Are you eating the Dirty DozenTM?
When it’s worth buying organic – and when it’s probably not
Organic produce is more expensive. But is it worth the extra cost? Which is averagely 47% more than conventionally produced fruits, vegetables and meat.
Since a main reason to buy organic is to avoid pesticide residue, you need to know which conventionally grown produce have the most pesticide residues on them – and which have the least. We list them below.
By buying organic versions of the ‘dirtiest’ produce i.e. with the most contamination, and by buying conventionally grown versions of the cleanest produce, you get the best value for money. (Assuming you can’t grow your own.)
Pesticide residues are not the only reason to consider organic produce. Other positives include:
- higher nutritional values
- the fact that conventional, high intensity farming is having an increasingly detrimental effect on the environment
We’ll consider these factors too.
But first are the levels of pesticide residues actually serious?
Over 230 different pesticide residues in some non-organic produce
In 2014 Newcastle University reviewed 343 studies on produce and found pesticide residues to be four times higher in conventional crops than in organic.
The UK government’s Department of Food and Rural Affairs (DEFRA), the World Health Organisation (WHO) and the US Department of Agriculture (USDA) all produce yearly reports on pesticide residues. The latest DEFRA report is for 2017. In general, its analysis of the most contaminated produce agrees with the others.
- USDA tests found a total of 230 different pesticides on the thousands of samples they analysed
- USDA found that 98% of strawberries, spinach, peaches, cherries and apples tested positive for pesticide residue
- In at least 12 crops, there were traces of multiple pesticides – whose potentially toxic effect could be amplified when in combination
- Researchers at Stanford University found that heavy metal contaminants in conventionally farmed produce was as much as 48% higher than in organic.
But can this contamination actually have an adverse health effect?
Health risk from pesticide residue
Firstly, pesticides are – by definition – toxic. The word means “kill pests”. Pesticides can harm more than just the pest targeted.
Initial exposure in humans rarely causes noticeable symptoms, so any harm can easily be overlooked. However, the cumulative effect of even low doses can potentially cause problems over time.
Chemical-based pesticides and pollutants have been shown to result in oxidative stress in the body which is linked to accelerated ageing processes and cell death.
Identified outcomes of pesticide residue include
- respiratory tract infections
- and possibly cancer
Glyphosate-based herbicides have been shown to cause DNA damage and act as endocrine disruptors in human cell lines.
A 2016 study published in Frontiers in Public Health states:
“Population-based studies have revealed possible relations between the exposure to organophosphorus pesticides and serious health effects including cardiovascular diseases, negative effects on the male reproductive system and on the nervous system, and dementia.
“Furthermore, prenatal exposure to organophosphates has been correlated with decreased gestational duration and neurological problems occurring in children.”
A recent study in the American Medical Association Journal found a connection between consuming high-pesticide foods and reproductive problems. Women who regularly ate produce known to have pesticide residue were 26% less likely to have a successful pregnancy and men had a lower semen quality.
Toxico-pathologist Dr Vyvyan Howard is a member of the UK government’s advisory committee on pesticides. She states:
“There is sufficient evidence already that the pesticide cocktail effect is producing changes. Exposure to chemicals that disrupt hormones in the womb could be the cause of the decreased age of puberty in girls and early onset of puberty is linked to a greater chance of developing breast cancer later in life.”
Organic produce has higher nutritional values
The University of Newcastle 2014 meta-analysis of 343 studies (published in the British Journal of Nutrition), concluded that organic crops contained significantly higher anti-oxidant levels than their non-organic counterparts.
Another European study confirmed that organic produce typically has 40% more anti-oxidants and also higher levels of minerals such as iron and zinc.
The reason is interesting. Plants produce anti-oxidant defences, mostly in their outer leaves and skins. These are not for our benefit, but as natural defences for the plant itself against insects, disease and the stress of photosynthesis.
Plants that are not sprayed with pesticides develop stronger defences, hence their higher protective anti-oxidant levels. This protection is mostly in the form of plant nutrients called flavonoids and polyphenols.
When we eat these plants, we ‘inherit’ and absorb these protective plant nutrients. The anti-oxidants in flavonoids are beneficial to us because they help neutralise free radicals – and research strongly suggests that excess free radicals are a major contributor to heart disease, cancer and even premature ageing itself.
