Seafood For Heart Health and Environmental Sustainability

December 17, 2024

Nutritious, eco-conscious selections include smaller fish species and shellfish such as clams and oysters

While many people default to popular seafood options like salmon, tuna, and shrimp in their diets, there’s value in exploring a broader range of marine proteins. Specifically, opting for seafood lower in the marine food chain (including herring, sardines, clams, and oysters) can deliver dual benefits – supporting both cardiovascular wellness and ecological balance. While seafood encompasses fish and shellfish, it falls under the broader classification of aquatic foods, which includes any edible species from marine or freshwater environments (see “What are aquatic foods?”). According to Christopher Golden, associate professor of nutrition and planetary health at the Harvard T.H. Chan School of Public Health, “The diverse varieties and benefits of aquatic foods remain largely unknown to most consumers.”

What are aquatic foods?

Aquatic foods, called blue foods, encompass water-dwelling organisms including animals, plants, and microorganisms. These can be either wild-caught or farm-raised, sourced from various water bodies, including freshwater lakes and rivers, coastal regions such as estuaries, and oceanic waters. Finfish, the largest category of aquatic foods, includes three main groups: small fish measuring up to 18 inches (like anchovies, herring, and sardines), medium-sized fish (such as mahi-mahi, salmon, trout, cod, and flounder), and large species that can grow up to 10 feet (including tuna and swordfish). The aquatic food category includes shellfish, seaweed, and even unique options like octopus hearts.

Terrestrial vs. aquatic foods: The benefits of healthy seafood

Both the Dietary Guidelines for Americans and the American Heart Association advocate consuming at least two seafood servings weekly for adults. Substituting seafood for land-based animal proteins like beef, pork, and chicken (particularly processed varieties) reduces saturated fat intake while increasing beneficial omega-3 fatty acids. These dietary changes may help reduce bodily inflammation and promote healthier blood lipid profiles. This could explain why regular fish consumers, particularly those eating fish twice weekly, show lower rates of heart attacks and cardiac-related mortality compared to non-fish eaters. While farmed salmon and canned tuna serve as healthy alternatives to hamburgers and processed meats, Golden suggests that incorporating smaller fish varieties offers even greater benefits.

Why small fish?

Small fish species like anchovies, herring, mackerel, and sardines serve as exceptional nutritional powerhouses, delivering not just protein but also essential micronutrients including iron, zinc, and vitamin B12, alongside heart-protective omega-3 fatty acids. Golden explains that since these fish are typically consumed whole (bones included), they provide substantial amounts of calcium and vitamin D. (It’s worth noting that mackerel is unique in this aspect – while its bones are too sharp or hard to consume when cooked fresh, the bones in canned mackerel are perfectly safe to eat.) An additional advantage of these smaller fish species is their lower likelihood of harbouring contaminants such as mercury and polychlorinated biphenyls (PCBs) compared to larger fish like tuna and swordfish. This is because larger fish accumulate these toxins by feeding on smaller fish.

Golden emphasizes that “Sardines and anchovies are key components of the Mediterranean diet, widely recognized as optimal for cardiovascular health.” While fresh varieties might be harder to find or more expensive, canned versions of these fish are readily available and budget-friendly alternatives. However, it’s important to note that most canned anchovies undergo salt-curing, resulting in high sodium content that could potentially elevate blood pressure.

For those wondering about serving suggestions, sardines packed in water or olive oil can be:
• enjoyed atop crackers or crusty, toasted bread with a fresh lemon squeeze
• transformed into a sandwich filling similar to tuna salad
• incorporated into a Greek salad
• mixed into pasta dishes, either with tomato sauce or combined with lemon, capers, and red pepper flakes

Have you sampled these seaweed selections?

For those willing to explore even lower in the aquatic food chain, seaweed – encompassing various marine plants and algae species – presents an interesting option. Nori, the seaweed sheets used in sushi rolls, might be familiar to many. Seaweed snacks are now available in Asian markets and many regular grocery stores. More adventurous consumers might consider trying kelp jerky or kelp burgers, available through online retailers. Kelp represents one type of brown seaweed, with numerous green and red varieties also existing.
While nutritional content varies significantly among seaweed species, they generally share characteristics of being low-calorie, fiber-rich, and contain iodine, essential for thyroid hormone production. Like land vegetables, seaweeds offer various minerals and vitamins. Though currently considered niche products in the United States, seaweed products may gain wider acceptance in coming years as consumers seek out sustainable seafood options.

