The Role of diet: Children & Adults with Learning Disabilities

Welcome to Omega Matters where we talk all things omegas. I'm Christina Jackson. This is Bill Harris, my dad. And today we are excited to bring in Dr. Rachel Gao. Dr. Gao is a child neuropsychologist specializing in ADHD and associated neurodivergent conditions in the overall field of nutritional neuroscience. She holds a PhD in child neuropsychology from King's College in London and is a registered nutritionist, which is under the category of science. She's a lecturer at several universities in the UK and trained here at the NIH stateside with Dr. Joe Hibbeln. She writes books and has created a nonprofit to help talk about this topic. Thank you so much for joining us, Rachel.

Yeah, it's my absolute pleasure. Thank you for inviting me. I'm excited to talk with you both today.

Yes, this is the hot topic that we are asked about all the time: kids, ADHD, omega-3s. So I'm always curious how you got into this field. How did you, what is your journey to get you to a place where you are so deeply involved in the research and the clinical side of this issue?

Sure. How long have we got? Do you want the short version?

Sort of short, sort of detailed, you know.

Yeah. It's been a long journey. I started out really just as a mom with my firstborn son who was diagnosed with ADHD and dyslexia. And then basically that completely transformed both of our lives. I knew something about dyslexia, I'd never really heard much about ADHD back then. Now it's a household term, but it wasn't then. I felt I had to start researching. Parents of children with neurodivergent conditions often become better researchers than FBI agents. We want to know every day, so that's what happened. Then I decided to enroll as a mature student. We can do that in the UK. On the back of life experience and age, I was granted entry without conventional entry criteria after an interview. I started a bachelor of science in psychology, which led to a master's in psychological research methods, which was really interesting because a lot of it was statistics but also learning to critique published research in terms of design and methodology. There was also a neat philosophy side that I loved. Then I was offered a PhD at King's College London at the Institute of Psychiatry in the Department of Child and Adolescent Psychiatry under one of the UK's leading authorities in ADHD research, Professor Eric Taylor, who was head of child medicine psychiatry. I was privileged to work with him and conducted a four-year project in child neuropsychology, trained also in child and adolescent psychiatry. I was invited to be a postdoctoral researcher in the section of nutritional neuroscience where I spent four years. I've just finished studying again, my PG CAP, a higher education training qualification to enable me to be more qualified in lecturing and teaching university students.

Wow. And you are a registered nutritionist. Yes, so you got that degree too and you're an author of Smart Foods. We'll show that more clearly. Show us your book. Smart Foods for ADHD? Is that what you said?

Smart Foods for ADHD and Brain Health.

Excellent. Wonderful. We should put that in our show. Years of knowledge. Well, you know, I wrote it after my PhD because I felt like I needed to share that information. Once you do your dissertation, it goes into the annals of science, but it doesn't necessarily drip into clinical practice or general popular culture. So that's awesome that you wrote a book about it. I did not know you had such a personal connection to this. That's really fascinating. I'm curious, when do you also work clinically with other kids? Is that part of where this study that you just published came from?

Yeah, that's interesting. I did for some time have a private clinic where I would screen children for ADHD and other neurodivergent conditions, and then depending on the outcome, work with a child adolescent psychiatrist who would handle the diagnostic evaluation, or refer within my network to a clinical psychologist or educational psychologist, whatever came up.

Okay. Excellent. So I guess with the study, if we want to get into the study that you did, you just published a study in Frontiers called A Closer Look at the Role of Nutrition in Children and Adults with ADHD and Neurodivergence. Can you tell us what the overall study rationale was and then the methods?

Yeah, of course. I think first and foremost, seeing families on a day-to-day basis for some time, I started to observe that upon having a blood draw, the child or young person often presented with a number of nutritional insufficiencies as well as food intolerances. Having a thorough look at their food diaries, I noticed really interesting relationships: these children were eating the very foods they were intolerant to. The main culprits were cow's milk, where they'd be guzzling dairy, or wheat gluten. I started looking into these what I felt were symbiotic relationships. For example, tests came up that they were intolerant to cow's milk, yet they were craving it and drinking it by the pipes. I felt that without knowing, this child was potentially feeding the dysbiotic pathogenic gut microbiome, facilitating its growth to the point of overcolonizing, potentially increasing risk for more serious conditions like leaky gut syndrome or gut dysbiosis. I decided this needed to be put together because observational data is interesting, but you need several case studies. In my case, there were about 80 families. I was a guest lecturer at the University of Roehampton with a dear friend, Dr. Simon Dyall, a world-renowned researcher in omega-3 fatty acids. I wrote to him, telling him about my preliminary observations and asking if he'd be interested in putting this data set together as a clinical project for some of his master's students. I was invited to collaborate and ended up supervising four master's students in clinical nutrition. We put together all the families. Each family would visit a clinic in W1 for a blood draw by a qualified phlebotomist or have a home visit, and then the data was analyzed. We put all the data together. Some families didn't consent, we lost touch with some, but it was a sizeable amount of data as a healthy starting point. We aim to build on this database and also collect data from non-diagnosed controls. That was really the start of it all.

