Vegetables are an essential part of a healthy diet, providing vitamins, minerals, fiber, and disease-fighting antioxidants. We can buy them fresh, frozen, or canned...but which type has the most nutrients?
People often assume fresh vegetables are highest in nutrients, but this is not always true. The nutritional content is dependent on a variety of factors. Vegetables can travel long distances and be exposed to light and temperature fluctuations which causes a loss of nutrients-especially vitamins A and C. One study published in the Journal of the Science of Food and Agriculture found most vegetables take 10-14 days to travel from farm to your table resulting in significant oxidation and loss of nutrients. Many vegetables are also picked before they reach peak ripeness, causing nutrients to never reach complete potency.
Frozen vegetables are picked at peak ripeness, steamed or blanched, and then frozen to lock in nutrients. Vegetables can lose nutrients during the washing, peeling, and steaming process; particularly vitamin C and several B vitamins. Some companies flash-freeze vegetables instead of steaming or blanching which retains the most nutrients.
Canned vegetables are also picked at peak ripeness, but are steamed or blanched for a longer time resulting in greater nutrient loss. Nutrients is further degraded during the high-heat process used to seal cans. In some cases though canning can increase the bioavailability of antioxidants, especially in tomatoes, corn, and carrots which is beneficial. When purchasing canned foods be aware of sodium content; salt is often added to preserve flavor and to prevent spoiling. A high sodium diet is unhealthy and not recommended so look for reduced sodium or no salt added canned foods.
The highest concentration of nutrients likely comes from seasonal vegetables from your garden or your local farmers market during summer or fall when they are picked at peak ripeness. For produce traveling long distances or during the off-season flash-frozen vegetables are the next best choice. Canned vegetables are convenient and still provide nutrients when necessary, but be cautious of the sodium content. Whether is fresh, frozen, or canned eat at least three servings of vegetables every day for good health.