You snooze you lose?
For this reason it is recomended that pregnant and breastfeeding women limit their consumption of fish most likely to contain high levels of PCBs and other pollutants such as dioxins.
PCBs were banned during the 1980s because of their harmful effects on human health, but prior to being banned they were used widely in electrical apparatus.
The proven negative health effects of PCBs are numerous and they have been shown to impact everything from the immune system to the brain.
These include oily fish such as salmon and sardines, as well as non-oily fish such as crab and sea bass. The recommended portion size is around 140 grams.
The main concern when it comes to consuming fish is the presence of heavy metals and other pollutants. A particular area of concern is polychlorinated biphenyls (PCBs).
Again, mercury can be found in a number of foods, but its occurrence in fish is thought to be especially high. One study found that 78% of participants’ intake came from fish and seafood.
However, Jonathan Napier of Rothamsted Research, Hertfordshire, says that concerns about the presence of heavy metals in fish have been over-exaggerated.
Due to the presence of mercury, the US Food and Drug Administration recommends that pregnant women consume only one portion per week of certain fish, including halibut and tuna.
For Napier, the metal content in fish is only a problem for fish that live a particularly long time, such as swordfish. Otherwise, the benefits of eating fish (omega-3) outweigh the risks.
Fish supplements may provide a risk-free omega-3 source. However, a study by the World Health Organization (WHO) suggests supplements don't have the same benefits as eating oily fish.
Both EPA and DHA have been shown to reduce inflammation in the body, thereby reducing the risk of illnesses such as heart disease, cancer, and diabetes.
A widely recognized benefit of eating oily fish, such as salmon and tuna, is a reduced risk of cardiovascular disease. This is due to the presence of omega-3 fatty acids EPA and DHA.
There are also plant-based sources of omega-3s and a 2014 study suggested that these may have health benefits similar to oily fish. There is no substantial research to support this yet, however.
Overall it seems that eating oily fish is important for getting omega-3s. It should be noted, however, that research shows the levels of omega-3s in the fish we eat are declining.
According to Cyrus Raji, assistant professor of radiology and neurology at Washington University, the connection may be because of the anti-inflammatory effect of fish.
Eating fish has long been associated with having a healthy brain. Indeed, studies have linked the consumption of omega-3s with slower cognitive decline.
Raji recommends starting to eat fish at least once a week in your twenties or thirties in order to make your brain as resistant as possible to dementia.
Independently of this, a recent study has also linked eating baked or broiled fish with having a larger brain volume, which is in turn indicative of better health.
Considerable quantities of PCBs still linger in our soil and water and although they are found in many foods and even drinking water, their concentration is usually highest in fish.
Although most scientists agree that the omega-3 content of oily fish makes it beneficial to human health, it is difficult to draw a conclusion about whether eating fish is healthy or not.
Fish is generally a more expensive food and it is widely accepted that socioeconomic status impacts health. It’s therefore possible that higher-income families are generally healthier.
Indeed, it is difficult to conduct population studies, such as the WHO study of the health benefits of fish supplements, that do not produce skewed results.
Although researchers of course try to account for such confounding variables, they may not always catch everything that could cause a skewed result.
Although fish supplies are in danger, we can all do our part to help maintain them, by making sure we choose the most sustainable fish available.
To complicate things further, research suggests that the health benefits from fish may vary from individual to individual, depending on a person’s ability to convert precursor forms of omega-3s.
Ultimately the question as to how healthy fish really is may soon become redundant, since fish is not a sustainable resource and stocks within biologically sustainable levels are dwindling.
It is understood that the ability of a given individual to convert EPA and DHA may come down to diet and lifestyle, but genetics could also play a part.
Going forward the focus is more likely to be on how omega-3s can otherwise be obtained. A key focus area is the growing and harvesting of algae.
For help with this, the Marine Conservation Society has produced a sustainability guide that lists 133 species of fish and gives them a sustainability rating.
Sources: (BBC) (Marine Conversation Society)
Another worry is the presence of mercury, which has been proven dangerous to developing fetuses and linked with diseases such as cancer and diabetes.
For a long time fish has been considered one of the healthiest food options out there. Its high levels of omega-3 and other beneficial nutrients have made it a go-to for people conscious of their health and well-being.
Yet concerns about the presence of pollutants and metals in the fish we eat mean that pregnant and breastfeeding women are advised to limit their consumption.
Check out this gallery for a closer look at how eating fish can impact our health.
Eating fish: how healthy is it really?
The benefits and drawbacks of seafood
HEALTH Diet
For a long time fish has been considered one of the healthiest food options out there. Its high levels of omega-3 and other beneficial nutrients have made it a go-to for people conscious of their health and well-being.
Yet concerns about the presence of pollutants and metals in the fish we eat mean that pregnant and breastfeeding women are advised to limit their consumption.
Check out this gallery for a closer look at how eating fish can impact our health.