GI News Briefs

The perils of iron overload
It’s well known that a chronic shortage of iron leads to anaemia. Too much iron can cause problems, too. Researchers writing in the January issue of Diabetes Care found that a high iron intake was associated with heart disease in women with diabetes. The researchers followed up 6,161 women from the Nurses’ Health Study with type 2 diabetes over 20 years to investigate the relationship of dietary iron and red meat to heart disease. After accounting for age and body weight, the researchers found that the women who had the highest intake of heme iron and red meat had a 50 per cent greater risk of developing heart disease than those with the lowest intake, especially if they were postmenopausal. The writers conclude that to prevent heart disease: ‘patients with type 2 diabetes may consider reducing their consumption of heme iron and red meat’.
– Diabetes Care 30:101-106, 2007

Hemoglobin model

GI Group: There are two dietary sources of iron that our bodies can use:

• Heme (haem) iron from animal foods such as meat, chicken, fish and offal
• Non-heme iron from eggs and plant foods such as legumes, cereal grains, nuts, seeds, dark green leafy vegetables and dried fruit.

If you have type 2 diabetes and you love your red meat, there’s no need to give it up. Just be quite moderate with the amount you eat as the researchers suggest. Did you know that 100 grams (3½ oz) of lean meat as part of a balanced diet will meet the daily nutrient needs of an adult?

When cloudy is better than clear
Researchers at the Agricultural University of Wroclaw have found that cloudy apple juice can have up to four times more antioxidants than clear because of the manufacturing process. The potent antioxidants in apples are polyphenols – also found in red wine, berries and dark chocolate. The scientists measured the amount of procyanidins, the main compounds that contain polyphenols, in two varieties of clear and cloudy apple juices. The cloudy apple juice, which contains more pulp, had higher concentrations of antioxidants and showed more antioxidant activity. They also found the same results for clear and pureed or cloudy strawberry juices.
– Journal of the Science of Food and Agriculture

GI Group: The apple juices GI-tested to date all have a low GI (37–44), but the cloudy juice, Wild About Fruit Apple Juice with Fibre, was the lowest. Remember a serve is a small glass, around 200 ml (7 fl oz).

Reducing the risk of dementia
Is insulin resistance a modifiable midlife risk factor for dementia? A new study published in the December issue of Diabetes Care reports that hyperinsulinemia is linked to cognitive decline. Hyperinsulinemia is a condition when the level of insulin in the blood is higher than normal. It is caused by overproduction of insulin by the body and is related to insulin resistance. The researchers from the Medical University of South Carolina examined 7148 healthy adults who were given a series of cognitive tests at the outset and followed up six years later. They report that those with the highest level of insulinemia had the significantly greater declines in delayed word recall and first letter word fluency.
– Diabetes Care 2006;29.2688-93

Setting GI labelling standards in Australia
In a world first, Standards Australia have released a standard for use by food manufacturers, accreditation bodies, regulators, educational institutes, testing laboratories, and research organisations that sets out a recognised scientific method for determining the GI of carbohydrates in foods.

What does it mean? It doesn’t change the GI in anyway, but it does stop manufacturers from making false claims about the GI on their product labels and in advertising and marketing. Australian consumers can now be confident that if the label says a food is ‘low GI’ then it really is low GI, and it really has been tested by an accredited laboratory such as Sydney University Glycemic Index Research Service. For a list of accredited laboratories around the world see ‘GI Testing’ in the right-hand column. If you head over to the SAI Global WebShop, you can buy a copy of the standard for GI testing (insert ‘glycemic index’ in the search box). The standard has been submitted to the International Standards Organisation for possible adoption by other member countries around the world, so eventually consumers in the United States, Canada and Europe and other parts of the world may benefit from this initiative.

Click on the document image for a preview (PDF, 550 kb).