One recent Ghanaian study on fishes specifically Nile Tilapia from Pra demonstrates that, they are not safe for human consumption drew my attention to what we consume in the name of healthy eating. The study conducted by Akonor et al.,2020, note: “Toxic metals analysis showed that there were appreciable concentrations of Cadmium, Arsenic, Lead and Mercury in the two river water samples (Ankobra and Pra) as well as in the two fish species (Oreochromis niloticus and Clarias anguillaris) muscle tissues”. The most interesting thing is that, the study found “Fishes (Nile tilapia) from Pra were above-set limits for human consumption hence is not safe for consumption”.
However, a retrospective study by Gbogbo et al., 2018, found the bigeye grunt (Brachydeuterus auritus) and Bagrid catfish (Chrysichthys nigrodigitatus) as the healthier alternative. Their study found low level of toxic metals in them.
Another study by Hasselberg et al., 2020, examines the nutrients and contaminants in processed indigenous fish species, that are often eaten. Samples of smoked, dried or salted Engraulis encrasicolus (European anchovy), Brachydeuterus auritus (bigeye grunt), Sardinella aurita (round sardinella), Selene dorsalis (African moonfish), Sierrathrissa leonensis (West African (WA) pygmy herring) and Tilapia spp. (tilapia) were collected from five different regions in Ghana.
Samples were analyzed for nutrients (crude protein, fat, fatty acids, several vitamins, minerals, and trace elements), microbiological quality (microbial loads of total colony counts, E. coli, coliforms, and Salmonella), and contaminants (PAH4 and heavy metals). They found “Except for tilapia, the processed small fish species had the potential to significantly contribute to the nutrient intakes of vitamins, minerals, and essential fatty acids. High levels of iron, mercury and lead were detected in certain fish samples”, Meaning that, tilapia consumption has no nutritional benefit compared to other fishes in Ghana. Listen to their conclusion:
“Of the analyzed fish species, tilapia stood out as markedly less nutrient dense. As tilapia is one of the species that could increase availability of fish through farming, the present results demonstrate that tilapia cannot substitute wild species in terms of micronutrient content. On the other side, the freshwater fish WA pygmy herring showed several nutritional characteristics of marine fishes. High concentrations of mercury and lead were detected in some fish samples, while elevated levels of PAHs were detected in all smoked samples.”
Tilapia?
Tilapia is the common name for nearly 100 species of white fish in the cichlid family. Tilapia are found in shallow streams, ponds, rivers and lakes. Tilapia adapt well to being farmed and are very inexpensive. They are farmed around the globe, but are especially common in many parts of Asia and the U.S. The largest tilapia producers in the world are China, followed by Egypt. In the U.S., it is the fourth most consumed fish.
Types
In recent times, the available species of tilapia are Nile, Blue and Mozambique. Oreochromis niloticus, or Nile tilapia, is the oldest variety and is native to northern Africa and Israel. Nile is one of the most adaptable fish, as it can be raised in various ways and is considered one of the most sustainable farmed fish.
On the other hand, Blue tilapia is mostly seen in Florida’s lakes, rivers and streams. This kind of specie can be found both saltwater and freshwater. However, because it doesn’t grow as quickly as Nile varieties, it’s not as commonly farmed.
The third is Mozambique tilapia introduced in U.S. for sport fishing and as a means of aquatic plant control. It is now found in tropical and subtropical habitats globally and is popular among fish farmers because it is easy to grow and readily adaptable.
Nutrition Contents
Tilapia is low in calories and fat but has abundant protein. There are other good source of several vitamins and minerals, including selenium, vitamin B12, niacin and phosphorus. According to the https://nutritiondata.self.com/facts/finfish-and-shellfish-products/9244/2: a 3.5-ounce(100grams) serving of cooked tilapia has the following nutrients:
- 128 calories
- 0 grams carbohydrate
- 26 grams protein
- 2.5 grams fat
- 54.4 micrograms selenium (78 percent daily value (DV)
- 1.9 micrograms vitamin B12 (31 percent DV)
- 4.7 milligrams niacin (24 percent DV)
- 204 milligrams phosphorus (20 percent DV)
- 380 milligrams potassium (11 percent DV)
- 34 milligrams magnesium (8 percent DV)
- 0.7 milligrams panothenic acid (7 percent DV)
- 0.1 milligrams vitamin B6 (6 percent DV)
- 0.1 milligrams thiamine (6 percent DV)
It further contain small amount of vitamin E, riboflavin, iron, zinc and copper.
