Is eating organic food better for your gut health?

To mark the Soil Association’s annual Organic September awareness month, our expert Nutritional Therapist, Ruth, writes about whether eating organic food is better for your gut health. We take a closer look at the potential benefits of eating an organic diet to overall health and the health of your gut microbiome, when compared to conventional grown/reared foods.

What is organic food?

The goal of organic farming practices is to maintain soil health, sustain ecological systems, maintain fairness in its relationship with the environment and protect the environment in its entirety. Organic farming is designed to mitigate environmental pollution and prioritise animal welfare through protective management strategies that prevent exposure to harmful pesticides, industrial solvents and synthetic chemicals.

Organic farming follows four guiding principles: health, ecology, fairness and care¹.

• Health: ensures that organic agriculture should sustain and strengthen the health of the soil, plants, animals, humans and the earth as a whole
• Ecology: focuses on living ecological systems and how organic agriculture should work with, sustain and emulate these systems
• Fairness: underscores the importance of relationships ensuring fairness in the common environment and life opportunities
• Care: advocates for safe and responsible agricultural management to protect current and future generations and the environment

To adhere to these principles, organic farming employs practices such as crop rotation, intercropping, polyculture, covering crops, seeding timing and mulching¹.

Organic farming is grounded in biological and ecological processes that mitigate the environmental impact of the agricultural practices whilst preserving the natural qualities of the foods. In this holistic approach, pest and disease control are achieved naturally, eliminating the need for synthetic chemicals utilised in conventional farming.

In the UK, the Soil Association charity was one of the founders of the global organic movement and continues to develop world-leading standards whilst running the UK’s largest organic certification body. They state that organic farming in practice looks like the following²:

• Fewer pesticides – Under the Soil Association’s organic standards, all weedkillers are banned, and farmers are only able to use a very limited number of naturally-derived pesticides as a last resort (like citronella and clove oil), but only under very restricted circumstances.
• No artificial fertilisers – Organic farming avoids the use of synthetic fertilisers, as the principles of organic farming are based on nourishing plants naturally, by building fertile soils.
• Higher animal welfare standards – one of the most important aspects of organic farming. Organic standards insist that animals are truly free-range; given plenty of space and fresh air and raised in conditions that suit their natural behaviour.
• No routine use of antibiotics – using them preventively is banned in organic farming, instead the animals’ natural immunity is supported.
• No genetic modification (GM) – organic standards ban the use of all GM ingredients, and animals on organic farms must be fed a natural, organic and non-GM diet.
• No artificial colours and preservatives – organic standards inhibit the use of toxic ingredients and must not contain hydrogenated fats.

In the past few decades, interest in organically produced food has steadily risen around the world. Several studies have reported different consumer motives to buying organic food, such as taste, health, environment, and even farmers’ welfare³, however the major determinants behind the purchase of organic products is the belief that organic food is healthier or has a superior nutritional profile⁴.

Skip to Key Takeaways

Is organic food better for you?

Organic foods may contain more nutrients:

• Higher antioxidant levels

A large meta-analysis of 343 peer-reviewed publications found that crops grown organically had substantially higher concentrations of a range of antioxidants such as polyphenols, when compared to conventionally grown crops. The figures of the different polyphenols examined ranged from 19% – 65% higher⁵.

Polyphenols are secondary plant metabolites, which protect plants from physical, chemical and biological stress – and can provide these protective effects to humans upon consumption. They are the most common phytochemical bioactive components in our diet, being present in a variety of foods such as fruits, vegetables, grains and legumes, beverages such as tea, coffee, chocolate and wine and in extra virgin olive oils⁸.

Polyphenols have demonstrated several benefits to human health, including immune modulating, antioxidant and anti-inflammatory action⁶.  

Dietary polyphenols can be particularly protective for cardiovascular health, where they have been suggested to prevent the occurrence of heart diseases such as strokes, hypertension, heart failure, and ischemic heart disease⁷.

• Higher omega-3 in organic dairy products

Over the last century, intakes of omega-6 fatty acids in Western diets have dramatically increased, while omega-3 intakes have fallen, resulting in omega-6/omega-3 intake ratios that have risen to nutritionally undesirable levels, generally 20:1, as opposed to the estimated 4:1 of our hunter-gather ancestors⁹. These changes in fatty acid intakes have come about largely due to increased intake of vegetable and seed oils and reduced intake of generally low consumption of oily fish, vegetables, fruits, and beans¹⁰.

