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Two thumbs up for Oatrim: human study shows a double benefit from this new fat substitute.

The diet got mixed reviews: "I had a hard time eating the spaghetti sauce, but I could eat the brownies or muffins with every meal," says Pat Howard, one of 24 volunteers in the first human study of Oatrim.

But this new ARS-developed fat replacer with an extra cholesterol-- lowering punch in the form of beta glucan got two thumbs up in its research debut.

Not only did the volunteers have a substantial drop in the artery-clogging LDL cholesterol without a decrease in beneficial HDL cholesterol; their glucose tolerance--ability to process sugar from a meal--improved significantly also.

The volunteers were selected for the study on the basis of elevated cholesterol levels, says Judith Hallfrisch, who heads carbohydrate research at the Beltsville (Maryland) Human Nutrition Research Center and co-led the study with nutritionist Kay Behall. It turned out that most of the volunteers also had elevated insulin levels, which means they were less efficient at metabolizing dietary sugar and at greater risk of developing diabetes.

Oatrim reduced the volunteers' insulin levels 11 to 24 percent, depending on the level of beta glucan in the fat replacer. And glucagon, a hormone that has the opposite effect of insulin and moves glucose from body cells into the blood, dropped a significant 16 to 36 percent. As a result of these hormone changes, the volunteers' blood glucose levels were 7 to 12 percent lower after eating Oatrim than they were before.

But the biggest surprise of the study may be Oatfim's main payoff: Most of the volunteers lost weight during the study, despite increases in their calories. As a group, they lost an average 4.5 pounds, says biologist Daniel Scholfield who worked with Hallfrisch and Behall. Nutrition researchers and dietitians carefully plan calorie intakes of each volunteer in human studies to prevent any changes in weight. Otherwise, it's not clear whether the results are due to the variable being tested or to a weight gain or loss. So the Beltsville dietitians were understandably disturbed that they could not maintain the volunteers' weight, even after increasing calories.

Since the study began in early spring, Hallffisch suspects some of the weight loss was due to an increase in the volunteers' activity as the days got longer. But Oatrim was a big factor.

"I think this is the value of Oatrim," she says. People can lower their cholesterol by making dietary changes, such as eating less fat and cholesterol or more beans, grains, and other highfiber foods. "Oatrim could replace fat and lower overall calorie intake without a loss of satiety. Nobody in the test complained about being hungry," she adds. "They were very full!"

The reason for this fullness lies in the unique property of Oatrim, says its developer, ARS chemist George E. Inglett at the National Center for Agricultural Utilization Research in Peoria, Illinois. The combination of beta glucan--a soluble fiber credited with the cholesterol-lowering property of oats--and amylodextrin makes Oatrim absorb water like a sponge and turn into a gel. Unlike other fat replacers, "it swells tremendously."

In the Beltsville study, researchers used two compositions of Oatrim--1 percent and 10 percent beta glucan. "The 10 percent tums into something like silly putty when mixed with water," Scholfield says. "The 1 percent is more fluid."

Hallfrisch and Behall wanted to test two levels of beta glucan on the volunteers to see if the amount of soluble fiber was important in lowering cholesterol levels. So half of the 24 volunteers got Oatrim with 1 percent beta glucan for 5 weeks of the study, and the other half got 10 percent beta glucan. Then each group switched to the other composition for 5 more weeks.

As it turned out, cholesterol levels dropped about the same on both compositions as did the volunteers' weight, says Behall. However, "there was a trend for 10 percent beta glucan to improve glucose tolerance more than the 1 percent beta glucan."

She says there are several theories on how soluble fibers such as beta glucan reduce cholesterol, but research has yet to substantiate any of them.

Neither Oatrim composition reduced blood triglyceride (fat) levels. But levels dropped significantly during the first week of the study when all volunteers were put on the same diet to start them out on equal footing before they got Oatrim. The equilibration diet, as it is called, contained 35 percent of calories as fat and was probably healthier than the diet volunteers normally ate, Behall notes.

After the first week, each volunteer got 50 grams--about one-half cup--of Oatrim powder in various foods throughout the day. The researchers modified standard recipes, using Oatrim to replace from one-quarter of the fat in such foods as muffins and cookies to all of the fat in pancakes and waffles.

This way they reduced the volunteers' daily fat intake to the recommended 30 percent of total calories. Oatrim supplied another 10 percent of calories, while other carbohydrates-- sugars and starches--accounted for 45 percent. And protein made up the remaining 15 percent.

Volunteer Mervin Parker, who says he usually "eats on the go" and consumes a lot of fast food, is anxious to get into another study. "It's healthy food; they cut out the things you shouldn't have. And it's convenient to have your meals prepared for you."

The Beltsville dietitians successfully hid the white powder in muffins, cakes, waffles, cookies, brownies, and meatloaf. But they couldn't disguise it so well in the Jell-O, yogurt, gravy, soups, spaghetti sauce, and fruit juices.