Scientific Studies on Tilapia: The good and bad side
The bad side of Tilapia consumption
Tilapia are fed with animal feces and illegal chemicals. Consumption of Tilapia presets with many controversies. Controversies in the way tilapia farmed and the nutritional profile. For instance, China is noted as one area where tilapia farming presents with many controversies. This stems from one study by the USDA, found that, fish farmed in China are normally fed feces from livestock in an effort to cut costs.
Alternatively, this can also increase the risk of contamination and foodborne illnesses such as Salmonella, which can be serious if left untreated. This is partly done to reduce costs of production, however, bacteria like Salmonella found in animal waste can contaminate the water and increase the risk of foodborne diseases. It is worthy to note that, the practice of employing animal feces as feed wasn’t directly associated with any specific fish in the report according to http://www.fao.org/in-action/globefish/market-reports/resource-detail/en/c/989532/. However, around 73% of the tilapia imported to the United States comes from China, where this practice is particularly common. Additionally, 64 percent of Chinese whole frozen tilapia exports went to African markets.
The 2007 report also noted that, African markets imported an average of 83 000 tonnes of whole frozen and breaded tilapia in 2016. Asian and Latin American markets continue to absorb much of their own domestic tilapia production, as it remains an affordable source of protein. The EU markets remained depressed in 2016, however imports for premium quality tilapia increased.
The report also explained that, with production problems in 2016 due to severe winter weather, total exports of tilapia stayed stable, amounting to 393 000 tonnes. Interestingly, frozen fillet exports declined by 4.5 percent to 146 400 tonnes, although it remained the main product exported. This decline was compensated for by increase of 0.14 percent and 8 percent in the whole frozen and breaded category. Interestingly, the report notes: “African markets were the main destination for these two tilapia products. Approximately 64 percent of Chinese whole frozen tilapia exports went to African markets in 2016 and 17 percent of Chinese breaded tilapia exports”.
The USA and Mexico are the two largest markets for Chinese tilapia, although year-on-year exports declined to the USA in 2016. Iran has emerged as the third largest market for Chinese frozen tilapia fillet, growing by a significant 53 percent in 2016 to reach 16 400 tonnes.
Apart from feces fed to Tilapia in China, which 64% are exported to African market, another potential issue is the risk of contamination and the use of harmful chemicals in many fish farmed in China. Some chemicals used for Tilapia farming are also illegal. This led to many tilapia imports from China to be rejected by the FDA between 2007–2012, including 187 shipments of tilapia. The report mentioned that the fish did not meet safety standards, as they were polluted with potentially harmful chemicals, including “veterinary drug residues and unsafe additives”
Another report conducted by https://www.seafoodwatch.org/ /m/sfw/pdf/reports/t/mba_seafoodwatch_tilapiachinareport.pdf, explained that, antibiotic resistance in certain strains of bacteria has been linked to tilapia farming regions in China as well.
These concerns have been raised in Africa as well. For instance, in one article by Konyim Okai, 2019, explained that, Nurudeen Tiamiyu, who happens to be the national vice-president of TADAN, raised the concern on safety of Tilapia from China imported into Nigeria. He notes: “These fishes being brought from China are rejected fishes that cannot enter the European or American market because of the issue of growth hormones and the very bad water conditions where these fishes are raised in volumes can hamper the health of people, but Nigerians are less concerned when it comes to buying cheap fish,” he said.
These concerns also pertain in Ghana, Kenya and other African countries. For instance, in Ghana, Peter Akpaglo, aquaculture consultant at the Association of Church-Based Development NGOs (ACDEP) advised Ghanaian fish farmers about buying fingerlings from “unknown sources”.
