Popcorn is increasingly popular as a healthy snack. It is low in calories, whole grain, high fiber and chock-full of healthy nutrients but as with many other foods the way popcorn is cooked and treated can make a huge difference.
WHOLEGRAIN, POLYPHENOLS AND MINERALS
Studies show that eating whole grains instead of refined grains lowers the risk of many chronic diseases (1&2). Whereas most snacks labelled whole grain may not be more than 51% wholegrain, popcorn is 100% unprocessed whole grain and popcorn eaters are found to have around 250% more whole grains in their diets than non-popcorn eaters. The reason whole grain is healthy is because most of the goodness in grains are in the outer bran layer and germ of the seed, which are often lost during milling.
In 2012 research at Scranton University found that popcorn contained even more antioxidant polyphenols than had been previously thought, more than in most fruit. Polyphenols possess numerous health benefits, including the prevention of degenerative diseases such osteoporosis, cardiovascular disease, cancer, neurodegenerative diseases and diabetes (3).
Popcorn can come in a variety of colours. The interior is generally white or cream and the yellower the colour the higher the content of nutritionally valuable carotenes and xanthophylls (beta carotene, lutein and zeaxanthin). Blue, purple or red kernels also contain anthrocyanins, which have been shown to be protective against both heart disease and cancer (4).
Popcorn also contains both magnesium and zinc, which are key minerals in the body and tend to be deficient in the UK diet.
CAN ALL CORN POP
There are five kinds of corn each characterized by slightly different structures and content, they all pop, but ‘popcorn’ or ‘flint corn’ has been selected to have a denser arrangement of cellulose fibers in the hull and the right balance of high storage protein and high-amylose starch. The dense cellulose fibre conducts heat several times faster than other corns and as the temperature inside the corn kernel reaches and passes boiling point, the protein and starch softens and any moisture turns to steam. As thousands of little steam pockets form, pressure inside the kernel builds and the hull breaks open. As it ‘pops’ the steam expands, puffing up the soft protein-starch mixture, which hardens and crisps as it cools.
BEST METHOD OF POPPING
Popcorn pops at around 380°F/190°C and can be popped in hot oil, hot air poppers or the microwave. For basic popcorn on a stove all you need is a heavy bottomed saucepan. You can just add the popcorn but most recipes recommend adding around 1tablespoon of olive oil or butter and then closing the lid and cooking over a medium heat until the popping slows (4-6minutes). Corn popped in a tightly covered pan or pot will retain moisture and will be tough and chewy, so you need to leave the lid slightly ajar. In the microwave rather than using microwave ready popcorn, it is possible to just put 3 to 4 tablespoons plain kernels into a brown paper bag, fold over the top twice to seal it closed and microwave for about 2 minutes, or until the popping slows to a few seconds between. Cook time will vary depending upon the microwave, so it may take you a few tries to figure out the perfect pop time for your machine. It is also possible to cook popcorn on an open fire, you put small handfuls of kernels onto tinfoil sheets with ½ teaspoon of oil, wrapping them up like crackers, with twists at each end and put them into the fire.
- Air-popped / stove popcorn has the lowest number of calories, microwave popcorn cooked with oil has twice as many calories as air-popped, with about 43% of microwave popcorn being fat, compared to 28% if you pop the corn in oil on a stove.
- Cinema popcorn can be very high calorie and high fat, a small salt popcorn at either Odeon or Cineworld containing more fat and more calories than a McDonalds burger and only fractionally less than a portion of fries. Buttered popcorn is even worse.
- Although there are some lovely new brands coming to market, ready-made popcorn & microwave popcorn can contain a lot of unhealthy oils and chemicals. It is always worth checking the label.
Once you have made your air-popped corn, you can add butter, oil, sugar or salt, or you can try an alternative ‘healthy’ topping. Sprinkling nutritional yeast on your air-popped popcorn adds a mild, nutty flavour and yeast is full of minerals or you could try drizzling it with balsamic vinegar, shaking it vigorously in a tightly sealed bag to coat each kernel. If you have a sweet tooth, reduce balsamic vinegar on the stove by about 50 percent. Balsamic vinegar reduction has a syrupy texture, is naturally sweet and balsamic vinegar is loaded with polyphenols. As an alternative to sugar try cinnamon, recent research has shown that cinnamon mimics insulin in your blood, helps to utilize glucose and can be beneficial in regulating blood sugar (5).
Nutrient data for popcorn, air-popped * Source: USDA Nutrient Data
|Nutrient||Unit||1 Value per100.0g||1 cup 8g||1.0 oz 28.35g|
|Total lipid (fat)||g||4.54||0.36||1.29|
|Carbohydrate, by difference||g||77.90||6.23||22.08|
|Fiber, total dietary||g||14.5||1.2||4.1|
|Vitamin C, total ascorbic acid||mg||0.0||0.0||0.0|
|Vitamin A, RAE||mcg_RAE||10||1||3|
|Vitamin A, IU||IU||196||16||56|
|Vitamin E (alpha-tocopherol)||mg||0.29||0.02||0.08|
|Vitamin D (D2 + D3)||µg||0.0||0.0||0.0|
|Vitamin K (phylloquinone)||µg||1.2||0.1||0.3|
|Fatty acids, total saturated||g||0.570||0.046||0.162|
|Fatty acids, total monounsaturated||g||1.100||0.088||0.312|
|Fatty acids, total polyunsaturated||g||1.900||0.152||0.539|
(1) Slavin 2004, Wholegrains and human health. Nutrition Research Reviews 17, 1-5
(2) Jonnalagadda et al 2011, Putting the Wholegrain Puzzle Together: Health Benefits Associated with Whole Grains – Summary of American Society for Nutrition 2010 Satellite Symposium. Journal of Nutrition 141, 1011s-1022s
(3) Scalbert et al 2005, Polyphenols: antioxidants and beyond, American Journal of Clinical Nutrition 81(1), 215s-217s
(4) Konczak & Zhang 2004, Anthocyanins – more than natures colours. J Biomed Biotechnol 2004(5): 239-240
(5) Leach & Kumar 2012, Cinnamon for diabetes mellitus. Cochrane Database Syst Rev. Sept 12;9
(6) USDA Database – www.ndb.nal.usda.gov/