Why Eat Organic?

Every year, millions of tonnes of pesticides are sprayed on farmland around the world to control weeds, insects and fungi. Small traces of them travel from the field into our food, our water and, as scientists can now measure, our bodies. So what do they do once they're inside us, and does choosing organic really make a difference?

What "organic" means

In the UK, food labelled organic must be grown to strict standards. Synthetic pesticides and weedkillers are heavily restricted, artificial fertilisers aren't used, and organic animals are raised with more space, access to outdoors and without the routine use of antibiotics. Farmers rely instead on healthy soil, crop rotation and natural predators to keep pests in check.

From the field into our bodies

Pesticide traces in food are tested against legal limits, and most samples fall within them. But scientists are increasingly asking a different question: what happens when we're exposed to small amounts of many different chemicals, every day, over a lifetime? (See Lightening the Load.)

One thing is clear: what we eat makes a big difference to how much reaches us. When children in one study switched to an organic diet, the levels of a common group of pesticides in their urine dropped to almost undetectable within days, and rose again when they went back to their usual food.¹ In another, families who ate an organic diet for just six days cut the levels of pesticides in their urine by around 60% on average.²

Within a week of eating organic, the body begins to clear its pesticide load.

Inside the food, not just on it

Many people believe a good wash under the tap makes conventional produce clean. Sadly, it doesn't. Many modern pesticides are systemic: they are designed to be absorbed through a plant's roots and leaves and carried in its sap to every part, including the fruit we eat. Others start on the surface but soak through the waxy skin over time. Either way, the chemicals leach into the flesh of fruits and vegetables, where no amount of washing, scrubbing or soaking can reach them.

Scientists have been able to watch this happen. In one study, researchers treated apples with two common pesticides and found that, within a day, both had moved through the peel and into the flesh. Washing removed some of what was on the skin, but not the residues that had soaked in, and even peeling couldn't remove them all.³

The main pesticide families

"Pesticides" covers hundreds of different chemicals. These are some of the most widely used, and what research has linked them with:

• Organophosphates, such as chlorpyrifos, malathion and diazinon. These insecticides work by blocking an enzyme that insects, and people, need for their nerves to work properly. In a study in California, children whose mothers had the highest exposure during pregnancy scored on average 7 points lower on IQ tests at age seven than those with the lowest.⁴ The World Health Organization's cancer agency classes malathion and diazinon as "probably carcinogenic to humans".⁵ (See Fertile Ground.)
• Triazines, especially the weedkiller atrazine. Atrazine is a well-known hormone disruptor: in one striking experiment, it turned male frogs into functioning females.⁶ It has been banned in the EU since 2004, partly because it contaminates drinking water, but it is still widely used in other countries whose produce may reach our shelves.
• Neonicotinoids, such as imidacloprid and clothianidin. These insecticides act on nerve receptors and are taken up into every part of the plant, so they can't be washed off. The EU banned three of them from outdoor use in 2018 to protect bees. In the US, they've been found in the urine of around half of the people tested.⁷ Their long-term effects on human health are still being studied.
• Glyphosate, the world's most widely used weedkiller. The WHO's cancer agency classes it as "probably carcinogenic to humans", although some food safety agencies disagree.⁵ A review found that people with the highest exposure, mostly farm workers, had a 41% higher risk of non-Hodgkin lymphoma.⁸
• Paraquat and rotenone. Both are now banned in the UK and EU, but they've taught scientists a great deal. People who had used either one were around two and a half times more likely to develop Parkinson's disease.⁹

At the level of our cells

Many pesticides are designed to disrupt the biology of living things, whether that's an insect's nervous system or a fungus's ability to grow. Our cells are very different, but some of these processes have close cousins in us.

A common thread is oxidative stress: a build-up of unstable molecules that wear down cells, damage DNA and fuel inflammation.¹⁰ Some pesticides also target the mitochondria, the tiny power stations inside our cells. Rotenone, for example, blocks the very first step mitochondria use to turn oxygen into energy. The cell can be surrounded by oxygen yet unable to use it, a kind of hypoxia at the level of the tissue. This is one reason energy-hungry tissues such as the brain and nerves seem especially vulnerable. In severe organophosphate poisoning, low oxygen also comes about more directly, as the muscles used for breathing begin to fail.

Detox under pressure

The liver clears chemicals in two main stages. In phase 1, enzymes change a chemical's structure, sometimes briefly making it more reactive. In phase 2, known as conjugation, the liver attaches a "handle", such as glutathione, so the chemical can be safely carried out of the body.

Glutathione is one of the body's most important protectors, working both as an antioxidant and as a phase 2 handle. Research shows that organophosphates can use it up and weaken the body's antioxidant defences.¹⁰ When phase 2 can't keep pace with phase 1, reactive by-products may linger and do more harm. Constant low-level exposure to many chemicals adds to the load on these pathways, which also deal with our own hormones and the medicines we take. (See The Hormone Web.)

