Thursday, August 25, 2011

Diet That Combines Cholesterol-Lowering Foods Results in Greater Decrease in LDL Than Low-Saturated Fat Diet


Persons with high cholesterol who received counseling regarding a diet that combined cholesterol-lowering foods such as soy protein, nuts and plant sterols over 6 months experienced a greater reduction in their low-density lipoprotein cholesterol (LDL-C) levels than individuals who received advice on a low-saturated fat diet, according to a study in the August 24/31 issue of JAMA.

Efforts have been made to improve the ability of conventional dietary therapy to reduce serum cholesterol through the inclusion of specific foods or food components with known cholesterol-lowering properties, singly or in combination (dietary portfolio), according to background information in the article. The long-term effect of such diets compared with conventional dietary advice has not previously been assessed.

David J. A. Jenkins, M.D., of St. Michael's Hospital and the University of Toronto, and colleagues conducted a multi-center trial to determine whether advice to eat a dietary portfolio consisting of foods recognized by the U.S. Food and Drug Administration as associated with lowering serum cholesterol achieved significantly greater percentage decreases in LDL-C levels compared with a control diet at 6-month follow-up. The control diet emphasized high fiber and whole grains but lacked components of the portfolio diet, which emphasized dietary incorporation of plant sterols, soy protein, viscous fibers, and nuts.

What are plant sterols and stanols?

Plant sterols and stanols are naturally occurring substances found in plants. They are present in small quantities in many fruits, vegetables, vegetable oils, nuts, seeds, cereals and legumes. They are also available as supplements.

Why are plant sterols and stanols important?

Research has shown that plant sterols/stanols included with a heart healthy eating plan may reduce your risk for heart disease. The sterols/stanols work by blocking the absorption of cholesterol in the small intestine. This lowers the low density cholesterol known as the 'bad' cholesterol (LDL ) by 6-15%, without lowering the good cholesterol known as the high density cholesterol ( HDL). Clinical research trials have documented safety and effectiveness for use by the entire family. Plant stanols/sterols do not interfere with cholesterol lowering medications.

The National Cholesterol Education/Adult Treatment III program guidelines recommend plant sterols/plant stanols as part of a heart healthy eating plan. Eating a heart healthy low fat diet that include eating plenty of fruits, vegetables, whole grain foods, plant sterols/stanols, plus regular physical activity help reduce the risk of heart disease. The Food & Drug Administration approved the health claim regarding the role of plant sterols esters in reducing risk of heart disease.

Effectiveness has been shown with dosages of 2 to 3 grams plant stanols per day.

Viscous fiber

There are 3 categories of cholesterol-lowering foods. One of them is viscous fiber - the 'sticky' type of soluble fiber found in oats, barley and beans, and certain vegetables such as okra and eggplant. Viscous fibers help binding the cholesterol in your digestive tract and sweep it out of your body. In another word, soluble fiber act as a sponge, absorbing cholesterol and carrying it out of your system. People at less-developed countries (such as China) are less prone to having high blood cholesterol because their diet are high on viscous fiber.

According to the recent American Journal of Clinical Nutrition (Vol. 83, No. 3, 582-591, March 2006) report, eating 1.5 cups of cooked oatmeal a day typically produces cholesterol-lowering results. Including 10 grams of viscous fiber a day has been shown to decrease LDL cholesterol by about 5%.

How to do it ? Start the day with oatmeal or psylliu-enriched cereal (I always add a bit of sugar to it). Try bean and barley-based soups, marinated bean salad, hummus sandwiches, black bean burritos and roasted eggplant. Flax is good, too. Not only does it have soluble fiber, but it's high in omega-3 fatty acids and lignans-also good for cholesterol.

Participants received dietary advice for 6 months on either the low-saturated fat therapeutic diet (control) or a routine or intensive dietary portfolio, for which counseling was delivered at different frequencies. Routine dietary portfolio involved 2 clinic visits over 6 months and intensive dietary portfolio involved 7 clinic visits over 6 months.

In the modified intention-to-treat analysis of 345 participants, the overall attrition rate was not significantly different between treatments (18 percent for intensive dietary portfolio, 23 percent for routine dietary portfolio, and 26 percent for control).

The researchers found that the change in LDL-C levels from the beginning of the study to week 24 in the control diet were -3.0 percent or -8 mg/dL. In the routine and intensive dietary portfolio interventions, the respective percentage changes were -13.1 percent or -24 mg/dL and -13.8 percent or -26 mg/dL for LDL-C levels.

"Percentage LDL-C reductions for each dietary portfolio were significantly more than the control diet. The 2 dietary portfolio interventions did not differ significantly. Among participants randomized to one of the dietary portfolio interventions, percentage reduction in LDL-C on the dietary portfolio was associated with dietary adherence," the authors write.

"In conclusion, this study indicated the potential value of using recognized cholesterol-lowering foods in combination. We believe this approach has clinical application. A meaningful 13 percent LDL-C reduction can be obtained after only 2 clinic visits of approximately 60-and 40-minute sessions. The limited 3 percent LDL-C reduction observed in the conventional diet is likely to reflect the adequacy of the baseline diet and therefore suggests that larger absolute reductions in LDL-C may be observed when the dietary portfolio is prescribed to patients with diets more reflective of the general population," the authors write.

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