1. Bisphenol A (BPA)
BPA is also linked to endocrine disorders, heart disease and cancer. Canned foods have high amounts of BPA that some study groups find unacceptable.
2. Sodium
You need not worry about the sodium content of fresh vegetables, but canned vegetables pose a sodium risk if you are on a low-salt diet for health reasons. Check the ingredients of canned vegetables because they carry high levels of sodium. Fortunately, food manufacturers, in response to consumer awareness about sodium, have responded with reduced-sodium varieties. Unfortunately, not all canned vegetable products have low-sodium versions that you can find easily in stores.
3. Sulfites
Sulfites are sulfur-based compounds added to food as preservatives. They are found in canned vegetables. About one out of 100 people is sensitive to sulfites, and reactions can be deadly. Sensitivity varies from person to person, but the reaction manifests itself in respiratory problems. Signs of a bad reaction develop in just 15 minutes to a half-hour after eating foods with sulfites.They take the form of shortness of breath or wheezing.
Food labels on canned vegetables may not say "sulfites" per se, but look for any of these ingredients which have sulfites in them: sulfur dioxide, potassium bisulfite, potassium metabisulfite or sodium sulfite.
Although these are three strong reasons to avoid canned vegetables, vegetables in general are the right choice for healthy eating. The perspective recommended by nutritionists is easy to live by: choose fresh or frozen vegetables first and canned vegetables second. A university study found that fiber and key vitamins in vegetables that underwent the canning process were not compromised as a result of canning. Just limit your use of canned vegetables if you are concerned about BPA, and look for reduced-sodium choices too.