Organic food is grown or reared without synthetic pesticides, artificial fertilisers, or genetically modified organisms (GMOs).
While GM foods are largely restricted in the UK, non-organic livestock are routinely fed GM ingredients — something organic standards prohibit entirely.
Organic standards also require that animals are genuinely free range, raised in environments that support their natural behaviours.
The routine use of preventative antibiotics — which accounts for around 30% of all antibiotic use in UK farming — is banned under organic certification.
Potential health concerns associated with non-organic food
The most significant health concern with non-organic food is pesticide exposure and its potential to accumulate in the body over time. Unlike many substances that are excreted, pesticides can bioaccumulate — building up in body tissues with each exposure. This process is further compounded by biomagnification, where organisms higher up the food chain accumulate greater concentrations of toxins from everything they have consumed below them. While individual pesticides are regulated for safety, long-term chronic exposure has been associated with:
- Parkinson’s disease
- Fertility issues
- Cognitive conditions including ADHD
- Disruption to the gut microbiome — affecting the diversity and balance of gut bacteria with far-reaching consequences for immunity, metabolism, and mental health
- Contribution to antibiotic resistance, through the routine use of antibiotics in non-organic farming
Research also points to meaningful positive benefits from choosing organic. The Nutri Santé prospective cohort study — one of the largest of its kind — followed over 70,000 adults and found that those who consumed the highest proportion of organic food had significantly lower rates of cancer and type 2 diabetes compared to those who ate little or no organic food.
Are some non-organic foods worse than others?
Organic food is always preferable, but it is not always affordable or accessible. Fortunately, the Pesticide Action Network UK publishes an annual report called the Dirty Dozen, identifying the most pesticide-contaminated foods — allowing you to prioritise where organic matters most.
The Dirty Dozen
- Grapefruit
- Grapes
- Limes
- Bananas
- Sweet peppers
- Melons
- Beans
- Chilli peppers
- Mushrooms
- Broccoli
- Aubergines
- Dried beans
The Environmental Working Group (EWG) produces a similar annual guide based on US foods, covering both the Dirty Dozen and the Clean Fifteen — which can also be a useful reference.
Other non-organic foods which can be particularly high in pesticide residue:
- Berries
- Oats
- Spinach, kale, and leafy greens
- Peaches, nectarines, and cherries
- Potatoes
- Celery
- Tomatoes
- Apples and pears
- Coffee and tea
Can washing fruit and vegetables remove pesticide residue?
Research suggests that plain water is as effective as commercial produce washes for removing surface pesticide residue. For more thorough removal:
- Soak in clean water for one to two minutes as a minimum
- For best results, soak in a solution of one tablespoon of bicarbonate of soda in two cups of water for twelve to fifteen minutes, then rinse — this has been shown to outperform other methods
- A five-minute soak is a practical everyday compromise
- Be aware that longer soaking may affect the texture of softer-skinned fruits
To sum up
- Non-organic foods can carry pesticide residues that, with regular long-term exposure, may pose risks to health
- Where budget allows, prioritise organic for the most contaminated foods on the Dirty Dozen list
- Always wash fruit and vegetables thoroughly in clean water
- For produce you are most concerned about, a bicarbonate of soda soak, followed by rinsing, offers the most effective residue removal
