Does Sugar cause ADHD? and can protein cure it?

“Don’t give them that! They’ll be bouncing off the walls all day!” - any parent at a birthday party from about 1984 onwards.

Is it true though? Can junk food - and particularly sugar - actually cause ADHD? Are the people who give you carrot sticks for Halloween onto something or are they, in fact, misunderstanding the data and creating core memories for the next generation in a way they wouldn’t want?

I remember watching TV in the 1980s - we had three channels folks - and hearing about E-numbers and how they were affecting children. I promptly finished off my glass of entirely synthetic juice (soda/pop), crumpled the bag of crisps into the bin and sped off to cycle around the neighbouring streets for a few hours… (only partly kidding).

The diet and ADHD connection - it’s (sort of real)

The facts are quite simple: yes, some children and adults with ADHD experience a change in behaviour after eating refined food, usually sugar.

The problem is that it’s usually not the one way relationship people imagine.

On the face of things the research seems to show that increased intake of sugary drinks and food is connected to the expression of ADHD type behaviour and problems - and the more sugary drinks kids had, the more ADHD their behaviour was observed to be in a Chinese study from 2016.

Recent studies seem to show that a high fructose diet in early life can affect adolescent rats and lead to more mental health problems… but is it actually causing the same problems in humans?

Highly refined and processed food and ADHD - what’s the connection?

What does diet do to our brains?

Remember the blog post about lack of sleep and how alzheimers can be connected to ‘metabolic inflammation’? The same ‘metabolic disregulation’ markers - caused by type 2 Diabetes, insulin resistance, etc - can be triggered by a diet that’s high in processed food and most of those contain sugar. If our diet is out of balance - and predominantly refined, processed food - then we are going to experience more of that from an early age.

But that doesn’t mean sugar causes ADHD.

And there are complicating factors that need to be taken into account before we start demonising a food and eliminating it completely.

The Reward Deficiency of ADHD

The biggest step forward in recent ADHD research (from 2007 onward) has been - I think- the work of Dr Norah Volkow and colleagues looking at the biology of addiction and the reward deficiency of ADHD brains. Keeping it as simple as possible:

ADHD is characterised by a dopamine-deficient brain. We can release more dopamine from looking for the substance (refined sugar) and in an untreated or unsupported ADHD state, have less impulse control to limit our intake. The sugar then causes other (negative) feelings from responses in the amygdala and we look for it AGAIN to reduce those negative feelings… It’s a perfect storm, all inside your body.

Take a minute to read that again. Our brains don’t have the same baseline level of dopamine: we look for dopamine (and this can be from food, gambling, sex, other substances etc) - and when we find it, depending on what that is, we then feel WORSE. The ‘bad’ feeling is sometimes because of a reaction in the rest of our brain, especially the amygdala.

Our friend the amygdala is the ‘guard’ that alerts us to danger - the food/drug can create a metabolic state of disregulation that our brain and body regard as DANGER - so our dopamine, already disappearing thanks to the extra powerful hoovers or transporters, needs to be topped up again because

humans want to feel good and be calm/happy.

Throw in the constant availability of food - especially cheap refined food which is more easy and cheaper than naturally grown, organic fruit, vegetables or meat in most places - and voila. Your brain, sugar, dopamine, rinse and repeat.

This doesn’t mean that sugar CAUSES ADHD - and in the first study I mentioned from China - and from lots of other ones - I’d argue that:

the reason more “significant and severe ADHD” appears in people who have higher sugar intake is because their particularly dopamine-deficient brains are driving them to find that sweet, sweet dopamine - not because the sugar causes the ADHD in the first place.

Wait, there’s more…

I’m going to mention in passing that the co-occurrence of ADHD with autism and other sensory processing issues means that kids with ADHD are LIKELY but not guaranteed to have sensory preferences for refined food - which is more likely to be higher in sugar. Again, the sugar does not CAUSE the autism - but it is part of the sensory profile that often leads kids to have entirely beige, safe diets.

Many people with ADHD and/or autism will look at this image and cringe. The ‘healthy’ diet promoted - and supported by science - is one that challenges us for several reasons.

• sensory preferences: unrefined food is less predictable, more ‘slimy’ etc.

• planning: most unpackaged ‘healthy’ food needs a modicum of prep. An ADHDer seeking urgent dopamine OR who has ignored their hunger cues for too long wants to eat NOW not in the 10 minutes it takes to make an omelette.