So a higher level of anti-oxidants in the diet has been linked to a reduction of chronic diseases such as heart disease and certain cancers – as well as improved skin health, and supporting the body’s natural repair processes.
The University of Newcastle study estimates that a switch to organic fruits, vegetables and cereals would provide additional anti-oxidants equivalent to eating between 1-2 extra portions of fruit and vegetables a day!
Local = fresher = higher nutritional value
There are two other reasons why organic food is higher in nutritional value.
Most is produced locally and is therefore fresher. Freshness and nutrition are linked because the level of vitamins, anti-oxidants and other nutrients in food declines over time.
Slower growth means more energy goes into developing nutrients
Organic fruits and vegetables also tend to grow more slowly – because they are not dosed with synthetic fertilisers. When plants are grown too quickly, they put most of their energy into simply getting bigger, rather than into developing a richer biochemistry.
Similar advantages apply to organic milk and meat production. Levels of anti-oxidants in milk from organic herds are up to 80% higher than in milk from conventional herds.
Organic is better for the environment
Fertilisers, pesticides and herbicides
Conventionally-grown crops rely extensively on chemical input to achieve high yields. These feature synthetic fertilisers containing “NPK” (nitrogen, phosphorus and potassium), pesticides and herbicides.
Excess nitrogen can adversely affect the pH of soil and NPK combinations can and do run off into groundwater and waterways. This causes an excess of algae and a resulting loss of oxygen in the water which is needed by both fish and aquatic animals. (However, to be even-handed, the manure slurry used in organic livestock farming can and does also result in a similar run-off.)
Intensive farming, synthetic pesticides and fertilisers are beginning to have a negative impact on the environment. The WWF has stated that unsustainable agriculture practices are the greatest immediate threat to the world’s species and ecosystems.
Ammonia from animal waste
Another problem caused by intensive livestock farming has recently emerged – the build-up of ammonia gas from animal waste in both the atmosphere and land around very large-scale farms.
Ammonia in the soil drives out wild flowers and encourages weeds. At higher levels it is damaging even to trees. Ammonia gas in the air is toxic to humans and can cause lung damage.
Chemicals cause decline in bees and other pollinating insects
One of the most significant cases of the over-use of chemicals in industrial agriculture and the resulting fall-off in species is the decline of pollinating bees. At least 25 species of bees are now severely threatened.
Bees are not the only pollinators, however, and it’s serious for the future of harvests that insect pollinators have decreased so significantly. There has also been a decline in 75% of butterfly populations due to agricultural advance into natural habitats.
When did you last see more than the occasional butterfly – or a car windscreen covered with insects?
Organic processes encourage farmers to maintain areas of farmland for local wildlife, including hedgerows, grassland, pools and ponds, all of which are needed for insects to breed.
Maintaining soil quality should be paramount
Organic systems minimise chemical inputs, relying mainly on animal manures and crop rotation to maintain the fertility of the soil and letting it become naturally enriched by the local wildlife. Weeds and pests are mainly controlled through physical and biological control methods.
The climate change link
The Food and Agriculture Organization of the United Nations has recently stressed the fundamental truth that soil quality is the foundation for all life and ultimately our health and even survival. They state:
“Lower greenhouse gas emissions for crop production and enhanced carbon sequestration, coupled with additional benefits of biodiversity and other environmental services, make organic agriculture a farming method with many advantages and considerable potential for mitigating and adapting to climate change.
“Many field trials worldwide show that organic fertilization compared to industrial mineral fertilization is increasing soil organic carbon and thus sequestering large amounts of CO2 from the atmosphere to the soil.”
So, it’s not just a reduction in pesticide residue or increased nutritional values that we should be considering. Huge resources are used in conventional farming that are generally unrecognised. They include artificial heat, light and petroleum-based fertilisers, all of which are minimised in organic methods.
Organic meat, dairy and eggs – are they better?
UK national guidelines require practices for organic certification that are associated with more humane treatment of animals. They spend more time in the pasture and are less likely to be farmed to produce a specified amount of milk or eggs per month. Which, it is claimed, leads to less stress and healthier foods being produced by these animals.