In the midst of speculation about illegally imported tilapia fingerlings being produced from China, he notes: “they have been found to contain high levels of unwholesome chemicals, and I strongly advise fish farmers to ensure that they only buy from trusted sources.” In 2019, Ghana’s minister of science and technology, Prof Kwabena Fimpong-Boateng, has directed that with effect from 1 March 2019, only approved hatcheries will be allowed to sell fingerlings in Ghana.
Additionally, in 2017, the then Minister of Fisheries and Aquaculture Development, Elizabeth Naa Afoley Quaye, warned fishmongers using Monosodium Glutamate to process expired fishes to halt the practice since it is harmful to human health. She further emphasized fishmongers around the Volta Lake and other coastal communities had been buying rotten or expired fishes from some cold stores, the practice known in local parlance as “Kodoso” and used Monosodium Glutamate to make them attractive to potential buyers.
The other concern is the illegal mining activities and impact on fishes in Ghana. Pollution of some water bodies has led to unsafe consumption of riverine fishes as well as a shortage of treated potable water principally because the cost of treating polluted water has become expensive across the country. A recent study by Akonor et al., 2020, evaluates Arsenic (As), mercury (Hg), Cadmium (Cd) and lead (Pb) concentrations in water and fishes from rivers Pra and Ankobrah where activities of artisanal gold mining were carried out resulting in gross pollution of the water bodies.
The study demonstrates that, both river water samples recorded ranges of 0- 0.0040, 0.0060- 0.0387, 0 – 0.0020, 0.006-0.0093 mg/l for Cadmium, Lead, Arsenic and Mercury respectively. For Cadmium and Arsenic, their levels were comparable (p > 0.05). However, detected values for Lead and Mercury were no comparable (p < 0.05). Toxic metals concentrations in the rivers decreased in the order of Hg > Pb > Cd > As. For the fish samples, values ranged 0-0.08, 0.04-0.42, 0-0.04, and 0.40- 0.60 mg/kg for Cadmium, Lead, Arsenic and Mercury respectively.
They explained that, appreciably high values were obtained for Mercury. Toxic metals concentrations in the rivers decreased in the order of Hg > Pb > Cd > As. Human health risk assessment from heavy metal exposure through fish consumption from the Rivers for both children and adults showed no significant non-carcinogenic adverse health risk to humans since all calculated values for Hazard Quotient (HQ) were < 1. They concluded: “Nonetheless, Target Hazard Quotient (THQ) values calculated for children and adult exposure to Cadmium and Mercury were > 1 which implied a likely cause of adverse effects during a person’s lifetime.”
They explained again: “Toxic metals analysis showed that there were appreciable concentrations of Cadmium, Arsenic, Lead and Mercury in the two river water samples (Ankobra and Pra) as well as in the two fish species (Oreochromis niloticus and Clarias anguillaris) muscle tissues.”
The most interesting thing is that, the study found “Fishes (Nile tilapia) from Pra were above-set limits for human consumption hence is not safe for consumption”. They however said, there was no cancer risk involved.
There is also the concern on the usage of explosives, chemicals, under-sized fishing nets, light fishing and other aggregating devices for fishing would collapse the fisheries sector if serious and pragmatic measures were not taken to address the menace.
In Kenya, at the University of Nairobia, one study conducted by Professor James Mbaria, head of the university’s department of Public Health, Pharmacology and Toxicology, demonstrates remains of 0.04 parts per million of lead, 0.005 ppm of mercury, over 0.001 ppm of arsenic and 1.2 ppm for copper, were found in farmed raised Tilapia, which indicated that the ponds used to farm the fish were possibly contaminated. According to WHO standards, the permissible levels are 0.5 ppm for lead and mercury, 1 ppm for arsenic and 30 ppm for copper. The report says that although these levels are permissible, “it is still worrying” that the presence of these chemicals can be detected.
The researchers explained: “long term exposure to these chemicals for the human body, through frequent consumption of such food, can have a disastrous effect, and therefore their presence and long-term effects in the human body poses serious health risks.” He emphasises that “heavy metals can be serious health hazards, and any potential dietary exposure to lead and mercury poses possible risk to human health.”
