When I was growing up, I would have occasion to attentively sit in on clinics in which my mother or father would see to the medical needs of a procession of babies and children. Bearing in mind such early influences, it perhaps comes as no surprise that I have quite an interest in such kids' stuff myself. My medical training undoubtedly exposed me to the best of what orthodox medicine has to offer. Witnessing, say, a skilled paediatric surgeon at work or the life-saving qualities of antibiotics in a baby with meningitis has convinced me what a potent force for good modern medicine can be.

However, my experience in medicine has also brought me face to face with many children whose long-term health issues have not been well served by conventional means. All too often, standard medical treatments for conditions such as eczema, asthma, hyperactivity and recurrent infections fail to really get on top of the problem. I have also seen many children who are suffering not only from their underlying problem, but also from the side-effects of one or more medications used to treat it.

It is partly these experiences that have led me to seek safer and more effective remedies in my own practice. Wherever possible, my aim is to find, and correct, the underlying cause of a health issue. Over the years, I have found that this approach is very often effective in resolving a wide spectrum of childhood illness. What I have learnt I have distilled into my latest book, Natural Health for Kids (£16.99, Penguin).

The book details the natural management of some 150 behavioural and physical conditions common in children. Many of the strategies I recommend involve dietary change. This basic approach is born out of the fact that diet is so often a core factor in health issues. Natural Health for Kids contains comprehensive and scientifically referenced information on what constitutes a truly healthy diet for children, and also offers practical advice on how to encourage little ones to eat nutritious fare, with a minimum of fuss.

While a good basic diet can prevent and even remedy many ills, sometimes a more tailored approach is required. In this extract from my book, I explore three specific dietary imbalances that are commonly found at the bottom of a child's health issue. The first of these, imbalance in blood-sugar levels, can manifest in a number of ways, including mood swings and behavioural problems, unexplained fatigue and food cravings. The other two are food sensitivity (a common cause of many conditions, such as asthma, eczema and recurrent ear, nose and throat problems), and an imbalance in certain fats in the diet (which is a frequent factor in learning and behavioural problems).

Working with children has convinced me that young bodies generally have the potential to snap back into shape quite quickly. For instance, I have seen efforts to stabilise blood-sugar levels transform little devils into little angels in a few short days, and the elimination of problem foods from a child's diet can bring about considerable resolution in their eczema or asthma in a week or two. My experience is that with the right approach, the boy or girl usually comes good in the end.

Blood-sugar balance and health

The body is constantly engaged in a biochemical balancing act in which it attempts to regulate its internal environment. Part of this process involves ensuring a relatively stable level of sugar in the bloodstream. However, in some children this mechanism can go awry, leading to peaks and troughs of blood sugar. In the short term, blood-sugar swings may manifest as problems such as mood swings, fatigue and food cravings. In the long term, this imbalance may predispose to a range of health issues, including weight gain and diabetes.

One of the principal hormones involved in the regulation of blood sugar is insulin. This hormone is secreted in response to rises in blood-sugar levels after the consumption of carbohydrate (sugar or starch). The chief effect of insulin is to reduce blood-sugar levels, thereby preventing excesses of blood sugar that can be damaging to the body. However, in certain circumstances, blood-sugar levels can rise considerably after a meal, which stimulates surges of insulin in the system. One potential effect of this is to drive blood sugar down to subnormal levels.

The effects of low blood sugar

Adequate blood-sugar levels are generally required to fuel both body and brain. When blood-sugar levels drop, this can cause energy to stall (typically in the mid- to late afternoon). Fluctuating blood-sugar levels often cause fluctuating mood, and this can manifest as deep depression or temper tantrums (and everything in between). Another common symptom of low blood sugar is food cravings. When a child's blood-sugar levels get low, it's natural for the body to crave foods that will replenish sugar quickly into the bloodstream. A child that 'needs' sweet foods such as biscuits, chocolate or highly sugared drinks from time to time is normally struggling with a blood-sugar issue.

The problems of excess insulin

While the symptoms of blood-sugar imbalance are most obvious when sugar levels are low, high blood-sugar levels and the surges of insulin this tends to induce can have hazards, too. One of insulin's effects is to stimulate the conversion of sugar into fat. Children with blood-sugar imbalance may therefore have a tendency to weight gain. Also, high levels of insulin in the body can increase the risk of what is known as type 2 diabetes in the long term.

Getting blood sugar back in balance

Children who have symptoms and signs of blood-sugar imbalance can generally expect to have more stable levels of mood and energy and more controlled hunger when steps are taken to correct this. A loss of excess weight, if this is an issue, is very likely, too.

One important factor in getting blood sugar back in balance is to eat a diet based on foods which give a controlled release of sugar into the body. The speed and extent to which a food increases blood sugar can be quantified using something called the glycaemic index scale. Here, the speed and extent of a food's sugar release into the blood stream is compared with glucose (the fastest-releasing food), which is given a value of 100. The higher a food's glycaemic index, the more disruptive its effects on blood sugar (and insulin) are, and the worse it tends to be for a child's health. What follows is a list of the commonly eaten carbohydrates and their respective glycaemic indices.

