Go Slow

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" 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

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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.

 

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Slow vs. low

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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.

 

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Keep it complex

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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.

 

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....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

 

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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

 

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