Against all the concerns in tilapia from China, Konyim Okai, 2019, explained that, Chinese fish (predominantly tilapia) exports to Kenya increased to $6.24 million in 2015 to over $20 million in 2017. She explains: “In October 2018, in response to a public outcry, President Uhuru Kenyatta ordered a ban on Chinese fish imports, to take effect on 1 January 2019. However, China retaliated by threatening to withhold funds for the completion of the strategic Standard Gauge Railway, which will link Kenya with its neighbours. In a rather swift reaction to this threat, Susan Imende, director of the Kenya Fisheries Service, announced that the ban had been lifted”.
Though, most African nations employed implementation of major aquaculture policies. “But China, a major provider of infrastructural and soft financial assistance, seems to have found a major destination for its fish, and not even presidential directives, it would appear, can stand in its way,” she says.
Its Omega-6 to Omega-3 Ratio May Lead to Inflammation
The added negative thing about tilapia is that, from the nutritional perspective, tilapia is also low in omega-3 fatty acids but high in omega-6 fats juxtaposed to other types of fish. Heart-healthy omega-3 fats are one reason why many people eat fish. Some types of seafood have more of this polyunsaturated fat than others. Salmon, for example, delivers 10 times the omega-3s per serving as catfish or scallops. We get the bulk of our omega-6s from corn, soybean, safflower, and other oils.
In one research, researchers from Wake Forest University School of Medicine bought 30 types of wild and farmed fish from supermarkets and fish markets across the United States. Using sophisticated equipment, they tallied up the proportions of various fats in each species. Among fish rich in omega-3 fats, wild sockeye salmon delivered 13 times more omega-3s than omega-6s. In farmed salmon and trout, omega-3 fats were three to five times more abundant.
For farmed tilapia and catfish, which offer only modest amounts of omega-3 fats, the proportions were reversed, with omega-6 fats about twice as abundant as omega-3s (Journal of the American Dietetic Association, July 2008). This is because these farmed fish are generally raised on corn, a good source of omega-6 fats. While omega-6 fatty acids play significant role in a healthy diet, the typical western diet contains a higher ratio of omega-6 fatty acids to omega-3s.
In 2008, the Harvard Heart letter, asserts that, Omega-3s and omega-6s are both essential fats, “meaning they are required for health and development and that the human body can’t make them from scratch but must get them, or their precursors, from food.”
The Heart Letter further explained that, with regards to omega-6 fats, the key issue has to do with linoleic acid, the main omega-6. It notes: “It is converted into arachidonic acid, a substance the body uses to make many important molecules, including some that stimulate inflammation and some that fight it, some that promote the blood’s tendency to form clots and others that discourage it.”
Hence, in theory, “eating too much omega-6 fat and too little omega-3 fat could promote inflammation, and thus heart disease”. The Wake Forest researchers notes: “All other nutritional content aside, the inflammatory potential of hamburger and pork bacon is lower than the average serving of farmed tilapia” because tilapia has more omega-6 fats and fewer omega-3s than red meat.
As it stands, there is still controversies surrounding omega-6 fats consumption. Others argued that, how the body uses arachidonic acid doesn’t depend on the ratio of omega-3 and omega-6 fats. Others overlooks the other good things that omega-6 fats do. These include lowering LDL and triglycerides, boosting protective HDL, and helping control blood sugar by making muscle cells respond more readily to insulin.
In fact, “the doubling of the intake of omega-6 fat in the American diet since 1960 is one reason why heart disease deaths have declined since then,” says Heart Letter advisor Dr. Walter C. Willett, professor of nutrition at Harvard School of Public Health.
A prospective study by Patterson et al.,2012, took a different opinion and asserts that not only can this poor omega imbalance drive up inflammation in the body, but it may also contribute to the development of chronic conditions like heart disease, Alzheimer’s disease and rheumatoid arthritis.
In a nut shell, the Harvard Heart Letter, 2008, explained that, “Plants are influenced by the soil they grow in; animals by the feed they get”. The Wake Forest study demonstrates that “corn-fed farmed fish end up with extra omega-6 fats in their tissues”. It further notes: “Some chicken, pig, and cattle farmers are going the opposite direction. By giving their animals feed with omega-3 fats, they are able to sell eggs and meat with an extra dollop of omega-3s”.
