A varied and balanced diet, as seen, can favorably affect the microbiome and stimulate the immune system. Of particular note, in the Covid era. The nutritional quality of individual foods, however, varies within the same product categories due to agronomic practices and production methods used. And organic foods have better characteristics. Brief scientific review.
Organic, environment and health
Organic is better, no ifs or buts. For the environment and society, as science shows, but also for health. There are two essential reasons for this:
– Absence of pesticide and agrotoxic residues . Which, as it turns out, can alter the microbiome. Specifically reducing the presence of health ‘ally’ bacteria and immune defenses,
– greater quali-quantitative bioavailability of nutrients and a greater variety of probiotic-effect microorganisms (4,6). As also shown in previous scientific studies to which we have already referred.
Organic foods, the microbiome, and the immune system
Polyphenols play a crucial role in reducing oxidative stress in the body and also therefore exert immune stimulation, as noted. (1) Organic vegetables are distinguished–compared to their counterparts produced through conventional, albeit ‘sustainable‘ agriculture–by higher contents of polyphenols and other antioxidants (e.g., carotenoids). And their concentration, in organic vegetables, is directly associated with microbiome health. (5)
The logic is simple, plants not treated with agrochemicals are forced to organize ‘according to nature’ to protect themselves. And they provide it by metabolizing phytonutrients such as precisely polyphenols. Which then also realize a protective function in the consumer of the relevant products. (2) The microbial composition of the soil is in turn related to the fertilizers used. Where the use of organic fertilizers increases microbiodiversity and the presence of microorganisms beneficial to food quality and wholesomeness. (6)
The gut microbiota-which influences the immune system-is indeed strongly influenced by diet, both positively and negatively. And from the inappropriate use of drugs(such as antibiotics). And the influence of the microbiota on immunological diseases such as obesity, type 2 diabetes, and cardiovascular disease is well known. (3)
Organic food, among other things, can help maintain optimal gut flora through probiotics that are present in fresh organic foods such as vegetables. (4)
Nutrients and antioxidants, the added bio-value
Numerous scientific studies show a more pronounced biological activity, in organic foods, than in conventional foods. In plant production as in animal production, with rare exceptions. (8) Protein-in plant and animal products-tends to be lower in quantity but better in quality and composition. Meat, milk and cheese have a more balanced fatty acid profile (Omega 6 / Omega 3), due to the quality of forage fed and grazed, as well as a higher content of polyunsaturated fatty acids and conjugated forms (10,11,12).
The enhanced antioxidant capacity of organic food products has been experimentally verified-with an effect on reducing oxidant activity in the body-through improved metabolic and cellular energy status. (18)
Figure 1. Difference in antioxidant activity of conventional and organic foods. The value of the medians should be observed. A higher number indicates a food with greater antioxidant action (De Lorenzo et al., 2009)
Organic spinach showed higher levels of polyphenols and flavonoids (+15%, on average) than conventional products (13). Tomatoes and processed products contain more polyphenols, carotenoids, flavonols and vitamin C. (14) Blueberries are richer in sugars, organic acids, phenolic substances and other phytochemicals with antioxidant action. (15) Organic oil olives also have a higher polyphenol content, with no recorded differences in fruit size and oil content. (16) Organic cauliflowers, in turn, showed higher polyphenol and carotenoid content in the Italian variety Velox (+21 and +13%. respectively). (17)
Environmental pollutants and the gut microbiota
Environmental pollutants-whose residues are more common in conventional agriculture, for various reasons related to the use of agrochemicals, on the other hand-cause a disruption on the gut microbiota. They thus reduce immune system efficiency and nutrient absorption, as well as contribute to other metabolic imbalances. (7) Among the various pollutants, nitrogen-especially in the form of nitrates, which are toxic to health-is also worth mentioning, and is present in lower amounts in organic soils and products than in conventional counterparts. (9)
Figure 2. Different influence of organic and conventional diet on gut microbiota (Hurtado-Barroso et al., 2017)
Organic Mediterranean diet, prevention and protection in Covid-19 era
The Mediterranean diet has roots dating back thousands of years in the culture of its peoples. It is recognized as one of the optimal dietary regimens for promoting longevity and quality of life, thanks to the miraculous balance of its constituent foods. The immune system is certainly affected in a positive way by this type of diet due to the higher concentration of soluble and insoluble dietary fiber, vitamins and minerals, polyphenols and other substances valuable in fighting oxidative processes. Many vegetables help to have more ready immunological responses, especially against viruses and bacteria. (19) Fiber and reduced saturated fat help maintain a better weight and decrease the risk of contracting infections such as pneumonia (the most common complication of Covid-19 infections). (20)
Some vitamins, by the way, play an important role in boosting the immune system. Vitamin D has been pointed to by several quarters-from the Academy of Medicine in Turin, Italy, as well as in a recent study published in Nutrients (21)-as a powerful ally in the prevention of infectious attacks, especially when related to respiratory tract infection. Vitamins A, C and E are in turn important for fighting free radicals and increasing defenses in the body. So is zinc, a mineral found in nuts and legumes that is useful in increasing the presence of white blood cells in the body. (22)
The organic system, in agrifood production, is aimed at ensuring the continuity of a tradition based on Respect for nature and the seasons, ecosystems and people. Nearly 80,000 enterprises operate in this field in Italy, mostly small and microscopic. Which bring to the territories, through ‘short supply chain’ models, value and health. Science and current events show us how this system can affect the protection of the environment and populations.