For a long time, traditional nutritional wisdom has dictated that foods rich in sugar produce rapid rises in blood sugar, while starches, because they need to be broken down to sugar prior to absorption, release more slowly into the bloodstream. However, the glycaemic index list (previous page) reveals that this is far from the truth. While some starches, eg oat porridge, release sugar relatively slowly, others - notably pasta, potato, most breads, rice and sweet corn - tend to be quite destabilising to the body's chemistry, particularly when eaten in quantity.

Some scientists have suggested that the preponderance of high-GI foods in many children's diets is a major factor in the burgeoning rates of obesity and diabetes seen in the young.

Getting good control over blood-sugar and insulin levels is a key aspect of health, and a crucial part of this is a diet based on low-GI foods. It is not necessarily important to get higher-GI foods right out of the diet, and neither is this realistic. However, what this is about is balance. It's about emphasising healthier, slower-releasing foods, while at the same time pulling back on the faster-releasing fare.

The importance of protein

One thing that seems to be particularly important for blood-sugar control is that there is adequate protein in the diet. In practice, a diet reasonably rich in protein does seem to stabilise blood-sugar levels and help combat the symptoms of hypoglycaemia. Good sources of protein in the diet include meat and fish. Eggs are another protein-rich food, as are beans, lentils, nuts and seeds.

Regular meals and snacking for better blood-sugar control

Whatever it is that a child consumes, eating small amounts of it more frequently will generally lead to more stable levels of sugar and insulin compared to eating that food in two or three big meals. Regular meals are important for children, but healthy snacks in between can be extremely useful, too. Fresh and dried fruit, cut-up raw vegetables, as well as nuts and seeds, all make eminently nutritious snacks that help keep blood-sugar levels on an even keel.

When steps are taken to stabilise blood-sugar levels, children generally enjoy more stable energy and mood, and have more controlled eating habits, too.

Children carrying weight that is surplus to requirements can generally expect to shed some of this in the long term, without the need to go hungry or restrict calories per se.

Food sensitivity

While food can have health-giving and healing properties, it can also cause considerable health issues. Food has the capacity to cause unwanted reactions in the body that are often grouped under the heading 'food sensitivity'. Food sensitivity may manifest as one or more of a wide variety of symptoms, including frequent colds, a blocked or runny nose, headaches and migraine, abdominal bloating, eczema and asthma. The identification and elimination of problem foods from the diet can often make a major change to a child's health and wellbeing.

What causes food sensitivity?

Conventional medical wisdom dictates that before food is absorbed through the gut wall into the bloodstream, it is first broken down into its smallest molecular constituents. However, contrary to received wisdom, food can sometimes make its way through the gut wall into the body in a partially digested form. Once in the body, the body may see these undigested food molecules as 'foreign', and may trigger a response from the body's immune system. Such reactions usually involve the production of substances called antibodies (also known as immunoglobulins).

One type of antibody involved in food-sensitivity reactions is known as IgE (which stands for immunoglobulin E). IgE is the type of antibody that is generally involved in immediate and obvious reactions to food such as the acute allergic reaction to nuts. Conventional tests such as IgE blood tests and scratch testing (in the skin) are generally useful for diagnosing such sensitivities.

However, not all food reactions involve IgE antibodies. Some, for instance, involve a different class of antibodies known as IgG. This type of antibody does seem to be responsible for more subtle food reactions, that in practice can be at the root of a number of childhood conditions, including glue ear, ear infections, eczema, asthma, recurrent tonsillitis, excess mucus or catarrh formation, hyperactivity, food cravings (particularly for things such as bread and cheese), dark circles under the eyes, irritable bowel syndrome, abdominal bloating and rashes in the skin. Drawing a distinction between IgE and IgG sensitivity is important, as conventional tests focus on IgE, and can therefore fail to identify problem foods that are causing unwanted reactions through other mechanisms.

Testing for food sensitivity

If you suspect your child might be food sensitive, then the next step might be to identify which food or foods are the problem. There are a variety of tests available for food sensitivity. Conventional blood tests for food sensitivity test for IgE, but IgG tests are available to the public - I find that these generally yield useful results. One laboratory, York Laboratories, is able to test IgG food sensitivity from a single drop of blood (see www.allergy-testing.com for more details).

Common problem foods

Food-sensitivity testing is not strictly necessary, however. Many children improve on elimination of the most common problem foods. These are:

Dairy products - such as milk, cheese, yogurt and ice cream

In practice, the foods that we appear to tolerate the best are those that have been in the human diet the longest. Dairy products are relatively new to the human diet (we have consumed milk for about the last 10,000 years of our two or more million years on this planet). One of the main elements in dairy foods that seems to provoke reactions is the protein molecules within them. Pasteurisation (a very new thing indeed) is believed to change the nature of dairy proteins,which does seem to increase the likelihood of us having a reaction to them. Be particularly suspicious of a dairy sensitivity in your child if he or she had colic as a baby, or suffers from frequent colds, a runny nose, ear problems or sore throats and/or tonsillitis.

