It was recently reported that PFAS (Per- and PolyfluoroAlkyl Substances), also known as 'forever chemicals', were found in more than half of fruit and vegetable samples tested in the UK. This has led to calls for pesticides containing these chemicals to be banned. But what risk does eating fruits and vegetables containing PFAS actually present to our health?
What actually are 'forever chemicals'?
PFAS are not just one thing. They are a large group of more than 10,000 chemicals with very strong carbon-fluorine bonds. Examples include perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA) and perfluorohexane sulfonate (PFHxS).
They are used to make products like fabrics, food packaging, non-stick cooking surfaces and pesticides that need stability to resist heat, oil, and water. But this stability also means that the chemicals are less biodegradable and so can persist in the environment, and in people, for a long time.
How dangerous are 'forever chemicals' to humans?
Research into the health impacts of PFAS is ongoing. Observational evidence and data from animal studies suggest associations between higher exposure to some specific PFAS and certain health effects, like increased cholesterol levels, thyroid and liver dysfunction, adverse pregnancy outcomes, and increased risk for some cancers.
Because of this, many governments have placed restrictions on the use of PFAS. Some have been banned outright and others are subject to maximum allowable limits in food and drinking water. Limits have been set in place of bans because the risks are not absolute or black and white.
The dose, frequency, route and duration of exposure, as well as lots of factors like health, genetics and other lifestyle habits determine the scale of the risk for each individual.
Evidence of harm typically comes from very high doses through exposure to contaminated sites. Some animal studies use very high doses, and animal research does not always correlate with human health effects due to differences between species.
Also, the data doesn’t apply to all PFAS. Some, while not broken down easily, are considered chemically inert because the molecules lack chemically active groups.
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How many 'forever chemicals' are in our food?
The report found PFAS were present in over half of all food samples tested in the UK. This sounds alarming, but most (98.8 per cent) were well below the maximum residue levels (MRL) allowed in food by law.
These levels are set and constantly reviewed to ensure exposure doesn’t reach risky levels, even for those eating a variety of foods that may contain some residues.
There are calls from some quarters to ban PFAS-containing pesticides, but it’s unlikely that they'll be eliminated entirely from food supplies as they have multiple uses. It’s important to note that as PFAS are a very broad range of chemicals they don’t all behave in the same way when it comes to health.
How do I reduce my risk?
PFAS are also present in cooking products and food packaging, so cutting out fruits and vegetables due to fear of PFAS isn’t likely to create a net benefit to health since these foods contain multiple essential nutrients and health-promoting bioactive compounds.
In fact, there is some evidence that high-fibre and high-folate diets, both of which are present in fruits, vegetables and grains, reduce the absorption and accumulation of PFAS in our bodies.
Thoroughly washing or peeling fresh produce can help to remove pesticides present on the surface. The use of running water is recommended to flush contaminants away but there is no evidence that using detergents provides any additional benefits.
This won’t always reduce levels to zero because PFAS may have been incorporated into the produce from the soil or water, and repel water, but since the dose matters when it comes to risks, elimination isn’t the necessary aim anyway.
Eating a diet high in variety also helps. Variety isn’t just about making sure that we get a diversity of nutrients into our diets, it is also about spreading risks. If you eat the same fruits and vegetables over and over you may increase your total exposure in the event of a contamination, for example.
Are organic fruits and vegetables lower in PFAS?
Organic farming avoids the use of man-made pesticides, reducing the likelihood of residues being detected. However, this doesn’t necessarily mean they are PFAS-free. PFAS have also been detected in organic foods through integration from soil and water.
Eating locally and seasonally where possible can also help to reduce the need for pesticide use – you'll be choosing foods that grow well in the local conditions.
Should we be worried?
The world, and our food chains in particular, are full of risks that are dangerous only in particular amounts and specific situations. But that doesn’t make all and any exposure a reason to panic. For example, the microbes responsible for food poisoning can’t be fully eliminated and most people will survive an encounter.
It is prudent to continue to study PFAS and other chemicals that have potential risks to human health. But it’s also important to continue to investigate other options for growing the vast amounts of food required to feed the world efficiently and economically.
Ultimately, caution should be taken not to stoke unnecessary fear, or to work with broad generalisations, as this can also cause harm to us when we are making our food choices.
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