Canned food, for some people something to be avoided at all costs like the plague because it is considered an unhealthy alternative to fresh food, for others the salvation after a day of work. Canned fruit, vegetables and legumes are practical and above all always available, throughout the year, but what happens to the nutrients? So let's see if canned products preserve their nutritional properties. Not only that, we will also try to understand if the cans in which the foods are stored can be considered safe. In the article we will refer to canned fruit, vegetables and legumes, not ready-made and finished recipes such as pasta with sauce or soups.
Canned foods and nutrients
Fresh foods are certainly the best source of nutrients, however, in some cases canned foods can preserve much of the properties of the starting product. Of course, the processing they are subjected to can partially alter some nutrients, but, as evidenced by scientific studies, all fresh foods that are characterized by a high quantity of some nutrients even if canned will continue to be precious sources of these nutrients (Cameron et al, Am J Public Health Nations Health, 1949). For example, canned peaches have been observed to have properties comparable to fresh ones, maintaining a fairly constant content of vitamins A, E, C and carotenoids even after more than three months of storage (Durst et al, J Sci Food Agric, 2013). Asparagus and beans also retain most of the vitamin C they contain, and apricots have been shown not to lose vitamin C and carotenes, which are also preserved in corn and canned carrots. B vitamins such as thiamin, niacin and riboflavin are generally preserved in canned fruits, vegetables and legumes (Cameron et al, Am J Public Health Nations Health, 1949). Canned tomatoes remain valuable sources of lycopene, an antioxidant with anticancer action (Jacques et al, Br J Nutr, 2013). Pineapple and mango preserve about 30% of vitamin C, almost all of the polyphenols and a part, between 20% and 50%, of carotenes (Arampath et al, Foods, 2021).
Canned foods, risks
Homemade tomato sauce, a freshly sliced pineapple, freshly cooked beans certainly have a great advantage, namely that we know the ingredients we put in. Canned foods, on the other hand, may have excessive amounts of salt or added sugar, which is why it is always good to read the label before buying. But the dangers don't stop there. In fact, even the cans used to contain the food can be a risk. Bisphenol A is a substance often used in the production of food packaging, including cans and tins, and, as observed, it can pass from packaging to food (Noonan et al, J Agric Food Chem, 2011). This substance is at the center of numerous discussions on its dangerousness. In fact, as reported in scientific studies, it is considered an endocrine disruptor and its accumulation in the body can favor inflammation and neurodegeneration (Hartle et al, Environ Res, 2016 - Jalal et al, Toxicol Rep, 2018).
Canned foods, conclusions
Without exaggerating, canned fruits, vegetables and legumes can be considered an interesting alternative as they allow you to quickly access foods that you might not be able to eat, because there is little time to cook them, such as tomato sauce or legumes, or because they are not readily available, such as mango or pineapple. Therefore, the intake of canned foods allows you to take, even when it would not be possible, fiber, vitamins, minerals and antioxidants (Freedman et al, J Acad Nutr Diet, 2016). And this is the great advantage of canned foods. However, as we have seen, processing can alter, at least in part, the nutrients and it is also necessary to pay close attention to the label to avoid taking too much sugar, salt or preservatives. As for bisphenol A, now the industry tends to replace it gradually. Therefore, nowadays it is possible to find foods in BPA free cans. Alternatively, it is also possible to find foods contained not in cans but in glass, which avoids contamination with bisphenol A and the associated risks.