For the past 3 years, the American Psychiatric Association annual meeting has included a session called “Food and Brain,” a whirlwind look at how diet can influence mental health. Only this year there was a twist: raw oysters shucked live at the podium.
“Some people think 9 AM is too early to have fresh oysters, but we don’t,” commented co-chair Drew Ramsey, MD, assistant clinical professor of Psychiatry at Columbia University College of Physicians & Surgeons in New York City, before announcing that throughout the presentation questions would be posed to the audience; get a question correct and walk to the front of the room to gulp an oyster.
Oysters, it turns out, are incredibly good for the brain, as Dr Ramsey reminded the audience throughout his presentation. And for the next hour and half, he and session co-chair, Emily Deans, MD, a private-practice psychiatrist in Massachusetts and a part-time instructor in psychiatry at Harvard Medical School, walked the audience through what, besides bivalves, constitutes a healthy-brain diet and why.
Dr Ramsey, in collaboration with the new International Society for Nutritional Psychiatry, is in the process of developing a standardized “brain food diet.” “Food is a very effective and underutilized intervention in mental health,” he started off. “We want to help our patients have more resilient brains by using whole foods…by helping get patients off of processed foods, off of white carbohydrates, and off of certain vegetable oils.”
Though the field is in its infancy, food psychiatry is increasingly being embraced by clinicians and researchers, as a paper published earlier this year in the Lancet Psychiatry attests. “Although the determinants of mental health are complex,” the authors wrote, “the emerging and compelling evidence for nutrition as a crucial factor in the high prevalence and incidence of mental disorders suggests that diet is as important to psychiatry as it is to cardiology, endocrinology, and gastroenterology.” Other recent work found that simply discussing diet with a counselor for just 6 hours over the course of 2 years dropped Beck Depression Inventory scores by 40% in elderly patients with depression.
“The data are very promising that we can positively influence mental health through dietary interventions,” commented Dr Ramsey.
Dr. Deans then took the mic took to explain how evolution has shaped the human diet. “Hominid diets have changed drastically through millions of years of evolution. We started with plants, insects, and larvae; but around 2 million years ago we began incorporating meats into our diets, contributing to the development of the advanced hominid brain,” she explained. “Then 1 to 2 million years ago we added tubers and bulbs. Finally, around 6000-10,000 years ago, agriculture was developed and we added grains, dairy, and legumes to our diets.”
But only in the past 100 years has our diet drastically switched from a whole foods diet to one that is more processed and high in refined carbohydrates; that includes more vegetable fats rather than meat fats; and preservatives, emulsifiers, and other additives, which appear to have contributed to a decline in our collective health.
The backstory of 20th century grain processing, specifically, is an inane one. Once-nutritious kernels were stripped of their nutrients as new refining practices emerged, only to have specific vitamins added back artificially, given the health problems associated with overly refined grains. Grains and other foods have been processed and preserved for thousands of years, but by using much healthier means. For example, fermentation of grains—and letting them sprout—increases nutrient availability.
The first quiz question then flashed on the screen: What food group is most closely associated with Homo sapiens’ brain evolution?
Early humans evolved in the African Rift Valley, which is near a seacoast. It’s possible that whatever evolutionary spark occurred that made us human occurred here, in part due to reliable access to seafood—oysters in particular—which glutted our brains with omega-3 fatty acids and cholesterol (our brains are composed of 60% fat).
Oysters and other mollusks are also very high in nutrients, including B12, which is commonly deficient in people consuming vegan or vegetarian diets and is necessary for myelin and neurotransmitter function. As Dr. Deans pointed out, oysters can be an option for some people avoiding meat for moral reasons; oysters don’t have a highly developed nervous system, so if they do feel pain—and many scientists believe that they may not—it’s most likely scant.
Dr. Deans then pointed out that despite focusing on specific nutrients or foods when considering nutrition, there has been a refreshing and hopefully more effective trend recently among experts to focus the influence of dietary patterns on brain health. Enter the Mediterranean diet.
A number of studies have linked the Mediterranean diet (high in fish oils, nuts, and grains and including maybe a little red wine) with advantageous effects on neurologic and mental health. Dr. Deans cited recent work reporting that adults who followed the Mediterranean dietary pattern the closest over 4.4 years had a significantly reduced risk of developing depression (40%-60%).Also, a 2014 meta-analysis by Felice Jacka, PhD, of Deakin University in Melbourne, Australia, and colleagues found that 47% of the randomized controlled trials included reported improved depression outcomes with dietary interventions, levels comparable to those of drug trials. These data are doubly promising given that dietary interventions are relatively low-risk.
