Pregnant and tuna

There are quite a few uncertainties about eating tuna during pregnancy. The focus is often only on the bacteriological safety of foods during pregnancy. Because tuna is sold alone or very fresh or canned, the chance of harmful bacteria is small. As a result, many pregnant women believe that eating tuna during pregnancy is harmless. Still, the FDA has set guidelines for pregnant women, breastfeeding mothers, and children that discourage high tuna consumption. This is due to the large amounts of mercury in tuna. But again there are uncertainties about this. This is mainly due to the different types and the different amounts of mercury that tuna can contain. Where skipjack and albacore tuna still contain acceptable levels of mercury, yellowfin, bigeye and bluefin tuna should be avoided because of the high mercury levels.

Tuna

The tuna belongs to the same family as the mackerel. A tuna is a predatory fish that is high in the food chain and eats, among other things, herring, mackerel, squid, sand eel and jellyfish. The fish is found in the Atlantic Ocean, Pacific Ocean and the Mediterranean Sea and sometimes migrates to the North Sea in summer. The flesh of tuna, unlike most other fish, is pink. The color darkens and browns as the fish is older. This can be counteracted by treating the tuna with carbon dioxide. However, this treatment is prohibited in Europe because it is then no longer possible to judge whether the fish is still fresh.

Tuna is a fish that contains very few omega-3 fatty acids compared to other fish. As a result, tuna does not have the health benefits that oily fish do.

In addition, tuna contains high concentrations of mercury. Mercury is harmful to health. Mercury can be particularly harmful to pregnant women, fetuses, infants and young children. Small amounts of mercury in a pregnant woman's blood can damage all of an unborn child's nervous system.

Positive points are that tuna is high in protein and low in carbohydrates and fats. This makes tuna a popular fish for bodybuilders or people on a low-carbohydrate diet. It does not provide too many calories, but still fills the stomach due to the proteins. In addition, the proteins help to prevent muscle breakdown.

Tuna contains vitamin B12, vitamin D, potassium, calcium, phosphorus, magnesium and zinc. Vitamin D is important during pregnancy because it is important for the construction of the skeleton and teeth of the baby. The recommended daily amount of vitamin D is therefore doubled during pregnancy. Calcium is also important for the construction of the skeleton. Calcium deficiency during pregnancy can cause calcium to be removed from the mother's bones, causing osteoporosis.

There are more than twenty species of tuna, five of which are widely consumed. The most commonly caught tuna is the skipjack tuna. This is also the smallest tuna compared to the other four species. This variety is widely used for canned tuna. After skipjack tuna, yellowfin tuna is the most commonly caught tuna. This variety is often sold fresh. This variety is also often used for frozen tuna, along with white or albacore tuna. Bluefin tuna is a more exclusive and expensive type of tuna that is often used for sashimi in Asian countries. Bluefin tuna is heavily overfished and is therefore highly endangered. You will therefore only find this giant tuna in more exclusive restaurants. For example, in 2013, 1.3 million euros was paid for a 222 kg bluefin tuna.

The different types of tuna also differ in weight and length. Bluefin tuna is by far the largest. In the past, bluefin tuna weighing up to 900 kilos were caught. In 2016, however, weights are often under 100 kilos and bluefin tuna weighing 200 kilos are an exception. After bluefin tuna, bigeye tuna is the largest commercial tuna, followed by yellowfin, albacore tuna and the smallest, skipjack tuna. The bigger the tuna, the greater the mercury contamination. For pregnant or breastfeeding women it is therefore wise to avoid the large tuna species.

Tuna can be prepared in different ways. The most famous are eating raw in sushi or sashimi, canning or cooking or baking fresh tuna.

Sashimi is a dish with raw fish. Fish species such as salmon, mackerel and tuna are often used for this. Bluefin tuna is sometimes used for sashimi in exclusive restaurants. This species has a red color and a fine structure. The taste is meaty which makes it look like steak. Due to the high price, a different kind, such as yellowfin tuna, is usually used for sashimi. If the tuna is really fresh, it will be low in bacteria. As a result, the chance of a Listeria infection from eating sashimi during pregnancy is small. The danger lies in the high degree of pollution in large tuna species. Because mercury levels can be very high, eating tuna is not recommended for pregnant and breastfeeding women.

Canned tuna is the most popular in the Netherlands. The canned version is often affordable and has a long shelf life. Young skipjack tunas are often used. The population of skipjack tuna is large compared to other tuna, which makes canned tuna more sustainable. Because this young species is much smaller than the average tuna, the mercury content and other waste products are lower. However, canned tuna is also not recommended for pregnant women.

Fresh tuna is often fried. It is usually cooked just like a steak, both sides are seared and the fish remains rosé on the inside. As with sashimi, eating raw fish is not the danger during pregnancy, but the high mercury levels in tuna that can be dangerous to the unborn child. Yellowfin tuna is often used for fried tuna. This strain contains quite high amounts of mercury and is therefore better avoided during pregnancy. If you still want to eat fried tuna, try getting a fresh skipjack or albacore tuna and eat a maximum of one slice of tuna per week.