Ask most people what ADHD is and they’ll talk about focus, fidgeting or losing their keys. The focus is primarily on the brain, but the people I work with present with symptoms and health concerns beyond the obvious ADHD cognitive issues.
It might be the little boy who hasn’t had a proper poo in five days or the teenager who gets headaches most afternoons. The dad who lives on antacids and has finally admitted he’s had IBS for years or the mum whose ADHD feels twice as hard in the week before her period. The girl who always seems to be spraining an ankle and complains her legs ache after school.
Most of them assumed these were separate problems, but this is unlikely and a big piece of research doing the rounds at the moment suggests the same. It found adults with ADHD were more likely to have 34 out of 35 physical health conditions the researchers checked. We need to talk more about this.
What the study found
The research was done in Sweden by the Karolinska Institute and published in The Lancet Psychiatry. They went through the health records of around 4.8 million people and compared adults with an ADHD diagnosis to those without. Rheumatoid arthritis was the only condition on their list that didn’t come up as more common in the ADHD group.
Some of the links were much stronger than others:
| Condition | How much more likely with ADHD |
|---|---|
| Alcohol-related liver disease | 4.7 times |
| Sleep disorders | 4.6 times |
| COPD | 3.2 times |
| Epilepsy | 3 times |
| Fatty liver disease | 2.9 times |
| Obesity | 2.7 times |
Gut problems were on there too and other studies have found people with ADHD are roughly 50% more likely to have gut symptoms like IBS, constipation or diarrhoea.
It starts young as well. A UK study that has followed nearly 11,000 people since they were born in 1970 found that children with lots of ADHD traits at 10 were more likely to have two or more health problems by their mid-40s and women seemed to be hit harder. This tells me we should be paying as much attention to the body as we do to behaviour and focus.
So why might this happen?
The researchers think genetics explains part of it and smoking, weight and mental health explained a bit more. Looking at it as a clinical nutritionist, there are a few other things I’d want to add.
The first is the gut. Your gut and brain are in constant conversation, mainly through the vagus nerve and the bacteria living in your gut help make the raw materials for dopamine and serotonin. Studies have found the gut bacteria of people with ADHD often look a bit different. Food sensitivities are common too and when the gut isn’t happy, it can cause symptoms like bloating and constipation, but it can also affect mood, sleep and concentration.
Then we need to factor in the impact of inflammation. A lot of the conditions in that study, from asthma to fatty liver, have a background level of inflammation in common, and inflammation can affect the brain too. Connective tissue disorders are also more prevalent and this makes us think more deeply about whether the blood-brain-barrier could also be compromised.
Blood sugar is also a huge factor in ADHD too. ADHD brains are drawn to quick rewards and sugar is about as quick as it gets. Add in skipped breakfasts and getting so absorbed in something that you forget lunch and you end up on a rollercoaster of crashes and cravings. Years of that can feed into weight gain and liver problems.
I also see a lot of the same nutrient gaps; iron, zinc, magnesium, vitamin D and omega-3 come up over and over in ADHD research and they’re needed all over the body, not just in the brain. Some ADHD medications take the edge off appetite too, which can make nutrient issues worse.
Sleep problems were more than four times as common in the study and a bad night throws off blood sugar, appetite and gut health and every ADHD symptom feels harder the next day. For women, hormones play a part because oestrogen affects dopamine, so a lot of women notice their ADHD changes through their cycle and gets harder in perimenopause. That might help explain why the UK study saw a stronger effect in women.
None of this will be news to a lot of neurodivergent families. You’ve probably been saying for years that the tummy aches, the sleep and the energy dips are all part of it. It’s good to finally have the research catching up. In my experience, when we sort out the gut, sleep and blood sugar, focus and mood improve too.
This is the work I do every day at Brain Food Nutrition, with neurodivergent children and adults. If any of this sounds familiar, you can find out more or book in here – https://brainfoodnutrition.co.uk/book-an-appointment/
