Organic vs non-organic: is there a benefit to our gut and overall health?

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By The Gut Health Doctor Team

Dr Megan Rossi in a lab looking through a microscope

The demand for organic food has increased rapidly in recent years – and with premium pricing – thanks to claims suggesting food grown organically is more nutritious and better for our health.


But is this health halo legit and are organic products worth the price tag for our health?


Here’s the latest research.


While I’m focusing on the gut health and overall nutrition aspect here, for many there are other good reasons to buy organic, including ethical and environmental. Producing organic food uses fewer pesticides and is largely considered to be more sustainable, potentially benefiting not just our inner universe of microbes, but our outer universe too (but that’s a whole other debate!)


When choosing organic, for most people it’s driven by the perceived health benefits as the top priority. In fact, studies show that even just buying organic food can make us feel better about our own wellbeing… cue the placebo effect! Our brain is hugely powerful.


What does organic actually mean?


Organic farming uses natural substances, such as animal and plant manures, and more ‘natural’ farming methods, with the aim of having minimal impact on the environment and maintaining natural resources. The end goal is more environmentally, socially and economically friendly production.


As such, organic food means it’s produced from a farming system that limits the use of synthetic fertilisers, pesticides and livestock feed additives and antibiotics. This means using genetically modified organisms (GMOs) is not allowed, while some ‘natural’ pesticides are permitted, along with certain antibiotics where they’re needed for medical conditions (rather than routine use for prevention). For animal products, in most countries, the animals need to be eating 100% organic feed, raised in living conditions like their natural habitats (i.e. grazing on pasture) and hormone-free.


The international rules and legislation for certified organic foods may vary. In the US, being certified organic means farmers and food producers are inspected every year by the USDA. In the EU, organic foods need to be approved by an organic certification body with regular inspections and a strict set of detailed regulations. 


In the UK, the Soil Association label is considered the ‘gold standard’ for organic labelling. Here, processed foods labelled as ‘organic’ need to have at least 95% organic ingredients and many artificial colourings and sweeteners are banned, including aspartame, monosodium glutamate (MSG) and sodium benzoate.


So are organic foods better for our health? Let’s take a deeper look at the research studies in three key areas.


  1. Nutrient density


For organic


  • There are some individual studies showing organic fruits and vegetables have substantially higher levels of polyphenols than non-organic versions (they’re a group of plant chemicals shown to have health benefits and antioxidant properties)


  • Many of these polyphenols have been linked to reduced risk of certain chronic diseases, including cardiovascular (heart) disease and some cancers


  • Some studies have suggested that there are higher levels of important omega-3 fatty acids in some organic dairy products compared to non-organic


  • Some observational studies (studies that follow a group of people over time) have suggested eating organic food could be associated with a lower risk of issues such as infertility, allergies and metabolic syndrome (i.e. diabetes, high blood pressure and obesity). 


For non-organic (conventional)


Limitations to the body of research

  • The research ‘for organic’ detailed above is limited to many observational studies (observing people’s habits versus actually intervening on them). In these observational studies, there’s a high risk of bias and therefore the results are less reliable, so I’d be very cautious of drawing any conclusions from this type of evidence (observational).
  • That’s because people who opt for organic food have been shown to be more likely to have a whole range of health behaviours, such as being more physically active, not smoking, and consuming more whole plant foods (there’s that all-important dietary diversity again!), than those who don’t. Therefore, the overall lifestyles and diet habits of those eating organic versus non-organic may be quite different. 
  • At this stage, we can’t be sure that any better health outcomes seen in an observational study are solely due to the organic produce in their diet, and not one of the other factors. We’ll need better quality studies before we can unpick this relationship and make claims.
  • It’s important to note too that studies comparing organic against non-organic are limited, as the nutrient content of foods will naturally vary – thanks to the soil conditions and when they’re harvested. There also isn’t a universally agreed definition of ‘organic food’, and different studies will use different lab techniques to analyse foods too. All in all making for somewhat inconsistent data.


For every study showing slightly higher micronutrient content in organic produce, there’s another study showing no difference.


  • Results from existing research are not consistent and the differences in real terms are very unlikely to be significant in terms of our day to day nutrition requirements (e.g. less than 0.01mg of difference).


  • A systematic review from 2020 (which combined the results of 35 studies to get a more robust overview of the evidence) looked at the nutrient content of organic foods versus non-organic and overall found no difference in the levels of vitamin C, beneficial plant chemicals (phenols) and minerals (including magnesium, potassium, calcium, zinc and copper).