When taken together, most of these dietary pattern studies, which have been conducted all over the world, consistently show that traditional, pre-processed diets are the healthiest, including for the brain. To that point, Dr. Deans presented the case of a patient she had treated: a 37-year-old psychologist with a long history of treatment-resistant depression, severe allergies, and asthma. After being started on the paleo diet—a diet mimicking what our hominid ancestors would have eaten (e.g., meat, nuts, berries) —not only did she lose 40 pounds, but her depression resolved without adjunct medications, and her allergy symptoms improved too.
Next, Dr. Deans presented the second quiz question: Which two dietary patterns are associated with higher rates of anxiety during pregnancy?
Answer: Vegetarian and high-sugar diets. (More on these later.)
To elaborate, Dr. Ramsey presented his simple rhyme for remembering a healthy brain-food diet: Seafood, greens, nuts, and beans (and some occasional dark chocolate). “We see it in clinical practice all the time: With a [healthier brain diet] people’s focus improves,” he said, “people’s energy improves, their self-confidence improves, and their involvement in their own self-care improves.”
Dr. Ramsey also acknowledged that it’s not as simple as telling someone to go eat kale and anchovies; clinicians should be helping patients incorporate these foods into their overall dietary patterns, including discussing how to prepare them in desirable ways. “People are often mainly eating for heart health; they’re counting calories rather than nutrients and are avoiding red meat. These are all rules of avoidance that aren’t actually helping put nutrients on a patient’s plate,” he commented.
So how does Dr. Ramsey encourage his patients to eat healthier in the interest of mental health?
“You don’t have to do some extensive food survey,” he says. “I’ll just say ‘Hey, let’s talk about food for a few minutes because it plays a big role in mental health.'” Dr. Ramsey will ask his patients what they’ve had for breakfast, lunch, and dinner over the past few days; he’ll sometimes even ask them to send him photos of their meals. If they’re not necessarily abiding by the healthiest dietary pattern, he’ll try to elicit brain-healthy foods that the patient does like and discuss working them into the patient’s diet. A recent patient of his didn’t realize that red peppers and eggs were so good for the brain; she loves them both.
“It’s not our job to say, ‘Eat vegan’ or ‘Eat paleo’; it’s to partner with our patients based on where they are and help them select more nutrient-dense foods,” says Dr. Ramsey. “Look for allergies, aversions, and even ask about what their childhood dinner table was like—looking for how people eat food and where improvements can be made.”
He also cautions to be on the lookout for too much beige: pizza, pasta, and rice. “Eat the rainbow,” he says, given that bold, bright colors in nature tend to signify valuable vitamins and phytonutrients (the reds, purples, and greens in particular).
Dr. Ramsey is currently co-developing a brain food manual to provide clinicians with key points about food groups and specific ingredients to help them talk to their patients. Part of the project entails developing a mathematical scale to rank the healthiest brain foods. The list is still in development. Despite all of the buzz around kale lately, however—including Dr. Ramsey’s successful book 50 Shades Of Kale—the trendy vegetable appears bested by a number of other vegetables, including mustard greens. In terms of meat and dairy, oysters, clams, and spleen will probably land near the top of the list. Spleen recipes aren’t exactly filling the pages of Bon Appétit, but given the recent foodie resurgence in organ meat, it is starting to appear on menus. Incidentally, most animals when hunting go for the organs first because of their nutritional value.
“Just have your patients circle two or three foods that they like and have them put that on the fridge,” Dr. Ramsey recommends, after which he’ll encourage patients to work these foods into their diet by swapping them for less healthy foods. A patient of his with a thing for white chocolate–covered pretzels—essentially nothing but refined carbohydrates—successfully transitioned to dark chocolate–covered almonds, two of the top brain foods. Almonds are a top source of vitamin E and have lots of monounsaturated fats, while dark chocolate (the higher percentage of cacao the better) is a major source of iron and flavanols. Another way to swap: “If somebody loves hamburgers,” says Dr Ramsey, “how about suggesting beef and vegetable stew instead?”
Dr. Ramsey then explained the specific health benefits of the major categories of brain foods, meaning those that are nutrient dense in ways that benefit the brain.
