Canned tomato secrets: Health benefits and hidden dangers revealed

Canned tomatoes are incredibly versatile. They make a great base for sauces, soups, ratatouille, salsa, and even smoothies. You can use them for pizza, shakshuka, homemade ketchup, and more. However, are they all beneficial?

While Italians are well-known for their canned tomato production, this method of preserving tomatoes actually originated in the United States. Harrison Woodhull Crosby, the chief gardener at Lafayette College in Pennsylvania, developed a primitive canning method for tomatoes in 1847.

A decade later, American President Abraham Lincoln, a tomato lover, praised canned tomatoes in one of his letters: "Cans of tomatoes are a testament to human ingenuity and versatility." Until the late 19th century, cans were made manually. The development of mechanical production methods eventually made canned tomatoes widely popular, a recognition that continues today.

Store shelves often overflow with canned tomatoes—whole, diced, and with different additives like basil, garlic, or chili peppers. Their convenience makes them an excellent choice for various cuisines, including Italian, Greek, Spanish, Balkan, and Mexican. They are perfect for sauces, meat dishes, and even soups like the tomato soup beloved by Poles.

What should you know before buying canned tomatoes?

Tomatoes in any form offer significant nutritional benefits. They are rich in lycopene, a pigment that gives them intense red color. Lycopene is a powerful antioxidant that helps inhibit the activity of free radicals, which can accelerate aging and contribute to cardiovascular diseases and cancer. An appropriate dose of lycopene reduces the risk of prostate and colorectal cancer.

Just one large tomato can provide nearly half of your daily vitamin C requirement. Vitamin C boosts the immune system, slows aging, and regulates the cardiovascular system. Tomatoes are also rich in vitamins A, E, and B group vitamins, as well as numerous minerals, especially potassium, which is essential for maintaining proper blood pressure and regulating the body's water balance.

These benefits are present in canned tomatoes, provided tomatoes are the main ingredient. Typically, tomatoes make up 60-65% of the can's contents, with the rest being tomato juice. It's worth looking for products with 98-99% tomato content.

Most canned tomatoes available also contain salt. However, you can find options without added salt, which is beneficial given that many people already consume too much sodium. The World Health Organization recommends a daily sodium intake that many people exceed, increasing the risk of hypertension, stroke, and other cardiovascular diseases. Excessive salt intake can also lead to osteoporosis, kidney disease, and stomach cancer.

Many canned tomatoes contain citric acid (coded as E 330) as an acidity regulator. While generally safe, excessive citric acid can damage dental enamel, hinder the absorption of certain microelements (especially calcium), and worsen conditions like cold sores. If possible, choose a can without this additive.

After opening a can of tomatoes, use the contents immediately or transfer them to a glass container along with the juice (to preserve the aroma) and refrigerate for no longer than 24 hours.

Storing preserves in the open can risk the leaching of Bisphenol A (BPA), a chemical used to coat the can's interior. Long-term BPA exposure can lead to obesity, hormonal disruptions, and increased cancer risk.

A recent study by the German consumer organization Öko-Test revealed that 18 of 20 tested cans of peeled tomatoes (eight from organic farms) had high BPA levels.

When choosing canned tomatoes, look for products labeled "Bisphenol A free" or "BPA free".