One study examining the fatty acid profile in milk, found that, averaged over 12 months, organic milk contained 25% less omega-6 and 62% more omega-3 fatty acids than conventional milk. All individual omega-3 fatty acid concentrations were higher in organic milk—α-linolenic acid (by 60%), eicosapentaenoic acid (EPA) (32%), and docosahexaenoic acid (DHA) (19%)—as was the concentration of conjugated linoleic acid (CLA) (18%).

The authors conclude that switching to organic dairy offers a viable option to reduce average omega-6/3 intake ratios, thereby reducing probable risk factors for a wide range of developmental and chronic health problems¹⁰.

A more recent meta-analysis found that concentrations of very long chain omega-3 polyunsaturated fatty acids (PUFAs) EPA/DHA were around 58% higher in organic compared to conventional milk¹¹. This difference is thought to be due to the high fresh forage intakes by grazing animals as prescribed by organic farming standards.

The current advice to improve EPA and DHA intake is to eat more oily fish, but higher fish consumption across the human population is thought to be impossible, as most of the world’s fish stocks are already fully or over-exploited. In addition, there are concerns about the sustainability/environmental impacts of fish farming as well as high toxin and heavy metal levels in oil-rich fish in some regions of the world¹¹. Therefore, it is thought to be essential to develop additional/complementary dietary approaches to increase omega-3 intake, and organic dairy offers one viable option.

• Improved fatty acid profiles in organic meat products

As with dairy, significant and nutritionally meaningful composition differences between organic and non-organic meat have been reported in the literature. One meta-analysis concluded that organically farmed meat was as estimated 47% higher in omega-3 fatty acids. A high grazing/forage-based diet and being reared outdoors for part of the year is thought to be behind the more healthful fatty acid profile in organic meat¹².

Other studies have demonstrated improved fatty acid profiles in organically reared chickens, with increased DHA, omega-3 PUFA, and decreased the ratio of omega-6 to omega-3 PUFA¹³, with similar results being seen in studies of other organically reared animals¹⁴.

There is evidence that following an organic diet can affect the plasma levels of certain nutrients, with one study comparing various biomarkers in those with low (<10%) or high (>50%) dietary intake of organic food. The authors discovered that high organic food consumers had considerably higher plasma concentrations of magnesium as well as fat soluble phytonutrients such as α-carotene, β-carotene, lutein, and zeaxanthin¹⁵.

Organic foods contain less pesticides

Likely to be of more importance than compositional differences between organic and conventional food, is what organic foods do not contain.

Increased public concerns about the negative environmental and health impacts of agrochemicals (pesticides, growth regulators and mineral fertilisers), used in conventional farming have been major drivers for the increase in consumer demand for organic foods over the last 20 years⁴.

Organic foods have been shown to have lower levels of toxic metabolites, including heavy metals such as cadmium, and synthetic fertilizer and pesticide residues⁵. Cadmium is a highly toxic metal which accumulates in the human body (especially in the liver and kidneys) and therefore dietary cadmium levels should be kept as low as possible, and in one analysis, levels were 48% lower in organic crops⁵.

The same study demonstrated that the prohibition of synthetic chemical pesticide use under organic farming standards results in a more than 4-fold reduction in the number of crop samples with detectable pesticide residues. Pesticide exposure has been linked to carcinogenic effects, endocrine-disrupting effects and neurotoxicity¹⁶.

Health implications of organic food

In summary, the evidence suggests that organic crops provide higher antioxidant levels, while organically raised meat and dairy products have a more favourable fatty acids profile, but, probably most important of all is the considerably lower levels of toxic metals and pesticide residues on organic food compared to conventional agriculture.

There is a lack of research, particularly long-term interventional studies on the role of organic food on human health, and evidence is further compounded by the fact that those who choose organic food tend to have healthier dietary patterns, with more vegetables, fruit and wholegrains and less meat, and each of these dietary characteristics is associated with a decreased risk for incidence of certain chronic diseases. Likewise, consumers who regularly buy organic food are also more physically active and less likely to smoke¹⁶.

That being said, cadmium, for example, is toxic to the kidneys, can demineralise the bones and is carcinogenic, and in non-smokers, food, particularly cereals and vegetables are the largest contributors^16.

So, when we consider that organically produced crops have a greater than 4 times lower level of this toxic metal, we can safely surmise that eating organic can be more protective to health than conventionally farmed foods. 

Organic food & gut health

Fewer pesticides

Exposure to a range of environmental pollutants, including pesticides, can have a harmful effect on the gut microbiome, affecting both its diversity and metabolic activity, which can, in turn have a negative effect on a variety of metabolic and immune functions¹⁷.

