Genetic Variation, Diet, Inflammation, and the Risk for COVID-19

COVID-19, which is caused by SARS-CoV-2, is characterized by various symptoms, ranging from mild fatigue to life-threatening pneumonia, "cytokine storm," and multiorgan failure. The manifestation of COVID-19 may lead to a cytokine storm, i.e., it facilitates viral replication that triggers a strong release of cytokines, which then modulates the immune system and results in hyperinflammation. Today's diet is high in omega-6 fatty acids and deficient in omega-3 fatty acids; this, along with a high fructose intake, leads to obesity, which is a chronic state of low-grade inflammation. Omega-6 fatty acids are proinflammatory and prothrombotic whereas omega-3 fatty acids are less proinflammatory and thrombotic. Furthermore, omega-3 fatty acids make specialized lipid mediators, namely resolvins, protectins, and maresins, that are potent anti-inflammatory agents. Throughout evolution there was a balance between omega-6 and omega-3 fatty acids with a ratio of 1-2/1 omega-6/omega-3, but today this ratio is 16-20/1 omega-6/omega-3, leading to a proinflammatory state. In addition, genetic variants in FADS1, FADS2, ELOV-2, and ELOV-5 lead to a more efficient biosynthesis of long-chain polyunsaturated fatty acids (PUFAs), e.g., of linoleic acid (LA) to arachidonic acid (ARA), and (alpha-linolenic acid) (ALA) to eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), leading to higher ARA levels. Because the US diet is already high in omega-6 fatty acids, the increased biosynthesis of ARA in people with the derived FADS haplotype (haplotype D) leads to an increased production of leukotrienes, thromboxanes, C-reactive protein (CRP), and eventually elevated levels of cytokines, like interleukin (IL)-1, IL-6, and tumor necrosis factor (TNF), which may increase susceptibility to COVID-19. About 80% of African Americans, 50% of Hispanics, and 45% of European Americans have the FADS haplotype D and are thus efficient metabolizers, which could account for the higher vulnerability of these populations to COVID-19. Therefore, another reason that African Americans and Hispanics are more susceptible to COVID-19 is that they have a higher frequency of haplotype D, which is no longer beneficial in today's environment and diet. Genetic variation must be considered in all studies of disease development and therapy because it is important to the practice of precision nutrition by physicians and other health professionals. The objective of this commentary is to emphasize the importance of genetic variation within populations and its interaction with diet in the development of disease. Differences in the frequency of genes and their interactions with nutrients in various population groups must be considered among the factors contributing to health disparities in the development of COVID-19. A balanced omega-6/omega-3 ratio is essential to health. Physicians should measure their patients' fatty acids and recommend decreasing the intake of foods rich in omega-6 fatty acids and increasing the intake of omega-3 fatty acids along with fruits and vegetables.

The need for precision nutrition, genetic variation and resolution in Covid-19 patients

The health of the individual and the population in general is the result of interaction between genetics and various environmental factors, of which diet/nutrition is the most important. The focus of this paper is on the association of high n-6 PUFA or low n-3 PUFA due to genetic variation and/or dietary intake, with changes in specialized pro-resolving mediators (SPMs), cytokine storm, inflammation-resolution and Covid-19. Human beings evolved on a diet that was balanced in the n-6 and n-3 essential fatty acids with a ratio of n-6/n-3 of 1-2/1 whereas today this ratio is 16/1. Such a high ratio due to high amounts of n-6 fatty acids leads to a prothrombotic and proinflammatory state and is associated with obesity, diabetes, cardiovascular disease, and some forms of cancer. In addition to the high intake of n-6 fatty acids that increases inflammation there is genetic variation in the biosynthesis of n-6 linoleic acid (LA) to arachidonic acid (ARA) and of linolenic (ALA) to eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Present day humans have two common FADS haplotypes that differ dramatically in their ability to generate long-chain fatty acids. The more efficient, evolutionary derived haplotype increases the efficiency of synthesizing essential long-chain fatty acids from precursors and could have provided an advantage in environments with limited access to dietary long-chain fatty acids ARA, EPA and DHA. In the modern world this haplotype has been associated with lifestyle-related diseases, such as cardiovascular disease, obesity, diabetes, all of which are characterized by increased levels of inflammation. African Americans and Latino populations have increased susceptibility and higher death rates from SARS-CoV-2 than whites. These populations are characterized by increased numbers of persons (about 80%) that are fast metabolizers, leading to increased production of ARA, as well as poor intake of fruits and vegetables. The combinations of fast metabolism and high n-6 intake increases their inflammatory status and possibly susceptibility of SARS-CoV-2. In vitro and human studies indicate that the specialized pro-resolving mediators (SPM) produced from the n-3, EPA and DHA influence the resolution of inflammation, allowing the tissues to return to function and homeostasis. The SPMs each counter-regulate cytokine storms, as well as proinflammatory lipid mediators via NFκB and inflammasome down regulation and reduce the proinflammatory eicosanoids produced from ARA. The nutritional availability of dietary n-3 fatty acids from marine oils enriched with SPM intermediate precursors, along with increasing local biosynthesis of SPMs to functional concentrations may be an approach of value during SARS-CoV2 infections, as well as in prevention, and shortening their recovery from infections. It is evident that populations differ in their genetic variants and their frequencies and their interactions with the food they eat. Gene-nutrient interactions is a very important area of study that provides specific dietary advice for individuals and subgroups within a population in the form of Precision Nutrition. Nutritional science needs to focus on Precision Nutrition, genetic variants in the population and a food supply composed of Nutrients that have been part of our diet throughout evolution, which is the diet that our genes are programmed to respond.

