Association Between Oyster Consumption and Hemoglobin Concentrations Among Ghanaian Women

Objectives

Oysters are a rich source of iron and consumption may reduce the risk of anemia. In 2017, a community in Ghana implemented an annual closed season of oyster harvesting between November–March, designed to benefit the sustainability of oyster harvesting. Our objectives were to determine the effect of the open and closed season on oyster consumption and anemia.

Methods

In a 6-month, longitudinal pilot study, we enrolled women in the Bortianor/Tsokomey area in Ghana and included 96 who regularly consume oysters during the open season and 40 who do not. Data were collected at two time points: 1) March 2020 (end of closed season) and 2) August 2020 (5 months into the open season). We collected the amount and frequency of oyster consumption using a 30-day food frequency questionnaire. We analyzed hemoglobin (Hb) concentrations using a Hemocue Analyzer 201. We used paired t-tests to analyze the difference in Hb concentrations and McNemar's test for anemia (Hb < 12.0 g/dL) between seasons and used independent t-tests between groups.

Results

At enrollment, mean ± SD age was 34 ± 8 y and BMI was 26 ± 5 kg/m2. Among women who ate oysters during the open season, Hb did not differ by season (closed season mean ± SD: 10.4 ± 2.6, open season: 9.8 ± 2.8, p = 0.06) and the prevalence of anemia was 74% in the closed season and 72% in the open season (p = 0.81). For women who did not eat oysters during the open season, Hb did not differ by season (closed season Hb mean ± SD: 9.6 ± 2.2, open season Hb: 9.9 ± 2.3, p = 0.15) and the prevalence of anemia in the closed season was 84%, and 78% in the open season (p = 0.35). During the open season, mean ± SD oyster consumption among women who ate oysters was 1726 ± 1685 grams, or 470 oysters per month. There was no difference between groups in Hb and anemia prevalence during the closed (Hb: p = 0.17, anemia: p = 0.16) or open (Hb: p = 0.15, anemia: p = 0.49) season.

Conclusions

The prevalence of anemia was high during both seasons in both groups of women. Implementing a closed season on oyster harvesting was not related to a higher prevalence of anemia among women that eat oysters. Further research into the causes of anemia among this population is needed and programmatic action to address the high prevalence of anemia in women of reproductive age is warranted in this area.

Funding Sources

University of Rhode Island start-up grant, awarded to Dr. Brietta M. Oaks.

Declining diversity of wild-caught species puts dietary nutrient supplies at risk

Although biodiversity loss adversely influences a variety of ecosystem functions, how declining wild food diversity affects nutrient supplies for people is poorly understood. Here, we analyze the impact of declining biodiversity on nutrients supplied by fish using detailed information from the Peruvian Amazon, where inland fisheries provide a critical source of nutrition for many of the region's 800,000 people. We found that the impacts of biodiversity loss on nutrient supplies depended on compensation, trophic dynamics, and functional diversity. When small sedentary species compensated for declines in large migratory species, fatty acid supplies increased, while zinc and iron supplies decreased. In contrast, the probability of failing to maintain supplies or nutrient supply risk increased when species were nutritionally unique. Our results show that trait-based regulations and public health polices need to consider biodiversity's vital role in sustaining nutritional benefits for over 2 billion people dependent on wild foods across the globe.

Substitution of inland fisheries with aquaculture and chicken undermines human nutrition in the Peruvian Amazon

With declining capture fisheries production, maintaining nutrient supplies largely hinges on substituting wild fish with economically comparable farmed animals. Although such transitions are increasingly commonplace across global inland and coastal communities, their nutritional consequences are unknown. Here, using human demographic and health information, and fish nutrient composition data from the Peruvian Amazon, we show that substituting wild inland fisheries with chicken and aquaculture has the potential to exacerbate iron deficiencies and limit essential fatty acid supplies in a region already experiencing high prevalence of anaemia and malnutrition. Substituting wild fish with chicken, however, can increase zinc and protein supplies. Chicken and aquaculture production also increase greenhouse gas emissions, agricultural land use and eutrophication. Thus, policies that enable access to wild fisheries and their sustainable management while improving the quality, diversity and environmental impacts of farmed species will be instrumental in ensuring healthy and sustainable food systems.

Fish Nutrient Composition: A Review of Global Data from Poorly Assessed Inland and Marine Species (P04-139-19)

Objectives

Our understanding of the nutrient contribution of fish to human diets relies on nutrient composition data for a starkly limited number of fish species. Yet particularly for the most nutritionally vulnerable fish consumers around the world, fish consumption includes a wide diversity of fish species whose nutrient composition data is disparate, poorly compiled, or unknown. To address the gap in understanding fish nutrient composition data, we reviewed the literature with an emphasis on small indigenous species of fish that are missing from global databases.

Methods

We conducted a systematic review by searching fish* AND *nutri* composition in 3 databases (EBSCO Host Agricola, Web of Science, and Web of Science using cabicode Food Composition and Quality) and one research journal (Journal of Food Composition and Analysis, search for fish*). We screened 3627 articles returned by search results and retained 81 articles containing 985 entries of nutrient composition data for fish and aquatic species (inclusive of duplicates). We compiled a database with all available information on fish nutrient composition (i.e., macronutrients, micronutrients, fatty acids, amino acids) and heavy metals (e.g., lead, mercury) on global fish and other aquatic animals, including both inland and marine species.

Results

We highlight fish and other aquatic animal species within our database that are particularly high in nutrients of global importance, including iron, zinc, calcium, vitamin A, and docosahexaenoic acid (DHA), and examine when a serving of fish and other aquatic animals can fill critical nutrient needs for pregnant and lactating women and children under two (Figure 1).

Conclusions

By collating the available nutrient composition data on small indigenous species of fish and other aquatic animals, we provide a resource for fisheries and nutrition researchers, experts, and practitioners to better understand these critical species and include them in food-based programs and policies.

Funding Sources

Cornell University's Atkinson Center for a Sustainable Future (to KJF) and the International Fund for Agriculture Development in partnership with WorldFish (to KB and SHT).

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