The foods that are really worth it if you go organic
A new study warns eating a Mediterranean diet can up your pesticide intake. Alice Hall investigates
With its wide variety of vegetables, nuts and fish, the Mediterranean diet is often hailed as the healthiest in the world. Previous studies have linked the diet with longer life, reduced risk of depression, improving heart health and protecting against dementia. But a new study offers a word of warning to the increasing numbers switching to a plant-based diet: it may increase your pesticide intake, compared to a regular British diet.
The research, published in the American Journal for Clinical Nutrition by the University of Oslo, found that swapping a western diet for a Mediterranean one resulted in more than three times the total intake of insecticide and organophosphates – the chemicals that poison insects and mammals. When the ingredients of a Mediterranean diet are farmed organically, the chance of pesticide intake can be cut by around 90 per cent, according to the research.
The researchers stressed that the study was small. But with plant-based lifestyles soaring in popularity, some experts say more research is urgently needed into our pesticide consumption and the potential impact on health. Each year, the government tests samples of groceries for chemicals to check if traces can be found in Britain’s food. Figures published by the Pesticide Action Network (PAN), a British charity, in September found 122 different pesticides in the 12 most polluted products, which the charity calls the “dirty dozen”. The research found that 87.2 per cent of grape samples contained pesticide residues, followed by 86.7 per cent of oranges and 81.9 per cent of dried fruits, such as raisins and sultanas.
In 2018, strawberries topped the US Environmental Working Group’s (EWG) Dirty Dozen list for the third year in a row, after more than 98 per cent of produce tested was positive for pesticide residue. Spinach, according to the EWG, has more pesticide residue by weight compared to any other products analysed; during testing the group found relatively high concentrations of permethrin, a known neurotoxin, on many samples.
Bell peppers and hot peppers were added to the EWG’S Dirty Dozen list this year, after nearly three-fourths of hot peppers were found to contain trace residues from highly toxic pesticides. According to PAN, washing can remove some of the pesticides left on fruit, but buying organic food is the best way to avoid consuming them.
The effect of pesticides on our health is still a topic of much debate: the Oslo researchers claim that following a non-organic Mediterranean diet may weaken people’s immune systems, affect fertility and even stunt the growth of children.
A study by Paris University published in 2018, on 68,000 people, found those who ate the most organic food were 25 per cent less likely to get cancer than the group who ate the least, though the study did not prove a causal link and scientists said it could be down to richer, better educated and healthier people choosing organic produce.
Experts point to the fact that the EU has one of the most protective pesticide regimes in the world – and the UK regime currently mirrors it. “All foods sold in the UK are regularly tested and have to meet really strict rules on pesticide levels to ensure they’re safe to eat,” says registered dietitian, and spokesman for the British Dietetic Association, Helen Bond.
Some research does suggest that organic fruit may be more nutritious. A study carried out at the University of
California compared levels of phenolic compounds, powerful health promoting phytochemicals, in strawberries, corn and Marion berries (a berry similar to a raspberry) in crops grown using chemical pesticides and crops grown organically. They found that the organically grown corn and berries contained over 50 per cent more of these phenolic compounds than the conventionally grown crops.
“One theory is that the phytochemical composition in conventionally grown crops is lower than in organic crops, because they don’t need to protect themselves from disease and pests; the weaker, more protected, the fruit, the less phytochemicals it has,” says Bristol-based nutritionist Rosie Letts. Nutritionists agree it’s preferable to eat non-organically grown fruit and vegetables over cutting them out altogether. But while adopting a strictly organic diet would put many Britons out of pocket, there are certain areas where it might be worth making the switch. Letts says soft-skinned fruits such as strawberries, raspberries and grapes often rank among the worst culprits for pesticide residue. “It’s worth buying organic soft-skinned fruits if you can afford it, although realistically it means eating seasonally,” she says.
Cost-wise, a pint of organic milk only costs about 15 pence more than conventional milk, but this small difference reaps benefits.
“The pesticides on cows’ food influence the chemical structure of the milk, and the level of contaminants in it,” says Letts. “The proportion of essential fat, and chemical residue levels, in organic milk and nonorganic milk are very different.”
According to a series of studies by researchers at Newcastle University, organic milk contains around 50 per cent more omega-3 fatty acids, whose benefits include improving brain and heart health, than conventionally produced milk. Studies by Glasgow and Liverpool Universities also found that organic milk has more Vitamin E and beta-carotene, which help to promote a healthy immune system.
If you’re buying meat, many experts advise focusing on buying organic, grass-fed meat if you’re able to. It is lower in fat and, like milk, is significantly higher in a number of nutrients, notably omega-3 fatty acids. “We know that animals who are fitter and healthier are better for us; their meat has lower levels of saturated fat, and is richer in Vitamin E and A, which supports our immune system,” says Letts. However, she stresses organic isn’t always a guarantee of welfare: a five-year US study showed that organic “health outcomes are similar to conventional dairies”. Where possible, it’s best to choose free-range meat from local butchers.
Bond believes that, overall, we shouldn’t let the ongoing research into pesticides come in the way of following a healthy, balanced and varied diet filled with plant foods – which remains one of the best things you can do to protect against disease and weight gain. She explains that seven out of ten adults are failing to hit the five-a-day target, rising to 88 per cent of teenagers.
“It’s important to be mindful of pesticides, but the bigger picture should be looking at your overall diet; what, and how much, we eat is much more important in terms of our health.”