1 June 2010

Get the Scoop on Nutrition with Emma Stirling

The scoop on tropical fruit

Emma Stirling
Emma Stirling APD

You don’t need a nutrition science degree to know that fruit is naturally nutrient rich. At least two serves a day will help boost your vitamin, mineral, dietary fibre and protective antioxidant intakes. But fruit is one food group that’s the cause of GI confusion. Why? Well even though all fresh fruits are labelled healthy, many tropical fruits are stamped with a moderate to high GI. But does this mean that you should bypass a juicy pineapple? Let’s explore. And before you GI pros jump ahead, read on as we have a new GI value to share (durian!).

Feeling fruity Now as you know it’s really tricky to predict the GI values of any food without laboratory testing. Right? But with fresh fruit, there are some factors that can guide us:

  • Type of carbohydrate: fruits with a higher ratio of fructose to glucose will have a lower GI.
  • Acid levels: the more acidic a fruit, the lower the GI value.
  • Dietary fibre content: fruits higher in soluble and insoluble dietary fibre (keep the skins on where possible please) help slow digestion and promote a lower GI.
Going troppo It’s true that temperate climate (often referred to as orchard) fruits tend to have a low GI. So you can snack with confidence on apples (GI 38), pears (GI 38), citrus like oranges (GI 42) and grapefruit (GI 25) and stone fruits like peaches (GI 42)and plums (GI 39). But when it comes to tropical fruit, things go a little troppo:

Mangoes (GI 51) and bananas (GI 52) are two of the few tropical fruits with a low GI. Pineapple (GI 59), paw paw (GI 56), rock melon/cantaloupe (GI 68) and watermelon (GI 76) tend to have moderate to high GI values. But remember it’s worthwhile to consider the glycemic load (GL) in these few instances. We touched on the type of carbohydrate above, but the amount of carbohydrate you eat at any meal or snack is also key to effective blood glucose control. The glycemic load of these tropical fruits is in fact low, because they are low in total carbohydrate content and high in water. That’s what makes them their juicy best. So isn’t that great news? You can still cool down with a slice of watermelon in the heat of summer – just watch your portion size.

Tropical fruit

Thanks to new data published in the Asia Pacific Journal of Clinical Nutrition we now know that one very tropical fruit, durian, has a low GI (49). Durian you ask? Well this is one fruit that you need to smell it to believe it. This heavy, soccer ball-sized, spiky fruit has a very pungent odour. And in my opinion I’m yet to meet anyone that eats enough durian to remotely worry about its GI. Revered in Southeast Asia as the “king of fruits” and described as “fragrant”, it remains very much an acquired taste elsewhere. Ripe durians are eaten fresh but have a short shelf life. In cooking they are used for preserves (jams and pickles), milk-based desserts and ice-creams, cakes, and confectionery; in some parts of Asia unripe durians are used as a vegetable. But in some South East Asian hotels durian are banned as the odour is so off-putting to foreign guests.

Mix it up Whatever your likes or dislikes, feel confident with all fruit. Mix up your fruit bowl for plenty of variety including other luscious, bright pigmented, tropical faves like guava and dragon fruit. And favour your local seasonal, regional produce. Research shows people who eat three or four serves of fruit a day, particularly apples and oranges, have the lowest overall GI and the best blood glucose control around town (or tropical jungle).

Emma Stirling is an Accredited Practising Dietitian, health writer and editor of The Scoop on Nutrition – a blog by dietitian experts. Check it out or subscribe for hot news bites and a healthy serve of what’s in flavour.

GI Group: Are any engineers listening? Prof Jennie Brand-Miller would love to buy a fruit bowl that kept fruit on the bench or table cool and in the line of sight of hungry children.


Nicole Senior said...

Thanks Emma. I absolutely adore Durian! I tried it on a holiday to Thailand and will never forget it's luscious sweetness and rich mouthfeel. The only way I can describe it is it a creaminess that we normally associated with high fat desserts like mousse or creme brulee, but without the tongue coating after-taste. It is, of course, virtually fat free, and is - paradoxically for it's mouthfeel - fresh and light. An amazing fruit I recommend everyone to try.

Emma Stirling said...

Thanks Nicole. I'd love to hear more from other Durian fans? How about you? As for me sorry, after 2 years living in steamy, humid Hong Kong all I can remember is the smell! But if you're prepared to prep for me....I'm there for dessert.

Anonymous said...

Great article. I enjoy Orchard Fruits and was wondering what the GI's are of the ground/vine type fruits: Blueberries, Strawberries.

Orchard and Troppo are a great way to remember GI ranges. Thanks for the info.


GI Group said...

Emma Stirling answers Marie's question:
'Hi Marie -- Thanks for your question and interest in GI. Remember how we talked about the carbohydrate content of fruit being a key factor? Well, apart from strawberries (GI 40), most berries actually have so little carbohydrate it’s difficult to test their GI. Because the average serve of most berries has very little impact on blood glucose levels, people with diabetes do not need to be too concerned about their GI values, as long as they don’t eat their way through the whole patch. Berries are nutrient dense and a top choice if you are watching your weight, as they have a high water content and are amongst the lowest kilojoule fruits around. Deep purple and blue pigmented berries are particular rich in anthocyanin antioxidants that may be protective to health, particularly brain aging. In the US, it’s possible to buy wild blueberries (V. angustifolium) and we know these have higher levels of antioxidants and a low GI 53. Wild blueberries are smaller, about one-third the size of cultivated, have a more intense flavor and retain their shape well in cooking. Go for seasonal beauties like my favourite raspberries, wild varieties if available, and stock up on frozen or canned in natural juice, in order to enjoy the ‘berry’ nice health benefits all year round.'

project timesheet said...

Re: keeping fruit cold in a bowl for kids and in their line of site...

What about small bowl of fruit placed inside large bowl of ice, sitting on a kitchen towel to absorb condensation?