"Overall, the food was real good," says volunteer Ray Mock. "Just in some of the items, there was a difference in consistency." For instance, the powder didn't always dissolve completely in some of the juices, he notes. "You had a little texture with your orange juice... more than just pulp."

Mock says he could "most definitely" tell the difference between 10 percent and 1 percent Oatrim. "Some of the foods with the higher percentage were kind of gummy."

That's no surprise because soluble fibers are gums.

Also, several of the volunteers experienced gastrointestinal discomfort on the higher fiber intake. But most adjusted after a while, Hallfrisch says. In fact, she sees Oatrim as a potential fiber source for the elderly. "It may be easier to digest than raw fruits and vegetables ." Having Your Cake--Eating It Too

Behall says Oatrim is easier to incorporate into food items than any of the other gums she has worked with-- and she has tried lots of them. Oatrim doesn't decrease the baked volume of the product like other gums, she notes. "We can have products that are comparable in looks and appearance, taste and texture to what we're used to, but with less fat. Plus, you get a bonus from the thickening quality of Oatrim. It maintains the texture."

According to Inglett, its gelling property "gives a more creamy, fatlike texture to foods than do other starch-- based fat substitutes on the market. And it does more for your health."

One gram of Oatrim gel--the form used most often in commercial foods--contributes only one calorie, compared to nine calories per gram of fat, he says. The gel behaves like shortening: It's solid at room and body temperatures but turns liquid at cooking temperatures.

Beta glucan, Inglett explains, is the principal fiber in oats and barley. It's a very long chain of glucose sugars linked together in a beta configuration rather than the alpha configuration of starch.

Since we don't produce enzymes to cut these beta links, the glucose units are not absorbed through the small intestine as is the case with starch. As a result, beta glucan provides few if any calories. The calories in Oatrim come, rather, from amylodexttin--shortened fragments of starch.

Inglett first announced development of Oatrim in April 1990. It is now being made and marketed under exclusive licenses by two partnerships in the food industry. One partnership is between Quaker Oats and France's Rhone-Poulenc. The other is a joint venture between the U.S. agribusiness giant, ConAgra, and A.E. Staley of Great Britain, called Mountain Lake Manufacturing.

Several products containing Oatrim are already on the market, with more on the way, says Inglett. He estimates that some 40 products are under development at the pilot level. "But they'll have many hurdles to cross to meet company standards before there's a product in the marketplace."

Steve Grisamore, general manager for Mountain Lake Manufacturing, says: "If the finished product doesn't taste like the full-fat product, people won't buy it. In general, people won't buy a product simply because it has beta glucan."

Grisamore says Mountain Lake is selling Oatrim under the trade name of TrimChoice. It is in several of ConAgra's Healthy Choice line of products-hot dogs, bologna, cheese, and 96-percent-fat-free ground beef. Smaller companies are using the fat-replacer in baked products, such as muffins and cookies, and in chocolate candy.

The Quaker Oats/Rhone-Poulenc partnership expected to have two grain-- based products on the market in the last quarter of 1993, according to John Kacher, with several more products due out in 1994. Kacher is business director of low-fat systems for Rhone-Poulenc, which does most of the marketing of Oatrim. Some of his customers are already marketing a no-fat pancake mix; a very low-fat, high-fiber nutrition bar; and a meatless frankfurter containing Oatrim, he said.

Kacher says Oatrim compares favorably with any currently FDA-approved fat replacer. "It's a crowded field--there are a lot of products out there." Commercially speaking, he echoes Grisamore. "There's not much interest in beta glucan, the fiber part. People will buy the product because it replaces fat." He says certain fat replacers should work better for certain products.

Grisamore agrees. He projects that the market will grow quickly once food companies learn how to make products that have qualifies similar to their fullfat counterparts. He says fat-free products are improving since they were first introduced in 1990, because the companies are realizing that it takes more than a single ingredient to replace fat. "I'm confident that people in the industry have identified that we need a systems approach--a combination of several ingredients."

Unfortunately for volunteer Vivian Shimanuki, whose cholesterol level "dropped dramatically" during the study, neither partnership sells the white powder used in the Beltsville study to consumers. "if I could find this kind of Oatrim out there, I would definitely add it to all my foods," she says emphatically.

Shortly after the study, Shimanuki had her cholesterol tested, and "it had gone back up with my normal type of eating," she says. "I know now that it can be controlled with the selection of food and enhanced, I'm sure, with Oatrim."

Judith Hallfrisch, Kay Behall and Daniel Scholfield are at the USDAARS Beltsville Human Nutrition Research Laboratory, Bldg. 307, 10300 Baltimore Ave., Beltsville, MD 20705-2350; phone (301) 504-8396, fax (301) 504-9456.

George Inglett is at the USDA-ARS National Center for Agricultural Utilization

Research, 1815 N. University St., Peoria, IL 61604; phone (309) 681-6363, fax (309) 681-6686.
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Title Annotation:includes related article on Research and Development Magazine's significant new technology award
Author:McBride, Judy
Publication:Agricultural Research
Date:Dec 1, 1993
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