Canned and frozen fruits and vegetables
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Canned and frozen fruits and vegetables

With current social distancing and quarantine measures, many people are relying in canned and frozen fruits and vegetables for their daily nutrient intake. While these foods tend to be regarded as nutritionally inferior, this is not always the case.

Canned fruits and vegetables

Canned fruits

Common canned fruits include apples, pears, peaches, pineapple and fruit salad. Canned fruit (preferably with no added sugar) is considered a suitable substitute for fresh fruit according to the Australian Dietary guidelines (1). However, it is important to note that canned fruit is either packed in fruit juice or syrup. The best option when eating canned fruit is to buy it in juice and drain it before consuming.

Canned vegetables

Common canned vegetables include legumes such as chickpeas, beans and lentils, artichokes, asparagus, peas, corn and tomatoes. Again, according to the Australian Dietary Guidelines, canned legumes with no added salt can be eaten instead of dried cooked ones.

Fresh vs canned

Carbohydrate, sugar and fibre

Canned fruits and vegetables can be significantly higher in sugar than their fresh counterparts. Conversely, starch can be higher in the fresh versions. Dietary fibre can be higher in either but in general terms all fruits and vegetables are good sources of fibre (2).

Vitamins

For fruit, the greatest differences are in beta-carotene (a precursor of vitamin A), thiamin (vitamin B1), vitamin C and folate. Note that beta-carotene can be higher in fruit canned in juice or syrup. Take this with a grain of sugar (pun intended) (2).

Vitamins levels in canned legumes don’t differ too much from those in their dried cooked form (2).

For vegetables and non-dried legumes, the canned versions have lower levels of thiamin, riboflavin, vitamin C and beta-carotene (2).

Minerals

Sodium can be extremely high in canned legumes and vegetables (2). Therefore, you should choose versions with no salt added when possible and add your own salt.

Other minerals that have significant differences between canned and fresh foods are zinc, potassium and magnesium, with some of those being higher in the canned varieties (2).

Shelf life, price and convenience

Canned fruits and vegetables can be kept for a long time (months to years) and therefore are a good option in times when you don’t have access to fresh food for a period of time. They are usually cheaper than their fresh counterparts. Finally, canned legumes and vegetables are also convenient because they don’t have to be cooked before consumption.

Health concerns

Consumption of canned foods has been associated with higher bisphenol A (BPA) in the urine (3). BPA is a synthetic chemical that can disrupt the endocrine system (3) and thus can lead to infertility, hormone-dependent cancers such as breast and prostate and polycystic ovary syndrome (PCOS) (4). Therefore, try to buy products in BPA-free cans or, if unsure, don’t rely heavily on canned foods.

Frozen fruits and vegetables

Frozen fruits

Frozen fruits

Common frozen fruits include blueberries, raspberries, strawberries, mixed berries, mango and bananas. Frozen fruit is great for smoothies and baking.

Frozen vegetables

Common frozen vegetables include peas, spinach and vegetable mixes. The texture of some vegetables changes significantly when frozen, so try to use them in dishes where texture is not super important, such as soups and frittatas.

Fresh vs frozen

Carbohydrate, sugar and fibre

The biggest differences are in starch and sugar in frozen vs fresh vegetables. Levels in fruit are virtually the same (2).

Vitamins

In general, the vitamin content in frozen fruit is not very different from the fresh varieties. The main exception is vitamin C (2), which is lost during storage.

For vegetables, there are significant differences in riboflavin (vitamin B2), vitamin C, beta-carotene and vitamin B6 (2).

Minerals

The only mineral with significant lower levels in frozen vs fresh fruit is iodine (2).

For vegetables, sodium, zinc, calcium are the minerals with greater variations (2).

Storage time, price and convenience

Frozen fruits and vegetables can be kept in the freezer for several months and therefore are a good option in times when you don’t have access to fresh food for a period of time. Obviously, you need access to a freezer and electricity. Frozen berries are normally a fraction of the cost of their fresh counterparts; frozen vegetables are also usually cheaper than fresh ones. Frozen vegetables and legumes are convenient because they don’t need to be washed, peeled or chopped.

Health concerns

The main health issue related to frozen fruit in Australia was an outbreak of Hepatitis A related to frozen berries a few years ago. Otherwise, frozen fruits and vegetables are totally safe.

References

  1. National Health and Medical Research Council. Australian Dietary Guidelines. Canberra: National Health and Medical Research Council; 2013.
  2. Food Standards Australia New Zealand (2014). AUSNUT 2011–13 – Australian Food Composition Database. Canberra: FSANZ. Available at www.foodstandards.gov.au
  3. Hartle JC, Navas-Acien A, Lawrence RS. The consumption of canned food and beverages and urinary Bisphenol A concentrations in NHANES 2003-2008. Environ Res. 2016 Oct;150:375-382.
  4. Konieczna A, Rutkowska A, Rachoń D. Health risk of exposure to Bisphenol A (BPA). Rocz Panstw Zakl Hig. 2015;66(1):5-11.

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