Wheat (including bread, pasta, pastry, biscuits, wheat-based snacks, wheat-containing cereal bars, cakes and wheat-based or wheat-containing breakfast cereals)

Like dairy products, wheat is a relatively recent addition to the human diet (about 10,000 years). Not only that, but wheat is one grain that has been modified over the years using plant-breeding techniques. In other words, the type of wheat we eat now is often quite different from the wheat we originally started eating all those years ago. It seems to be true that the more of a food we eat, the more likely we are to develop a sensitivity to it. The fact that wheat is such a staple in our diets may be another reason why it is a common cause of food sensitivity.

Any food your child craves or doesn't seem to be able to do without

Children sometimes crave and become quite wedded to the very foods they are sensitive to. A child, for instance, who loves bread and pasta is quite likely to be wheat sensitive. One that adores milk or cheese is probably harbouring a dairy problem. What causes this phenomenon is not known for sure, though it's probably not too dissimilar to the cravings that individuals can get for other things that are not good for the body, such as nicotine, alcohol and caffeine.

Removal of problem foods from a child's diet very often leads to a swift resolution of food sensitivity-related symptoms. However, a child has to eat something. Natural Health for Kids contains comprehensive information about alternative foods, including non-dairy sources of calcium.

Fatty-acid imbalance

Dietary fats come in a variety of forms which can have quite distinct health effects in the body. Recent years have seen a lot of scientific interest in what are known as polyunsaturated fats found in a variety of foods, including vegetable oils and oily fish. While these fats may have broadly beneficial effects for the body, it now appears as though many children are subject to health issues as a result of an imbalance of these important fats in the diet.

Polyunsaturated fats come in two main types: the so-called omega-3 and omega-6 fatty acids. The major omega-6 fatty acid in the diet is known as linoleic acid, which is found most abundantly in plant oils such as hemp, pumpkin, sunflower, safflower, sesame, corn, walnut and soya oil. The major omega-3 fatty acids in the diet come in the form of alpha-linolenic acid (ALA) from plant sources such as flaxseed, and fats known as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) that are mainly found in oily varieties of fish. Linoleic acid, ALA, EPA and DHA are often referred to as essential fatty acids (EFAs).

Both omega-3 and omega-6 fats have important roles to play in the body, though their actions are roughly antagonistic. For instance, omega-6 fats tend to encourage blood clotting and inflammation, while omega-3 fats have quite the reverse effects. What this means is that the relative amounts of these two main types of fat in the body are critical to health. Some scientists believe that the ideal ratio of omega-6:omega-3 fats in the diet is 1:1. However, the British diet is typically low in omega-3 fat, and usually supplies several times the amount of omega-6. The surfeit of omega-6 fat in the diet, coupled with a general deficiency in omega-3 fats, can have profound effects on health.

One of the fundamental roles of omega-3 fats is in the structure and function of the brain. DHA is believed to be important in the building of the brain during pregnancy, and in maintaining its growth and development after birth. EPA is also important, and seems to play some role in the day-to-day running of the brain. A deficiency of omega-3 fats is believed to contribute to a variety of issues, including dyslexia, dyspraxia (lack of co-ordination), attention deficit hyperactivity disorder (ADHD) and depression.

Correcting a fatty-acid imbalance

Improving the balance of fats in a child's body is usually about cutting back on omega-6 fats, while at the same time increasing omega-3 consumption. Foods rich in omega-6 fats to limit in the diet include many vegetable oils that are used in the manufacturing of fast and processed foods and margarine. Good sources of omega-3 fats to emphasise include oily fish, such as salmon, trout, mackerel, herring and sardine. Two or three portions of this each week will help ensure a good intake of omega-3 fats if a child will eat them. Omega-3 enriched eggs are another option.

However, not all children will eat oily fish. Fortunately, concentrated fish-oil supplements (rich in EPA and DHA) are available in a variety of forms, and do offer an alternative to non-fish-friendly kids. These can be taken in capsule form (as directed on the label) or opened into soups, sauces, stews or casseroles. Vegetarian children may benefit from taking DHA extracted from algae (eg Cerebrum vegetarian DHA, available from healthspan.co.uk). Another alternative is to supplement a child with flaxseed oil at a dose of about 1 tbsp a day. Flaxseed oil is very rich in ALA, some of which will convert to EPA and DHA within the body.

Correcting a fatty imbalance in a child's body can take a few weeks or months, though the effects are usually well worth the wait. Apart from external effects such as healthier skin and hair, it is usual to see internal improvement, too. Often, this will manifest as improved mood and behaviour, as well as an enhanced ability to focus, concentrate and learn. Ensuring a healthier balance of fats in a child's diet is food for thought indeed.