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Coronavirus, Omega 3 and the immune system

April 13, 2020

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Coronavirus reaffirms the need to strengthen the immune system through proper nutrition. Omega-3 fatty acids play an essential role in protecting the human body from inflammation and strengthening its defenses. Let’s see why.

Table of Contents

The molecules of life

Lipids, or fats, are one of the four molecules of life. Along with nucleic acids (DNA, RNA), carbohydrates and proteins. Without each of these four molecules, cells and organisms would not be able to live. The most important function of lipids is to compose cell membranes, to which is added-among others-the communication between cells. Thus thus regulating mechanisms including growth, sexual development, metabolism, and the immune system.

The fatty acids that make up lipids are divided into saturated and unsaturated. The latter, in turn, are distinguished into:

– unsaturated fatty acid(MUFA, monounsaturated fatty acid), in which olive, canola and high oleic sunflower oils are rich,

– polyunsaturated fatty acids(PUFAs). We now turn to the latter.

PUFAs, the polyunsaturated fatty acids

Polyunsaturated fatty acids are termed essential because the body is unable to synthesize them and therefore needs to take them in through food. The most important PUFAs are Omega 6 and Omega 3. (1)

Omega-3s are abundant in fatty fish and crustaceans (shrimp, krill). As well as in flax seeds, nuts, hemp oil and chia seeds, algae and microalgae. The most important ω-3s include α-linolenic acid of plant origin, as well as eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids of marine origin. (2)

Omega-6s are present both in some plant foods (e.g., vegetable oils, seeds, cereals, nuts) and in the meat of animals fed rations rich in their plant sources (e.g., flax, berries. With differences varying between ruminant and non-ruminant animals). Among the most important ω-6 are linoleic acid and arachidonic acid. (3)

The balance between Omega 6 and Omega 3 is critical. In fact, ω-6 helps regulate the immune system through stimulating inflammatory processes to defend the body. Precisely for this reason, it must overabund dietary intake of ω-3s, which instead exert anti-inflammatory activity. (4)

Omega 3 and the immune system

PUFAs, Omega 3 in particular, are great allies of the immune system. Through a series of complex biochemical mechanisms, ω-3s exert a powerful anti-inflammatory action that contributes to, among other things, the prevention of serious diseases such as obesity, cardiovascular disease, atherosclerosis, cancer, autoimmune diseases, and many others (5)

Recent studies have shown that omega-3 fatty acids also play an important role in immuno-modulation. (6) And it is the rapidity and efficiency of the immune response that is responsible for the ability to respond to bacterial and viral attacks. (7)

Diseases modulated by the action of Omega-3s from fish (Parolini, 2019).

Upper respiratory tract infections are found to have a reduced incidence due to the support of ω-3 fatty acids. (8) Since the respiratory system is a target of several viruses–a from seasonal influenza to the new coronavirus (9)–the potential of Omega3s in contributing to their prevention can be inferred.

Omega3 and gut microbiota

The gut microbiota, as noted, plays a key role in modulating metabolic responses and the immune system (in addition to thermoregulation and other functions). And it too is strongly influenced by dietary intakes of ω-3.

In fact, the daily intake of Omega-3s can regulate the species and concentration of the population of microorganisms that make up the microbiome. These fatty acids, in particular, are able to produce metabolites that positively affect the immune system. (10)

The balance of the microbiome, known as gut eubiosis, is important in the prevention of various chronic-degenerative diseases. (11) In antithesis to the situation of disequilibrium, known as dysbiosis. An experimental study conducted by daily administration of Omega-3 dietary supplements (EPA and DHA, 4 g/day for 8 weeks in healthy adults) showed their ability to promote the balance of the gut microbiota. (12)

Effect of Omega-3 on gut flora and its resulting action on the body (Costantini et al. 2017).

Omega 3, dose-dependent efficacy

The effectiveness of Omega 3 on human health is dependent on a number of factors. The daily dose is one of the most important to achieve appreciable effects. Depending on gender and age, specific amounts should also be considered, to be taken with a diet rich in their food sources and possible supplements.

