GI News Briefs

The calcium factor
A recent study in March Diabetes Care reports that over a 6-month period, a diet rich in low-fat dairy calcium boosted weight loss in overweight people with type 2 diabetes – particularly in females. Those with the highest intake of dairy calcium were 2.4 times more likely to see a weight loss of greater than 8% versus those with the lowest intake of dairy calcium, despite consuming more kilojoules (calories). Such a diet may be helpful for people with diabetes who find it hard to stick to other weight loss regimes suggest the authors Dr Danit R. Shahar from Ben Gurion University and colleagues.
Diabetes Care 2007;30:485–489

Does the diabetes clock start ticking earlier for women?
The diabetes clock may start ticking in women long before it’s possible to diagnose it by rising blood glucose levels according to new research published in February Diabetes Care. Epidemiologists at the University at Buffalo report that risk factors for diabetes found in the blood, such as markers of endothelial dysfunction, chronic sub-acute inflammation and blood clotting factors, are present early on in women who eventually progress from normal glucose status to prediabetes. The study involved 1,455 healthy men and women from the Western New York Health Study who were given a physical examination when they entered the study and for the follow-up. Results showed that 52 women and 39 men had progressed from normal blood glucose levels to prediabetes over the previous six years. Whether this relates to the higher risk of heart disease among women with diabetes needs more study. Meantime, lead author Richard Donahue, PhD, professor of social and preventive medicine and Associate Dean for research in UB’s School of Public Health and Health Professions suggests that women whose blood glucose increases over time, even if it doesn’t reach diabetic levels, should be screened more intensively for cardiovascular disease.
Diabetes Care 2007;30:354–359

What does endothelial dysfunction mean?
GI Group: The endothelium are the cells that line the inner surface of all our blood vessels including arteries and veins. Endothelial dysfunction is a physiological dysfunction of their normal biochemical processes and is thought to be a key event in developing atherosclerosis and significant in predicting stroke and heart attacks.

Cross-section of the vascular endothelium

Does the low GI diet have enduring merit?
‘A low-GI diet [is] a prudent approach to the prevention and treatment of diabetes, heart disease and obesity’ concludes Dr David Ludwig from the Department of Medicine, Children’s Hospital Boston in The Lancet. In reviewing the evidence for the benefits of low GI eating he says: ‘The low-GI diet, with its focus on carbohydrate quality rather than quantity, aims to address an underlying physiological cause of diseases arising from excessive swings in postprandial glycemia. Because the diet does not restrict either fat or carbohydrate, it may be more behaviourally sustainable. Although the data are variable, most published studies report beneficial effects of lowering the GI and virtually no study suggests potential for harm (by contrast with low-fat and very-low-carbohydrate diets that can adversely affect some risk factors for cardiovascular disease).
The Lancet Vol 369 March 17, 2007

Dr David Ludwig

Nuts over nuts
A review by Australian nutrition experts in Current Opinion in Lipidology provides further support for the heart-health benefits derived from regularly eating nuts. In their conclusions, researchers Dr Alison Coates and Professor Peter Howe describe nuts as ‘ready-to-eat snack foods that are satisfying, have healthy lipid profiles, and are excellent sources of protein … There’s an extensive body of literature describing the beneficial effects of regular consumption of nuts on blood lipid profiles, and there are also different ways that bioactive nutrients in nuts can act – possibly synergistically – to improve blood circulation by enhancing the ability of blood vessels to dilate,’ said Professor Howe. Beyond the direct heart health benefits, nuts can offer a wider array of benefits, including:

• weight loss in an energy restricted diet
• satiating effect to balance appetite and energy through high fibre, protein and energy content, and
• improved insulin sensitivity, with a positive impact on type 2 diabetes risk.

‘Many would-be nut eaters are concerned that the high fat content of nuts will contribute to weight gain,’ said Dr Coates, although evidence suggests this is not the case.
Current Opinion in Lipidology 2007 Feb;18(1):25–30.

Hyperglycemia and cancer risk
Swedish researchers report a statistically significant association between cancer and hyperglycemia in Diabetes Care and write that: ‘A lifestyle that decreases blood glucose levels may reduce overall cancer risk not only among overweight or obese subjects but most likely also among subjects with normal body weight. At the same time, current evidence suggests that such a strategy also would contribute to the prevention of diabetes and cardiovascular disease.’ In their prospective cohort study, Dr Par Stattin of Umea University Medical Center and colleagues examined data from 31,304 men and 33,293 women who had participated in a larger study and identified a total of 2478 cases of cancer. They found that abnormal glucose metabolism was associated with an increased risk of cancer overall in women but not in men. However, for both men and women, high fasting blood glucose was significantly associated with an increased risk of cancer of the pancreas, endometrium, urinary tract and malignant melanoma.
Diabetes Care 2007;30:561-567.