Seafood: Seafood is packed with brain-healthy omega-3 fatty acids. These healthy fats are also abundant in plants like chia and flax, but plant-based sources aren’t as efficiently converted to docosahexaenoic acid (DHA), an important structural component of neuronal membranes. DHA also influences the expression of brain-derived neurotrophic factor (BDNF), which can benefit people who have mood and anxiety disorders. Bivalves like mussels, oysters, and clams are the top source of vitamin B12 as well as zinc: Six oysters (only about 10 calories each) provide 240% of our recommended daily B12 intake and 500% of our recommended zinc intake! Seafood is also a leading dietary source of vitamin D (we don’t get it all from the sun) as well as iodine and chromium. Although many people worry about mercury in fish, Dr. Ramsey provided an easy way around the concern: Eat small fish like sardines, anchovies, and herring, which typically don’t accumulate toxic levels.
Leafy greens: A great base for a brain-food diet, leafy greens are a good source of fiber, folate (derived from the word foliage), magnesium, and vitamin K. Perhaps surprising, kale, mustard greens, and bok choy provide the most absorbable form of calcium on the planet, more so than milk. Greens also provide flavanols and carotenoids that have beneficial epigenetic influences (e.g., including upping hepatic toxin processing). One cup of kale provides 600% of daily vitamin K, 200% of vitamin A, and over 100% of vitamin C—all for only 33 calories. For those who are greens-phobic, Dr. Ramsey ran through a list of preparation methods to make them more appetizing: sauté them with olive oil and garlic; put them in a smoothie; bake some kale chips.
Nuts: Nuts had a bad rap for a while because of their high fat content. But, as Dr. Ramsey revealed, “There’s great news here. We’ve overestimated the caloric content of nuts. Anytime you look at the calories in nuts, take off 25%.” Nuts are packed with healthy monounsaturated fats. They help keep us full and also aid in absorbing fat-soluble nutrients. Nuts also provide fiber as well as minerals like manganese and selenium. A serving of 22 almonds (just 162 calories) contains 33% of our recommended vitamin E, plenty of protein, and minerals, including iron. One study from 2013 found that the Mediterranean diet augmented with nuts is associated with significantly higher BDNF levels in patients with depression.
Legumes: Dr. Ramsey is pro-meat, but he acknowledges that many people are eating far too much and the wrong types of meat, and that nuts and legumes are a great alternative source of protein and nutrients. Small red beans in particular are the top antioxidant-containing food, while just 1 cup of lentils contains 18 g of protein and 90% of the recommended daily folate intake. “It’s a requirement in my practice that you get a slow cooker and an oyster shucker,” said Dr. Ramsey to laughs from the audience.
Some data suggest that vegan and vegetarian diets are associated with improved mood. But as previously mentioned, these dietary patterns can result in B12 deficiency, which has been associated with brain atrophy and developmental delay. Hence, supplementation is important in this population. Vegetarianism has also been linked with depression, anxiety, and eating disorders, as well as increased healthcare utilization and worse quality of life.[8,9] These negative associations also could be due to the fact that it’s harder to absorb nutrients like zinc, iron, and certain omega-3s from plants.
“The notion that the vegan diet is the healthiest diet on the planet is probably incorrect,” said Dr. Ramsey, before explaining that he just feels that we should approach meat in our diets differently.
The average American consumes over 200 pounds of meat and fish per year. “That’s not sustainable for the planet,” commented Dr. Ramsey, “especially if you look at the amount of beef we consume. We want to help patients use beef and seafood more as flavorings on top of a plant-based diet.” This type of diet echoes Thomas Jefferson’s approach to nutrition, now en vogue with many nutrition experts: “I have lived temperately, eating little animal food, and that not as an aliment, so much as a condiment for the vegetables which constitute my principal diet.”
A modest amount of meat in the diet has its benefits, including nutrient availability: Hemoglobin-derived iron is up to 40% more absorbable than plant-based iron. Unlike most plants, meat provides all of the amino acids necessary for protein synthesis. Dr. Ramsey emphasized the importance of seeking out leaner, grass-fed meats if one has the means. Aside from the grim state of large-scale meat companies—the packed cages, animal cruelty concerns, the overuse of antibiotics—industrially raised animals reared on corn instead of grass have excessive intramuscular fat to a degree not found in nature, which is not as healthy for us.
