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Does severe picky eating have a cause? Or do kids just become fierce picky eaters for no reason? Some become so picky, they end up on feeding tubes for lack of food. They simply won’t eat. And if they do, they may stick to milk, dairy food, formulas based on milk or pea protein (think Pediasure, Boost, Orgain, Muscle Milk, Ripple, Kate Farms), or only eat that white / beige diet of cheese, pizza, Goldfish crackers, mac and cheese. Presenting other foods often means big tantrums. They become anemic, constipated, pale, unhappy, hyper. They may have extra challenges like autism or ADHD or anxiety. And, they have severe picky eating – that is, they eat as few as four foods, or even one food, in different formats. For example, if your child eats Pediasure, yogurt, and mozzarella cheese, they eat variations of just one food (dairy).

When I see severe picky eating in my pediatric nutrition practice, I am usually looking at a child who can’t function well, may be underweight or overweight, constipated, unable to sleep normally, doesn’t speak or socialize typically, may have volatility or combative or defiant demeanors, or have attention/focus issues. I start where I’ve seen this start in hundreds of cases before: Assessing if these kids are literally chemically addicted to the food they’re eating, and if those effects are causing the picky eating as well as many other problems. On the upside, it’s not complicated. Downside? There may be a strict elimination diet in your future, if this is your kiddo. Back to the good news: A correctly implemented elimination diet can bust the picky eating – and improve the other problems too.

What’s happening here is this: Leaky gut + wheat or dairy proteins = opiates. Yep, actual opiate-like protein fragments that form when gluten (wheat protein) or casein (milk protein) are poorly digested.

Picky eaters are – quite often – addicted to the opiate-like compounds that form from wheat and dairy proteins. If a child has a leaky gut, this can easily happen. While other factors and scenarios can worsen the picture, this addicting opioid effect is often the node of trouble that arrests all progress. I have witnessed even feeding therapy and tube feedings strategies fail, when this is overlooked.

The opiate-like compound that can form from milk is casomorphin. From wheat, it’s gliadorphin. Casomorphins and gliadorphins are naturally occurring compounds derived from the digestion of dairy and wheat proteins. Notice that these sound like “morphine” – that’s because the are actually opiate-like. They bind the same receptors in the brain and nervous system that bind opioid drugs like Oxycontin, codeine, Vicodin, or fentanyl. Similar compounds can form from soy protein, pea protein, and whey protein also, if digestion is weak and gut is leaky. These “dietary opiates” or “endorphin peptides” were first described in 1979. They can have opioid-like effects on the brain – and can drive severe picky eating. Here’s how:

  1. Casomorphins:
    • Source: Casomorphins are made from casein, a protein found in milk and dairy products.
    • Opioid-like effects: When casein is broken down during digestion, it liberates smaller protein fragments (peptides) called casomorphins. If a child has leaky gut, casomorphins are readily absorbed (they’re too big to pass through a gut wall with healthy tight junctions). These peptides can bind to opiate receptors in the brain and nervous system. Some effects include feelings of relaxation – many parents report to me that once their kids eat their picky-eater favorite dairy food, they behave better – at first. Not long after, they may become hyper, silly, inattentive, or even volatile or combative. Sleep cycles may be disrupted too.
    • Preference for dairy products: In kids with a leaky gut scenario, eating dairy products can lead to the absorption of casomorphins, which can make kids more inclined to choose dairy-based options – leading to a preference for them over other foods.
  2. Gliadorphins:
    • Source: Gliadorphins come from the digestion of gluten, the protein in wheat, barley, and rye. Gluten is also in oats that are not certified gluten free, and in many processed foods as a flavoring or thickener.
    • Opioid-like effects: When gluten is digested, it creates protein fragments called gliadorphins. A healthy non-leaky gut finishes protein digestion down to the tiny individual amino acids that proteins are made of, leaving little gliadorphin to absorb. But if a child has leaky gut, it’s easy for gliadorphin to be absorbed. Like casomorphin, gliadorphins bind opiate receptors in the brain and nervous system. Mood, behavior, and addictive eating effects ensue!
    • Preference for gluten-containing foods: Eating gluten can make gliadorphins. If absorbed, then these can make kids picky for gluten-rich foods, at the expense of trying non-gluten options.

