When frozen, most of the beneficial properties are preserved. Trace elements, protein and carbohydrate are almost not affected. Only vitamins suffer, and not all. Let's take it in order.
If anyone suffers from freezing, it's vegetables. Vitamin C is almost completely destroyed from freezing. However, it is quite capricious in terms of any processing: if we eat a vegetable or fruit not raw, but underwent any processing, even if it was cut in the light, vitamin C already suffers. And besides vitamin C in vegetables and fruits, there are no more vitamins - the fact that they are a storehouse of vitamins is a myth. Trace elements are a completely different matter. These are chemicals - zinc, selenium, potassium, magnesium - such microscrews that are involved in chemical reactions in our body - in the process of cell repair, the process of fighting infections, and so on. There are a lot of trace elements in fruits and vegetables, they, in fact, make them so useful, and what is important: trace elements do not suffer at all during freezing.
If we talk about fish, there are certain losses of Omega-3 during freezing, but if the fish has been properly frozen and not re-frozen, then the losses are small. The easiest way to find out about the quality of freezing: there should be no ice on the product.
In chicken, protein is important for us, and it does not suffer in any way. In beef, iron is also important for us, especially for women who have systematic blood loss, and iron does not disappear anywhere when frozen. The vitamins that are in meat, group B and group E, they are not as capricious as C, and although they suffer, they are generally preserved.
Yes, the taste of frozen foods may suffer, but this quite a subjective point. We are used to being critical of frozen food, although if we do not know that the food has been frozen, we may not even notice it.
When cooking frozen meat, you just need to remember that the food must be completely defrosted before cooking. do not throw frozen chicken directly into the pan. Because then the droplets of water that have frozen in the fat, when heated abruptly, break apart the fat molecules and this forms trans fats, which are very harmful to health.
Of course, when choosing between fresh and ice cream, you must choose fresh. But in the seasonality in our country, freezing is a good way out so that vegetables are present in the diet all year round. And when choosing between ice cream and canned, it is better to choose ice cream. A canned product is worse because no additional substances are used during freezing, and preservatives and sometimes dyes are used during canning.
All the benefits of products are preserved in frozen form. Often, vegetables and fish are frozen instantly, barely torn from the garden or caught from the water, and fresh products lose a lot during transportation and storage. However, the preparation of the product cannot be swept aside. You are unlikely to eat raw, thawed fish. Therefore, in the end, it all depends on the method of heat treatment. But frozen foods are really more healthy.