The increase in childhood illness is linked to the industrialised food they eat, according to the authors of a new book. Lisa Salmon finds out more.

A number of childhood illnesses are on the rise in the UK. Why?

According to a paediatrician and a university medical anthropology professor who've co-written a new book What's Making Our Children Sick?, the "epidemic" increase in chronic, hard-to-diagnose childhood health problems - ranging from allergies and asthma to autism and ADHD - can be attributed to "the cumulative outcome of being born into and living in an environment that has been made toxic by agrochemical industrialised food production".

The authors, Dr Michelle Perro and Professor Vincanne Adams, claim that unless children are eating 100% organic food or home-grown vegetables, they are eating "toxic ingredients" like pesticides, hormones and antibiotics that are harmful to their health.

What illnesses could be linked to food?

A broad spectrum of childhood illnesses can be tied to exposure to food and environment, say Perro and Adams. The illnesses include basic digestive disorders from reflux and constipation to colitis, immune disorders such as allergies and asthma, and neurocognitive disorders such as autism, ADHD and various mood disorders. Obesity, diabetes and other endocrine issues can also be related to the food supply and exposure to environmental endocrine disruptors, they say.

"There are other concerns that are not as well-publicised but are equally troublesome, such as sleep disorders and fatigue. Many kids just don't feel well!" says Perro, a former director of the Paediatric Emergency Department at New York's Metropolitan Hospital.

Certainly, a number of these health problems have become increasingly prevalent in UK children - Allergy UK says the percentage of children with allergic conditions has risen dramatically. Childhood cases of eczema and allergic rhinitis (hayfever) have both trebled over the last 30 years, and the prevalence of children with peanut allergy in western nations has doubled in just 10 years.

In addition, in the five years up to 2012 the number of children classed as being autistic in the UK rose by more than 50%.

How has food changed?

Although many factors are linked to chronic illnesses in children, Perro and Adams focus on what they say is one of the biggest causes: industrialised food.

They say over the past 20 years there have been significant changes in the food supply, and weed and insect resistance has led to "alarming" increases in the amount of pesticides in food. The most significant increase, they say, has been in the use of glyphosate-based herbicides and ever more toxic formulations of new pesticides.

"Foods once considered 'healthy' are now potentially full of toxicants that are causing systemic issues in our children's guts," explains Adams, who says that while there are no good studies of the effects of these foods in humans, animal studies point to major concerns including disruptions of the microbiome, leaky gut and dysbiosis (an imbalance between good bacteria and bad bacteria in the gut) that can lead to malfunctioning immune systems and inflamed brains.

Other toxic factors

There are many factors beyond food that may be involved in poor childhood health, say Perro and Adams, including toxins and toxicants such as plastics, flame-retardants, air pollution, electrosmog (EMFs), and chemicals from cleaning products and body products, plus stress.

Although tests can evaluate children's exposure to and carrying load of these toxicants, they are rarely used. "The tools of medicine have not caught up with the kinds of pathogens our kids are exposed to," stresses Adams, a medical anthropology professor at the University of California, San Francisco.

"Children are not managing this toxic soup well, and with the additional assault of food that's full of pesticides, we are seeing precipitous declines in their health."

What can parents do?

The situation can be improved, promises Adams, who says an easy first step is to buy organic food and use filtered water. However, she says that as many families can't afford to buy organic produce, it's important for them to do little things like cooking at home rather than eating out, and packing healthy school lunches for their children.

"Parents need to embrace the idea that food matters," she says, explaining it will help their children have healthy children in turn too.

"The impact of food is not only on children's health but also on the health of future generations."

How long does it take for a child's health to improve?

The speed of health improvement after a diet change depends on the underlying health of the child and their pre-existing diet, explains Perro, who says the biggest improvements are often in children who were initially sickest.

For others, the changes may be slower, especially if the family is already eating well, but getting to the root issues (sensitivities to specific foods, or even chronic infections such as Lyme disease) takes time.

Children who are chronically ill may develop picky eating habits, and well-meaning parents might give in to their child's demands, often for sugary or carb-containing foods, because they fear the child isn't getting any nutrition.

"It's hard to change dietary habits," says Perro, "but a wonderful side-effect of treating the child is that, when changes are made, often the whole family's health improves."

Never too late to change

The earlier families change their diet the better, says Perro, so even before couples become parents it's useful to do a 'pre-pregnancy clean-up' of both partners' diets.

"However, it's never too late to begin the process, whether there's a sick child at home or not," she stresses.

"Even small changes can make a difference. There will be bumps in the road and bad days, but improvements will be seen if the child has been consuming a healthy diet."