GI of over 2,480 individual food items published
The International tables of glycemic index 2008 produced by researchers from the University of Sydney’s Human Nutrition Unit have been published online in Diabetes Care. The tables give the GI (glycemic index) of over 2,480 individual food items – doubling previous data. The key findings says lead researcher Fiona Atkinson are:
- Most varieties of legumes, pasta, fruits and dairy products are low GI.
- Breads, breakfast cereals, rice and snack products, including wholegrains, are available in both high and low GI forms.
- Most varieties of potato and rice are high GI, but lower GI ones are available.
- The GI of some foods such as oatmeal/porridge appears to be increasing possibly reflecting food industry efforts to provide convenience for the consumer with faster cooking products.
- The GI of foods must be tested locally because manufacturers in different countries prepare and process foods, particularly cereal products, in different ways. For example, Kellogg’s Special K™ and All-Bran™, for example, are different formulations in North America, Europe and Australia.
‘Low GI foods have benefits for everybody,’ says Prof. Jennie Brand-Miller from Sydney University’s Human Nutrition Unit. ‘They can keep you feeling full longer, help you achieve and maintain a healthy weight and provide you and your brain with more consistent energy throughout the day. They can also have a major effect on the way the body functions and whether or not you develop health problems. If you have constantly high blood glucose and insulin levels due to eating a high GI diet, for example, you may literally “exhaust” your pancreas over time and eventually this can lead to pre-diabetes and type 2 diabetes.’
‘The GI was a controversial topic among researchers and health authorities for many years, for a variety of reasons, she says. ‘But today, studies from major leading medical institutions and research universities around the world have repeatedly demonstrated that the GI is a clinically proven tool in its application to weight control, diabetes and coronary health. Moreover, the International Diabetes Federation and diabetes organisations in many countries have endorsed the judicious use of the GI in the dietary management of diabetes.’
To create the 2008 tables, University of Sydney researchers spent over two years systematically sorting through all the published and unpublished sources of reliable GI values. ‘What’s unique about the 2008 tables,’ says Brand-Miller, ‘is that there are actually two tables, the first is a list of GI values derived from testing foods in healthy people, and the second primarily from individuals with impaired glucose metabolism.’
In their conclusion, the researchers emphasise that the GI should not be used in isolation. Food choices should be based on overall nutritional content along with the amount of saturated fat, salt, fibre and of course the GI value.
Age-related macular degeneration (AMD) is one is the most common causes of blindness in the over-50s, currently responsible for 14 million cases of blindness or severe visual impairment worldwide.
Dietary factors are known risk factors for AMD. In ‘Food for Thought’ (May 2006) we reported on research suggesting that the quality of the carbohydrates you eat may help to bring it on — or hold it off. A recent study published in the American Journal of Clinical Nutrition confirms that it would be a good idea to make a low GI diet part of any AMD prevention plan along with foods you already know about such as dark green leafy vegetables, a variety of fruits (all different colours) and fish. Prof. Paul Mitchell from Sydney University’s Department of Ophthalmology says the prospective population based study shows that a high GI diet is a risk factor for early AMD — the recognized precursor of sight-threatening late AMD. ‘Low-glycemic-index foods such as oatmeal may protect against early AMD,’ say the researchers in their conclusion.
Check your fracture risk
The Garvan Institute’s Dubbo Osteoporosis Epidemiology Study has followed more than 2,500 people aged over 60 from Dubbo (in Australia) for almost 20 years. It’s the world's longest osteoporosis study and the first to include men. Three-quarters of the risk of developing osteoporosis is genetic. But, according Assoc. Prof. Tuan Nguyen, ‘men with prostate cancer should consider seeking evaluation for osteoporosis, particularly if they are being treated with androgen deprivation therapy as they face a 50 per cent higher risk of fracture, which increases to nearly double the risk if they are receiving androgen deprivation therapy’. Using data collected in the Dubbo study, the Garvan Institute has formulated a web-based tool to enable people to calculate their fracture risk: www.fractureriskcalculator.com.
2008 Physical Activity Guidelines for Americans
The US Government has issued its first-ever Physical Activity Guidelines for Americans. They describe the types and amounts of physical activity that offer substantial health benefits for adults and children.
November 14: World Diabetes Day focuses on diabetes and children
World Diabetes Day is a campaign that each year features a theme chosen by the International Diabetes Federation to address issues facing the global diabetes community. In 2008, the World Diabetes Day theme is diabetes in children and adolescents. For more information: www.worlddiabetesday.org
Catherine Saxelby reviews Portion Perfection by Amanda Clark
Finding it hard to lose that excess weight? Could be that you’re eating ‘the right stuff’ but just eating too much of it. A new book published in Australia called Portion Perfection is a visual weight control plan that shows you exactly the right amount to eat if you want to lose or maintain weight. It includes everyday and occasional foods (such as treats like chocolate or wine) and spells out just how much you can eat for a number of different diet levels. The best thing about this book is that it has hundreds of pictures showing brands of packaged foods – not something normally found in a diet book. You’ll find almost every brand of yoghurt, cereal, muesli bar and crisps available in Australia shown as well as sushi, nuggets and take-aways. There’s also a Portion Perfection plate and bowl to help you serve up the right amount. For more information, check out www.greatideas.net.au.
The giveaway is now closed.
Check 'COMMENTS' for the winners and Great Ideas In Nutrition's special offer for residents of Australia who order the Portion Perfection book, plate and bowl before 5pm on Friday 7th November 2008.