  • Intervention studies, where participants were provided with an organic diet versus non-organic (either a single food such as carrots, tomatoes or apples, or the whole diet), tested people’s blood and urine. Interestingly, even though fresh organic tomatoes were found to contain higher levels of vitamin C, this didn’t seem to have any effect on how much our body actually absorbs. The majority of the results showed no, or minimal, differences between the two groups on antioxidant effects or the nutrient concentrations in the blood. For example, one study measured the effects of eating organic tomatoes versus non-organic and found no difference in the levels of lycopene or vitamin C in the blood after 3 weeks of eating.


Nutritional Nugget: Lycopene is a health-promoting plant chemical in tomatoes that has been shown to increase your skin’s defence against the sun and is also linked with better heart health and a lower risk of prostate cancer.


All in all, the consensus is that there isn’t a meaningful difference in nutritional value between organically and conventionally produced foods. Season and soil conditions are likely to have much more of an impact.


          2. Pesticide residue


For organic


  • As a result of the different pesticide use, organic crops have less pesticide residue. One study (albeit small) has shown a reduction in the amount of pesticides found in urine when a group of 16 people switched from a convention diet to organic.


  • High dose pesticides have been associated with numerous negative health effects, including on our skin, brain, cancer risk and gut health.


  • For babies and young children, they are thought to be particularly sensitive to pesticide residues, with high pesticide exposure potentially increasing the risk of negative effects on things like birth weight and birth abnormalities.


For non-organic (conventional)


  • When it comes to the pesticide use in non-organic produce, in most countries these are tightly regulated and independent reviews have found most to be below the levels that have been deemed ‘safe’ by governing bodies. But whether these doses risk any harm to our health remains to be seen (see section below on our gut microbes!).


  • Thoroughly washing, or peeling, is likely to remove the majority of pesticide residue, although this is dependent on the type of pesticide used.


In summary, while the level of pesticides is higher in non-organic produce, it’s unlikely to be harmful to our human cells and therefore have largely been considered non-toxic. That’s because these ‘safe’ levels of pesticides don’t have the ability to affect the normal function of our human cells. (Just like most food additives – one for another post!)


But what about our gut microbes?

This is where things start to get really interesting, as biased as we may be! You see, our gut microbiota (or GM, the trillions of microbes living in our gut) has largely been overlooked in the research, and therefore in the official legislation, so far.


But given our gut is the first stop for our food and exposure to pesticide residues, it can’t be ignored when it comes to the impact on our overall health.


          3. Here’s what the research shows when it comes to our gut health…


  • Recent test tube and animal studies have shown some synthetic pesticides (e.g. glyphosate) may have a direct toxic effect, as well as an indirect negative effect on the gut microbiome


  • Pesticides seem to have the ability to act on our gut microbes and affect what chemicals they produce (at least in animals) – including affecting the production of short-chain fatty acids (SCFAs) that are linked with balancing our blood sugar, stimulating our immune system and much more


  • The make-up of our GM may also be altered by pesticide intake (again all based on animal studies i.e. don’t freak out just yet!), and this disruption to the balance of microbes we have COULD impact our gut lining and inflammation if consumed at high enough levels.


Ultimately, at the moment we’re lacking human studies to be able to explore the full impact of pesticides on our gut microbiome. Humans and animals are very different, so we can’t directly translate findings from animal studies into recommendations for humans. In fact the majority of animal study findings don’t translate when tested in humans. But watch this space!


Organic doesn’t always mean ‘healthy’


Last but not least, just because a food says it’s organic does not necessarily mean it’s good for you. Take organic cola, for example. Organic cola has pretty much the same added sugar content as regular cola.


An ‘organic’ label on a fast-food product does not mean it’s more nutritious, although some companies have been quick to cash in on the claims.




Overall, while organic food may reduce your exposure to pesticides (remember non-organic are still regulated for safe levels in most western countries), it’s unlikely to impact your nutrient intake in any meaningful way – non-organic produce is just as nutritious for the most part.


In terms of the impact of pesticide residue on your gut microbes, there is much more research to be done. But it is worth washing your plants well before eating.


If you’re lucky enough to be able to buy organic or have access to farmers’ markets and want to make that choice, go for it.


Either way, don’t be limited to only buying organic produce, especially if it’ll risk reducing the variety of plants in your diet. It’s certainly better to eat conventional plant foods (fruits, vegetables, wholegrains, legumes, nuts and seeds) than to miss out. And don’t be fooled by the ‘organic’ food label hype on fast-food products.


If it’s optimising nutrition you’re after, it’s worth thinking about filling up your freezer with frozen vegetables for maximum nutrients – more on that to come on the hub soon!


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