A question of hormones

Hormones are the body's messengers, working in tiny amounts. Some pesticides, such as atrazine, are known as endocrine disruptors, because they can mimic, block or interfere with these messages. The European Union now has specific rules for identifying and restricting pesticides that disrupt hormones.

Because hormones are so powerful at such small doses, scientists are especially interested in exposure at sensitive times of life, such as pregnancy, early childhood and puberty. It's one reason many parents choose organic food for their families, and many people trying to support their hormonal health choose it for themselves.

The immune system and autoimmunity

A growing body of research suggests that pesticides can unsettle the immune system, making it either under-active or over-active.¹¹ In a study of more than 76,000 women in the US, those who had regularly applied insecticides themselves at home or in the garden for many years had around double the risk of rheumatoid arthritis and lupus, two autoimmune conditions.¹²

How might this happen? In autoimmunity, the immune system mistakes the body's own tissues for an invader. Scientists think chemicals may play a part through a kind of autoimmune mimicry. Some pesticides can attach to the body's own proteins and change their shape, so they look foreign. The immune system attacks the altered protein, and may then go on to attack the body's normal, unaltered tissue too, because the two look so alike. The same kind of confusion happens in molecular mimicry, where the immune system mistakes a microbe for the body's own tissue. Add in oxidative stress, a disturbed gut and a weakened gut lining, and the immune system may be pushed further out of balance.

Breaching the body's barriers

Our bodies are protected by remarkable barriers: the gut lining, which decides what passes from food into the blood, and the blood–brain barrier, which guards the brain. Both depend on cells sealed tightly together.

The gut is on the front line. Glyphosate works by blocking an enzyme plants use to make certain building blocks. Human cells don't have this enzyme, but many bacteria do. Researchers estimate that more than half of the core bacterial species in the human gut may be potentially sensitive to glyphosate,¹³ and studies in animals have found it can change the activity of the gut microbiome.¹⁴ Early animal studies also suggest that some pesticides may loosen the gut lining and the blood–brain barrier, letting through substances that would normally be kept out. Research in people is still at an early stage, but it's an important new question about what our food may be carrying.

What the bigger studies show

• More goodness. A review of 343 studies found that organic crops contained between about 20% and 70% more of many antioxidants, along with less of the toxic metal cadmium and pesticide residues around four times less often.¹⁵
• Better fats. Organic milk and meat contain around 50% more omega-3 fats, on average, than non-organic.¹⁶
• A possible link with lower cancer risk. In a French study following nearly 69,000 adults, those who ate organic food most often had a 25% lower risk of cancer than those who ate it least.¹⁷ This kind of study can't prove cause and effect, but it's an encouraging sign.
• Richer wildlife. Organic farms support, on average, around a third more species of plants, insects and birds than conventional farms.¹⁸

Going organic on a budget

Organic food can cost more, but often it's less about how much we have and more about where it goes. It's worth taking an honest look at the little luxuries that slip by unnoticed: the coffee and bagel in a smart café twice a week, another pair of shoes, a new top, the latest gadget. Each one feels small, but together they can add up to more than the difference between conventional and organic food.

What if some of that money went instead into the best-quality food you can find? Food is something you invest in every single day, and it becomes the very cells of your body. Nourish yourself well, and you may find you can let go of half the supplements in your cupboard. (See Food as Medicine.)

You don't need to change everything at once:

• Start with what you eat most. Swapping the foods you eat every day makes the biggest difference.
• Check the Dirty Dozen. Some foods carry far more pesticide residues than others. Berries, apples, grapes, leafy greens and potatoes tend to carry more than foods with thick peel you throw away. Pesticide Action Network UK publishes a yearly UK Dirty Dozen: the foods most worth buying organic.
• Don't worry about the Clean Fifteen. Some foods rarely carry much residue at all, so buying them organic matters less. Avocados, sweetcorn, pineapple, onions and cabbage often appear on the Clean Fifteen list, published each year by the Environmental Working Group in the US.
• Try a veg box or farmers' market. Local and seasonal organic produce is often better value.
• Buy in bulk online. Online retailers such as Buy Whole Foods Online offer a vast range of organic foods that most supermarkets don't stock, from grains, pulses and flours to nuts, seeds and dried fruit. Buying in larger bags brings the price down a great deal, often making organic staples very economical.
• Buy frozen. Frozen organic berries and vegetables are often cheaper and just as nourishing.
• Grow your own. Even a few pots of herbs or salad leaves on a windowsill help.
• Give them a bicarbonate soak. If you can't buy organic, soak fruit and vegetables for 12–15 minutes in a bowl of water with bicarbonate of soda (about 2 teaspoons per litre), then rinse well. In a laboratory study, this removed surface pesticides from apples far better than plain water.³ Remember, though, that it only cleans the skin: it can't remove pesticides that have already soaked into the flesh, so it's a helpful extra step rather than a replacement for organic.

At Rootwise, reducing everyday chemical exposure is often part of a plan for better energy, hormonal balance and gut health. We'll help you find simple, affordable changes that fit your life.