By contrast, and in accord with our FADS framework and the mixed distribution of FADS haplotypes in European American populations, these participants failed to benefit similarly, regardless of baseline fish intake or baseline CVD risk. Collectively, these data suggest that AfAm populations may benefit from ω-3 long-chain PUFA supplementation, and both ancestry and FADS variability should be factored into future clinical trial designs. Such heterogeneity in the FADS cluster and other genes should inform the design of future clinical trials and may offer the opportunity to personalize recommendations of long-chain ω-3 PUFA supplementation to individuals of different ethnicities.The human gut responds rapidly to significant changes in the diet, and long-term dietary habits can exert strong effects. The influence of dietary components has had a long history of impact on gut health and maintenance of high gut microbial diversity. However, the gut microbiomes in humans are highly diverse and variable among individuals. Moreover, the influence of specific dietary components on the gut microbiome community structure and microbial metabolic function may vary among individual microbiomes. Thus, diet–microbiome interactions are highly individual and idiosyncratic, especially over one’s liftetime.

Myriad dietary compounds are known to modulate human gut microbiome structure and function, grow bag gardening with impact on disease; among these, dietary fibers were first established for their protective effects against chronic disease at population scales, which are widely believed to be largely mediated by the microbiome. Although dietary fiber intake is widely associated with positive health outcomes, persistent public health and nutrition messaging in many such nations has made only modest gains in increasing consumption. Thus, dietary fibers remain, to date, the only microbiome-focused nutrient with established dietary guidelines for population-scale health. If populations are recalcitrant to increasing their overall fiber intake, dietary fiber-based strategies to improve health must seek to identify the fiber types most active in stimulating the appropriate microbiome responses to benefit host physiology. This is not trivial in that 1) as a category, “fiber” simply means the non–human-digestible plant components and includes a vast array of molecular structures, both soluble and insoluble; and 2) the mechanisms by which these divergent structures alter the structure and function of gut microbiota, thereby influencing health, are poorly understood. Coupled with the fact that many fiber intervention studies do not specify or characterize the fiber structures employed , it is very challenging to discern which structural variables are influential on the responses of gut microbiota, both in vitro and in vivo. Consequently, the ways in which fiber structures differentially influence ecology in the gut and metabolic function suggest that specific fibers can be targeted to desirable microbial consumers, thereby potentially being health beneficial at much smaller daily doses and at population scales .

Fiber polysaccharide structures contain a dizzying array of linkages among glycosyl residues that, in turn, generate strong differences in higher-order structure of these substrates. Because microbial carbohydrate-active enzymes are highly specific to the bonds they hydrolyze, differences in genome content or regulation of these carbohydrate-active enzymes can drive division of labor in degradation of polysaccharide consumption. The Lindemann laboratory at Purdue University has demonstrated that 1) metabolism of fibers is emergent across individuals but structural differences select for similar microbiota across donors and 2) polysaccharides can structure communities and maintain diversity against high-dilution pressure. These data strongly suggest that fiber fine structures are highly selective for consortia of fermenting microbes and sustain them in diverse communities, potentially serving as a basis for targeting these microbiota in the midst of complex and idiosyncratic human gut communities. The hypothesis is that there are general ecologic strategies that microbes use to gain advantage with respect to fiber fermentation and possible downstream health benefits. It is believed that these strategies are genetically encoded; thus, they provide a foundation for engineering fibers that will allow the gut microbiome to be manipulated for predictable outcomes across disparate individuals. To test the hypothesis that subtle differences in polysaccharide structure select for distinct microbial communities, 2 subtly different model polysaccharides, red and white sorghum arabinoxylan were fermented with identical microbiota. RSAX was slightly more complex at the level of branching diversity than WSAX and maintained a more diverse microbiome in which members of Bacteroides spp., especially B. ovaThus, were dominant. In contrast, WSAX promoted the growth of Agathobacter rectalis and Bifidobacterium longum-dominated communities. Interestingly, these polysaccharides selected forgenomically identical strains across 3 unrelated donors.

Alongside the differences in community structure, RSAX and WSAX were fermented to different metabolic outcomes. Further, when fed to mice, WSAX and a human-derived microbial consortium adapted to its use modified the cecal metabolism of mice in sexspecific ways. interestingly, the effects of transient human microbes could be seen in metabolite profiles and in postantibiotic community resilience in the mice. Our data suggest that 1) polysaccharide fine structure deterministically selects for fermenting communities; 2) fine polysaccharide variants often target largely the same microbes across individuals; and 3) in turn, these differences lead to divergent metabolic outcomes, which are potentially impactful on host physiology and resilience to stress. Together, these results suggest that well-characterized fiber structures may be used to influence human health at population scales and relatively small doses.During my first summer on the Tanaka Farm in western Washington State, I accompanied an indigenous Mexican picker, Abelino, to see a physician . His knee was injured while picking strawberries two days prior. It was Saturday and the only clinic open was a private urgent care clinic. After the initial physical examination, brief history-taking, and knee X-ray, the physician matter-of-factly suggested my friend do lighter work on the farm, ‘‘something sitting down, maybe at a desk.’’ Abelino responded with a quiet, respectful laugh. On Monday the next week, Abelino asked for lighter work at the farm office. The bilingual receptionist told him in a frustrated tone, ‘‘No, porque no’’ . Later that month, I accompanied Abelino to the busy clinic of a rehabilitation medicine physician for follow-up. This physician asked me to translate that Abelino ‘‘hurt his knee’’ because he had been ‘‘picking incorrectly’’ and did ‘‘not know how to bend over correctly.’’ Notably, in her rush, she had not asked Abelino any details about his work, including how he bent over. Years later, Abelino still tells me he has occasional knee pain and that ‘‘los medicos no saben nada’’ . This brief vignette focuses on what physicians and public health practitioners often characterize as risk behaviors—choice of job or poor body posture.