Bivalve benefits

Bivalves, which include clams, oysters, mussels, and scallops, are aquatic organisms characterized by their distinctive two-shell structure. While they provide excellent protein, their relatively low-fat content doesn’t match the omega-3 levels found in smaller, oily fish species. Nevertheless, these molluscs’ are nutritional powerhouses, rich in essential micronutrients like zinc and vitamin B12. The zinc content supports immune system functionality, while vitamin B12 is crucial in red blood cell formation and nerve health.
Golden recommends trying canned mussels or oysters served on crackers or bread. These versatile seafoods can be enjoyed in various preparations – steamed, sautéed, or grilled – and make excellent additions to pasta dishes, salads, or hearty soups. Some studies suggest that mussels may be good for weight loss due to their high protein and low-calorie content.

Environmental advantages of sustainable seafood

Compared to land-based food sources, aquatic foods demonstrate significantly lower greenhouse gas emissions and a reduced carbon footprint. The production of terrestrial protein sources, particularly beef, pork, chicken, and dairy products, demands substantial resources including land, water, pesticides, and energy for grain production to feed these animals. While farm-raised fish also require grain and fish meal derived from smaller fish species, wild-caught fish generally present a more environmentally conscious choice. Golden notes that consuming small fish species proves even more beneficial for ecosystem balance. He also mentions that salmon farming practices are evolving, with some aquaculture companies developing innovative, nutritious feed alternatives that eliminate the need for fish meal.
From an environmental sustainability perspective, bivalves stand out as superior sources of animal protein. Golden emphasizes that “Bivalves can be ‘nature positive’ because they don’t require feed and they filter and clean up water.” This makes them an excellent choice for those looking to reduce their climate impact through their seafood choices.

Crustacean concerns?

Historical medical advice cautioned individuals with elevated blood cholesterol against excessive consumption of shrimp, crab, and lobster due to their cholesterol content. However, current understanding of dietary cholesterol’s limited impact on blood cholesterol levels has made this concern less significant. Many people wonder, “Is lobster high in cholesterol?” While it does contain cholesterol, it’s also low in saturated fat, making it a reasonable choice when consumed in moderation. Moreover, these crustaceans offer high protein content while maintaining low fat levels.
Regarding shrimp, America’s preferred seafood choice, selective purchasing is crucial. Consider avoiding Southeast Asian farmed shrimp, as their production methods often result in environmental and health concerns, including habitat destruction, pollution, and inappropriate antibiotic use. For guidance on sustainable seafood choices, consult the Monterey Bay Aquarium Seafood Watch program or other reputable sustainable seafood guides.

Adding aquatic foods to your diet: Best seafood in US

Despite the common association between coastal regions and seafood availability, these products are accessible throughout the United States. Golden suggests exploring larger Asian markets for less common varieties, as they typically stock diverse fish and bivalve selections. Many supermarkets now have a dedicated seafood counter offering a range of options, including sustainable seafood choices like Arctic char and Alaskan wild salmon.
Those interested in expanding their seafood horizons should consider trying a canned fish subscription service. These services often provide various sustainably sourced seafood options, introducing consumers to exciting new flavors while supporting responsible fishing practices.

When selecting seafood, it’s important to consider personal health and the broader impact on marine ecosystems, fish stocks, and local fishing communities. Overfishing and unsustainable aquaculture practices can destroy habitat and disrupt our oceans’ delicate balance. By choosing sustainable seafood options, consumers can support responsible management of our marine resources and help ensure food security for future generations.

Remember to adhere to FDA guidelines for safe seafood purchase and preparation. Additionally, resources like the Monterey Bay Aquarium Seafood Watch program can help you make informed choices about the best seafood options that support both your health and the health of our oceans. By considering factors such as fishing methods, bycatch rates, and the overall impact on biodiversity, you can enjoy the nutritional benefits of seafood while contributing to the preservation of our marine environments.

Julie Corliss (January 1, 2024). Seafood selections that help your heart — and our planet. https://www.health.harvard.edu/heart-health/seafood-selections-that-help-your-heart-and-our-planet. Accessed December 17, 2024