Due to this, The American Heart Association and others recommend eating fish, preferably oily fish, twice a week. “Good choices include salmon, trout, albacore tuna, sardines, anchovies, mackerel, and herring”. Additionally, they agreed that, Tilapia and catfish offer less in the way of omega-3 fats, but “still give you more of them than beef, pork, chicken, or turkey”. They believe that, since tilapia is also an excellent source of protein, is low in saturated fat, and is rich in essential trace minerals, even this low-omega-3 fish is a good choice for dinner, hence, a place on the dining table.
The good side of eating Tilapia
Apart from the controversies surrounding tilapia consumption, studies have also found some good side of tilapia in the diet. From the nutritional point of view, tilapia also contain many nutrients, including selenium, vitamin B12, niacin and phosphorus. The tilapia nutrition profile according to Axe, 2021, also boasts a “whopping 26 grams of protein per serving, putting it right on par with other high-protein foods like poultry and meat”.
Wu , 2016, explained that, protein plays key role in our health and plays a key role in tissue repair, muscle growth, energy levels and immune function. Increasing your intake of this essential macronutrient can also help keep your waistline in check. Blom et al., 2006, further expatiates that, protein reduces the levels of ghrelin, which is the hormone that stimulates feelings of hunger, whilst a retrospective study by Weigle et al., 2005, agrees that, it decreases appetite and calorie consumption to support weight loss.
Also, tilapia fish is regarded as a lean protein and contains less than 3 grams of fat per serving, it is also lower in calories than other types fish. Salmon, for example, contains 206 calories per serving whereas sardines provide 208 calories. For this reason, it can easily be incorporated into a low-calorie diet for those looking to lose weight.
Juxtaposed to other types of seafood, tilapia is also widely available and relatively inexpensive. It also has a very mild flavor, making it a good option to start including more seafood in the diet for those who might not regularly eat fish.
Better option than Tilapia?
The primary concern with tilapia has to do with bad farming practices in China. I believe that, it is best to avoid tilapia from China and look for tilapia from other parts of the world or alternatively, we should look with our Ghanaian community and promote good tilapia and other farming practices. The challenge is that about 64% of tilapia produce is shipped to Africa from China, meaning, the tilapia farming is very low in Africa as a whole and we depend on China. So what do we do? Other alternative for importers and consumers will be from the United States, Canada, the Netherlands, Ecuador or Peru according to https://www.seafoodwatch.org/recommendations/search?query=%3Aspecies%3BTilapia.
Health line, also recommends that, wild-caught tilapia are preferable to farmed fish. “But wild tilapia is very hard to find. The vast majority of tilapia available to consumers is farmed”. The other good and safer to consume are Fish like salmon, trout, Snapper, Mackerel, Cod and herring with much more omega-3 fatty acids per serving than tilapia. Furthermore, these fish are easier to find and devoid of banned chemicals used in some tilapia farming in China. Additionally, catfish is a healthier alternative by Gbogbo et al., 2018 as is free from toxic metals in Ghana.
Take Home
- Tilapia basically consist of 100 different species within the cichlid family.
- Many types exit such as Mozambique, Blue and Nile, which is also known by the tilapia scientific name, Oreochromis niloticus.
- The most important question: Is it good now to eat tilapia? From the studies; there are many controversies: serious issues to deal with tilapia farmed in China and Ghana as well especially, has loaded with a higher risk of contamination with harmful bacteria, heavy metals, chemicals, pesticides and antibiotics.
- The added bad guy is the higher amount of omega-6 fatty acids than other fish. This means that, eating a high ratio of omega-6 to omega-3 fatty acids might trigger inflammation and chronic disease. In Ghana, Hasselberg et al.,2020 study found no nutrient in tilapia.
- Against negatives, the other positive effect is that tilapia is cheap, low in calories and high in protein and affordable compared to other fish. It is a lean source of protein that is also high in several vitamins and minerals, such as selenium, vitamin B12, niacin and potassium.
- I recommend that we must pay attention to where we get our tilapia from, or alternatively, eat tilapia occasionally.