As an example, organophosphate pesticides, frequently found in fruit and vegetables have demonstrated a decrease in the levels of beneficial bacteria such as Bifidobacterium and Lactobacillus, along with an increase in the abundance of pathogenic strains.

This shift in microbial composition may lead to alterations in pH levels or the stimulation of short-chain fatty acids (SCFAs), which in turn can inhibit the colonisation of potentially harmful bacteria in the gut¹⁸. Similar effects have been observed in a number of commonly used pesticides, herbicides and fungicides¹⁷.

We can, therefore, infer that organic farming, which strictly inhibits the use of such pesticides will pose a far lesser disruption to gut health.

Higher nutrient content

As discussed, organic foods have been shown to be higher in antioxidant nutrients; in particular, polyphenols. The intestine is a prime target for polyphenols. Although they have low bioavailability in the bloodstream, polyphenols can be retained in the gut for a longer time, reaching high concentrations due to their complex structure and food matrix composition, thus promoting beneficial gut effects.

Growing evidence suggests that polyphenols exhibit prebiotic properties and antimicrobial action against pathogenic bacteria, in addition to modulating gut metabolism and immunity and displaying anti-inflammatory effects¹⁹.

Lower antibiotic exposure

Overly prevalent prophylactic use of antibiotics in animal production is an important factor contributing to increasing human health problems due to resistant bacteria, whereas antibiotic use is strongly prohibited in organic farming. It has been predicted that by 2050, 10 million deaths world-wide will be attributable to antimicrobial resistance²⁰. Using antibiotics in animals may raise the risk of transmitting drug-resistant bacteria into the human microbiome, either by direct infection or by transferring resistant genes from agriculture into human pathogens²¹.

Diverse soil microbiome

The large diversity of microbiota in soil affects its microbial ecology, including its primary productivity and nutrient cycling.

There is also a close link between the soil microbiome and the microbiome of the human gut.

In our modern lifestyles, the diversity of the gut microbiome has decreased, partly as a result of reduced contact with soil, increased hygienic measures, antibiotics and a processed diet with low levels of fibre.  At the same time, loss of soil biodiversity is taking place, with the increasing use of agrochemicals, low plant biodiversity and rigorous soil management practices used in conventional farming²².

Conversely, organic farming has been shown to enhance the total microbial abundance and activity in agricultural soils on a global scale, both of which are well-known indicators of soil quality²³. 

The Clean 15 and Dirty Dozen

Organic food does undoubtedly incur a higher price and may therefore not be accessible to all – but by making smart food choices, you can help to reduce your exposure to potentially harmful toxins from your diet.

The Pesticide Action Network (PANUK) analyses the results of the UK’s annual residue testing programme and produces a list known as the “Dirty Dozen”: the fruit and vegetables most likely to be contaminated with multiple pesticides²⁴. The 2024 list, based on data from 2022 is as follows:

Fruit/Vegetable	% of samples with multiple pesticide residues
Peaches/Nectarines	85%
Grapes	84%
Strawberry	83%
Cherries	81%
Spinach	73%
Apples	72%
Brussel Sprouts	50%
Cucumber	47%
Tomato	46%
Apricots	43%
Lettuce	39%
Beans with pods	38%

PAN UK does not produce a so called “Clean 15” list of the produce with the least residues because the “government testing programme is so limited that we would not want to give the impression that certain produce is guaranteed to be free from pesticide cocktails”.

However, the Environmental Working Group (EWG); a non-profit organisation based in the United States have produced a list of the fruits and vegetables with the lowest level of pesticide residues, according to their analysis of the most recent U. S. Department of Agriculture data²⁵.

• Avocados
• Sweetcorn
• Pineapple
• Onions
• Papaya
• Sweet peas (frozen)
• Asparagus
• Honeydew Melon
• Kiwi
• Cabbage
• Mushrooms
• Mangoes
• Sweet Potatoes
• Watermelon
• Carrots

Of course, the EWG’s report is specifically concerned with vegetables and fruits in the US, but it is likely that most of this list is transferable worldwide, and it can act as a useful guide as to which conventionally farmed foods may not be so high in pesticide residues and can therefore be safely included in a healthy diet.

It is beyond the scope of this blog to discuss the animal welfare and environmental impacts of conventional versus organic farming, but these are other considerations and more information is available on the Soil Association website.