Did you have this paper that's coming out in Frontiers? Why don't you tell us about that before I ask you more questions?

Yeah, of course. Many parents or carers of neurodivergent children also have the challenge of that child being a fussy eater or picky eater. This is quite common and spoken about quite a bit. Should we pause because my coffee machine is running? I don't know, it just switched on magically.

Well, I'm also—my light, and we are in a new building and it turns off when I don't move enough. So if it goes black a few times, I'm just going to wave.

So children with ADHD and other neurodivergent conditions tend to be picky eaters, fussy eaters. They also have an increased risk of developing disordered eating or problematic eating. Some common disorders include avoidant and restrictive eating patterns, ARFID-like traits, which are very common in children with both ADHD and autism spectrum disorders. There's food neophobia, a reluctance or outright refusal to try new foods. It's estimated that around 20% of children with ADHD develop some type of eating disorder, although other research suggests it's higher, up to 37%. We also know that OCD is associated with orthorexia nervosa. There is a frequent pattern of high levels of food selectivity, avoidance of entire food groups, strong preferences for certain foods, and lots of sensory aversions to taste and textures. It's not uncommon for a young person with ADHD or ASD not to eat fruits and vegetables until their mid-20s to early 30s.

Oh wow. I did not know it went on until then, and fruits and vegetables are very large food groups to avoid. What you said about them seeking out dairy is interesting. It's as if the gut biome is not able to absorb when it's inflamed. I've never heard that they actively seek out food that is also inflaming their guts, but they're not actually getting what they need from it. Is the same thing happening with grains? Milk has so many nutrients, and magnesium was one of the main ones you found a lot of relationships with in this paper. Do often times they eliminate these foods and that helps with symptoms, or not?

Yeah, it's really hard to eliminate foods, especially for children who are such fussy eaters. The research has shown that children with ASD frequently consume fewer vegetables, fruits, and high-fiber foods, which are obviously needed for the gut, and instead rely heavily on ultra-processed foods and refined carbohydrates. There's a lot of research demonstrating that, so this is not new knowledge. It's very common knowledge that children with neurodivergent-related conditions are at risk of nutritional insufficiencies. I'm particularly interested in how that influences brain activity and function, especially mood, because we know that certain nutrients are absolutely critical to regulate our serotonin and dopaminergic systems in the brain. We see a lot of dysregulated behaviors in these children. It is a real struggle. There's been lots of research in the field of nutritional psychiatry showing a lack of antioxidants, polyphenols, lower fiber, magnesium, folate. These are commonly found in food sources that are rejected by neurodivergent children due to their complex textures and bitter tastes. That contributes unknowingly to micronutrient insufficiencies, which obviously impacts their behavior as well.

Can we bring it around to omega-3? That's our primary interest here.

Yes, yes. In this paper, we looked at 57 people, and we measured blood levels of a variety of nutrients including omega-3. What did we find? Approximately 63% of the full sample presented with suboptimal omega-3 index scores. For those that don't know, the omega-3 index is the sum of EPA and DHA, the two key highly unsaturated fatty acids we need for optimal brain function. We used the OmegaQuant as well because it's comprehensive and provides a detailed overview of not just omega-3 fatty acids but much more. The mean omega-3 index was 4%, which is very low. We know through the work of other research groups in England, like the DUG study and Dr. Alex Richardson, that the mean omega-3 index in UK school children was 2.4%, very low. The omega-3 index is increasingly being used in nutritional psychiatry research. When I was at the NIH, we measured the omega-3 index in a group of adults with ADHD who took part in our NORA study, the world's first randomized placebo-controlled clinical trial to look at omega-3 versus placebo in the brain activity of adults with ADHD using neuroimaging techniques. It was a 16-week RCT that unfortunately never got published but should have been. We found an omega-3 index of 4.2 in those adults.

I'm sure the general public would say, well, you did this study, why didn't you publish it?

