterol were found to have a 300 percent higher risk of depression than their counterparts with higher cholesterol. 25 A 1997 Swedish study identified a similar pattern: Among 300 otherwise healthy women aged thirty-one to sixty-five, those in the bottom tenth percentile for cholesterol levels experienced significantly more depressive symptoms than the others in the study with higher cholesterol levels. 26 In 2000, scientists in the Netherlands reported that men with long-term low total cholesterol levels experienced more depressive symptoms than those with higher cholesterol levels. 27 According to a 2008 report published in the Journal of Clinical Psychiatry, “low serum cholesterol may be associated with suicide attempt history.” 28 The researchers looked at a group of 417 patients who had attempted suicide—138 men and 279 women— and compared them with 155 psychiatric patients who had not attempted suicide, as well as 358 healthy control patients. The study defined low serum cholesterol as less than 160. The results were quite dramatic. It showed that individuals in the low-cholesterol category were 200 percent more likely to have attempted suicide. And in 2009, the Journal of Psychiatric Research published a study that followed nearly forty-five hundred U.S. veterans for fifteen years. 29 Depressed men with low total cholesterol levels faced a sevenfold increased risk of dying prematurely from unnatural causes such as suicide and accidents than the others in the study. As noted earlier, suicide attempts have long been shown to run higher in people who have low total cholesterol. I could go on and on showcasing studies from all around the world that arrive at the same conclusion for both men and women: If you’ve got low cholesterol, you’ve got a much higher risk of developing depression. And the lower you go, the closer you are to harboring thoughts of suicide. I don’t mean to say this in a casual manner, but we have documented proof now from many prestigious institutions of just how serious this cause-and-effect relationship is. This relationship is also well documented in the field of bipolar disorder. 30 Those who are bipolar are much more likely to attempt suicide if they have low cholesterol. The Gluten Blues Science has long observed an overlap between celiac disease and depression, much like the overlap between celiac and ADHD and other behavioral disorders. Reports of depression among celiac disease patients began appearing in the 1980s. In 1982 Swedish researchers reported that “depressive psychopathology is a feature of adult celiac disease.” 31 A 1998 study determined that about one-third of those with celiac disease also have depression. 32, 33 In one particularly large study published in 2007, Swedish researchers again evaluated close to fourteen thousand celiac patients and compared them to more than sixty-six thousand healthy controls. 34 They wanted to know the risk of being depressed if you have celiac disease as well as the risk of having celiac disease if you are depressed. It turned out that celiac patients had an 80 percent higher risk of depression, and the risk of actually being diagnosed with celiac disease in individuals who were depressed was increased 230 percent. In 2011, another study from Sweden found that the risk of suicide among people with celiac disease was increased by 55 percent. 35 Yet another study done by a team of Italian researchers found that celiac disease ups one’s risk of major depression by a stunning 270 percent. 36 Today, depression is found in as many as 52 percent of gluten-sensitive individuals. 37 Adolescents with gluten sensitivity also face high rates of depression; those with celiac disease are particularly vulnerable, with a 31 percent risk of depression (only 7 percent of healthy adolescents face this risk). 38 A logical question: How does depression relate to a damaged intestine? Once the lining of the gut is injured by celiac disease, it is ineffective at absorbing essential nutrients, many of which keep the brain healthy, such as zinc, tryptophan, and the B vitamins. What’s more, these nutrients are necessary ingredients in the production of neurological chemicals such as serotonin. Also, the vast majority of feel-good hormones and chemicals are produced around your intestines by what scientists now call your “second brain.” 39 The nerve cells in your gut are not only regulating muscles, immune cells, and hormones, but also manufacturing an estimated 80 to 90 percent of your body’s serotonin. In fact, your intestinal brain makes more serotonin than the brain that rests in your skull. Some of the more critical nutritional deficiencies that have been linked to depression include vitamin D and zinc. You already know the importance of vitamin D in a multitude of physiological processes, including mood regulation. Zinc similarly is a jack-of-all-trades in the body’s mechanics. In addition to aiding the immune system and keeping memory sharp, zinc is required in the production and use of those mood-friendly neurotransmitters. This helps explain why supplemental zinc has been shown to enhance the effects of antidepressants in people with major depression. (Case in point: A 2009 study found people who hadn’t been helped by antidepressants in the past finally reported improvements once they started to supplement with zinc. 40 ) Dr. James M. Greenblatt, whom I mentioned earlier, has written extensively on this topic and, like me, sees a lot of patients whose antidepressants have failed them. Once these patients avoid foods containing gluten, their psychological symptoms resolve. In another article for Psychology Today, Greenblatt writes: “Undiagnosed celiac disease can exacerbate symptoms of depression or may even be the underlying cause. Patients with depression should be tested for nutritional deficiencies. Who knows, celiac disease may be the correct diagnosis and not depression.” 41 Many physicians ignore nutritional deficiencies and don’t think about testing for gluten sensitivity because they are so used to (and comfortable with) writing prescriptions for medication. It’s important to note that a common thread in many of these studies is the length of time needed to turn things around in the brain. As with other behavioral disorders, such as ADHD and anxiety disorder, it can take at least three months for individuals to feel a total sense of relief. It’s critical to stay the course once embarking on a gluten-free diet. Don’t lose hope if you don’t have significant improvements right away. But do realize that you’re likely to experience a dramatic improvement in more ways than one. I once treated a professional tennis instructor who was crippled by depression and not improving despite the use of multiple antidepressant medications prescribed by other doctors.