The over-65s should pay special attention to taking sufficient Omega-3s. Clear positive effects have been observed in this age group in decreasing oxidative stress, which is associated with a reduction in the onset of chronic degenerative diseases. (13)

Situations of metabolic decompensation , such as childbirth, may in turn influence the onset of diabetes. Omega-3 supplementation has also been found to be very helpful in reducing the risk of developing type 2 diabetes in these cases. (14) As well as, in general, to contain its effects. (15)

Omega3, dosage and sources

Three servings of fish each week should meet Omega-3 requirements, tentatively estimated at 500 mg/day of EPA and DHA. (16) The American Heart Association suggests higher doses for individuals with established cardiovascular problems, up to 1 g/day of EPA and DHA. (17) In cases of very severe triglyceridemia, recommended doses may rise from 2 to 4 g/day of EPA and DHA. (18) For other conditions (obesity, type 2 diabetes, etc.) there is still no scientific consensus on recommended doses. (19)

The source of Omega-3s also deserves consideration. Large pelagic fish may be contaminated with heavy metals (181 notifications of such cases were registered in the European Alert System on Food and Feed Safety, RASFF, in 2018). Therefore, smaller fish species and in any case caught (or raised) in less polluted seas should be favored. (20)

The beneficial effects of regular fish consumption-even in canned fish (e.g., canned tuna and mackerel. Trout, salmon and other smoked fish)-are in each case estimated to outweigh those of contaminants. (21). Among other things, regular fish consumption is important as a source of vitamin D-essential to the immune system, even in the Covid era-and trace elements (e.g., iodine, selenium). (22)

Fish oil-even in encapsulated form, in the form of supplements-is then referred to by some researchers as the most effective source of ω-3. (23) In this regard, the Food & Drug Administration (FDA, USA) considers 3 g/day of fish oil intake to be safe for health. (24) WHO (World Health Organization) then established contaminant limits (dioxins, heavy metals) and oil purity criteria that must be ensured globally to ensure the safety of such products. (25)

Food and health, memory of Hippocrates

‘Let food be your medicine and medicine be your food’ (Hippocrates of Coo, 460-377 BC).

2400 years and counting (!). A varied and balanced diet such as the Mediterranean diet with plenty of fresh seasonal vegetables and fruits, true mines of antioxidants. Whole grains and legumes as primary sources of carbohydrates. And quality protein from a variety of sources-even in vegetarian and vegan diets-at every stage of life. To grow and stay healthy, even in older age. Extra virgin olive oil and dried fruits, great allies of health. A special focus on vitamin D, which is particularly valuable for immune defense. In the providential assurance of overall coverage of vitamin and mineral needs.

Andrea Adelmo Della Penna and Dario Dongo

Notes

(1) Russo (2009). Dietary n-6 and n-3 polyunsaturated fatty acids: from biochemistry to clinical implications in cardiovascular prevention. Biochem. Pharmacol. 77:937-946, doi: 10.1016/j.bcp.2008.10.020

(2) Saldeen et al. (2006). Omega-3 Fatty acids: structure, function, and relation to the metabolic syndrome, infertility, and pregnancy. Metab. Syndr. Relat. Disord. 4:138-148, https://doi.org/10.1089/met.2006.4.138

(3) Patterson et al. (2012). Health implications of high dietary omega-6 polyunsaturated fatty acids. J Nutr Metab. 2012:539426, doi: 10.1155/2012/539426

(4) Di Nicolantonio et al. (2018). Importance of maintaining a low omega-6/omega-3 ratio for reducing inflammation. Open Heart 5:e000946, doi: 10.1136/openhrt-2018-000946

(5) Chilton et al. (2017). Precision Nutrition and Omega-3 Polyunsaturated Fatty Acids: A Case for Personalized Supplementation Approaches for the Prevention and Management of Human Diseases. Nutrients 9:1165, doi:10.3390/nu9111165

(6) Gutiérrez et al. (2019).
Effects of Omega-3 Fatty Acids on Immune Cells.
Int. J. Mol. Sci. 20:5028, doi:10.3390/ijms20205028

(7) Husson et al. (2016).
Modulation of host defense against bacterial and viral infections by omega-3 polyunsaturated fatty acids.
Journal of Infection 73:523-535, http://dx.doi.org/10.1016/j.jinf.2016.10.001

(8) Raposo et al. (2017). Intake of vitamin C, vitamin E, selenium, zinc and polyunsaturated fatty acids and upper respiratory tract infection – a prospective cohort study. European Journal of Clinical Nutrition (2017) 71, 450-457, doi:10.1038/ejcn.2016.261