I've been trying for 10 years, so make of that what you will. Not dead yet. Kept getting blocked. Yeah, shame. But I try. I've been talking about it in presentations, discussing what I can, and some of it has been semi-published. I'm going to try and go back to it.

We're very interested in trying to figure out how we can define a healthy target omega-3 index for kids. What data set would we use to define normal healthy kids? If you can find those kids, can you get blood samples from them and use their omega-3 level as a theoretical target for health? What do you think?

Yeah, I mean, in your paper, you defined healthy using the standard of under 4% and over 8%, which were originally set up for adults because we didn't have data in kids. That's a challenge we're facing now. People want to know if those are the right numbers for adults or if they should aim for something else in kids. That's a really relevant and important point. The scale is for adults, but it's increasingly being applied in research with children, so I think it will need to be adjusted accordingly. That said, we still know that children eat very little fish, oily fish, and seafood. I take diaries so I get to see it firsthand, as well as the blood. There's no real general consensus. There are recommendations by authorities like Goyens and Iversen for 250 milligrams as the average amount a child should consume, and government recommendations of one to two portions of oily fish and seafood. But I do feel we need firmer recommendations, given the brain is the fattiest organ in the body and DHA plays a critical role in cell signaling across neuronal networks, making for faster, more efficient communication, plus the other roles of these brain-essential fats.

In trying to link ADHD with low omega-3, it becomes a chicken and egg thing. If they don't eat omega-3, their blood levels are low. We don't know if that's part of the causal pathway or just a result of having ADHD. How can we make a causal connection?

Yeah, it's way more complex than that. The biochemical pathway in terms of conversion from alpha-linolenic acid to EPA and DHA is highly problematic and mediated by a multitude of factors, including whether the child is male or female, their background diet, and genetic activity, like the delta-5 and delta-6 desaturase enzyme activity, which can potentially be impaired. That needs more research. I wanted to do that type of research as a PhD student, look at stable isotopes to map and trace absorption, but it was costly and we ran out of time and money. Nutritional research is not easy. I think what's really difficult is that many psychiatrists and psychologists come into the field without biochemistry or nutritional training, jumping on the bandwagon to conduct an RCT without measuring baseline levels of the child's omega-3 and omega-6 fatty acid levels before supplementing. They don't adjust the dose or look at the formula; they don't understand the difference between omega-3 and omega-6. I've looked at Cochrane reviews where they've just thrown everything in—garbage in, garbage out—and they adopt researchers with no biochemistry training to be lead authors. Nutritional research is far from easy. Also, nutrients don't work in isolation; they work in synergy. When you eat a piece of fish, you don't just get the omega-3s, but also the multivitamin, iron, magnesium, selenium, zinc, all working together to facilitate absorption into red blood cells. Often people take their one gram of fish oil daily without changing their background diet. As I was taught at NIH by Bill Lands, you have to elevate the omega-3s and simultaneously decrease the omega-6s. It's not easy.

Have you seen an older paper where they did blood levels of normal controls, ADHD, and autism spectrum and found low DHA and also low arachidonic acid, the omega-6? So it was just low essential fatty acids across the board. What do you think about that in context with what you saw here?

Yeah, it's a great question. Both omega-3 and omega-6 are essential polyunsaturated fatty acids. There's a lot of vilification of omega-6, mainly due to a lack of education. We obviously need omega-6; it's brain-essential. We have to be careful with the amount we consume through ultra-processed foods because the processing of oils containing omega-6, the refining and hydrogenation, may be linked to harms. Whereas if you have something unrefined and virgin, it's going to be a lot—I hate the word 'cleaner,' but you know what I mean. Omega-6s alert us to injury; if I cut myself, that wound becomes inflamed, signaling I need to treat it. But if the wound is still red and inflamed three months later, I'm in trouble. That's a simplistic way, but yes, it's linked to inflammation. Instagram has gone crazy over this; you see it all the time. We need to be careful with misinformation. Nutritional education is critical. I love that you guys have this podcast. Your dad is one of the top researchers in this field, and you're doing an amazing job of re-educating everyone.

Oh, stop. What do I think? I think we need to take closer looks. It's a very complex picture, not as well understood as we think or would like. It's not always clear-cut. This field is expanding rapidly, which is wonderful. When I first started, nutritional psychiatry wasn't as big as it is now. It's growing with more research investment. I had to come to America to get funding to do the research I wanted. Nutritional research was not funded at all in the UK.

Do you recommend for parents with kids who have ADHD to give them omega-3 supplements?

