You Are What You Eat: How Diet Impacts Cognitive Function & Mood

Dr. Chapa:
We've all heard the phrase "you are what you eat," but are we now at a point where science is backing up that old saying?  Welcome to Clinician's Roundtable on ReachMD.  I'm your host, Dr. Hector Chapa, and here today to share the real science on how diet can impact cognitive function and mood is Dr. Kellie Moore.  Dr. Moore is a naturopathic physician with her own practice called Presh Health in Washington. 

Dr. Moore, thanks for being here today.  

Dr. Moore:
Thank you so much for having me.  

Dr. Chapa:
This is a great topic.  It's a good subject because there's a lot of interest about this, so I'm really excited for it.  So Dr. Moore, before we dive into the topic of how our diet can affect our mental processes, can you first tell us a little bit more about what a naturopathic physician does? 

Dr. Moore:
Sure.  In Washington State, we're actually licensed as primary care providers.  And when I talk to prospective patients about the way that a naturopath like myself will typically approach a condition, I use the analogy of a pyramid of treatment options, and at the very top of the pyramid you have surgery and medication—which, of course, come in very useful  for certain conditions—and then at the bottom of the pyramid, we have lifestyle modifications, and I divide up that—the bottom of that pyramid into five pillars:  stress management, nourishment, movement, rest, and connections.  And each of those has categories within them.  And then between that part of the pyramid, that base lifestyle piece and medicine, we have things like nutraceuticals, so things like magnesium, vitamin D, vitamin C, and then botanicals, and then hormones, so in my scope of practice, I can work pretty much through all the way up to pharmaceuticals.  Wherever I intervene, I'm also always making sure that we're taking care of those five pillars of health in some kind of way. 

Dr. Chapa:
Wow, I really like that.  That's the first time I've heard about those five pillars put in that perspective.  And as we do so much education on the physical health and training on pathophysiology—I have to be honest—I agree with you that this issue of behavioral health and just lifestyle modification is highly important.  Well, one of those behavioral modifications that we can do, of course, is our diet.  Now multiple studies have found a correlation between a high diet that's high in refined sugars, that it impairs brain function, along with a worsening of symptoms of mood disorders, like depression.  So can you explain this relationship between what we eat and how we feel mentally? 

Dr. Moore:
Yeah, so there's a few different mechanisms that connect what we eat with our mental health and our cognition.  So first of all, just simple things—like you said, you are what you eat—like we literally make our neurotransmitters from the food we eat, right? 

And so having those ingredients is important for mental health, and then things like blood sugar regulation, which I think we're all pretty familiar with in terms of how it can impact mood.  And then there's things like inflammation, which is a superpower.  It's a great thing to be able to have to protect us from illness and also to help us heal.

But when it persists chronically, then we do have evidence for it impacting our neurological function, and that is—you know, inflammation is very much impacted by diet in a couple of different ways.  We can consume a lot of proinflammatory foods and then we can also be deficient in nutrients that help us reduce inflammation and process endogenous and exogenous toxins. 

Dr. Chapa:
So Dr. Moore, specifically, which foods should we avoid? 

Dr. Moore:
Right.  So, when you're talking about foods to avoid for optimal mental and physical health,  the first thing on the list is sugar. 

Added sugar, and then even more processed forms of sweeteners—corn syrup, high-fructose corn syrup—those are all proinflammatory, and they also mess with our blood sugar regulation, so that's the first thing on the list.  And then we have other foods that are high in calories but low in nutrient density, so you're basically wasting those calories because you're not using them to consume nutrients, so those would be things—you know, the classic example would be something like french fries,

And then we have alcohol, and caffeine also can impact mental health.  But really, when I'm talking to patients about optimal diet, I don't like to get super specific.  I like people to have as broad of a diet as possible, but within that be eating foods in their ‘wholest’ form possible and steering away from highly processed food.  Or some physicians refer to them as food-like substances.  They don't even count them as food because they're not nourishing. 

Dr. Chapa:
For those of you just tuning in, you're listening to Clinician's Roundtable on ReachMD.  I'm Dr. Hector Chapa, and I'm speaking with Dr. Kellie Moore about the ways in which diet can impact our cognitive function. 

So Dr. Moore, we focus on specific types of food and diet as it relates to our cognitive function and mood, but what about these caffeinated beverages that you just spoke about?  We hear a lot of data on the potential benefits of caffeine and coffee—for example, when taken in moderation.  So is caffeine a friend or foe as it relates to our mental well-being? 

Dr. Moore:
It's very individualized, and it does depend on quantity.  So as you mentioned, especially coffee can be a source of antioxidants and a lot of people say it's one of the higher sources of antioxidants, so it certainly does have benefits, but it depends on how quickly your body can process that caffeine, and it also depends on how much you're having. Unless my patients are really struggling with stress or anxiety or some other hormonal imbalance, I typically don't tell them to completely avoid caffeine, but I will also remind them that caffeine can be a vehicle for sugar and excess dairy and when taken past sort of 2:00 p.m., it can be problematic for sleep.  So that's kind of the balance I like to strike.  I don't like to be really restrictive with my patients, and I talk a lot more about what to include in the diet versus what to exclude; but certainly, caffeine has its light side and dark side, like most things in life. 