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References

1. Gomiero, T., Pimentel, D., & Paoletti, M. G. (2011). Environmental impact of different agricultural management practices: conventional vs. organic agriculture. Critical reviews in plant sciences, 30(1-2), 95-124.
2. The Soil Association (2024). What is organic. Retrieved August 29, 2024, from https://www.soilassociation.org/take-action/organic-living/what-is-organic/
3. Kushwah S, Dhir A, Sagar M, Gupta B. Determinants of organic food consumption. A systematic literature review on motives and barriers. Appetite. 2019 Dec 1;143:104402. doi: 10.1016/j.appet.2019.104402. Epub 2019 Aug 14. PMID: 31421197.
4. Vigar V, Myers S, Oliver C, Arellano J, Robinson S, Leifert C. A Systematic Review of Organic Versus Conventional Food Consumption: Is There a Measurable Benefit on Human Health? Nutrients. 2019 Dec 18;12(1):7. doi: 10.3390/nu12010007. PMID: 31861431; PMCID: PMC7019963.
5. Barański M, Srednicka-Tober D, Volakakis N, Seal C, Sanderson R, Stewart GB, Benbrook C, Biavati B, Markellou E, Giotis C, Gromadzka-Ostrowska J, Rembiałkowska E, Skwarło-Sońta K, Tahvonen R, Janovská D, Niggli U, Nicot P, Leifert C. Higher antioxidant and lower cadmium concentrations and lower incidence of pesticide residues in organically grown crops: a systematic literature review and meta-analyses. Br J Nutr. 2014 Sep 14;112(5):794-811. doi: 10.1017/S0007114514001366. Epub 2014 Jun 26. PMID: 24968103; PMCID: PMC4141693.
6. Yahfoufi N, Alsadi N, Jambi M, Matar C. The Immunomodulatory and Anti-Inflammatory Role of Polyphenols. Nutrients. 2018 Nov 2;10(11):1618. doi: 10.3390/nu10111618. PMID: 30400131; PMCID: PMC6266803.
7. Iqbal I, Wilairatana P, Saqib F, Nasir B, Wahid M, Latif MF, Iqbal A, Naz R, Mubarak MS. Plant Polyphenols and Their Potential Benefits on Cardiovascular Health: A Review. Molecules. 2023 Sep 1;28(17):6403. doi: 10.3390/molecules28176403. PMID: 37687232; PMCID: PMC10490098.
8. Calabriso N, Massaro M, Scoditti E, Carluccio MA. Dietary Polyphenols and Their Role in Gut Health. Nutrients. 2023 Jun 6;15(12):2650. doi: 10.3390/nu15122650. PMID: 37375554; PMCID: PMC10302038
9. DiNicolantonio JJ, O’Keefe JH. The Importance of Marine Omega-3s for Brain Development and the Prevention and Treatment of Behavior, Mood, and Other Brain Disorders. Nutrients. 2020 Aug 4;12(8):2333. doi: 10.3390/nu12082333. PMID: 32759851; PMCID: PMC7468918
10. Benbrook CM, Butler G, Latif MA, Leifert C, Davis DR. Organic production enhances milk nutritional quality by shifting fatty acid composition: a United States-wide, 18-month study. PLoS One. 2013 Dec 9;8(12):e82429. doi: 10.1371/journal.pone.0082429. PMID: 24349282; PMCID: PMC3857247.
11. Średnicka-Tober D, Barański M, Seal CJ, Sanderson R, Benbrook C, Steinshamn H, Gromadzka-Ostrowska J, Rembiałkowska E, Skwarło-Sońta K, Eyre M, Cozzi G, Larsen MK, Jordon T, Niggli U, Sakowski T, Calder PC, Burdge GC, Sotiraki S, Stefanakis A, Stergiadis S, Yolcu H, Chatzidimitriou E, Butler G, Stewart G, Leifert C. Higher PUFA and n-3 PUFA, conjugated linoleic acid, α-tocopherol and iron, but lower iodine and selenium concentrations in organic milk: a systematic literature review and meta- and redundancy analyses. Br J Nutr. 2016 Mar 28;115(6):1043-60. doi: 10.1017/S0007114516000349. Epub 2016 Feb 16. PMID: 26878105; PMCID: PMC4838834.