• preparation: there are many steps to making food that isn’t in a can. Many.

• experience & education: although I know that the professional kitchen can be a place where ADHD shines, for most mortals the time, education and patience it takes to learn to cook really tasty food feels overwhelming. We know that the takeaway or snack will hit the spot and we will learn some other time (never).

This sounds grim. What can we do?

There are solid reasons to try and improve our general diet - not least because adults with ADHD are twice as likely to be diagnosed with Type 2 diabetes and we know that is connected to a higher risk of dementia. No thanks.

Education - about ADHD, the elevated risks and how to improve our diet

Learning more about what ADHD is and how we can manage it is always the best, first step.

(congratulations! you’ve ticked that one off already)

Improving your diet is a slightly tricker topic - especially if you’ve got sensory issues that limit your range of acceptable food.

Find a neurodivergent affirming dietician

I’ve been pleasantly surprised to find more ADHD friendly nutritionists and dieticians online but as always, make sure that they are comprehensively trained and understand your circumstances and needs. Ideally your local healthcare provider will be able to connect you with someone but if not, look at the national body that governs dieticians in your country.

Focus on protein first

The studies all say the same thing: adding more protein will help your brain. There are two reasons and summarising them

• protein helps to build neurotransmitters (i.e. dopamine) because of the ‘building blocks’ it contains. This is incredibly important during adolescence - but in adults, you might find that restricting protein actually releases more dopamine. Find out what works for YOUR brain by experimenting - e.g. having protein first thing (scrambled eggs, or scrambled tofu or protein drink: if you can’t ‘do’ soggy food, try baked tofu pieces that have been coated in nutritional yeast before going into the oven and serve with a dip that you like).

• a diet with a higher focus on protein reduces the ‘hedonic’ or reward response that can set our brains off on a dopamine seeking path very quickly.

I personally have experienced this twice: when I completely removed refined sugar and focused on protein and vegetables with a very little fruit, after a few days I was absolutely not interested in any of my usual snacks. This lasted until I had ‘a treat’ for a birthday or special occasion and very quickly returned to my normal eating habits. This is just an anecdotal, personal experience and is NOT medical advice or dietary guidance - I’m just sharing what I’ve experienced in the past.

A dopamine boosting diet - but without extremes

there’s a fashionable ‘dopamine diet’ going around that is not one most nutritionists would recommend because it restricts carbohydrate and focuses on weight loss. That might be part of your goal but is more likely when you’re feeling GOOD and your ADHD is being well supported.

Instead, think about adding these to make your diet more dopamine - and brain chemistry - friendly.

 L-Tyrosine

Tyrosine is an amino acid that helps your brain build dopamine (and is included in the recipe for lisdexamfetamine…) You can’t access dopamine directly from food, so try to include Tyrosine instead: You can get it from:

• lean animal protein - chicken, beef, lamb, fish, pork…

• avocados

• bananas

• dairy, cheese in particular

• soybeans

• nuts

• beans

• whole grain

• apples

• broad beans (high in l-dopa, the direct precursor to dopamine, can cross the blood-brain barrier!)

Other dopamine building ingredients include:

B vitamins, vitamin D, niacin, zinc, selenium and iron, amongst others.

A balanced, nutrient-rich diet is key! Think whole foods (lots of vegetables and fruit, green leafy vegetables, oily fish) as a daily staple.

If you have a limited diet, please find professional help to make sure you are getting what you need.

Probiotics

Additionally, research shows that over 50% of dopamine is produced in the gut, so looking after your gut microbiome is key. 

Probiotic-rich foods like kefir, kimchi, sauerkraut, kombucha come with a whole array of health benefits, so make sure you include them in your daily menu.

Reduce…

Yes, sorry - reduce refined sugar. It’s got a lot of negative consequences.

And saturated fat - it also affects your dopamine sensitivity…

Other dopamine thieves

include too much caffeine, which we often use to boost our brains if we are unmedicated. Bizarrely it can lead to really HIGH dopamine concentrations - so our brains usually respond by changing how it responds to the levels and we are back on the ‘hunt for reward’ path again.

If you are struggling with a diet that’s high in sugar, I want you to be reassured that you are not ‘weak’, you are not ‘failing’, you are not ANY of the negative messages society - and your brain - will give you.

You live in a world where the kind of stress and strain we swim in every day depletes our dopamine - and other lovely neurotransmitters - and it’s only natural that we look for ways to restore balance.

