How Much Fish Should You Eat Per Week

A girl holds a fish in her hands

A plethora of individuals eschew piscine consumption due to apprehensions about contaminant presence. This trepidation, however, may not be rooted in sound rationale.

Piscatorial fare is quintessential for a nutritious regimen. Ichthyic offerings, along with other marine sustenance, are replete with beneficial long-chain omega-3 lipids and are imbued with other salubrious elements such as vitamin D and selenium. They boast a high protein content while being modest in saturated fats. Convincing evidence underscores the cardioprotective and vasculature-enhancing properties of fish or fish oil consumption. An extensive review of 20 studies, encompassing a vast cohort, elucidates that consuming roughly one to two 3-ounce portions of oleaginous fish weekly — think salmon, herring, mackerel, anchovies, or sardines — slashes cardiac disease mortality risk by 36 percent.

The consumption of fish combats cardiac ailments in multifarious ways. Omega-3 lipids in fish shield the heart from erratic and potentially lethal cardiac rhythm anomalies. They also mitigate blood pressure and heart rate, ameliorate blood vessel functionality, and, in elevated dosages, curtail triglycerides and might alleviate inflammation. Such robust and consistent evidence has led the Dietary Guidelines for Americans, the American Heart Association, among others, to advocate biweekly fish consumption.

American Heart Association – Eat Fish Twice Per Week

Regrettably, a mere fraction of Americans adhere to this counsel. Roughly a third partake in seafood weekly, while nearly half indulge in fish only sporadically or abstain altogether. Beyond mere disfavor for fish, this paucity in consumption is likely also influenced by perceptions surrounding cost, availability at purveyors, and uncertainty in culinary preparation. Furthermore, some abstain from seafood, fretting over potential harm from mercury, pesticide residues, or other possible toxins in certain fish types.

Should one renounce fish due to potential contaminants? This subject is mired in controversy, often more emotionally than factually driven. Here’s the current understanding of the benefits and risks associated with fish and other seafood consumption:

Acknowledged or Probable Benefits

Comprehensive human studies, spearheaded by Harvard School of Public Health luminaries Dariush Mozaffarian and Eric Rimm, deduce that ingesting about 2 grams per week of omega-3 fatty acids from fish — equivalent to one or two servings of fatty fish weekly — significantly diminishes heart disease mortality. Additionally, both observational and controlled trials have ascertained the critical role of fish’s omega-3 fats in the optimal development of an infant’s brain and nervous system. It’s observed that offspring of mothers who ingest lesser amounts of fish or omega-3’s during gestation and lactation exhibit signs of delayed cerebral development.

Potential Benefits

Consuming fish once or twice weekly might also lower stroke, depression, Alzheimer’s disease, and other chronic conditions’ risks.

Possible Risks 

Various pollutants infiltrate our food chain, impacting everything from produce to meats. Fish are not exempt from this. Present concerns center around mercury, polychlorinated biphenyls (PCBs), dioxins, and pesticide residues. High mercury levels can harm adult nerve functions and impede the brain and nervous system development in fetuses or young children. The impact of mercury at lower concentrations, as typically found in fish, sparks debate, with links to subtle nervous system developmental shifts and a potential uptick in cardiovascular disease risk. The case for PCBs and dioxins is less definitive. A comprehensive assessment by the Institute of Medicine deems the cancer risk from PCBs as “overstated.”

Striking a Balance

Eschewing fish is one strategy to circumvent mercury or PCBs. But does this approach align with the overarching benefits of fish consumption? Mozaffarian and Rimm offer perspective in their Journal of the American Medical Association analysis:

  1. They posit that if 100,000 individuals regularly consumed farmed salmon over seven decades, the incremental PCB intake could theoretically precipitate 24 additional cancer cases but avert upwards of 7,000 heart disease-related demises;
  2. PCB and dioxin levels in fish are relatively low, akin to those in meats, dairy, and eggs;
  3. Over 90% of the PCBs and dioxins in the U.S. diet stem from non-seafood sources, including meats, dairy, eggs, and vegetables. Given these minor health impacts, the scant levels in fish, and the major non-seafood sources, PCBs and dioxins in fish shouldn’t sway your seafood selection (similarly to how they don’t affect your choices in vegetables, meats, dairy, or eggs). An exception exists for locally caught freshwater fish — it’s prudent to heed local consumption advisories.

Learn more about a new study from Harvard School of Public Health and Brigham and Women’s Hospital, debunking the link between mercury exposure and heart disease.

At typical consumption levels, the evidence for mercury’s effects in adults is limited and conflicting. Thus, the Environmental Protection Agency, Food and Drug Administration, Institutes of Medicine report, and Mozaffarian and Rimm’s analysis all conclude this evidence doesn’t warrant limiting adult fish intake, given the established heart disease benefits. In fact, the simplest method to sidestep contaminant worries is to diversify your seafood choices.

