The Opioid Effect: How Food Fragments in the Bloodstream Can Influence Cravings

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Why some foods feel irresistible

Picture a string of pearls. That’s your meal, long chains of proteins that digestion should clip into single pearls (amino acids) or tiny pairs (dipeptides). These are what the our body is able to absorb.  However when our digestion stalls – because of low enzyme output, chronic stress, inflammation, rapid eating, poor sleep, infections, medications, or microbiome imbalance – larger fragments can linger. If this meets increased gut permeability (often called ‘leaky gut’), small protein fragments may slip into the bloodstream. Food itself should never be in the blood — only nutrients from food.

Many people describe a pattern: “I’m grand all day… then the bread/cheese calls me.” That tug is not only emotional. In some, it may be biochemical.

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The gut-brain conversation and the blood-brain barrier

The bloodstream that collects nutrients from your gut also supplies your brain. The brain is guarded by the blood-brain barrier (BBB), a highly selective filter. We once thought the BBB was almost impenetrable, now newer research shows its permeability can change with inflammation, stress, infections, and metabolic strain. When the gut barrier is leaky, the BBB is sometimes more porous too, which may allow unusual signals – including certain food fragments – to influence brain chemistry.

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Exorphins: food fragments that act a bit like opioids

Some protein fragments structurally resemble opioids ( the body’s  pain and pleasure  modulating messengers).  Your body makes endorphins that fit opioid receptors like a key in a lock – cue the warm lift you feel after a run, a good laugh, or a sunset. Strong drugs like morphine and heroin hijack the same locks.

Two food‑derived peptides get the most attention:

• Beta‑casomorphin – a casein fragment from cow’s milk products.
• Gluteomorphin (gliadorphin) – a gluten fragment from wheat, barley, rye, and products made from them.

These exorphins can bind to opioid receptors. They don’t create a dramatic high; the effect is subtler — a steady nudge towards “I need cheese/bread every day” or “once I start, I can’t stop.”  For a subset of people, that nudge can drive cravings, overeating, brain fog, and fatigue.

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What I see in clinic

Across two decades in practice, I’ve watched patterns repeat. Some clients trial four weeks without dairy or gluten and feel indifferent. Others feel intense resistance, even when they’re coming to me for change. That resistance isn’t a character flaw, it may reflect how strongly those foods engage their reward circuits. When withdrawal‑like symptoms crop up in week one –  headaches, irritability, yawning, low energy, poor sleep – they usually pass by day 4-7.  Adults, teens, and parents of children and teens, report steadier energy, calmer digestion, clearer skin, and more stable mood.

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Where this matters most

The opioid excess theory doesn’t claim that gluten or dairy are universally problematic. It proposes that in susceptible individuals, exorphins may amplify symptoms in:

• Autism spectrum conditions

• Schizophrenia and psychosis‐spectrum presentations

• Bipolar disorder and recurrent depression

• Anxiety, OCD‑like patterns, and irritability

• Binge‑eating tendencies and weight gain

• IBS, bloating, diarrhoea/constipation, reflux

• Migraine, brain fog, fatigue, disordered sleep

The degree of impact varies person to person. Genetics, microbiome, immune tone, sleep, stress load, and nutrient status all modulate the effect. This is why a carefully run trial is more informative than making any assumptions.

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A clear four‑week protocol (safe, structured, supportive)

Week 0: Prepare

• Eat regularly to stabilise blood glucose.
• Stock balanced swaps: lactose‑free or A2 dairy if appropriate, or calcium‑rich alternatives (fortified plant milks/yoghurts, small fish with bones, sesame/tahini, leafy greens). For gluten‑free, favour whole‑food carbs (potatoes, rice, quinoa, buckwheat, oats labelled gluten‑free).
• Prioritise protein (poultry, fish, eggs, legumes, tofu, lean meats) and fibre (vegetables, fruit, pulses) to support satiety.

Weeks 1–4: Omit completely

• If assessing casein: exclude cow’s milk, yoghurt, cheese, ice‑cream, whey/casein proteins. Consider whether goat/sheep products are included in your trial or not — we can decide based on symptoms.
• If assessing gluten: exclude wheat, barley, rye, spelt, and common sources (breads, pastas, pastries, most gravies/sausages, many processed foods). Choose naturally gluten‑free staples and check labels carefully.
• Support the exit: hydration, magnesium‑rich foods (pumpkin seeds, cocoa, leafy greens), omega‑3 (oily fish, walnuts), and consistent sleep.

Week 4+: Re‑challenge (the diagnostic moment)

• Add back one food at a time (e.g., milk on day 1; nothing new on day 2–3). Track you or your childs mood, cravings, gut symptoms, skin, sleep, energy. Clear flares suggest sensitivity. No change suggests wider causes are likely.

Do this with professional guidance to avoid nutritional gaps and to interpret results without bias.

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Book Nutrition Consultation ONLINE or in-person

I offer ONLINE Nutrition Services and care and in‑person appointments in Adare, Newcastle West Limerick, Abbeyfeale, Midleton, Youghal East Cork, Cork, and Dungarven.  As a Registered Nutritionist, Clinical Hypnotherapist, Advanced RTT,  and Psychotherapist, I combine nutrition, counselling, psychotherapy, hypnosis, clinical medical hypnotherapy, nutrition with a functional medicine approach to help you make confident, sustainable change.