The physicians involved in Abelino’s care consider these risk behaviors to be the genesis of his suffering. This focus keeps them inadvertently unaware of the macro-social structures that produce suffering. In this article, I propose the concept of structural vulnerability as an important counterpoint to the common individualistic focus on risk behavior in medicine and public health. This concept trains the gaze onto the social structures that produce and organize suffering into what public health denotes as health disparities. I flesh out the concept of structural vulnerability through a thick description of the complex hierarchy at work on the Tanaka berry farm in Washington State . This hierarchy produces vulnerability to suffering through differential demands, pressures, and bodily practices in work. I avoid the pitfalls of a simplistic, plastic grow bag unidirectional understanding of structural violence by illustrating the ways in which macrostructures produce vulnerability on every level of the farm hierarchy. The concept of structural vulnerability directs blame and interventional attention away from the victims of suffering and toward the social structures producing and organizing their suffering.The Tanaka Farm is located in Skagit County, Washington, employing approximately 500 people during the picking season, May through November. During the winter and early spring, the farm employs approximately 80 workers. The farm is well known for strawberries, many from the ‘‘Northwest variety’’ cultivated by the founder of the family farm. The business is vertically integrated, from seed nursery to berry fields to processing plant, with almost all berries produced on the farm sold under larger labels. The farm consists of several thousand acres, much of the land visible west of Interstate-5. Most of the land consists of long rows of strawberry plants, although several fields are dedicated to raspberries, apples, and organic or ‘‘traditional’’ blueberries. At the base of a forested hill on the edge of the farm lies the largest migrant labor camp on the farm, housing approximately 250 workers and their families during the harvest . Immediately above this camp are five large houses partially hidden by trees with floor-to-ceiling views of the valley. Two other labor camps are partially hidden behind the large, concrete processing plant and the farm head quarters. The camp closest to the road houses 50 year-round employees and the other, a few hundred yards away, holds almost 100 workers and their families during the harvest. Diagonally across from these two labor camps and the processing plant are the houses of some of the Tanaka family. The one most visible from the main road is a semi-Jeffersonian, one-story, brick house with white pillars behind a white, wooden fence. The Tanaka Farm adverThises itself as ‘‘a family business spanning four generations with over 85 years experience in the small fruit industry.’’ On a more subtle level, farm work is produced by a complex segregation, a conjugated oppression . In Bourgois’s analysis of a Central American banana plantation, ethnicity and class together produce an oppression phenomenologically and materially different than that produced by either alone. In contemporary US agriculture, the primary lines of power fall along categories of race, class, and citizenship. The complex of labor on the Tanaka Farm involves several hundred workers occupying distinct positions from owner to receptionist, crop manager to tractor driver, berry checker to berry picker . People on the farm often describe the hierarchy with vertical metaphors, speaking of those ‘‘above’’ or ‘‘below’’ them or of ‘‘overseeing.’’ Responsibilities, anxieties, privileges, and structural vulnerability differ from the top to the bottom of this hierarchy . In congruence with the vertical metaphors utilized by those on the farm, the remainder of this article will move ethnographically from those considered at the top to those considered at the bottom.This farm is owned and run by third-generation Japanese-Americans whose parents’ generation lost half their land during the internment in the 1940s. Their relatives, with hundreds of acres on Bainbridge Island, Washington, were interned suddenly and the government sold their land out from under them. Those in the Skagit Valley had time to entrust their farm to a white family, and thereby avoided the same fate. Today, the third generation of Tanaka brothers makes up the majority of farm executives. The following are abbreviated profiles of key farm executives, focusing on their anxieties. In these profiles, we see that the growers’ worries are focused on farm survival in a bleak landscape of competition with increasing corporate agribusiness, expanding urban boundaries, and economic globalization. These anxieties are founded in the reality of ongoing farm closures throughout the region.Over the course of this research, many of my friends and family who visited automatically blamed the pickers’ poor living and working conditions on the growers and assumed that these growers could easily rectify the situation. This supposition is supported by other writings on farm workers, most of which describe the details of pickers’ lives but leave out the experiences of the growers . The fact that the perspectives of farm management are generally overlooked encourages readers’ assumptions that growers are wealthy, selfish, or unconcerned. The stark reality and precarious future of the farm described next remind us that the situation is more complex. The corporatization of US agriculture and the growth of global free markets squeeze growers such that they cannot imagine increasing the pay of the pickers or improving the labor camps without bankrupting the farm. Thus, many of the most powerful inputs into the suffering of farm workers are structural, not willed by individual agents. In this case, structural violence is enacted by market rule and later channeled by international and domestic racism, classism, sexism, and anti-immigrant prejudice . The structural nature of the labor hierarchy comes into further relief when the hopes and values of the growers are considered.