For pregnant women, the calculus favors fish consumption. High mercury levels can hinder an infant’s cerebral growth, but scant omega-3 intake is equally perilous. Studies, like one encompassing nearly 12,000 pregnant women, show that children of mothers consuming less than two fish servings weekly fare worse in intelligence, behavior, and developmental assessments than those whose mothers ate fish at least biweekly. Harvard research indicates that six-month-olds exhibit superior visual recognition when their mothers consumed at least two fish servings weekly during pregnancy but maintained low mercury levels. Several other studies corroborate these findings regarding maternal fish or fish oil intake and infant brain development.

Hence, women, particularly those pregnant or nursing, should realize that completely avoiding seafood might detriment their offspring’s neural development. The most salubrious approach for expectant or nursing mothers and young children is to eat two weekly seafood servings, including up to one of white (albacore) canned tuna, steering clear of the four high-mercury fish species (shark, swordfish, tilefish, king mackerel). It’s imperative to acknowledge that the array of seafood deemed safe far surpasses the limited species to avoid. The Environmental Protection Agency and Food and Drug Administration advise:

  • Abstain from shark, swordfish, king mackerel, or tilefish due to high mercury levels;
  • Consume up to 12 ounces weekly of a variety of lower-mercury fish and shellfish. Shrimp, canned light tuna, salmon, pollock, and catfish are safer choices. Albacore tuna has more mercury, so limit its intake to once weekly. You can explore a table detailing various fish, their omega-3 content, and their average contaminant load online in Mozaffarian and Rimm’s article;
  • Heed local advisories on the safety of locally caught fish. In the absence of guidance, eat up to 6 ounces weekly of locally caught fish, refraining from other fish that week.

Thus, these recommendations underscore that except for a few species, fish consumption is generally advisable for pregnant women, nursing mothers, and young children, enhancing rather than hindering health.

Girl cooking fish

What If You Detest Fish?

Not all omega-3s originate from fish. Americans also ingest plant-based omega-3s, alpha-linolenic acid (ALA), found in flax seeds, walnuts, and certain vegetable oils. In the human body, ALA isn’t significantly converted to the marine omega-3s, EPA, and DHA. Therefore, existing evidence doesn’t endorse substituting ALA for seafood. However, observational studies, like the Nurses’ Health Study, suggest that extra ALA might reduce cardiovascular disease risk. Another analysis from the Health Professionals Follow-up Study intimates that higher ALA intake is particularly beneficial for heart disease protection in individuals with minimal fish consumption. While these findings await replication in randomized trials, augmenting your diet with ALA-rich foods may bolster your health.

Is Tilapia a Real Fish?

A common query that often surfaces in discussions about seafood consumption is the legitimacy and nutritional value of tilapia. Tilapia is indeed a real fish, belonging to a group of freshwater fish species inhabiting shallow streams, ponds, rivers, and lakes. Despite some misconceptions, tilapia is not a “manufactured” fish but a genuine species that has been part of the human diet for centuries. Its popularity in aquaculture stems from its hardy nature and its ability to thrive on a vegetarian diet, making it an environmentally sustainable choice.

When considering the role of tilapia in a healthy diet, it’s essential to recognize its nutritional profile:

  • Protein-Rich: Like other fish, tilapia is a good source of high-quality protein, which is crucial for muscle building and repair;
  • Low in Fatty Acids: Although it’s lower in omega-3 fatty acids compared to fatty fish like salmon and mackerel, tilapia still contributes to a balanced diet;
  • Vitamin and Mineral Content: Tilapia provides essential vitamins and minerals, including B-vitamins, phosphorus, and selenium.

In the context of the broader discussion on fish consumption and health, tilapia offers a versatile and accessible option. Its mild flavor and ease of preparation make it a popular choice for many, especially those who might be less inclined towards more “fishy” tasting varieties. While it may not boast the high omega-3 content of some other fish, its lean protein and low-fat profile align well with a heart-healthy diet. Moreover, for those concerned about contaminants in seafood, tilapia, especially when responsibly farmed, presents a low-risk option.

Thus, incorporating tilapia into one’s diet can be part of a diversified approach to seafood consumption, complementing the intake of other fish varieties that are richer in omega-3 fatty acids. Balancing tilapia with other nutrient-rich fish ensures a comprehensive uptake of the essential nutrients beneficial for heart health and overall well-being.

Let’s sum it up

In conclusion, navigating the complexities of fish consumption reveals a clear tilt in favor of its health benefits. Despite concerns about contaminants like mercury and PCBs, the evidence robustly supports the cardiovascular and developmental advantages of regular fish intake, particularly for heart health and infant brain development. For those cautious or unable to consume fish, alternative sources of omega-3s, like flax seeds and walnuts, offer supplementary benefits. Ultimately, incorporating a variety of fish into one’s diet, mindful of the few high-mercury species to avoid, presents a wise strategy for enhancing overall health, particularly for pregnant women, nursing mothers, and young children. This balanced approach underscores the importance of informed dietary choices, blending caution with the recognition of substantial nutritional benefits.

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