Pescatarianism is a branch of vegetarianism.
Pescatarians consume a primarily plant-based vegetarian diet, while avoiding animal-origin food, except fish.
Pesco-vegetarianism, pescotarianism and pescatarianism are all used interchangeable and refer to the same dietary pattern.
Vegetarian diets, especially unbalanced ones, are generally lacking in vitamin B12, vitamin D, iron, zinc, iodine, and omega-3 fatty acids (Neufingerl & Eilander, 2021).
Fish products, such as salmon, tuna, and sardines are however a good source of protein, and essential micronutrients such as vitamin B12, vitamin D, selenium and omega-3 polyunsaturated fatty acids (Lund, 2013).
The omega-3 polyunsaturated fatty acids in fatty fish are essential for all stages of human life, they play an important role in cell membranes, inflammation, cardiovascular health and even cancer prevention (Eliseo & Velotti, 2016; Gil & Gil, 2015).
Some people may prefer a pescatarian diet, over a vegetarian diet, because it provides them with a key source of protein, fats and essential nutrients, that they might not have gained through a purely plant-based diet.
Others may be following a pescatarian diet for environmental reasons, religious reasons, or because they enjoy fish products, and would prefer to cut out other meat products such as poultry, beef and dairy.
In this article we explain (in plain English!) the conclusions of scientific studies that have looked at pescatarianism.
Vegetarian diets consist of plant-based foods rich in whole grains, legumes, nuts, seeds, fruits, and vegetables, while avoiding red meat, processed meat products, refined foods, and sweets.
There are several variations of a vegetarian diet:
Drawbacks of Pescatarianism
In this section, we will discuss the drawbacks of a pescatarian diet.
It is important to consult with your doctor or a dietitian before choosing to follow a pescatarian diet.
Exposure to Harmful Toxins
Fish consumption may put you at risk of exposure to harmful toxins.
A 2015 review published in the British Journal of Nutrition, analysing the health risks and benefits of fish consumption, states that fish consumption puts individuals at a higher risk of ingestion of harmful toxins such as heavy metals, pesticides, and polycyclic aromatic hydrocarbons (PAHs), all of which have detrimental effects to human health “the most concerning problem from a public health point of view is the exposure to low doses of chemical pollutant mixtures (heavy metals and organic compounds such as organochlorine pesticides, polycyclic aromatic hydrocarbons, PCB, dioxins and dibenzofurans)” (Gil & Gil, 2015).
This being said, the authors Gil & Gil (2015) went on to conclude that the risk associated with fish consumption does not outweigh the benefits, and that fish consumption should not be discouraged or feared “for major health outcomes among adults, the vast majority of epidemiological studies have proven that the benefits of fish intake exceed the potential risks excepting a few selected species in sensitive populations” (Gil & Gil, 2015).
Fish consumption poses a threat to pregnant women.
The same study also went on to state that mothers consuming fish products may put their new-borns at risk of neurological and neurodevelopmental problems due to exposure to toxins “there is convincing evidence of adverse neurological/neurodevelopmental outcomes in infants and young children associated with methylmercury exposure during fetal development due to maternal fish consumption during pregnancy. Dioxins and polychlorinated biphenyls present in contaminated fish may also develop a risk for both infants and adults” (Gil & Gil, 2015).
Pregnant women should not follow a pescatarian diet.
Fish and seafood are one of the main foods causing allergic reactions to affected individuals.
The Encyclopaedia of Human Nutrition, defines a food allergy as “a form of adverse reaction to food in which the cause is an immunological response to a food” (Caballero, 2005).
According to the Food Allergen Labeling and Consumer Protection Act of 2004 (FALCPA), the main food allergies that account for 90% of food-related allergic reactions include: milk, eggs, fish, shellfish, tree nuts, peanuts, wheat, and soybeans (FDA, 2022).
Food-related allergic reactions can be mild to severe.
Individuals who are allergic to fish and seafood products should not follow a pescatarian diet.
Benefits of Pescatarianism
Despite the drawbacks of a pescatarian diet covered in the previous section, increasing evidence suggests that a pescatarian diet may provide you with an array of health benefits.
In the sections that follow we highlight studies that have linked pescatarianism with health benefits such as:
A pescatarian diet may aid in weight loss.
A study published in the journal, Public Health Nutrition, investigated the link between plant-based diets (including pescatarianism) and cases of overweight/obesity in an Australian group of older women.
