Moderate-Fat Diet May Be Better at Reducing Heart Risks
MONDAY Nov. 16, 2009 -- A moderate-fat diet may work better than a low-fat regimen for people suffering from metabolic syndrome, a collection of conditions putting them at higher risk for cardiovascular disease, new research finds.
"This is a good study that essentially confirms that the current recommendations are appropriate," said Alice Lichtenstein, a spokeswoman for the American Heart Association (AHA). "Since 2000, the AHA has been recommending not a low-fat diet, but one that is low in saturated fats and trans fatty acids."
People with metabolic syndrome are glucose-intolerant, meaning they can't process blood sugar well. Low-fat, high-carbohydrate diets exacerbate this condition, Lichtenstein explained.
To be diagnosed with metabolic syndrome, you must have three or more of the following risk factors for heart disease: belly fat, high triglycerides, low good cholesterol, high blood sugar and high blood pressure.
The study was among several to be presented Monday at the AHA's annual meeting in Orlando, Fla. Researchers from the University of Washington in Seattle randomized 71 men and women with metabolic syndrome into one of two diet arms, the first made up of 40 percent fat, 45 percent carbohydrate and 15 percent protein (the moderate-fat diet) and the other, the low-fat diet, containing 20 percent fat, 65 percent carbs and 15 percent protein. Saturated fat content was about 8 percent in each, and each had about the same amount of fiber.
Levels of LDL (or "bad") cholesterol fell 3.4 milligrams per deciliter (mg/dL) on the low-fat diet compared with 11.6 mg/dL on the moderate-fat plan. HDL (or "good") cholesterol also fell, by 4.9 mg/dL on the low-fat plan and by 1.9 mg/dL on the other.
C-reactive protein (CRP), a marker of inflammation linked to heart disease, fell more in the low-fat group than in the moderate-fat group (0.82 mg/L versus 0.63 mg/L), but the authors considered it a good drop in both cases.
While triglycerides, another measure of heart health, increased 11.1 mg/dL on the low-fat diet, they dropped 28.6 mg/dL on the other plan.
Experts familiar with the study aren't surprised by the findings. "This sort of falls within the boundaries of what we used to call the Atkins diet, which was a high-lipid and low-carb diet. Normally this kind of diet suppresses appetite, improves diabetes," said Dr. Alfred Bove, president of the American College of Cardiology. "This diet looks like it does a good job of altering the negative metabolic effects of early diabetes or high carbohydrate stimulation," he said.
"Much of this we've known before, but the idea is that a moderate-fat diet is something most people can tolerate," Bove said. "It probably affects the way insulin is released because if you have a lot of carbohydrates in the diet, you tend to generate a lot of insulin, and insulin is the hormone that lowers blood sugar," Bove explained. "In addition to lowering blood sugar, it also increases appetite so a lot of people on high-carb diets are restimulated to eat more."
Another study found yet more evidence to recommend the famed DASH (Dietary Approaches to Stop Hypertension) diet, an eating plan that has been found to lower blood pressure. DASH calls for a diet high in fruits and veggies and low in total fat, saturated fat and cholesterol. Red meat and sweets are limited as well.
This study showed that the diet lowered coronary heart disease risk for a decade by 18 percent compared with people eating as usual and 11 percent compared with people in a fruit- and vegetable-rich program.
"We took our data and plugged it into the Framingham risk equation used to estimate heart disease risk and found a 20 percent reduction in risk of heart disease," said study senior author Dr. Lawrence Appel, professor of medicine at Johns Hopkins Medical Institutions in Baltimore. "We don't have a 40,000-person randomized trial but, next to that, this is probably one of the best analyses to show that the DASH diet should reduce heart disease as well as blood pressure."
Although the DASH diet is recommended to reduce blood pressure, there had been some "quirks" in previous data leading people to question the program's net effect, Appel said.
A third study confirmed that even small helpings of fruits and veggies can boost your health.
In a Columbia University Medical Center study of 501 patients, just one extra serving of fruits or vegetables was linked with lower levels of both CRP and cholesterol. And adding another gram per day of omega-3 fatty acids, found in fish as well as plant-based oils, also was associated with a drop in CRP levels.
Lowering intake of saturated and trans fats meant reductions in both total and LDL cholesterol, the researchers, led by Dr. Lori Mosca, found.
And more calories from alcohol seemed to move HDL cholesterol levels down, although other measures did not change.
The American Dietetic Association has more on healthy eating.
Posted: November 2009