Your child is an amazing creation whose every cell depends on the food you provide. What may be more difficult to imagine is how foods can affect their moods; perhaps their orientation toward particular substances, rewards or risks – even what you assume to be the essential nature of their personality.

The brain and Gut (see TIPS) are on intimate terms. Although food quality is obviously important, even more significant is how well your child breaks down and utilises that food (Digestion). The finest diet is of no benefit until it is sufficiently broken down by enzymes and digestive juices into core nutrients: glucose from carbohydrates, amino acids from Protein , fatty acids from fats, vitamins, Minerals and water. These are the raw materials critical for all growth, repair, protection and energy.

As soon as a meal is reduced to these life-sustaining constituents, they are absorbed through the wall of the small intestine and sent to the Liver. The liver takes these building blocks and creates Skin, hair, blood, hormones, antibodies – virtually everything needed for life. Survival depends on the successful transportation of nutrients from the 7 metres of minutely coiled and folded small intestine. If fully stretched out this is larger than a tennis court and has a sausage skin-like wall or membrane only one cell thick. All this maximises surface area for ease of absorption.

However the size and permeability leaves the area vulnerable to attack by pathogens (viruses, bacteria, parasites and fungi) and inflammatory agents such as allergens, or otherwise inadequately digested food molecules. So seriously does the body view these potential assaults that about 80% of the immune system is situated along the gut. Whatever weakens the gut, weakens immunity and vice versa. An inflammatory cascade develops that affects both systems and the entire brain/body network.

Your child’s body is composed of many trillions of cells, each one studded with tiny receptors. These docking sites function like sensors and scanners. Sitting along the cellular membrane they vibrate and wait alertly for chemical messages. One of the first receptors studied was the opiate receptor, a responsive keyhole for such drugs as heroin and morphine (Moods and Foods). A map of opiate receptors in the brain shows their concentration in areas associated with pleasure, emotion, pain and sense perception. They also reside on immune cells lining the gut.

Why Foods Are Favourites

Incompletely digested food particles (often a protein fraction or peptide) can pass through a weakened intestinal wall and onto the open motorway of the bloodstream. They can then cross into the brain and – like pharmaceuticals and street drugs – chemically orchestrate how a child thinks and feels.

A healthy intestinal wall will not allow such intruders to pass and sends rogue peptides for excretion. But consistent stress, pathogenic invaders, poor nutrient and enzyme levels, or unaddressed food sensitivities all encourage ‘leaky gut’ or increased intestinal permeability. Undigested molecules are viewed as threats and can stimulate an immune response. This can be identified by the presence of antibodies that are made in defense against them.

Some reactions are not allergen-specific though and cannot be measured by standard blood or skin prick tests. This is where hair analysis by a qualified lab is so helpful, especially for determining hard to observe cyclical or delayed reactions to substances (Why You May Be Allergic to the 21st Century). These may be inhalants (eg pollen); food fractions (eg Gluten); toxins (eg MSG); or topicals (eg detergent and other Chemicals).

Two possible food culprits that have the most research are: dairy products, and gluten-associated grains (wheat, rye, barley and oats). Respectively these contain protein fractions including casomorphine and gluteomorphine. Some people are not able to adequately digest these which can affect memory, learning, mood or any aspect of health. Yet these foods can become particular favourites. As the undigested fraction moves through the gut wall and is targeted as a dangerous invader, Adrenal hormones rise as does an emergency release of blood sugar to deal with the crisis. Energy and alertness briefly elevate and the person subconsciously associates these substances with enhanced pleasure and vitality.

Such opioids can create a pattern of compulsive intake. Some people say they don’t have food cravings but this may be – as their diet reveals– because they are already ingesting their preferred ‘drug’ several times each day! When there are unaddressed health issues, the brief ‘high’ of opiate receptor stimulation encourages a strong urge for repetition. Like a heroin fix for an addict, intake brings illusory reprieve but at long-term cost. A new study reported in The Lancet showed that putting children with ADHD on a low-allergenic diet decreased symptoms by 78%. When common processed foods were returned to the diet 63% had a substantial relapse in behaviour. Interestingly, the usual IgG blood markers (the mainstream test for allergies) did not relate to outcome.

Building the Brain Network

Exercise is critical for brain function, mind, mood, and stress management. Brain derived neurotrophic factor (BDNF) is produced inside brain neurons or nerve cells, particularly in the hippocampus or learning centre. BDNF builds and maintains the mega-motorway cell structure that supports all brain communication. If you sprinkle BDNF on neurons in a Petri dish they will grow new branches (Brain).

You can increase BDNF with mental, physical and social exercise. In both animal and human studies this results in swiftly improved moods and sense of reward, ability to learn, focus and recall. Studies on rats also show that social and emotional deprivation can physically shrink brains, while an environment of enhanced stimuli produces heavier brains with improved neuronal structure that fires signals efficiently.

One of the speediest ways to produce more BDNF is with physical exercise. It is unleashed when blood pumps vigorously. When exercise is aerobic and requires skill – as with tennis or dancing for example – then the synaptic connections become more complex. In contrast, refined Sugar suppresses BDNF activity. It and damaged fats (The Fats of Life) generate Inflammation linked with depression and other mental health problems. The brain is more than 50% fat. Each cell membrane is composed of fat and needs the right balance between sufficient saturated fat and cholesterol for firm support (but not too much to make it rigid) and sufficient unsaturated fat to keep it flexible (but not too much to make it flaccid). The quality of the cell membrane helps determine which messages dock and trigger constructive or destructive response from the genes housed within the cell’s core.

Free Stress Antidote

One of the antidotes to stress is high intensity exercise. By copying the state of anxious arousal with its increased heart rate and breathing, a child can learn that these states do not need to mean doom but can instead relate to increased confidence and capability. Brain scans show that the reasoning and regulating centre of the pre-frontal cortex is smaller in chronically anxious people (and those with attention disorders such as ADHD). Their fear, danger and survival centre – the amygdala – tags too many situations as threatening and keeps flooding the system with the stress hormone cortisol. During exercise, calmative neurotransmitters and hormones are produced by the brain and heart. Some of these triple in production during pregnancy to suffuse the mother and protect the baby’s brain from the toxic effect of stress.

Sustained physical activity also triggers the production of more receptors on cells as docking sites for insulin. Insulin is the hormonal courier driver that delivers glucose – your child’s chief brain and body fuel source – to hungry cells. The brain is the first to feel its lack with consequent moodiness and dulled ability to reason or remember. In time, impaired access to glucose leads to obesity (Weight) – or hidden visceral fat in sedentary, thin children – and increased risk for diabetes, cardiovascular disease, and hormone-related cancers. Each meal and snack needs to regulate blood sugar levels for happy, healthy function (see The Shape Diet). The brain grows fastest in the first three years of life. Studies done of ages 3 to 8 showed a diet high in processed rather than whole foods is linked with a lower IQ (Journal of Epidemiology).

If your child has unexplained health problems despite genuine efforts, then a personalised nutritional and allergenic assessment can remove a lot of mystery, time- and money-consuming attempts. Some schools are paying for consultations to help children and teens with health and behavioural problems. Luring a teenager to a first appointment can be challenging. Everyone has a leverage point though. Tell them that a consultation can improve such factors as skin, hair, nails, weight and sports’ performance.

And you can casually add that most celebrities from pop stars to athletes have their own nutritionist – so how cool is that.