GI Q&A with Prof Jennie Brand-Miller
I always pick a healthy wholegrain bread like a wholemeal sandwich bread, but a friend told me it wasn’t low GI which might be why I am having trouble managing my sugar. Is that true?
There are countless reasons to include more whole grains in your diet, but it’s hard to go past the fact that you are getting all the benefits of their vitamins, minerals, protein, dietary fibre and protective anti-oxidants. Studies around the world show that eating plenty of whole grains reduces the risk of certain types of cancer, heart disease and type 2 diabetes.
But ‘whole grain’ and ‘low GI’ are not the same. Indeed many wholegrain breakfast cereals and breads like wholemeal (whole-wheat) bread have a high GI because they are just as finely milled as their ‘white’ counterparts and will shoot your blood glucose levels sky high. You get double the benefit if your whole grains are also low GI – that’s why we like to specify whole kernel grains because they not only have all the nutritional benefits of whole grains, they help you keep those blood glucose levels on an even keel.
There’s no international definition of ‘wholegrain’. It can mean slightly different things in different countries. For example, a few years ago, Food Standards Australia New Zealand (FSANZ) expanded the legal definition for packaging labels to allow more foods including wholemeal foods that contain all of the natural constituents (that may be high GI) to include ‘wholegrain’ on the label.
If you have diabetes or metabolic syndrome and low GI foods are an important part of your diet, what should you do? If there’s no GI rating on the label, follow our rule of thumb, if you can’t see the grains, then don’t assume it’s low GI. Why not follow up and encourage the manufacturers to have their products glycemic index tested?
New GI values with Fiona Atkinson: Indian whole wheat roti (flatbreads)
A new study from India published online in the British Journal of Nutrition reports that roti made from whole wheat and from atta mix have a low GI.
- Whole wheat roti GI 45
- Whole wheat plus atta mix roti GI 27
The GI testing was conducted using the international standardised method. The whole wheat roti were made using branded commercial whole wheat flour (Pillsbury, General Mills India). The atta mix roti were made using whole wheat flour plus atta mix (roasted bengal gram flour, psyllium husk and debittered fenugreek (methi) flour. 459 g atta mix (about 1 lb) was added to 2 kg (about 2 lb 4 oz) whole wheat flour as per manufacturer’s (Marico Ltd) instructions. The roti dough was rolled out to approximately 15 cm (6 in) in diameter, cooked fairly well on both sides on hot griddle and tossed on direct flame to puff.
The authors conclude that: ‘both types of roti could be incorporated into the Indian diets to replace existing high GI food choices such as refined grains. However, selecting the atta mix could further reduce the overall dietary glycemic load which could be beneficial in a population, which is highly susceptible to type 2 diabetes and insulin resistance.’
GI testing by an accredited laboratory
Dr Alexandra Jenkins
Glycemic Index Laboratories
36 Lombard Street, Suite 100
Toronto, Ontario M5C 2X3 Canada
Phone +1 416 861 0506
Research Manager, Sydney University Glycemic Index Research Service (SUGiRS)
Human Nutrition Unit, School of Molecular and Microbial Biosciences
NSW 2006 Australia
Phone + 61 2 9351 6018
Fax: + 61 2 9351 6022
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