Vegetarian diets that include fish while excluding other meats are quite common. About 5-10% of those who identify as vegetarian also eat fish regularly. But if fish comes from animals, why do many vegetarians make an exception to eat finned sea creatures? The reasoning behind pescatarianism versus vegetarianism is multifactorial. Examining health effects, ethics, and environmental sustainability provides insight into why fish holds a unique place in plant-based eating patterns.

Why Do Some Vegetarians Eat Fish But Not Other Meat?

Vegetarianism is a popular dietary choice adopted by millions around the world for reasons spanning ethics, environment, and health. While vegetarians exclude meat, poultry and seafood from their diets, many still consume fish and shellfish. This has led to the creation of the term "pescatarian" to refer to those who abstain from eating all meat and meat products with the exception of fish and other seafood. But why do some vegetarians make this exception for aquatic animals? This article will explore the reasons behind this dietary choice.

Defining Pescatarians vs Vegetarians

First, it helps to define what constitutes a pescatarian versus a vegetarian diet.
Pescatarians, sometimes called “fish-atarians,” are semi-vegetarians who abstain from eating all meat and poultry while including seafood like fish and shellfish in their diets. Pescatarianism occupies a middle ground between vegetarianism and omnivorous diets.
In contrast, vegetarians avoid consuming any flesh foods. There are several types of vegetarian diets:

• Lacto-ovo vegetarians eat eggs and dairy products but no meat, fish, or poultry. This is the most common type of vegetarian diet.
• Lacto vegetarians exclude eggs along with meats but include dairy products.
• Ovo vegetarians avoid all dairy products but do eat eggs.
• Vegans refrain from all animal products including eggs, dairy, meat, poultry, fish and in some cases honey.

For those who value animal rights, pescatarianism may seem contradictory or illogical at first glance. But health considerations and environmental factors offer some context behind why many vegetarians make exceptions for finned, edible sea creatures.

Health Motivations for Including Fish

One of the main motivators for adopting a vegetarian or pescatarian diet is improving health. Both diets have been associated with health perks like lower heart disease risk, healthier body weight, and reduced Type 2 diabetes rates compared to non-vegetarian patterns.
However, pescatarians argue that the inclusion of fish and shellfish may provide some unique health advantages over strict vegetarian eating:

Heart Health

Fish is rich in omega-3 fatty acids like EPA and DHA. These polyunsaturated fats have been shown to benefit cardiovascular health by:

• Reducing inflammation
• Improving cholesterol levels
• Lowering blood pressure
• Decreasing risk for blood clots

For pescatarians focused on optimizing heart health, fish provides a potent source of heart-healthy fats not found in plant foods.

Brain Health

The anti-inflammatory effects of omega-3s are also thought to benefit the brain. Some studies link higher omega-3 intake from fish to improvements in:

• Cognitive function
• Memory
• Mental health conditions like depression and ADHD

Many vegetarians thus feel periodic fish consumption may offer neurological perks.

Vitamin B12

Vitamin B12 is crucial for neurological health and red blood cell formation. While vegans must supplement B12, pescatarians can get this important nutrient from fish and shellfish. Clams, mackerel, and salmon are particularly good sources of vitamin B12.

Vitamin D

Vitamin D promotes calcium absorption and bone health. Seafood like salmon and tuna provide easily absorbed vitamin D. Vegans must get vitamin D from UV light, fortified foods, or supplements.

Lean Protein

Meats and poultry are high in protein as well as saturated fats. Fish provides plentiful protein in a low-fat package. For vegetarians trying to get sufficient protein from plant-based sources alone, the addition of seafood helps meet protein needs efficiently.
When it comes to health, pescatarians argue that periodic fish consumption offers significant benefits from omega-3 fats, vitamins B12 and D, and lean protein that may be harder to obtain from plant sources alone.

Ethical Considerations in Pescatarianism

At first glance, it may seem contradictory for vegetarians to shun meat but embrace seafood. However, some pescatarians cite ethical justifications for avoiding terrestrial animal products while permitting responsibly sourced fish:

Perceived Lower Sentience in Fish

Research on pain perception in fish is limited and conflicting. Some studies suggest fish lack the neural complexity to experience suffering as acutely as mammals and birds.
While open to debate, this belief allows certain vegetarians to justify humanely caught fish as an ethically acceptable food source while rejecting factory farmed mammals and poultry where suffering is evident.

Avoiding Mammal/Bird Slaughter

All slaughter of sentient creatures raises ethical issues for vegetarians. However, the harvesting methods for terrestrial livestock are especially inhumane in many modern factory farms.
Certain vegetarians may perceive eating wild-caught or sustainably raised seafood as a “lesser evil” that avoids direct support of cruel practices toward more obviously sentient cows, pigs, and chickens.

Population Sustainability

Fishing and hunting policies regulate which marine species are under threat versus maintaining stable populations that can be harvested responsibly. Certain vegetarians may feel eating fish within sustainable quotas is ethically defensible in a way depleting threatened land mammals and birds is not.
While plant-based eaters debate these rationales, they illustrate how some pescatarians weigh ethical considerations differently for aquatic creatures versus more intelligent terrestrial species.

Environmental Motivations for Inclusion of Seafood

In addition to health and ethics, environmental sustainability is another motivation for vegetarian and plant-based diets. Here, pescatarians feel seafood offers environmental advantages over other meats.