Dr. Chapa:
And before I leave, I do want to touch one more issue here because you mentioned sugars.  Are all sugars bad?  Or what about this, you know, the brown sugars or the quote "more natural" sugars?  Is there such a thing?  Because I know some of the listeners will have that question, because I do.  Are you saying cut out all sugars completely?  Because that's kind of a miserable life.  So help us find this balance here. 

Dr. Moore:
Yeah, yeah, I'm always looking to strike a balance.  And so, if you think about any food, nothing in life is all good or all bad, right?  Everything has that possibility to be good or bad.  So sugar can bring a lot of joy, like you said, and there's a lot of aspect to food and nourishment that is not nutritional, that is cultural, and experiential so I don't like to take that away from people completely, but there is a spectrum of  more to less healthy forms of sweeteners.  At the very bottom of that spectrum of food-like substances that I really encourage people to avoid are high-fructose corn syrup and corn syrup.  So steering clear of those, you can still get a sweet treat with sugar.  As you sort of work up that scale, you get things that are even less refined.  So whenever you're thinking about  the nutritional value of a food, you're always thinking about how much is it processed.  So brown sugar is less processed than white sugar.  Sugar cane is less processed than brown sugar.  And so you move along that scale, and then you can also look at things like the glycemic index of a sweetener.

So the coconut sugar will have a lower glycemic index than something like cane sugar.  And then you even have things like dates or dried fruits that we tend to think of as a healthy food but that can have a lot of sugar and can be problematic for people who struggle with blood sugar regulation. So when I'm talking to people who do have elevated glycemia with elevated fasting insulin, elevated lipid and they're struggling with metabolic health, I remind them that fruit can be viewed more as a treat or a dessert, especially fruits that are not berries.  Berries, I've put into the category of okay for most people most of the time, but foods like apples or bananas or things with a very high sort of surface area to volume ratio, those are going to have fewer nutrients and more sugar, so I remind people to see this as a treat and then to also eat them when they do eat them with fat and protein because that will help slow down the breakdown of the sugar that's in them. 

Dr. Chapa:
Well, so for example, my children, who are teenagers now, they'll do, the banana with peanut butter, so that's a good idea then. 

Dr. Moore:
Yeah, definitely. 

Dr. Chapa:
Wow, that's really interesting.  So now that we've covered a lot of ground today, Dr. Moore, before we wrap up, can you give us some high-yield takeaway points regarding our diet, specifically as it relates to our mental health? 

Dr. Moore:
Yeah.  So one tool I wanted to share is the Modified Mediterranean Diet that was used in the SMILES trial, which was one of the first randomized controlled trials that showed the impact of diet on mental health.  We're very familiar with the Mediterranean Diet for cardiovascular health, and this study shows the benefit for mental health as well, and that's a resource that you can look up as a provider.  Just look for the Modified Mediterranean Diet food pyramid.  And it breaks down food categories into what is recommended daily and what is recommended weekly, and it's pretty similar to a typical Mediterranean Diet, but it does include lean red meat because lean red meat is high in minerals like zinc and certain B vitamins that are really important for mental health. 

And then another tool that can be really useful for clinicians is something called The Antidepressant Food Scale, and this was designed by a couple leaders in neuropsychiatry, specifically Dr. Drew Ramsey and his colleague, and what they did was they looked for all the nutrients that have evidence for being important for mental health, and then they looked for foods that have high quantities of those nutrients, and so these are foods that you can encourage patients to include in their diet.  But just zooming out from a really broad perspective, when I'm advising patients on diet, I talk about aiming for three servings of protein the size of the palm of your hand per day, aiming for about seven servings of veggies—a serving is half a cup cooked or a cup raw—and then a handful of nuts, a tablespoon of olive oil and depending on the person, we may add in certain quantities of grains or legumes or meat, but that's how I start advising people on their diet.  And honestly, Dr. Chapa, a lot of people are starting from a place in their diet that's very far from the recommendation, right? 

And so I like to really teach people as a first step to look at their plate, look at the food on their plate and notice what colors are on it, and if it's all brown or yellow, then add a handful of spinach or add a handful of blueberries because those two foods go with almost anything.   And color is where we're getting a lot of these nutrients that are really important for mental health, especially leafy greens. We also talk about trying to eat a rainbow of food every day, but really for a lot of people, just adding color to their plate is going to be really an important first step. 

Dr. Chapa:
I mean, such a basic thing that we take, honestly, for granted every day, every one of us.  Especially I think in this country, as Americans, just diet, just we have food always around us, but it's such an important factor in really not just our physical health but our mental health, as you had said, Dr. Moore, so those are certainly some great points for us to take with us today. So I want to thank my guest, Dr. Kellie Moore, for sharing the science on how diet can impact our cognitive function and mood.  Dr. Moore, it was great speaking with you today. 

Dr. Moore:
Thank you so much. 

Dr. Chapa:
I'm Dr. Hector Chapa.  To access this and other episodes in our series, visit ReachMD.com/CliniciansRoundtable, where you can Be Part of the Knowledge.  Thanks for listening.