Sushi – a Japanese dish – is becoming more and more popular in our country. Some know it well; others have never tried it yet. Is sushi healthy and is it worth eating?
Is sushi healthy?
Popular today sushi…
For hundreds of years, not only the Japanese, but also other Asian residents, have been eating fermented fish. Later, it was fermented with the addition of rice to speed up the fermentation process, and the rice was then discarded. In the barrel alternately rice and fish were placed and pressed with a boulder. Later on, they also started to eat the rice. However, due to the long fermentation process, which could last even a year, they began to consume rice seasoned with rice vinegar. How does sushi look today? In addition to sour rice, seafood is added – it’s usually a raw fish (although it may be marinated or boiled). It’s all then wrapped in nori kelp.
Nutritional values of sushi components
White rice is a source of complex carbohydrates that provide us with energy, slowly decomposing. Rice is also a source of high protein, while at the same time low in fat. It does not contain gluten, so it can be consumed by people who are allergic to this protein. In the rice there are B vitamins and minerals, such as: phosphorus, magnesium, calcium, zinc, manganese, cobalt or fluoride. Fish deserve special attention because they are most often one of the main components of sushi.
Fish are a group of products with a very high nutritional value. On average, fish contain 50-85% water, 10-25% protein, 0.2-54% fat, 0.5-5.6% mineral salts and 0.1-0.4% carbohydrates. The composition of fish meat varies depending on the species, age, place of feeding, time of fishing, etc.
Particularly noteworthy is the high protein content in fish, which is highly digestible due to the low content of connective tissue. Fish fats are also easily assimilated and have a low melting point. These fats have valuable dietary properties due to their high content of n-3 and n-6 acids. The n-3 acids inhibit the development of atherosclerotic lesions by lowering the „bad” LDL cholesterol fraction, reducing the tendency to clot formation, normalizing blood pressure and improving heart function. They also inhibit neoplastic processes, inflammatory and allergic reactions and beneficially affect the nervous system. Species particularly rich in fat are salmon, mackerel, herring, and sardine.
Fish fats also contain vitamins A, D, E. Fish also contain large deposits of vitamins from group B. Fish is also a source of many minerals (phosphorus, sulphur, chlorine, potassium, sodium, magnesium, calcium or iron). Also nori kelp, used to wrap rice stuffing, is very healthy. They contain a significant amount of protein, carbohydrates, and minerals: magnesium, calcium, iron, copper, zinc, bromine, manganese and iodine, which allow proper functioning of the thyroid gland. Nori seaweeds also contain a number of B vitamins (B1, B2, B5, B6, B12) as well as vitamin C and vitamin A.
Threats caused by sushi consumption
Caught fish may already contain some amount of bacteria, and inappropriate storage at temperatures above 0 ° C may further increase their amount. What’s more, bacteria living on the meat of fish cause its decomposition, resulting in the formation of histamine in fish. Histamine is a chemical substance that naturally occurs in our body, however, ingesting it in large quantities triggers a toxic reaction – scombrotoxin. Thermal treatment does not break down this compound. Symptoms of scombrotoxin are: drop in blood pressure, headache, nausea, vomiting, diarrhoea, high fever, difficulty breathing, and redness on the face, local swelling, and possible feeling of burning and tingling in the mouth.
Fish that can be particularly dangerous in this case are mackerel, hake, and tuna. Fortunately, this is a fairly mild disease, it can develop very quickly – from a few minutes to several hours, and its duration is from a couple to several hours.
Viruses are another threat when eating fish. Very often you can be poisoned by the hepatitis A virus. Fish virus infection is the result of human pollution of the water environment or contamination of fish meat during its processing.
Another possible problem is parasite poisoning. Particularly noteworthy is the Anisakis simplex nematode, which causes anisakiasis. After eating contaminated fish, there are: sometimes very severe stomach pain, nausea, vomiting, and allergic symptoms: feelings of burning in the mouth, redness, inflammation of part of the skin. Symptoms may appear from a few hours up to 2 days after the parasite is consumed. Most often, we can catch these parasites by eating salmon, hake, mackerel and cod.
As a result of environmental pollution, fish may also accumulate heavy metals in their bodies, such as mercury, cadmium or lead. Frequent consumption of fish exposed to contamination with these metals can be harmful to human health.
Therefore, sushi should be avoided by children and pregnant women.
How can you protect yourself?
Firstly, it’s important to quickly cool and / or freeze the fish that’s caught. The growth of bacteria is then inhibited. Freezing fish at -20C for at least 24h protects against Anisakis simplex parasite poisoning. It’s also important to apply appropriate hygiene practices when processing and preparing fish.
An important point is also where the fish come from. Fish bred in aquaculture – artificially built reservoirs – are free from contamination with parasites that cause anisakiasis. The only threat may be residues from veterinary medicine, which is why it’s important for breeders to comply with the set standards.
Is the sushi full of calories?
Rice, skim fish or seaweed kelp are not caloric products. The calorie content of sushi is most influenced by other additives: fatty fish, fatty cheeses, egg yolk, mayonnaise or high-energy avocados.
Sample portion (30g) of sushi – one „roll” – with raw tuna – fatty fish – is 42 kcal. However, this is a small portion. For comparison, a sandwich with a slice of graham bread, a teaspoon of butter, a slice of ham – a turkey slice, a lettuce leaf and an olive (60g) is 127 kcal. Sushi is served in small portions. However, we must make sure that those portions do not increase and not to eat sushi too often, because then it can become a source of a large number of calories.
Wasabi, a very hot paste dyed green, and soy sauce served for sushi contain very high amounts of sodium, so people with hypertension and tendencies to embolism and oedema should avoid it.
To eat, or not to eat?
Absolutely. Nothing will happen to us, even if we eat sushi with oily fish and mayonnaise from time to time, especially since the portions are small, and the relative caloricity in one sushi roll is low. We can also always choose lean fish and less caloric additives.