1. More Efficient Feed Conversion: Cows, pigs, and chickens are inefficient converting feed to meat, requiring massive inputs of grain crops and water. Farmed fish like tilapia and carp can produce the same edible protein pound for pound of feed more efficiently.
2. Lower Carbon Footprint: Production of red meat especially has a very high climate change impact. The carbon footprints of responsibly farmed seafood like mollusks and finfish are estimated to be markedly lower than terrestrial livestock.
3. Population Management: Regulated fishing targeted at abundant stocks may offer a sustainable harvest of wild animals compared to clear-cutting of forests for cattle grazing, for example. Fishing quotas allow exploitation of food resources while keeping populations stable.
4. Preserving Biodiversity on Land: Overfishing is still a serious concern. But obtaining more dietary protein from well-managed fisheries and aquaculture may alleviate pressures to sacrifice wildlife habitats for farmland. More seafood could mean less land degradation.

While not unanimous, these arguments suggest nutritional, ethical, and ecological considerations all potentially come into play when vegetarians decide whether to apply their diet principles to aquatic creatures.

Health Outcomes of Pescatarianism vs Vegetarianism

So how do the health effects of pescatarianism actually compare to stricter lacto-ovo, lacto, ovo, or vegan vegetarian eating patterns?
Overall, both pescatarians and vegetarians tend to have lower rates of obesity, diabetes, cancer, and cardiovascular disease compared to omnivores.
However, there is some evidence eating patterns that include seafood while excluding other meats may offer marginal health advantages:

• Heart Health: Pescatarians appear to have lower rates of hypertension, chronic inflammation, high cholesterol, atherosclerosis, heart attack, and stroke compared to both vegetarians and meat-eaters. Omega-3s from fish likely contribute to cardiovascular protection.
• Weight Status: One 2021 study of over 14,000 people found pescatarians had a 13% lower risk of obesity compared to vegetarians. Inclusion of fish protein while avoiding red meat may benefit body weight control.
• Mental Health: Some population studies show lower rates of depression and better self-reported mental health among pescatarians versus vegetarians. Omega-3s may play a role in this neuropsychiatric advantage.
• Nutrient Adequacy: Compared to vegetarian diets, those including seafood seem to more consistently meet nutrient recommendations for proteins, omega-3s, B12, vitamin D, iron, and zinc. This improves general health and reduces nutrition deficiencies.

While both diets are health-promoting, evidence suggests periodic fish and shellfish consumption may offer some enhancements in nutritional quality and chronic disease protection versus strict vegetarian eating patterns.

How Often Do Pescatarians Eat Fish?

Pescatarians vary in terms of their personal rules and frequency of seafood intake. Some choose to eat fish:

• Once or twice weekly
• Only a few times per month
• Only when dining out
• Only on special occasions
• When they crave it or feel they need more protein or omega-3s

There are no absolute rules dictating how often pescatarians must eat fish. The ideals of this plant-based eating style are to maximize intake of vegetables, fruits, nuts, seeds, beans, and whole grains while allowing seafood in moderation or as desired for added flexibility.

Potential Downsides of Pescatarianism

While research suggests pescatarian diets offer some health boons, there are also a few potential downsides to consider:

1. Increased Mercury Exposure: Seafood contains methylmercury, an organic mercury compound that can be toxic at high intake levels. Large, predatory fish accumulate the most mercury. Consuming a variety of seafood and limiting intake of high-mercury varieties like tuna can minimize risks.
2. Overfishing Concerns: Some types of seafood like shrimp, Atlantic salmon, and certain tuna species are severely overfished. Choosing sustainable seafood is important to avoid contributing to depletion of ocean resources and irreversible harm to marine ecosystems.
3. Foodborne Illnesses: Raw or undercooked fish and shellfish can cause foodborne infections. Proper food handling of seafood is essential. At-risk groups like pregnant women and those with compromised immunity may still wish to avoid high-risk raw seafood like sushi.
4. Fewer Phytonutrients: Pescatarian diets provide fewer antioxidants, polyphenols, and other protective plant compounds compared to vegan or vegetarian eating patterns with more vegetables, fruits, nuts, seeds, beans, and grains.
5. Animal Welfare Concerns: Fishing and shellfish harvesting methods impact animal welfare in ways that may still conflict with certain vegetarians’ ethics. Endangered sea turtles, dolphins, and other animals can get caught in fishing gear, for example.

For those considering pescatarianism, weighing whether potential benefits outweigh these downsides requires careful analysis of one’s own health status, ethics, and environmental stance.

Transitioning to a Pescatarian Diet

Vegetarians interested in allowing seafood while excluding other meats can transition gradually with a few simple tips:

1. Start by adding in one fish or seafood meal per week while maintaining a primarily plant-based diet.
2. Choose low-mercury, sustainable seafood options like wild salmon, tilapia, shrimp, or scallops.
3. Learn new recipes to integrate seafood into vegan staples like stir-fries, tacos, buddha bowls, and curries.
4. Take care to properly handle, prepare, and cook seafood to reduce infection risks.
5. Consider algal oil supplements as an alternative omega-3 source if desired for heart benefits.
6. Stick to vegetables, fruits, whole grains, nuts, seeds, and legumes as your dietary foundations.
7. Ensure reliable sources of protein, iron, zinc, calcium, vitamins D and B12 from non-meat sources.
8. Talk to your doctor or dietitian if you have any concerns about nutrition needs.

With a gradual transition focused on complementary plant proteins and seafood in moderation, pescatarianism can be an appropriate choice for some vegetarians looking to optimize health.