Their findings highlight that women following a pescatarian diet, were more likely to have a lower body weight (BW), body mass index (BMI), and waist circumference (WC) than those who consumed meat often “Compared to regular meat eaters, BW, BMI and WC were significantly lower in pesco-vegetarians” (Ferguson et al., 2021).
Another study conducted by scientists from the University of Oxford, evaluated the association between dietary patterns and body mass index (BMI) using the data of 38 000 participants in the EPIC-Oxford study.
Their findings highlight the fact that vegetarians, including pescatarians are slimmer than omnivores “Fish-eaters, vegetarians and especially vegans had lower BMI than meat-eaters” (Spencer et al., 2003).
Lower Blood Pressure
A 1996 study published in The Lancet, evaluated the influence of high dietary intake of fish on cardiovascular risk factors such as hypertension, high cholesterol and obesity in a population of Tanzanian village dwellers.
The authors of the study reported a strong positive relationship between a high intake of fish and reduced blood pressure “the fish-consuming group had lower mean blood pressure than the vegetarian group” (Pauletto et al., 1996).
They also reported that incidences of hypertension were less frequent in the fish consuming population “The frequencies of definite and borderline hypertension (by WHO criteria) were lower in the fish-consuming than in the vegetarian group” (Pauletto et al., 1996).
Improved Heart Health
A pescatarian diet may provide protective benefits to your cardiovascular health.
A study published in the British Journal of Nutrition, evaluated the effectiveness of various styles of vegetarianism (including pescatarianism) and their impact on cardiovascular health in a Swiss population.
Researchers made use of data from the Swiss Bus Santé study, a cross-sectional population-based study that has gathered data annually since 1993.
Their findings suggest that vegetarian diets, including pescatarianism, provide protective benefits to your cardiovascular health.
Cardiovascular risk factors include hypertension, high cholesterol, and obesity.
In this study, pescatarians were found to have lower body mass index (BMI), total cholesterol and LDL (bad cholesterol) compared to omnivores “Pescatarians had a lower BMI, a lower total cholesterol and LDL. They also had a lower blood pressure” (Wozniak et al., 2020).
In another study, scientists from the University of Oxford, evaluated the influence of vegetarian dietary styles and risk of ischaemic heart disease and stroke.
Data of 48 188 participants was obtained from the EPIC-Oxford study (1993-2001), with a follow-up period of 18 years.
Their findings suggest that participants who followed a pescatarian diet were less likely to suffer from ischaemic heart disease than their fellow meat eaters “fish eaters and vegetarians had 13% and 22% lower rates of ischaemic heart disease than meat eaters, respectively” (Tong et al., 2019).
With pescatarians having greater levels of “good” HDL cholesterol compared to omnivores “Fish eaters had slightly higher plasma concentrations of HDL-C than meat eaters” (Tong et al., 2019).
A 2021 study by scientists from the Department of Health Management, at Tokai University, Japan, investigated the influence of the consumption of one meal a day containing fish, soy and vegetable products on lifestyle-related diseases in middle-aged working Japanese men.
Participants were instructed to adhere to this dietary plan for 4 weeks.
Their findings suggest that incorporating one meal a day of fish and soy was able to lower the rate of lifestyle-related diseases (LRD), with improved HDL “good” cholesterol levels “The daily intake of a nutritionally balanced lunch containing soy and fish nutrients was proven to reduce the risk factors of LRD; with lower cardiovascular risks epidemiologically if salt intake is optimized” (Mori, 2021).
A 2010 study published in the journal, Circulation, evaluated the link between dietary protein sources (red meat, poultry, fish, and nuts) and the risk of coronary heart disease (CHD) in a population of middle-aged women.
Data was obtained from the Nurses’ Health Study, with a follow-up period of 26 years.
They reported that woman consuming less red meat, and instead obtained their protein from poultry, fish and nuts were less prone to develop CHD “Higher intakes of poultry, fish, and nuts were significantly associated with lower risk” (Bernstein et al., 2010).
They also reported that substituting red meat for the equivalent serving of fish saw a 24% reduction in chance of developing CHD “In a model controlling statistically for energy intake, 1 serving per day of fish was associated with a 24% lower risk of CHD compared with 1 serving per day of red meat” (Berstein et al., 2010).
Pescatarianism may provide protection against cancer.