The other ways to restore balance take time, they sometimes take more money, and they are always just a bit more effort - at least to begin with - than the fast and easy alternative.

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Warmly,

Katherine

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Further Reading:

Yu CJ, Du JC, Chiou HC, Feng CC, Chung MY, Yang W, Chen YS, Chien LC, Hwang B, Chen ML. Sugar-Sweetened Beverage Consumption Is Adversely Associated with Childhood Attention Deficit/Hyperactivity Disorder. Int J Environ Res Public Health. 2016 Jul 4;13(7):678. doi: 10.3390/ijerph13070678. PMID: 27384573; PMCID: PMC4962219.

Barrett CE, Jiang M, O'Flaherty BG, Dias BG, Rainnie DG, Young LJ, Menigoz A. Early life exposure to high fructose diet induces metabolic dysregulation associated with sex-specific cognitive impairment in adolescent rats. J Nutr Biochem. 2023 Apr;114:109220. doi: 10.1016/j.jnutbio.2022.109220. Epub 2022 Nov 23. PMID: 36435289; PMCID: PMC9992084.

Johnson RJ, Gold MS, Johnson DR, Ishimoto T, Lanaspa MA, Zahniser NR, Avena NM. Attention-deficit/hyperactivity disorder: is it time to reappraise the role of sugar consumption? Postgrad Med. 2011 Sep;123(5):39-49. doi: 10.3810/pgm.2011.09.2458. PMID: 21904085; PMCID: PMC3598008.

Gondré-Lewis MC, Elman I, Alim T, Chapman E, Settles-Reaves B, Galvao C, Gold MS, Baron D, Kazmi S, Gardner E, Gupta A, Dennen C, Blum K. Frequency of the Dopamine Receptor D3 (rs6280) vs. Opioid Receptor µ1 (rs1799971) Polymorphic Risk Alleles in Patients with Opioid Use Disorder: A Preponderance of Dopaminergic Mechanisms? Biomedicines. 2022 Apr 7;10(4):870. doi: 10.3390/biomedicines10040870. PMID: 35453620; PMCID: PMC9027142.

Volkow ND, Michaelides M, Baler R. The Neuroscience of Drug Reward and Addiction. Physiol Rev. 2019 Oct 1;99(4):2115-2140. doi: 10.1152/physrev.00014.2018. PMID: 31507244; PMCID: PMC6890985.

Dehnavi AZ, Zhang-James Y, Draytsel D, Carguello B, Faraone SV, Weinstock RS. Association of ADHD symptoms with type 2 diabetes and cardiovascular comorbidities in adults receiving outpatient diabetes care. J Clin Transl Endocrinol. 2023 Apr 11;32:100318. doi: 10.1016/j.jcte.2023.100318. PMID: 37124458; PMCID: PMC10130340.

Naneix, F., Peters, K.Z., Young, A.M.J. et al. Age-dependent effects of protein restriction on dopamine release. Neuropsychopharmacol. 46, 394–403 (2021). https://doi.org/10.1038/s41386-020-0783-z

Journel M, Chaumontet C, Darcel N, Fromentin G, Tomé D. Brain responses to high-protein diets. Adv Nutr. 2012 May 1;3(3):322-9. doi: 10.3945/an.112.002071. PMID: 22585905; PMCID: PMC3649463.

Kühn, S., Düzel, S., Colzato, L. et al. Food for thought: association between dietary tyrosine and cognitive performance in younger and older adults. Psychological Research 83, 1097–1106 (2019). https://doi.org/10.1007/s00426-017-0957-4

Wang GJ, Volkow ND, Thanos PK, Fowler JS. Imaging of brain dopamine pathways: implications for understanding obesity. J Addict Med. 2009;3(1):8-18. doi:10.1097/ADM.0b013e31819a86f7

Medical University of Vienna. "Dopamine: Far more than just the 'happy hormone'." ScienceDaily. ScienceDaily, 31 August 2016. <www.sciencedaily.com/releases/2016/08/160831085320.htm>.

Galland L. The gut microbiome and the brain. J Med Food. 2014;17(12):1261-1272. doi:10.1089/jmf.2014.7000

Hryhorczuk C, Florea M, Rodaros D, et al. Dampened Mesolimbic Dopamine Function and Signaling by Saturated but not Monounsaturated Dietary Lipids. Neuropsychopharmacology. 2016;41(3):811-821. doi:10.1038/npp.2015.207