139 Nutrigenetics/Nutrigenomics: Nutrient-gene interactions in humans and animals

Human beings evolved on a diet that was balanced in the omega-6 and omega-3 essential fatty acids to which their genes were programmed to respond. Studies on gene-nutrient interactions using methods from molecular biology and genetics have clearly shown that there are genetic differences in the population, as well as differences in the frequency of genetic variations that interact with diet and influence the growth and development of humans and animals, as well as overall health and chronic disease. Nutrigenetics refers to studies on the role of genetic variants and their response to diet. For example, persons with genetic variants in the metabolism of omega-6 and omega-3 fatty acids have different levels of arachidonic acid (AA) and eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) based on the type of genetic variant in the Fatty Acid Desaturase 1 (FADS1) and Fatty Acid Desaturase 2 (FADS2). At the same level of linoleic acid (LA) and alpha-linolenic acid (ALA) a person with a genetic variant that increases the activity of the FADS1 will have a higher AA in the red cell membrane phospholipids and a higher risk for obesity and cardiovascular disease. Nutrigenomics refers to how nutrients (diets) influence the expression of genes. For example, diets rich in omega-3 fatty acids, EPA and DHA decrease the expression of inflammatory genes and as a result decrease the risk of obesity and cardiovascular disease. Thus, through studies on Nutrigenetics/Nutrigenomics nutritional science stands at its “golden threshold” where personalized nutrition is the future, to improve an individual’s health.

Effects of Weekly Running Volume on Polyunsaturated Fatty Acid Metabolism: An Observational Study in Non-elite Marathon Runners (P08-100-19)

Objectives

Tissue availability of polyunsaturated fatty acids (PUFA) depends on several factors, including dietary intake, physical exercise, genetic variation and metabolic turnover. However, there is limited evidence whether running training activity per se may influence indices associated with PUFA metabolism such as Omega-3 (ω-3) index and arachidonic acid (AA)/eicosapentaenoic acid (EPA) ratio. The objective was to examine the association between kilometres (Km) run per week and changes in ω-3 Index and AA/EPA ratio.

Methods

We conducted a retrospective, observational, cohort study of 257 non-elite runners (mean age: 40.85 ± 12.17 years) who consumed no fatty acid supplements and provided a blood sample for analysis. The whole blood samples were collected by finger sticks, stored on absorbent filter paper, and then PUFA were quantified by gas chromatography (GC) and ω-3 Index and AA/EPA ratio measured.

Results

In a multivariate linear regression model, a gradual decrease of the ω-3 Index was observed with higher weekly running distance (β = −0.528; 95% CI −0.039 to −0.026; R2 = 0.447; P < 0.0001). We also found a progressive increase of the AA/EPA ratio in subjects who ran greater weekly distances (β = −0.341; 95% CI −0.071 to −0.038; R2 = 0.320; P = 0.001). No other significant associations were observed with other variables, including years of running training and weekly training frequency (hours/week). Finally, as expected, a significant inverse correlation between ω-3 Index and AA/EPA ratio (β = −0419; 95% CI −3.407 to −1.821; R2 = 0.336; P < 0.0001) was detected.

Conclusions

These findings suggest that distance running training and its weekly volume may negatively contribute to changes of the ω-3 Index and AA/EPA ratio. Further studies with greater sample size will be required to replicate and extend these data.

Funding Sources

This work was supported, in part, by a grant from “Fondazione Paolo Sorbini per la scienza nell'alimentazione”.

Supporting Tables, Images and/or Graphs

Relationship Between Distance Run Per Week, Omega-3 Index, and Arachidonic Acid (AA)/Eicosapentaenoic Acid (EPA) Ratio: An Observational Retrospective Study in Non-elite Runners

Background: Tissue availability of polyunsaturated fatty acids (PUFA) depends on several factors, including dietary intake, physical exercise, genetic variation, and metabolic turnover. However, there is limited evidence whether running training activity per se may influence indices associated with PUFA metabolism such as Omega-3 (ω-3) index and arachidonic acid (AA; 20:4ω-6)/eicosapentaenoic acid (EPA; 20:5ω-3) ratio.