The high content of omega-3 fatty acids, a type of polyunsaturated fatty acid, is thought to provide a protective benefit against cancer, by reducing inflammation, causing cell death and preventing growth of cancerous tumours “long-chain omega-3 PUFAs from fresh fish, nuts and seed oils, which exert anti-inflammatory effects and anti-neoplastic activities by inducing autophagy and apoptotic cell death in human cancer cells, including breast cancer” (Augimeri &Bonofiglio, 2021).
A 2013 systematic review published in the journal, Nutrition Reviews, examined the relationship between esophageal cancer (EC) and red meat and fish intake. Scientific studies between 1990 and 2011 were analysed.
Their findings suggest that greater contents of fish in one’s diet, led to reduced chances of developing esophageal cancer “high fish intake might be related to a lower risk for EC” (Salehi et al., 2013).
The authors of the present study also reported that the esophageal cancer risk decreased by almost 40% with every additional 50 g of fish added to the diet daily “The dose-response analysis performed with seven of the studies also indicates that each 50 g increment of fish intake per day corresponds with a 38% reduction in risk for EC” (Salehi et al., 2013).
A 2022 study published in the journal, BMC Medicine, investigated the link between vegetarian and non-vegetarian dietary styles and all cancer.
They reported that fish-eaters were less likely to develop cancer “Compared with regular meat-eaters, being a low meat-eater, fish-eater, or vegetarian were all associated with a lower risk of all cancer” (Watling et al., 2022).
They also reported that men who consumed fish and a vegetarian diet were less likely to develop prostate cancer “In men, being a fish-eater or a vegetarian was associated with a lower risk of prostate cancer” (Watling et al., 2022).
Reduced Risk of Dementia and Cognitive Decline
The high content of omega-3 fatty acids in a pescatarian diet may be protective against cognitive decline and dementia.
A 2021 review published in Nutrition Reviews, evaluated various scientific studies related to fish intake and risk of dementia, Alzheimer’s Disease, and cognitive decline.
They reported that consumption of at least 2 servings of fish a week resulted in a 30% lower risk of Alzheimer’s Disease “fish intake of up to 2 portions (250 g) per week was associated with a 10% reduction in all-cause dementia and a 30% reduction in Alzheimer’s Disease risk” (Kosti et al., 2021).
They did however note that the protective effect did not increase with further intake above 2 portions/week “The protection offered by fish intake against cognitive decline levels off at intakes higher than 2 portions/week” (Kosti et al., 2021).
A review published in The Journal of Nutrition, Health and Aging, evaluated the association between fatty acid consumption and risk of cognitive impairment or dementia in a Dutch population.
Data from the Zutphen Elderly Study and the Rotterdam Study was analysed.
Their findings highlight that a diet high in omega-3 fatty acids from fish is protective against dementia “A high fish consumption, an important source of n-3 PUFAs, reduced the risk of dementia” (Kalmijn, 2000).
The author also went on to report that fish intake was also linked to a reduced risk of cognitive decline “A high fish consumption tended to be inversely associated with cognitive impairment and decline” (Kalmijn, 2000).
Mental Health Benefits
Pescatarianism may provide positive benefits to your mental health, and reduce risk of depression.
A 2018 review conducted by scientists from the Department of Food and Nutrition, at the Kyung Hee University, Korea examined the relationship between fish or omega-3 fatty acid ingestion and depression.
Data from 10 cohort studies and over 100 000 participants was evaluated.
They reported that fish or omega-3 intake was linked to a reduced incidence of depression “Our findings provide quantitative evidence for a modest inverse association between fish or omega-3 fatty acid intake and risk of depression, especially in women” (Yang et al., 2018).
A 2016 review published in the Journal of Epidemiology and Community Health, investigated the link between fish intake and rates of depression.
Data from over 150 000 participants, across 26 studies was analysed.
The authors of the present study reported that participants with a higher dietary fish intake, were less prone to develop depression “This meta-analysis indicates that high-fish consumption can reduce the risk of depression” (Li et al., 2016).
In conclusion, evidence suggests that a pescatarian diet is able to provide numerous benefits to your health, including:
While a strict vegetarian diet may be lacking in vitamin B12, omega-3’ fatty acids, selenium, and zinc, a pescatarian diet provides these essential nutrients to your diet.
A well-planned, balanced pescatarian diet, containing fish and seafood, and rich in healthful plant-based foods such as whole grains, legumes, fruits, vegetables, nuts and seeds can provide you with the nutrition your body needs to maintain optimal health.
Lastly, it is important to always consult with your primary care physician when choosing to follow a new diet.