Well, my motto is foods first. You have to address the diet. I think it's really frustrating because nutrition is often addressed from the neck down in terms of its preventative role in metabolic health diseases like type 2 diabetes, obesity, stroke, and cardiovascular disease. The role of nutrition in the activity and function of the human brain is not well understood, especially by those in privileged positions to make changes like our GPs. If someone turns up at the GP surgery saying they have low energy, fatigue, anxiety, or tearfulness, they won't ask what they eat. That question seldom features in mental health screening, which I call brain health. We're not at the stage of recommending simple tests like the omega-3 index test, things we can do at home, giving the patient authority to be agents of change over their own lives. We need to get power back to the patient, allow them a voice, and say there are things you can do at home, like testing your omega-3 index, and giving them that critical, potentially life-saving information, rather than just writing a prescription for an SSRI and telling them to come back in six months. Brain health is so much more than that. I want to see that change in my lifetime.

Yeah, we agree. Especially in kids. Many parents don't want to jump to medicine; they want to try everything else they can first. It's interesting that we have the same issues in the States around nutrition. It's too big for GPs to get into. It would be an amazing place for registered dietitians or nutritionists to have a bigger role. Along with being able to test this nutrient, one of many, but it is one of the key critical ones that is fairly deficient. In this population, it seemed like the overall rate of omega-3 deficiency is probably 50-60% of kids in the US. We often see kids have lower levels of omega-3s compared to adults. That's part of where we're trying to assess whether 8% is appropriate for kids. They can get to 8% with supplementation. There are also functional foods, emulsions, and ways to hide vegetables or omega-3s in something more palatable. They're more likely to have something processed with sugar, but you're trying to dose them up to start addressing symptoms and move toward a more balanced diet.

There's a lot there. I love the fact that you're making America healthy again. We'll see.

We were doing that before the last election.

I love that there's been some cleaning up going on, a focus on food dyes already banned in England and Europe. Children are the most vulnerable; they are rewarded with ultra-processed foods for exam marks or behavior. It's hard because we're all indoctrinated into it as part of our society. A lot of these non-nutritive foodstuffs are not the diet of our ancestors; they're not how we used to eat. I would like us to get back to basics. I know it's tough; I've been a single mom myself, and it's really hard. But get back in the kitchen, select your own ingredients, prepare and make your own meals. It takes time and getting up earlier, but it's so important because we've become too reliant on supermarket foods. Often parents don't check labels. Emerging research shows dietary emulsifiers are acting like laundry detergents in our guts, stripping away healthy gut microbes. In my research, looking at the children's group only, we found nutrient values below recommended ranges for vitamin D. We know from research that vitamin D has a moderately favorable antidepressant effect, helping reduce symptoms of depression and anxiety. In England, 65% of the UK population is estimated to be vitamin D deficient because we spend much of our time under dark gray rainclouds with little direct skin exposure to sunlight. Also iodine: 53% of the group had insufficient iodine levels, which directly impacts brain function. Zinc: 71% had lower than recommended values. Vitamin E and alpha-carotene, the antioxidants, were all below recommended ranges, as well as the omega-3 index. None of the children had optimal values; the mean score was around 4%. So there's stuff going on. It's a small group and only preliminary, we're not making big claims, but I hope it inspires researchers in nutritional psychiatry to take a closer look at the role of nutrition in ADHD and other neurodivergent conditions. We also found interesting relationships between nutrient levels and ADHD symptoms. Magnesium was moderately negatively correlated with total ADHD index scores, and related to children's behavior—the lower the magnesium, the higher the disruptive behavior scores. Omega-3 was negatively related to learning and language scores—the lower the omega-3, the higher the learning and language difficulties. These were all in children. The relationships between food and brain health deserve much greater investment, and research funds must be allocated to this study.

That is a great message to end on. That's the message we like to get out too. We could talk a lot about this, but it brings it back to what needs to be done: more research to understand the role of nutrition in children's mental development and mental health.

Can I just say something to end? For me and many others in this field, the future of brain health and well-being requires a whole-person, holistic, intuitive, and personalized model. You've got the nutritional biochemistry, lifestyle, behavior, beliefs and habits, psychological thoughts, emotions, cognition, physiological factors, and interconnected biological systems. These are all key contributing factors to brain health and wellness, and for building brain health resilience in a protective way against premature disease development.

Very good. Keep up your work in this field. We're looking forward to seeing what else you come out with and to checking out your book. Thank you so much for coming to talk with us today.

My absolute pleasure. It was a joy. I really enjoyed it. Thank you for inviting me. It's lovely to see you again.

All the best. Thanks. Okay.