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Frequently Asked Questions

Do food‑derived peptides cause autism, bipolar disorder, or schizophrenia?

No. Neurodevelopmental and psychiatric conditions are multifactorial. Genetics, prenatal exposures, trauma, infections, immune and metabolic factors, sleep, and environment all contribute. What the exorphin research suggests is that, for some, gluten or casein‑derived peptides may exacerbate specific symptoms e.g., irritability, sleep disruption, hyperactivity, stereotypies, gut distress, brain fog.  In those cases, a correctly run dietary trial can reduce symptom load alongside ongoing medical and psychological care.

How would I know if exorphins are a problem for me or my child?

Red flags I commonly see: powerful pull towards bread, pasta, cheese, or milk; feeling unusually low, foggy, or sleepy after meals rich in those foods.  Or the  ‘can’t stop once I start’ eating.   IBS symptoms.   Eczema and acne flares.   Migraines.    Pronounced week one withdrawal symptoms and issues when you attempt to reduce these foods.   While none of these prove an opioid effect, however together they justify a supervised trial with your Registered Nutritionist.

Is there a difference between A1 and A2 dairy proteins?

Casein comes in variants. A1 beta‑casein , this is common in many modern dairy herds, and can yield certain beta‑casomorphins during digestion. A2 beta‑casein, found in some herds and in goat and sheep milk,  may behave differently for some people. Responses are individual. We can structure a trial that first removes all casein, then re‑introduces A2 to see if it’s tolerated in the body.

What about oats and ‘gluten‑free’ labelling?

Oats contain avenin, not gluten, but cross‑contamination with gluten grains is common. Choose oats labelled gluten‑free during any trial. Some people who are sensitive to gluten also react to oats; we can test this in a later phase if needed.

Can this approach help with ADHD, Anxiety, or low mood issues?

Diet is not a replacement for medical care or mental health. However stabilising blood sugar, correcting nutrient deficits such as iron, zinc, B‑vitamins, omega‑3, and by removing personal trigger foods can noticeably improve focus, irritability, sleep quality, and energy. In clients with clear exorphin sensitivity, removing the triggers often reduces urgency around snacking and improves emotional steadiness.

I tried going gluten‑free and felt worse. Why?

Two common reasons: 1) Under‑eating protein and fibre – swaps like gluten‑free toast and biscuits can be lower in fibre/protein, spiking blood sugar. 2) Withdrawal window – days 2-5 can feel rough (headache, low mood). Both are fixable with better meal design and gentle support. If symptoms persist, we reassess — the diet might not be your driver.

Will fermented dairy (yoghurt, kefir) or long‑aged cheeses be easier?

Fermentation and ageing can partially break proteins into smaller fragments, but they don’t guarantee a casomorphin‑free food. In sensitive people, even small amounts can restart cravings or symptoms. That’s why the diagnostic phase is strictly complete for four weeks.

Could enzymes help me digest these proteins?

Lactase helps with lactose (the milk sugar) –  useful for lactose intolerance –  but does not address casein peptides. Multi‑enzyme blends can support protein digestion in general, yet they are not a substitute for a proper elimination‑rechallenge when we are testing an exorphin mechanism.

What tests exist for leaky gut or exorphins?

Options include lactulose-mannitol permeability testing, zonulin markers, stool tests for microbiome balance and inflammation, and nutrient status panels. Urinary peptide tests have been explored in research settings but are not widely standardised clinically. In practice, a meticulous  Food‑and‑Symptom  trial  often gives clearer answers, faster, at lower cost.

Can exorphins contribute to weight gain?

They can, indirectly, by increasing food ‘wanting’,  dopamine linked drive,  and blunting satiety cues. If you pair that with modern ultra‑processed foods and erratic sleep, and it’s easy to overshoot our daily intake. A well constructed elimination trial often reveals how much easier appetite regulation becomes without constant nudges from trigger foods.

Is this safe for children or during pregnancy?

Any dietary restriction for children or during pregnancy should be supervised to protect growth and nutrient sufficiency. With planning, it can be done safely. We focus on calcium, iodine, vitamin D, B‑vitamins, iron, protein, and overall energy  – and we will liaise with your GP or your consultant as needed.

How soon might I notice a difference?

Many people feel shifts by day 4–7 , fewer cravings, lighter mood on waking, calmer gut. For neuropsychiatric symptoms, meaningful changes often become clearer after week 3–4. If nothing has changed by week 4, we look elsewhere such as with sleep, iron status, thyroid, B12, omega‑3, trauma load, medications, infections, ultra‑processed food exposure.

What happens if my reintroduction is negative?

That’s a win – you’ve learned those foods are not your triggers. We pivot to other avenues with strong evidence for mood, energy, and gut health: protein distribution, fibre diversity, aim for 30 plants per week), omega‑3 intake, iron and B12 status, circadian‑friendly sleep, stress reduction strategies you can actually stick with, and targeted hypnotherapy for cravings.

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