- As it stands, Gbogbo et al., 2018, study found the bigeye grunt (Brachydeuterus auritus) and Bagrid catfish (Chrysichthys nigrodigitatus) as the healthy alternative.
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Photo: Dr. Raphael Nyarkotey Obu, RND, PhD
The writer is on a mission to provide you and your family with the highest quality nutrition tips, scientific herbs and healthy recipes in the world.
DISCLAIMER This post is for enlightenment purposes only and should not be used as a replacement for professional diagnosis and treatments. Remember to always consult your healthcare provider before making any health-related decisions or for counselling, guidance and treatment about a specific medical condition.
The writer is an honorary Professor of Holistic Medicine & Naturopathic Physician. Nyarkotey is also a chartered Management Consultant(ChMC), Chartered Institute of Management Consultant, Canada. President, Nyarkotey College of Holistic Medicine and currently, LLB level 300 law student. Contact: 0241083423/0541234556
References
- GLOBEFISH – Information and Analysis on World Fish Trade, 2016. http://www.fao.org/in-action/globefish/market-reports/resource-detail/en/c/989532/
- Seafood Watch, nd. https://www.seafoodwatch.org/-/m/sfw/pdf/reports/t/mba_seafoodwatch_tilapiachinareport.pdf
- Flap over tilapia sends the wrong message, 2008. https://www.health.harvard.edu/newsletter_article/Flap_over_tilapia_sends_the_wrong_message
- Josh Axe, Top 23 High-Protein Foods to Eat (for Weight Loss and Muscle Gain). https://draxe.com/nutrition/protein-foods/
- Patterson, E., Wall, R., Fitzgerald, G. F., Ross, R. P., & Stanton, C. (2012). Health implications of high dietary omega-6 polyunsaturated Fatty acids. Journal of nutrition and metabolism, 2012, 539426. https://doi.org/10.1155/2012/539426
- Wu G. Dietary protein intake and human health. Food Funct. 2016 Mar;7(3):1251-65. doi: 10.1039/c5fo01530h. PMID: 26797090.
- Blom WA, Lluch A, Stafleu A, Vinoy S, Holst JJ, Schaafsma G, Hendriks HF. Effect of a high-protein breakfast on the postprandial ghrelin response. Am J Clin Nutr. 2006 Feb;83(2):211-20. doi: 10.1093/ajcn/83.2.211. PMID: 16469977.
- Weigle DS, Breen PA, Matthys CC, Callahan HS, Meeuws KE, Burden VR, Purnell JQ. A high-protein diet induces sustained reductions in appetite, ad libitum caloric intake, and body weight despite compensatory changes in diurnal plasma leptin and ghrelin concentrations. Am J Clin Nutr. 2005 Jul;82(1):41-8. doi: 10.1093/ajcn.82.1.41. PMID: 16002798.
- Efua Konyim Okai,2019. Africa’s tilapia farmers rise to Chinese challenge. https://thefishsite.com/articles/africas-tilapia-farmers-rise-to-chinese-challenge
- Ghana: Use of harmful chemicals for fish preservation harmful to consumers – Minister. https://fcwc-fish.org/other-news/ghana-use-of-harmful-chemicals-for-fish-preservation-harmful-to-consumers-minister
- Kortei, N. K., Heymann, M. E., Essuman, E. K., Kpodo, F. M., Akonor, P. T., Lokpo, S. Y., Boadi, N. O., Ayim-Akonor, M., & Tettey, C. (2020). Health risk assessment and levels of toxic metals in fishes (Oreochromis noliticusand Clarias anguillaris) from Ankobrah and Pra basins: Impact of illegal mining activities on food safety. Toxicology reports, 7, 360–369. https://doi.org/10.1016/j.toxrep.2020.02.011
- Astrid Elise Hasselberg ,Laura Wessels ,Inger Aakre, Felix Reich, Amy Atter, Matilda Steiner-Asiedu, Samuel Amponsah, Johannes Pucher ,Marian Kjellevold(2020). Composition of nutrients, heavy metals, polycyclic aromatic hydrocarbons and microbiological quality in processed small indigenous fish species from Ghana: Implications for food security. Plosone https://doi.org/10.1371/journal.pone.0242086
