Glycemic index predicts blood sugar level after meal

Last Updated: 2006-07-06 14:52:33 -0400 (Reuters Health)

NEW YORK (Reuters Health) - Assessing a meal using the glycemic index, which lists the quality of carbohydrates contained in many common foods, appears to be a good way to predict the effect a meal will have on blood sugar levels, important information for diabetes, according to the results of a study published in the American Journal of Clinical Nutrition.

Dr. Thomas M. S. Wolever, of the University of Toronto and colleagues examined whether overall carbohydrate content and glycemic index of individual foods, as given in published tables, determined the effects of a realistic mixed meal on the blood sugar in normal subjects.

The team measured the responses to six test meals in 16 subjects in Sydney and eight meals in 10 subjects in Toronto, and then pooled the results. The meals varied in amount of calories, protein, fat, available carbohydrates and glycemic index score.

The blood sugar and insulin responses to the Sydney test meals varied over a 3-fold range. For the Toronto test meals, the blood sugar responses varied over a 2.4-fold range.

The team found no correlation between the blood sugar levels and fat or protein content of the test meal, but there was a significant correlation with carbohydrate content and glycemic index alone, which accounted for 88 percent of the variation in the blood sugar response.

"The good news is that the glycemic index works," Wolever said in a press release. "For sensible people it makes a lot of sense" It uses a "simple proportional measure -- like mixing paint."

SOURCE: American Journal of Clinical Nutrition, June 2006.

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Death risk rises in women as obesity worsens

Last Updated: 2006-07-06 16:22:33 -0400 (Reuters Health)

By Martha Kerr

NEW YORK (Reuters Health) - Obesity is known to increase a person's risk of death and now, new findings from a study of more than 90,000 women indicate that the risk continues to increase as the severity of obesity worsens.

"It's not good enough to consider obesity alone," principal investigator Dr. Kathleen McTigue of the University of Pittsburgh, Pennsylvania, told Reuters Health. "You need to look at degree of obesity."

In a study published in the Journal of the American Medical Association, McTigue and colleagues evaluated the impact of body weight on death risk in 90,185 women enrolled in the Women's Health Initiative Observational Study. On average, the patients were followed for 7 years.

Body mass index (BMI), a measure of body weight for height, was used to classify the women as normal weight, overweight, or obese. Normal weight was defined as a BMI from 18.5 to 24.9 and overweight was a BMI from 25 to 29.9. The investigators defined three categories of obesity: obesity 1 (BMI of 30 to 34.9), obesity 2 (BMI 35 to 39.9) and extreme obesity (BMI 40 and higher).

"The risks of extreme obesity have not been well-defined," McTigue noted. But this study had enough subjects to assess that risk, she added.

As weight increases, so does the risk of death, but the risk is not statistically significant until one becomes obese, McTigue said. Compared with normal-weight women, she continued, "the risk of dying was increased 12 percent in all women in obesity category 1, while risk was increased 86 percent over seven years in women in obesity category 3."

In a University of Pittsburgh release, the researcher pointed out that "earlier studies, which tended to reflect lower degrees of obesity, may underestimate the risks of extremely obese individuals and overestimate the risk for mildly obese individuals in diverse groups."

She concluded, "More accurately assessing weight-related health risk may both improve policy decisions about obesity and assist women in making informed decisions about their health."

SOURCE: Journal of the American Medical Association, July 5, 2006.

Copyright © 2006 Reuters Limited. All rights reserved. Republication or redistribution of Reuters content, including by framing or similar means, is expressly prohibited without the prior written consent of Reuters. Reuters shall not be liable for any errors or delays in the content, or for any actions taken in reliance thereon. Reuters and the Reuters sphere logo are registered trademarks and trademarks of the Reuters group of companies around the world.