Objective: To examine the association between kilometers (Km) run per week and changes in ω-3 index and AA/EPA ratio.

Methods: We conducted a retrospective, observational, cohort study of 257 non-elite runners (mean age: 40.85 ± 12.17 years) who consumed no fatty acid supplements and provided a blood sample for analysis. The whole blood samples were collected by finger sticks, stored on absorbent filter paper, and then PUFA were quantified by gas chromatography (GC) and ω-3 index and AA/EPA ratio measured.

Results: In a multivariate linear regression model, a gradual decrease of the ω-3 index was observed with higher weekly running distance (β = −0.033; 95% CI −0.039 to −0.026; R² = 0.447; p < 0.0001). We also found a progressive increase of the AA/EPA ratio in subjects who ran greater weekly distances (β = 0.092; 95% CI 0.038 to 0.146; R² = 0.320; p = 0.001). No other significant associations were observed with other variables, including years of running training and weekly training frequency (hours/week). Finally, as expected, a significant inverse correlation between ω-3 index and AA/EPA ratio (β = −2.614; 95% CI −3.407 to −1.821; R² = 0.336; p < 0.0001) was detected.

Conclusions: These findings suggest that distance running training and its weekly volume may negatively contribute to changes of the ω-3 index and AA/EPA ratio. Further studies with greater sample size will be required to replicate and extend these data.

An Increase in the Omega-6/Omega-3 Fatty Acid Ratio Increases the Risk for Obesity

In the past three decades, total fat and saturated fat intake as a percentage of total calories has continuously decreased in Western diets, while the intake of omega-6 fatty acid increased and the omega-3 fatty acid decreased, resulting in a large increase in the omega-6/omega-3 ratio from 1:1 during evolution to 20:1 today or even higher. This change in the composition of fatty acids parallels a significant increase in the prevalence of overweight and obesity. Experimental studies have suggested that omega-6 and omega-3 fatty acids elicit divergent effects on body fat gain through mechanisms of adipogenesis, browning of adipose tissue, lipid homeostasis, brain-gut-adipose tissue axis, and most importantly systemic inflammation. Prospective studies clearly show an increase in the risk of obesity as the level of omega-6 fatty acids and the omega-6/omega-3 ratio increase in red blood cell (RBC) membrane phospholipids, whereas high omega-3 RBC membrane phospholipids decrease the risk of obesity. Recent studies in humans show that in addition to absolute amounts of omega-6 and omega-3 fatty acid intake, the omega-6/omega-3 ratio plays an important role in increasing the development of obesity via both AA eicosanoid metabolites and hyperactivity of the cannabinoid system, which can be reversed with increased intake of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). A balanced omega-6/omega-3 ratio is important for health and in the prevention and management of obesity.

The impact of the Bellagio Report on healthy agriculture, healthy nutrition, healthy people: scientific and policy aspects and the International Network of Centers for Genetics, Nutrition and Fitness for Health

The Bellagio Report on Healthy Agriculture, Healthy Nutrition, Healthy People was the result of a meeting held at the Rockefeller Foundation Bellagio Center in the fall of 2012. The meeting was science based but policy oriented. The Bellagio Report concluded that: (1) sugar consumption, especially in the form of high-energy fructose in soft drinks, poses a major and insidious health threat, particularly for children; (2) current diets in most populations, albeit with regional differences, are deficient in omega-3 fatty acids but too high in omega-6 fatty acid intake, and (3) not all calories are the same since calories from different sources (i.e. glucose or fructose or omega-6 or omega-3 fatty acids) have different metabolic and neurohormonal effects. This paper summarizes the scientific progress and policy actions that have occurred in these three areas. Genetic variation in populations and gene-nutrient interactions are fundamental concepts that need to be taken into consideration in growth and development and in the prevention and management of chronic noncommunicable diseases since there is enormous variation in both the frequency of genetic variants and dietary composition worldwide. Furthermore, this paper updates the Bellagio Report in terms of the scientific and policy aspects, both of which have expanded over the past 2 years, and describes the progress made in establishing an International Network of Centers for Genetics, Nutrition and Fitness for Health.

