Among the three popular types of miso soup, I am not sure about canned mackerel miso soup.
For one, a mackerel is a fish, and I have reservations about eating fish.
Please read the following for details.
Another point is that it is canned food, and I am not certain about the safety of it. Canned foods may contain BPA, a chemical that has been associated with health problems like heart disease and type 2 diabetes. Canned foods are designed for preservation, and it is okay to eat them in times of natural disasters or camping, but I don’t think they are designed to be eaten on a regular basis. The fact that it is canned, it can travel long distance which makes it not Shindofuji, local and seasonal.
What is Shindofuji? Watch this video.
The last element is that it is creating a fad and canned mackerel makers are increasing its production, and the production can not keep up with the demand. I believe in the natural process, and we should eat what is available. Pushing to increase the production sounds unnatural to me, and it is like putting the cart before the horse. Not living according to natural rhythm is one of the reasons why we are not healthy. I believe in diversity in food, and we should eat all kinds of food. If mackerel is not available, we can eat other fish, or we can eat other kinds of miso soup. There are plenty of beneficial miso soup types: tomato miso soup, ginger miso soup, broccoli miso soup, black vinegar miso soup, and many more. If you want to eat mackerel miso soup, you can use fresh fish instead of canned one, too.