“We want to get people off of this stuff,” concluded Dr. Ramsey.
Dr. Deans took the stage to discuss one of today’s trendiest health issues: gluten.
“There are some real issues,” she began, “but I think most people can tolerate whole grains and gluten quite well.” About 2% of Americans have celiac disease and are allergic to gluten, even in microamounts. Gluten sensitively is a bit more controversial; it’s reportedly found in up to 6% of adults, yet 11% of adults now purchase gluten-free foods.
One related area that may deserve particular attention is the possible relationship between gluten and psychosis. The CATIE trial demonstrated that patients with schizophrenia have significantly elevated antigliadin antibodies (gliadin is a component of gluten); over 23% of schizophrenic patients had moderate to high antigliadin antibodies compared with just 3.1% of controls. “Maybe we should be checking our psychotic patients for celiac disease,” commented Dr. Deans, before walking the audience through an anecdotal case.
A very skinny, 37-year-old woman with no psychiatric history had become increasingly paranoid and psychotic within 1 year. She had lost her job, become homeless, and alienated family and friends. She underwent numerous drug treatment trials to no avail. Eventually she arrived at the hospital, and because of her weight, an endocrinologist suggested celiac disease. Though initially skeptical, the patient agreed to go to the state hospital where she was kept on a gluten-free diet for 3 months. She stabilized.
Subsequently she consumed a gluten-heavy meal and her antigliadin antibodies skyrocketed again; she ended up back in hospital. “They called and asked me about meds,” recounted Dr. Deans, “but I said, ‘No meds; just keep her gluten free.'” Once again, the patient quickly remitted.
“I just think that if we’re going to start recommending things like MRI for first-episode psychosis, screening for celiac disease is a lot cheaper and might be good to think about,” said Dr. Deans. But for most people, she commented, going gluten free probably won’t have much of an effect. “All of these gluten-free options are great for people with celiac disease, but otherwise I don’t think that a gluten-free muffin is particularly healthier than your white flour muffin in terms of brain health.”
Like gluten, discussion of the microbiome now appears almost daily in lay and professional media. “A gastro friend of mine thinks we should play a drinking game,” joked Dr. Deans, “where anytime someone mentions the microbiome, we take a drink.”
Our microbiomes contain well over 1 million genes, compared with our 23,000 genes. Furthermore, the commensal microbiome accounts for 90% of the cells in our bodies. Among other functions, these gastrointestinal symbiotes help form and maintain our immune system and aid in digestion, so their health is critical to our health. The understanding of how microbiota contribute to our mental and medical well-being is rapidly advancing.
For example, there is considerable overlap between irritable bowel syndrome and depression and anxiety. “My contention is that they are the same pathology that are expressed in different phenotypes,” posited Dr. Deans. Gut pathogens cause inflammation and increase factors like IL-6 and interferon gamma—findings also seen in depression—ultimately reducing the conversion of tryptophan to serotonin. Dr. Deans wonders whether chronic inflammation might be at the core of conditions such as depression and anxiety and introduced the concept of psychobiotics, or the idea that microbiota can influence the mind and mental health.
One of the most powerful interventions to alter our microbiome is diet. Research shows that stressed mice experienced changes in the gastrointestinal microbiota, reflecting the gut-brain relationship. There are 260 million neurons connecting the gut and the brain; furthermore, many commensal gut bacteria make neurotransmitters and communicate with the brain via the vagus nerve. “I don’t know what they’re saying to us,” joked Dr. Deans, “but let’s just say that if you get a fecal transplant, you want to get if from a happy, mellow person.”
Although the science of probiotic therapies is relatively young, it’s clear that these commensal organisms co-evolved with us and are adapted to our diet. One study out of The Netherlands found that a 4-week regimen of multispecies probiotics can reverse cognitive reactivity to sad mood. Another study explored what would happen if a group of African Americans in Atlanta swapped diets with a group of rural black South Africans. The investigators were curious to see whether dietary differences could help explain the drastically differing rates of colon cancer between the two populations (65:100,000 in African Americans vs < 5:100,000 in rural South Africans). The South African diet was high in fiber and prebiotics, while the American diet was much higher in junk food, refined carbohydrates, and animal fats. Within 14 days of switching to the South African diet, healthy butyrate-producing microbial species increased by 258% in the American population. Butyrate is a byproduct of bacterial fermentation in the colon and is thought to protect against colon cancer.