12. Średnicka-Tober D, Barański M, Seal C, Sanderson R, Benbrook C, Steinshamn H, Gromadzka-Ostrowska J, Rembiałkowska E, Skwarło-Sońta K, Eyre M, Cozzi G, Krogh Larsen M, Jordon T, Niggli U, Sakowski T, Calder PC, Burdge GC, Sotiraki S, Stefanakis A, Yolcu H, Stergiadis S, Chatzidimitriou E, Butler G, Stewart G, Leifert C. Composition differences between organic and conventional meat: a systematic literature review and meta-analysis. Br J Nutr. 2016 Mar 28;115(6):994-1011. doi: 10.1017/S0007114515005073. Epub 2016 Feb 16. PMID: 26878675; PMCID: PMC4838835.
13. Molee W, Khosinklang W, Tongduang P, Thumanu K, Yongsawatdigul J, Molee A. Biomolecules, Fatty Acids, Meat Quality, and Growth Performance of Slow-Growing Chickens in an Organic Raising System. Animals (Basel). 2022 Feb 24;12(5):570. doi: 10.3390/ani12050570. PMID: 35268139; PMCID: PMC8908829.
14. Kilar J, Kasprzyk A. Fatty Acids and Nutraceutical Properties of Lipids in Fallow Deer (Dama dama) Meat Produced in Organic and Conventional Farming Systems. Foods. 2021 Sep 27;10(10):2290. doi: 10.3390/foods10102290. PMID: 34681339; PMCID: PMC8534888.
15. Baudry J, Ducros V, Druesne-Pecollo N, Galan P, Hercberg S, Debrauwer L, Amiot MJ, Lairon D, Kesse-Guyot E. Some Differences in Nutritional Biomarkers are Detected Between Consumers and Nonconsumers of Organic Foods: Findings from the BioNutriNet Project. Curr Dev Nutr. 2018 Nov 15;3(3):nzy090. doi: 10.1093/cdn/nzy090. PMID: 30842992; PMCID: PMC6397420.
16. Mie A, Andersen HR, Gunnarsson S, Kahl J, Kesse-Guyot E, Rembiałkowska E, Quaglio G, Grandjean P. Human health implications of organic food and organic agriculture: a comprehensive review. Environ Health. 2017 Oct 27;16(1):111. doi: 10.1186/s12940-017-0315-4. PMID: 29073935; PMCID: PMC5658984.
17. Ali A, AlHussaini KI. Pesticides: Unintended Impact on the Hidden World of Gut Microbiota. Metabolites. 2024 Mar 7;14(3):155. doi: 10.3390/metabo14030155. PMID: 38535314; PMCID: PMC10971818.
18. Yuan X, Pan Z, Jin C, Ni Y, Fu Z, Jin Y. Gut microbiota: An underestimated and unintended recipient for pesticide-induced toxicity. Chemosphere. 2019 Jul;227:425-434. doi: 10.1016/j.chemosphere.2019.04.088. Epub 2019 Apr 13. PMID: 31003127.
19. Calabriso N, Massaro M, Scoditti E, Carluccio MA. Dietary Polyphenols and Their Role in Gut Health. Nutrients. 2023 Jun 6;15(12):2650. doi: 10.3390/nu15122650. PMID: 37375554; PMCID: PMC10302038.
20. Marquardt RR, Li S. Antimicrobial resistance in livestock: advances and alternatives to antibiotics. Anim Front. 2018 Apr 19;8(2):30-37. doi: 10.1093/af/vfy001. PMID: 32002216; PMCID: PMC6951930.
21. Chang Q, Wang W, Regev-Yochay G, Lipsitch M, Hanage WP. Antibiotics in agriculture and the risk to human health: how worried should we be? Evol Appl. 2015 Mar;8(3):240-7. doi: 10.1111/eva.12185. Epub 2014 Aug 2. PMID: 25861382; PMCID: PMC4380918.
22. Blum WEH, Zechmeister-Boltenstern S, Keiblinger KM. Does Soil Contribute to the Human Gut Microbiome? Microorganisms. 2019 Aug 23;7(9):287. doi: 10.3390/microorganisms7090287. PMID: 31450753; PMCID: PMC6780873.
23. Lori M, Symnaczik S, Mäder P, De Deyn G, Gattinger A. Organic farming enhances soil microbial abundance and activity-A meta-analysis and meta-regression. PLoS One. 2017 Jul 12;12(7):e0180442. doi: 10.1371/journal.pone.0180442. PMID: 28700609; PMCID: PMC5507504.
24. The Dirty Dozen – Pesticide Action Network UK (pan-uk.org)
25. EWG’s 2024 Shopper’s Guide to Pesticides in Produce | Clean Fifteen

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nutrition@cytoplan.co.uk
01684 310099

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Last updated on 6th September 2024 by cytoffice