Impact on Picky Eating:

  1. Reinforcement of Preferences: Eating a steady, narrow diet of wheat and dairy foods in the context of leaky gut will lavish the addictive effects of casomorphins or gliadorphins on the brain and gut. This reinforces a preference for these foods, making kids unwilling to try new or different foods.
  2. Sensory Preferences: Casomorphins and gliadorphins can alter the sensory experience of eating. Children may become accustomed to the specific textures and flavors of wheat and dairy foods  – that beige or white food diet – which can make them more resistant to trying foods with different textures or tastes.
  3. Withdrawal Symptoms: If a child has been on a steady supply of casomorphins or gliadorphins from weaker digestion, leaky gut, and a picky narrow diet, they can experience withdrawal symptoms when these foods are removed. Irritability, tantrums, foul mood, and harder campaigns to wait it out for the beige food are common. I have seen uncanny abilities in kids to sniff out foods with even trace amounts of gluten or casein in them, so they can keep getting that little bit of opiate like effect. This can further reinforce their picky eating habits.
  4. Constipation: Like any opiate narcotic, casomorphin and gliadorphin can slow gut motility down and cause constipation. They can also dull sensation for stooling, making it hard for kids to potty train and sense when to go.

The cool part of the story is that this opioid effect from casein is genius for newborns and babies. Since the baby’s gut wall is more permeable at birth, casomorphins can be had from breast milk or milk based formula alike. Great! Babies are happy, they can sleep a lot, and this also helps neurons in the brain grow fast.

But once a child reaches age 18-24 months, the gut is working toward sealing itself. It should function as a more discerning interface with the outside world (here is a great explanation of what we know so far about phases of gut development in babies.) That means casein (and gluten too) should be more completely digested, and absorbed more as individual amino acids, rather than large peptide chunks that look like an opiate molecule. Besides slow or arrested language development, a constipated stool pattern, dilated pupils, picky eating, sensory dysregulation, and some beyond-fierce tantrums when favorite foods aren’t presented, another sign that opiate-like peptides may be affecting the brain is head circumference. The baby’s head may grow, grow and keep growing at the top of the chart, even outpacing the child’s velocity for weight and height.

This is where picky eating can become a more serious problem. It may alter brain structure and function, if not redirected. There is evidence that diet sourced opiate like peptides change how neurons grow, and how they undergo a process called pruning. Pruning is a process that is essential to normal development and learning. The first phase of neuronal pruning begins shortly after birth and continues into adolescence. During this period, the brain produces an overabundance of synaptic connections. These early connections are important in our first year or two for basic functions, but not all of them are necessary for long-term functioning. As a child interacts with their environment, learns new skills, and experiences different stimuli, certain synapses are strengthened through a process known as synaptic potentiation, while others are gradually eliminated through synaptic pruning. This helps to refine and optimize the neural circuits, making them more efficient and specialized.

A second phase of pruning occurs during adolescence and early adulthood. The teen decade is characterized by significant changes in brain structure and function. This phase of pruning brings the maturation of higher cognitive functions, such as abstract thinking, complex problem-solving, and emotional regulation – in other words, adulting!

Diet sourced opiate peptides can interfere with the pruning process. Here’s how:

  • Altered Neurotransmitter Levels: Opioid peptides can influence neurotransmitters involved in neuronal pruning. This could disrupt the signaling pathways that initiate and complete the pruning process.
  • Disrupted Synaptic Plasticity: Opioid peptides can affect synaptic plasticity, which is intertwined with neuronal pruning. If the normal balance of excitatory and inhibitory signals in the brain is disrupted by opioid peptide activity, it can interfere with the timing and precision of synaptic pruning.
  • Influence on Neurotrophic Factors: Opioid peptides may also impact neurotrophic factors, the molecules that support nerve cell survival, growth, and development. Changes in the availability or activity of these factors could potentially affect neuronal pruning.

If picky eating is present with developmental delays, and especially with diagnoses of autism, ADHD, or conduct disorders, an elimination diet has potential to turn the tide. I have many clinical anecdotes from families seeing a whole new child emerge once the haze and confusion of opiate like chemistry fades away. The most common phrase I hear is “the fog lifted”. I also often hear of abrupt positive shifts for trying new foods and textures, learning to sleep, being more calm and having more self regulation, reduced texture sensitivities, and becoming more capable with peers or at school.

While an elimination diet has great potential, it is challenging, and it is paramount that even more nutritious foods are given in place of the foods withdrawn. For a detailed how-to on making this option work, see my e book on Milk Addicted Kids.The main caveat is this: All gluten, dairy, soy, pea protein concentrates, and whey protein must be completely and strictly eliminated for a 4-6 month period before evaluating the diet’s efficacy. Learn why, and how to do this, in my e book. Contact me here if you have more questions, and thanks for stopping by!