Over-use of antibiotics in conventional livestock farming
Conventionally reared animals are routinely fed antibiotics, since it is permitted to use antibiotics prophylactically (preventively), ie. even when no disease has been diagnosed. This is because intensive production in confined conditions means the outbreak of disease is liable to be more frequent and harder to control.
In most countries, more antibiotics are used in animal production than for human health. In European countries the use of antibiotics in agriculture accounts for almost two thirds of all antibiotics used. In the UK, the figure is around 40%.
This is both triggering and contributing to a dangerous rise in antibiotic-resistant bacteria as humans ingest these antibiotics through the food chain.
Scientist rarely use emotive language but Dame Sally Davies, Chief Medical Officer for England, stated recently that:
“We are really facing a dreadful post-antibiotic apocalypse.”
Organic certification prohibits antibiotics as preventatives
Less intensive farming, as used on organic farms, means reduced risk of transmitted disease and therefore there is less need for antibiotics (which are not permitted to be routinely used as a preventative).
Organic meat, dairy and eggs are higher in Omega 3
Poultry: Organic poultry is almost always raised without the routine use of antibiotics. Moreover, organic poultry cannot be fed “litter”, a mixture of droppings, spilled feed, and ground feathers. Meat and eggs from organic poultry are higher in Omega 3.
Meat: Organic cattle are also raised without routine antibiotics. Meat from grass-fed animals tends to have higher levels of Omega 3 and other polyunsaturated fatty acids than grain-fed cattle.
Milk: Organic milk tends to contain more beneficial Omega-3 fatty acids and more vitamin E than non-organic – though a huge 2016 study published in Food Science and Technology suggests that many study results are contradictory, and the difference may be more to do with output from different breeds than organic versus non-organic.
Eggs: The nutritional advantage of organic over conventional is clearer in eggs than other animal products. The same Food Science and Technology study found that organic eggs contained a greater quantity of lutein and zeaxanthin compared to free range and barn eggs. Lutein and zeaxanthin are powerful anti-oxidant compounds, with particular importance for eye health.
But if you are looking for the most environmentally friendly way to eat meat and animal products – the real answer is to eat less of them!
The Dirty DozenTM
This list – in DESCENDING ORDER of badness – is taken from www.ewg.org who have actually trademarked the name The Dirty DozenTM.
Any % in brackets is the percentage of samples that DEFRA found contained residues in the UK, although DEFRA omitted several fruits and vegetables from their survey.
Ideally buy these 12 fruits and vegetable as organic (or grow your own), because the following produce, when conventionally grown, generally has high pesticide residues.
- Strawberries – over 33% of strawberries tested had over 10 separate pesticides
- Spinach – 97% contained pesticide residue, including permethrin, a neurotoxic pesticide
- Nectarines – 94% contained at least 2 pesticides
- Apples – The USDA found a total of 47 different pesticides on apples, 6 of which are either known or suspected carcinogens. (UK 80%)
- Grapes – on average contain at least 5 pesticide residues (UK 87%)
- Peaches – on average contain at least 4 pesticide residues
- Cherries – on average contain at least 5 pesticide residues (UK 95%)
- Pears – more than half had 5 or more pesticide residues (UK 94%)
- Tomatoes – on average contain over 4 pesticide residues
- Celery – 95% contained pesticide residue
- Potatoes – one pesticide, chlorpropham, predominates on potatoes. It is used to control sprouting during storage.
- Sweet (bell) and Hot Peppers – often contain traces of highly toxic pesticides
Note: Fruits and vegetables with thin skin or no skin, where you tend to EAT the skin, are often best bought organic, since they have a higher risk of cross-contamination and pesticides are more easily absorbed.
Fruits and vegetables with a thick peel which you don’t usually eat, such as avocados or bananas, have a lower risk – so they tend to feature on the Clean 15.
The DEFRA UK list also highlights the following produce that have a high percentage of pesticide residue:
- Lemons and limes 96%
- Oranges 93%
- Parsnips 88%
THE CLEAN SIXTEEN
Lowest pesticide residues, so much safer to buy non-organic
- Peas frozen
- Aubergine / Eggplant
- Honeydew Melon
- Cantaloupe Melon
What is the definition of ORGANIC?