[Bellagio Report on Healthy Agriculture, Healthy Nutrition, Healthy People]

The Bellagio Report on Healthy Agriculture, Healthy Nutrition, Healthy People is the result of the meeting held at the Rockefeller Foundation Bellagio Center in Lake Como, Italy, 29 October-2 November 2012. The meeting was science-based but policy-oriented. The role and amount of healthy and unhealthy fats, with attention to the relative content of omega-3 and omega-6 fatty acids, sugar, and particularly fructose in foods that may underlie the epidemics of non-communicable diseases (NCD's) worldwide were extensively discussed. The report concludes that sugar consumption, especially in the form of high energy fructose in soft drinks, poses a major and insidious health threat, especially in children, and most diets, although with regional differences, are deficient in omega-3 fatty acids and too high in omega-6 fatty acids. Gene-nutrient interactions in growth and development and in disease prevention are fundamental to health, therefore regional Centers on Genetics, Nutrition and Fitness for Health should be established worldwide. Heads of state and government must elevate, as a matter of urgency, Nutrition as a national priority, that access to a healthy diet should be considered a human right and that the lead responsibility for Nutrition should be placed in Ministries of Health rather than agriculture so that the health requirements drive agricultural priorities, not vice versa. Nutritional security should be given the same priority as food security.

Dietary omega-3 fatty acid deficiency and high fructose intake in the development of metabolic syndrome, brain metabolic abnormalities, and non-alcoholic fatty liver disease

Western diets are characterized by both dietary omega-3 fatty acid deficiency and increased fructose intake. The latter found in high amounts in added sugars such as sucrose and high fructose corn syrup (HFCS). Both a low intake of omega-3 fatty acids or a high fructose intake contribute to metabolic syndrome, liver steatosis or non-alcoholic fatty liver disease (NAFLD), promote brain insulin resistance, and increase the vulnerability to cognitive dysfunction. Insulin resistance is the core perturbation of metabolic syndrome. Multiple cognitive domains are affected by metabolic syndrome in adults and in obese adolescents, with volume losses in the hippocampus and frontal lobe, affecting executive function. Fish oil supplementation maintains proper insulin signaling in the brain, ameliorates NAFLD and decreases the risk to metabolic syndrome suggesting that adequate levels of omega-3 fatty acids in the diet can cope with the metabolic challenges imposed by high fructose intake in Western diets which is of major public health importance. This review presents the current status of the mechanisms involved in the development of the metabolic syndrome, brain insulin resistance, and NAFLD a most promising area of research in Nutrition for the prevention of these conditions, chronic diseases, and improvement of Public Health.

Action plan for healthy agriculture, healthy nutrition, healthy people

In October 2010, the World Council on Genetics, Nutrition and Fitness for Health promoted a scientific meeting in Ancient Olympia, Greece, on the theme Healthy Agriculture, Healthy Nutrition, Healthy People. The meeting focused on evolutionary aspects of human diet through the life cycle in terms of genetic predisposition, overall health, prevention of disease and of unhealthy behaviors, such as poor physical activity, and dietary changes caused by the introduction of modern agriculture, from the Agribusiness to systems of food production, from climate changes to the needs imposed by urban agriculture and architecture. Nutritional medical (mostly cardiological) and political aspects of disease prevention through healthy dietary habits and physical activity have always been seen in isolation. The meeting, the first of its kind, treated such aspects together, recognizing the importance of integrating and initiating a dialogue between these disciplines. The meeting gathered together experts in cardiovascular prevention, nutrition, as well as politicians, for a global discussion of these themes. A summary statement was then compiled, focusing on the main themes on which a consensus had been reached. I strongly believe that such themes have great relevance for public health, raising the need for disseminating them as widely as possible. I am thankful to the Editor of the Italian Journal of Medicine for allowing this summary document to be made available for the first time in Italy.Raffaele De Caterina

Bellagio report on healthy agriculture, healthy nutrition, healthy people

The Bellagio Report on Healthy Agriculture, Healthy Nutrition, Healthy People is the result of the meeting held at the Rockefeller Foundation Bellagio Center in Lake Como, Italy, 29 October-2 November 2012. The meeting was science-based but policy-oriented. The role and amount of healthy and unhealthy fats, with attention to the relative content of omega-3 and omega-6 fatty acids, sugar, and particularly fructose in foods that may underlie the epidemics of non-communicable diseases (NCD's) worldwide were extensively discussed. The report concludes that sugar consumption, especially in the form of high energy fructose in soft drinks, poses a major and insidious health threat, especially in children, and most diets, although with regional differences, are deficient in omega-3 fatty acids and too high in omega-6 fatty acids. Gene-nutrient interactions in growth and development and in disease prevention are fundamental to health, therefore regional Centers on Genetics, Nutrition and Fitness for Health should be established worldwide. Heads of state and government must elevate, as a matter of urgency, Nutrition as a national priority, that access to a healthy diet should be considered a human right and that the lead responsibility for Nutrition should be placed in Ministries of Health rather than agriculture so that the health requirements drive agricultural priorities, not vice versa. Nutritional security should be given the same priority as food security.