Dr. Deans then mentioned the recent media coverage of a geneticist who put his son on a 10-day all-McDonald’s diet and measured his microbiome before and after. It was found that the son reduced the diversity of his microbial species by 40%, as assessed by three different labs. (In all fairness, he was restricted to burgers and fries and not the healthier options that McDonald’s offers.)
Finally, to close out the session, Dr. Ramsey returned to the stage and asked, “So, can you eat to build a better brain? We think that you can if you focus on dietary patterns and not a single food here or there.” He also reminded the audience to help their patients identify and increase their consumption of nutrient-dense foods and to “eat the rainbow,” assuming, he cautions, that the rainbow doesn’t include bright red Gummi Bears.
“I don’t know of anything else that can potentially decrease the risk of depression in a population by 40%,” he concluded. “Perhaps diet is the closest we’ve come to prevention in psychiatry.”
Following the talk, the packed room had lots of questions. Below are the highlights.
Question 1: What’s healthier: raw food or cooked food?
“What could be more human than a cooking fire, right?” asked Dr. Deans rhetorically. She explained that cooking tends to increase nutrient availability and decrease toxins, and that many grains as well as potatoes are actually poisonous raw. “I’m not a huge fan of this raw-food movement,” she said, “but some foods—greens especially—can be healthier raw because cooking breaks down nutrients.” Dr. Ramsey then chimed in: “I recommend a mix of cooked and raw foods to my patients. But we invented fire and started cooking for a reason.”
Question 2: Should we worry about recommending too many high-cholesterol foods like oysters, particularly in people with high cholesterol?
“Dietary cholesterol really doesn’t affect blood levels of cholesterol that much,” responded Dr. Ramsey, “One of the main drivers of heart disease is high triglycerides, which come heavily from eating glucose and fructose.” But he did caution that if patients have high cholesterol or an abnormal cardiovascular condition, then it’s important to get a patient’s primary care doctor or cardiologist involved.
Question 3: We hear a lot about certain spices being healthy. Can you comment on this?
“That’s a great point,” answered Dr. Ramsey, “You can’t just tell people to eat grass-fed beef; spicing is important both for flavor and possibly health.” Evidence suggests that curcumin, an ingredient in turmeric, increases BDNF. Other research has found that populations that eat more curry have a decreased risk for dementia, while rosemary extract may help prevent cognitive impairment. “Many spices seem to have healing properties,” Dr. Ramsey commented.
Question 4: Is coffee and tea consumption healthy?
The data on coffee are very good. “I had a patient who was drinking nine Diet Cokes a day,” recalled Dr. Ramsey. “I switched him over to coffee. It’s still a low-calorie drink, but now he’s getting healthy flavonoids. And tea is one of my favorite ways to try to get people off of soda; there are so many teas available with antioxidant properties.” Earlier this year, a study out of Japan reported that higher consumption of green tea is associated with a lower risk for dementia or mild cognitive impairment.
“Most coffee data have been positive, even with high intake,” commented Dr Ramsey, though, as he pointed out, transient increases in blood pressure and anxiety can occur.
Question 5: Is milk healthy for the brain?
“Milk consumption is an interesting adaptation in the human race since the advent of agriculture,” explained Dr Deans, “and lactase persistence in adults—meaning you can digest lactose into adulthood—has evolved six separate times over the past 6000 years. Clearly there’s an evolutionary population advantage to it.” Milk consumption may help explain why modern humans are so much taller than other hominids.
Dr. Ramsey then mentioned the fact that people started avoiding dairy in part as reaction to the “China study,” a large epidemiologic study that reported a correlation between dairy and cancer. “But this is one of those cases where we take a correlational study and go crazy with it,” he said. “The data have also been called into question.” Dr. Ramsey explained that milk is reasonably nutrient dense and that he’s not pro- or anti-dairy.
Question 6: What about fasting?
Although the “Food and the Brain” session at the American Psychiatric Association annual meeting focused on what to eat in the interest of brain health, intermittent fasting might also be beneficial for the brain. In addition to helping maintain a healthy weight, fasting induces ketosis. Ketone metabolism has been shown to be beneficial for the brain and improve cognition in patients with mild cognitive impairment or Alzheimer disease. Keep in mind that fasting can come with risks for some people, particularly diabetics, and should be discussed with a healthcare provider.