To qualify as an organic product, there are a number of standards that farmers and producers have to meet and maintain according to the criteria outlined by an official accreditation body, such as the Soil Association. Such stipulations include:
- Minimisation of pesticide use, with certain chemicals and toxins being banned on all occasions
- Absolutely no use of artificially produced fertilisers or herbicides
- Minimising negative impacts of farming on wildlife, while actively promoting diversity and species conservation
- No Genetically Modified Organisms (GMOs) to be grown or sold as organic
Could we feed everyone organically?
The Department of Crop and Soil Sciences at Washington State University published a meta-analysis of international farming practices in 2016.
It found that organic farming overall is about 15% – 20% less productive than large-scale conventional farming.
It draws the sensible conclusion that:
“No single approach will safely feed the planet. Rather, a blend of organic and other innovative farming systems is needed.”
A reducitarian/flexitarian approach
Here is one way forward.
The amount of total agricultural land devoted to meat/dairy production (meaning direct grazing, plus land for animal feed) is an astonishing 58%.
If we devoted less land to animal production, we would free up more for plant production. It is then likely that we could substantially increase organic growing methods and still feed an increased estimated 9 billion population by 2050. Especially if we make serious efforts to cut food wastage.
There are so many more vegetarian and vegan meat alternatives easily and relatively cheaply available now. These are not just commercial “products” like textured soy protein, tofu and Quorn – but myriad beans, peas, nuts, lentils, chickpeas, wholegrains etc, which have a high protein content and can be added to most meals.
1. Try to avoid the Dirty Dozen as conventionally farmed – and switch to organic as often as possible or affordable. Other produce is generally as safe in either form.
2. Buy fruits and vegetables at the peak of their season, when they’re not only the freshest, but also the least expensive. Freeze or bottle them, if possible, for the winter.
3. The most nutritionally powerful fruits and vegetables are often rich in colour. Because the most protective plant nutrients – called flavonoids and polyphenols – are mostly colourants in the plant’s outer layers. They include lycopene, beta carotene and lutein.
That group includes blackberries, blueberries, raspberries, papaya, strawberries, mangoes, plums/prunes (prunes are just dried plums), oranges, red grapes, cherries, sweet potatoes, spinach, kale, chard, broccoli, red pepper, butternut and other orange/yellow squashes. Non-coloured power plant foods include onions and garlic.
4. Organic eggs do have a higher nutritional content and are worth buying. Organic meat and dairy generally have a better healthy Omega 3 fat content – and it won’t have been routinely pumped full of antibiotics.
Aim for at least 3 meat-free days a week. It will improve your health and is one of the main environmentally protective actions you can take as an individual.
5. Meta-studies by University College London and the American Cancer Society define the ideal protective intake of fruits and vegetables as 9 -10 portions a day! If that’s a target too far, consider a supplement that includes a range of plant polyphenols and flavonoids.
6. You can find an eating plan that takes all this into consideration here – https://nutrishield.com/wp-content/uploads/2018/03/CR-News-Food-table.pdf
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Fruit and vegetable intake and their pesticide residues in relation to semen quality among men from a fertility clinic. Chiu YH, Afeiche MC, Gaskins AJ, Williams PL, Petrozza JC, Tanrikut C, Hauser R, Chavarro JE. Hum Reprod. 2015 Jun;30(6):1342-51. doi: 10.1093/humrep/dev064. Epub 2015 Mar 30.
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Chemical Pesticides and Human Health: The Urgent Need for a New Concept in Agriculture. Polyxeni Nicolopoulou-Stamati, Sotirios Maipas, Chrysanthi Kotampasi, Panagiotis Stamatis, Luc Hens : Front Public Health. 2016; 4: 148.
Pesticides in the Modern World – Effects of Pesticides Exposure: Alewu B, Nosiri C. In: Pesticides and human health. Stoytcheva M, editor. InTech; (2011). p. 231–50.
Sources of exposure to and public health implications of organophosphate pesticides: Jaga K, Dharmani C. Rev Panam Salud Publica (2003)
Conventional and organic foods: A comparison focused on animal product: Fernanda Galgano et al; Food Science & Technology, 20