(9) Ministry of Health. New coronavirus and Covid-19. 6.4.20, http://www.salute.gov.it/portale/nuovocoronavirus/dettaglioContenutiNuovoCoronavirus.jsp?lingua=italiano&id=5337&area=nuovoCoronavirus&menu=vuoto

(10) Kim et al. (2016).
Gut Microbial Metabolites Fuel Host Antibody Responses.
. Cell Host Microbe 20:202-214, doi: 10.1016/j.chom.2016.07.001

(11) Parolini (2019). Effects of Fish n-3 PUFAs on Intestinal Microbiota and Immune System. Mar. Drugs 17:374, doi: 10.3390/md17060374

(12) Watson et al. (2018). A randomized trial of the effect of omega-3 polyunsaturated fatty acid supplements on the human intestinal microbiota. Gut 67:1974-1983, doi: 10.1136/gutjnl-2017-314968

(13) Rees et al. (2006). Dose-related effects of eicosapentaenoic acid on innate immune function in healthy humans: a comparison of young and older men. Am. J. Clin. Nutr. 83:331-342

(14) Yessoufou et al. (2015). Beneficial Effects of Omega-3 Polyunsaturated Fatty Acids in Gestional Diabetes: Consequences in Macrosomia and Adulthood Obesity. Journal of Diabetes Research, doi: 10.1155/2015/731434

(15) Rylander et al. (2014). Consumption of lean fish reduces the risk of type 2 diabetes mellitus: a prospective population based cohort study of norwegian women. PLoS ONE, vol. 9, no. 2,Article ID e89845, doi: 10.1371/journal.pone.0089845

(16) International Society for the Study of Fatty Acids and Lipids (2004). Recommendations for intake of polyunsaturated fatty acids in healthy adults. https://www.issfal.org/assets/issfal%2003%20pufaintakereccomdfinalreport.pdf

(17) Lichtenstein et al. (2006). Diet and lifestyle recommendation revision 2006: a scientific statement from the American Heart Association Nutrition Committee. Circulation 114:82-96

(18) European Food Safety Authority (2009). Scientific Opinion on the substantiation of health claims related to EPA, DHA, DPA and maintenance of normal blood pressure (ID 502), maintenance of normal HDLcholesterol concentrations (ID 515), maintenance of normal (fasting) blood concentrations of triglycerides (ID 517), maintenance of normal LDL-cholesterol concentrations (ID 528, 698) and maintenance of joints (ID 503, 505, 507, 511, 518, 524, 526, 535, 537) pursuant to Article 13(1) of Regulation (EC) No 1924/2006. EFSA Journal 7:1263, https://doi.org/10.2903/j.efsa.2009.1263

(19) Fetterman et al. (2009). Therapeutic potential of n-3 polyunsaturated fatty acids in disease. Am. J. Health Syst. Pharm. 66:1169-1179, doi: 10.2146/ajhp080411

(20) Mozaffarian (2009). Fish, mercury, selenium and cardiovascular risk: current evidence and unanswered questions. Int. J. Environ. Res. Public Health 6:1894-1916, doi: 10.3390/ijerph6061894

(21) Mahaffey et al. (2011). Balancing the benefits of n-3 polyunsaturated fatty acids and the risks of methylmercury exposure from fish consumption. Nutr. Rev. 69:493-508, doi: 10.1111/j.1753-4887.2011.00415.x

(22) United Kingdom Scientific Advisory Committee on Nutritions (2004). Advice on fish consumption: benefits and risk. https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/338801/SACN_Advice_on_Fish_Consumption.pdf

(23) Weber et al. (2006). Prevention of cardiovascular diseases and highly concentrated n-3 polyunsaturated fatty acids (PUFAs). Herz 31(Suppl 3): 24-30,

(24) Lorente-Cebriàn et al. (2013). Role of omega-3 fatty acids in obesity, metabolic syndrome, and cardiovascular diseases: a review of the evidence. J. Physiol. Biochem. 69:633-651, doi:10.1007/s13105-013-0265-4

(25) Council for Responsible Nutrition (2006). A voluntary monograph on long chain Omega-3 EPA and DHA. https://www.crnusa.org/

Andrea Adelmo Della Penna

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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.