Dario Dongo and Andrea Adelmo Della Penna
Notes
(1) Polyphenols and the immune system, see https://www.greatitalianfoodtrade.it/salute/polifenoli-e-salute-i-vegetali-amici-del-sistema-immunitario
(2) Barański et al. (2014).
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. 112: 794-811, doi: 10.1017/S0007114514001366
(3) Miele et al. (2015) Impact of gut microbiota on obesity, diabetes and cardiovascular disease risk. Curr. Cardiol. Rep. 17:120, doi: 10.1007/s11886-015-0671-z
(4) Torjusen et al. (2014). Reduced risk of pre-eclampsia with organic vegetable consumption: Results from the perspective Norwegian Mother and Child Cohort Study. BMJ Open. 4e006143, doi: 10.1136/bmjopen-2014-006143
(5) Ozdal et al. (2016).
The reciprocal interactions between plyphenols and gut microbiota and effects on bioaccessibility
. Nutrients 8:78, doi: 10.3390/nu8020078
(6) Hartmann et al. (2014). Distinct soil microbial diversity under long-term organic and conventional farming. ISME J. 9:1177-1194, doi: 10.1038/ismej.2014.210
(7) Jin et al. (2017).
Effects of environmental pollutants on gut microbiota
. Environ. Pollut. 222:1-9, doi: 10.1016/j.envpol.2016.11.045
(8) Hurtado-Barroso et al. (2017).
Organic food and the impact on human health.
Critical Reviews in Food Science and Nutrition. doi: 10.1080/10408398.2017.1394815
(9) Vallverdù-Queralt et al. (2016). Foodonomics: a new tool to differentiate between organic and conventional foods. Electrophoresis 37:1784-1794, https://doi.org/10.1002/elps.201500348
(10) Średnicka-Tober et al. (2016) Composition differences between organic and conventional meat: a systematic literature review and meta-analysis. Br. J. Nutr. 23:1-18
(11) Średnicka-Tober et al. (2016) Higher PUFA and n-3 PUFA, conjugated linoleic acid, α-tocopherol and iron, but lower iodine and selenium concentrations in milk: a systematic literature review and meta- and redundancy analyses. Br. J. Nutr. 115:1043-1060, doi: 10.1017/S0007114516000349
(12) Palupi et al. (2012). Comparison of nutritional quality between conventional and organic dairy products: a meta-analysis. J. Sci. Food Agric. 92:2774-2781, doi: 10.1002/jsfa.5639
(13) Koh et al. (2012). Effect of organic and conventional cropping systems on ascorbic acid, vitamin C, flavonoids, nitrate, and oxalate in 27 varieties of spinach (Spinacia oleracea L.). Agric. Food Chem. 60: 3144-50, doi: 10.1021/jf300051f
(14) Vallverdù-Queralt et al. (2014). Differences in the carotenoid profile of commercially available organic and conventional tomato-based products. J. Berry Res. 4:69-77, doi: 10.3233/JBR-140069
(15) Wang et al. (2008). Fruit quality, antioxidant capacity, and flavonoid content of organically and conventionally grown blueberries. J. Agric. Food Chem. 56:5788-94, doi: 10.1021/jf703775r
(16) Rosati et al. (2014). Effect of agronomical practices on carpology, fruit and oil composition, and oil sensory properties, in olive (Olea europaea L.). Food Chem. 159:236-43, doi:10.1016/j.foodchem.2014.03.014
(17) Lo Scalzo et al. (2013). Variations in the pythochemical contents and antioxidant capacity of organically and conventionally grown Italian cauliflower (Brassica oleracea L. subsp. botrytis):results from a three-year field study. J. Agric. Food Chem. 61:10335-44, doi: 10.1021/jf4026844
(18) De Lorenzo et al. (2009).
Role of the Organic Mediterranean Diet on health status.
.
(19) Craddock et al. (2019). Vegetarian-based dietary patterns and their relation with inflammatory and immune biomarkers: a systematic review and meta-analysis. Adv. Nutr. 10:433-451, doi:10.1093/advances/nmy103
(20) Alwarawrah et al. (2018). Changes in nutritional status impact immune cell metabolism and function. Front. Immunol. 9: 1055-1069, doi: 10.3389/fimmu.2018.01055
(21) Grant et al. (2020). Evidence that vitamin D supplementation could reduce risk of influenza and COVID-19 infections and deaths. Nutrients 122:988, doi:10.3390/nu12040988
(22) Barnard et al. (2019). Plant-based diets for cardiovascular safety and performance in endurance sports. Nutrients 11(1):130, doi: 10.3390/nu11010130
Dario Dongo, lawyer and journalist, PhD in international food law, founder of WIISE (FARE - GIFT - Food Times) and Égalité.
Graduated in Food Technologies and Biotechnologies, qualified food technologist, he follows the research and development area. With particular regard to European research projects (in Horizon 2020, PRIMA) where the FARE division of WIISE Srl, a benefit company, participates.
