Guest guest Posted June 5, 2005 Report Share Posted June 5, 2005 " HSI - Jenny Thompson " <HSIResearch HSI e-Alert - Go Slow Wed, 25 May 2005 07:30:00 -0400 HSI e-Alert - Go Slow Health Sciences Institute e-Alert **************************************************** May 25, 2005 Dear Reader, Are you tired of hearing about low-carb this and low-carb that? No problem. Today I'm going to tell you about " slow-carbs. " According to a study that appears in the May 2005 issue of the American Journal of Clinical Nutrition, most of us can eat all the carbs we want - just so long as they're slow. And the slower the better. ----------- Slow vs. low ----------- I've actually covered slow-carbs in previous e-Alerts, but without the catchy name. A slow-carb diet is essentially a diet that restricts carbohydrates that rate a high glycemic index (GI). A quick review: Low GI foods (such as meat and most fruits and vegetables) prompt a slow increase in blood sugar levels, while high GI foods (such as foods with added sugar, processed baked goods and starchy foods) produce a quick spike in blood sugar levels. A steady intake of high GI foods promotes a gradual insensitivity to insulin - the precursor of type 2 diabetes. Researchers at Children's Hospital in Boston designed a study to test the effectiveness of a slow-carb, low-GI diet using two key measures: weight loss and cardiovascular disease risk. Twenty-three obese subjects were divided into two groups. One group of 12 subjects followed a conventional low-fat, reduced calorie diet. The other group of 11 subjects followed a low-GI diet, avoiding starchy foods and consuming protein along with any carbohydrates they ate. In addition, subjects in the low-GI group were unrestricted in their calorie intake. They were allowed to eat their fill and snack between meals. Subjects in both groups were urged to exercise regularly, and they all received counseling to help them stick to their diet and exercise regimens. After one year the results were dramatic: Low-fat diet subjects lost just over six percent of their body weight on average, while low-GI diet subjects lost an average of nearly eight percent of their body weight. In addition, one of the key markers for heart disease was much improved by the low-GI diet. Low-fat dieters reduced their triglyceride levels by less than 20 percent on average. Subjects on the low-GI diet, however, reduced triglycerides by nearly 40 percent. Another heart health marker provided an impressive result. Concentrations of plasminogen activator inhibitor 1 (a coagulation factor that increases blood clot risk) increased by more than 33 percent among the low-fat dieters, but DECREASED nearly 40 percent in the GI-diet group. ----------- Keep it complex ----------- In the e-Alert " So Five Minutes Ago " (2/23/04), I predicted that the buzz about low-carb diets would eventually evolve into popular recognition of the glycemic index as a logical dietary guide. I really wasn't going too far out on a limb with that prediction. The glycemic index has been around for awhile, and it provides a convenient way to sort out simple carbs from complex carbs. In a nutshell, simple carbs are fast (high GI), and complex carbs are slow (low GI). If your diet includes mostly complex carbs, you won't put undue stress on your pancreas (the organ that uses insulin to remove sugar from the bloodstream). A high intake of simple carbs, on the other hand, prompts an over-secretion of insulin and, in time, a cycle of extreme blood sugar swings as the body desperately attempts to auto-regulate. The problem is further complicated when the simple carbs come from refined sources (and they mostly do). Refining strips away natural fiber that slows the release of sugar into the system. HSI Panelist Allan Spreen, M.D., offers a more in depth look at the carbs issue in the e-Alert " Complex Made Simple " (6/23/04). As for the glycemic index, there are several sources on the Internet that estimate the GI value of different foods. One in particular - glycemicindex.com - provides a complete GI database. The slight drawback for those of us in the U.S. is that the database is sometimes specific about brand names, which are mostly Australian and European (the site is maintained by the University of Sydney). Nevertheless, the database offers an excellent guide for making low GI dietary choices. **************************************************** ....and another thing Tea for two...plus several hundred. In the e-Alert " Tea Off " (4/27/05) I told you about laboratory research that revealed how green tea may inhibit an enzyme that promotes cancer cell growth. In 2003 a team of researchers from the Department of Preventive Medicine at the University of Southern California (USC) took green tea research out of the laboratory and into the homes of hundreds of women, with promising results concerning the prevention of breast cancer. The USC team interviewed almost 1,100 Asian American women (aged 25 to 74) living in Los Angeles. 501 women had been diagnosed with breast cancer, and 594 were cancer-free. Between 1995 and 1998, each subject was interviewed in person to determine a wide variety of factors, including food and beverage intake, personal medical history, family health history, and general lifestyle details such as smoking habits and alcohol intake. An examination of the data showed that women in the non-cancer group were much more likely to be regular green tea drinkers. In fact, on average, those who drank at least 8.5 milliliters (less than half a cup) of green tea each day, had a reduced breast cancer risk of nearly 30 percent. Those who consumed more than 8.5 milliliters reduced their risk even more. But while more may be better when it comes to green tea, a high intake comes with a note of caution. EGCG is a type of flavonoid that's abundant in green tea and is believed to be the active ingredient responsible for fighting cancer. But high levels of EGCG may reduce folate levels. The average green tea drinker can address this by increasing dietary sources of folate (chicken liver, lentils, asparagus and spinach) and by taking a folic acid supplement. Pregnant women, however, should be cautious about green tea intake because low folate levels increase the risk of causing neural tube disorders to unborn children. Patients with cardiovascular problems also need to keep folate levels high. To Your Good Health, Jenny Thompson Health Sciences Institute **************************************************** Sources: " Effects of an Ad Libitum Low-Glycemic Load Diet on Cardiovascular Disease Risk Factors in Obese Young Adults " American Journal of Clinical Nutrition, Vol. 81, No. 5, May 2005, ajcn.org " Low Carb Out, Slow Carb In? " Daniel DeNoon, WebMD Medical News, 5/11/05, my.webmd.com " Green tea and risk of breast cancer in Asian Americans " International Journal of Cancer, Vol. 106, No. 4, 574-579, 9/10/03, interscience.wiley.com **************************** Quote Link to comment Share on other sites More sharing options...
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