番茄社区

Sedentary individuals at risk for cardiovascular disease appeared to benefit from adding pecans to their regular diet, reducing bad cholesterol and triglycerides when compared with study participants who did not have pecans during an 8-week period, researchers reported.

Study participants on the pecan diet had an average decrease in fasting total cholesterol of about 10 mg/dL compared with a 5.5 mg/dL increase among individuals in the non-pecan group (P<0.05), reported Liana Guarneiri, a PhD candidate at the University of Georgia in Athens.

"Daily pecan consumption improves fasting and postprandial blood lipids in adults that are at-risk for cardiovascular disease," Guarneiri said in a presentation at the ObesityWeek virtual meeting.

She noted that previous studies have shown that eating pecans had a positive effect on blood lipids among people who were healthy; her team's current study aimed to determine if pecan consumption would also help people at risk of cardiovascular disease by reducing blood lipid levels.

The researchers recruited 52 individuals for the randomized, parallel, controlled trial. They ranged in age from 30 to 75 and were assigned to three groups:

• One group of 16 people added pecans to their regular diet

• A second group of 18 substituted pecans for isocaloric foods -- i.e., of equal calories -- from their regular diet

• A third group of 18 were assigned to a nut-free diet

At baseline and at the conclusion of the trial at 8 weeks, a high-fat breakfast shake was consumed with postprandial blood draws over 4 hours to determine changes in blood lipids.

Guarneiri reported the following in addition to the favorable changes in total cholesterol for the participants who were eating pecans:

• Low-density lipoprotein cholesterol decreased 14 mg/dL in the group that just added pecans to their diet and decreased 9 mg/dL in the group that substituted pecans, but increased 6 mg/dL in the non-pecan-eating group (P<0.01)

• Triglycerides decreased 14 mg/dL in the group that just added pecans to their diet and decreased 13 mg/dL in the group that substituted pecans, but increased 27 mg/dL in the non-pecan-consuming group (P<0.001)

• Non-high density lipoprotein cholesterol decreased 11 mg/dL in the groups that added or substituted pecans to their diet, but increased 7 mg/dL in the non-pecan-consuming group (P<0.01)

• Non-esterified fatty acids (or free fatty acids) decreased from pre- to post-intervention by 11 mEq/L in the group that added pecans to their diet compared with a 0.06 mEq/L increase among the nut-free control group (P<0.05); however, the difference between the group that substituted pecans for other foods did not achieve a reduction that was statistically different from the reduction observed among the nut-free participants

Asked for her perspective, Sharon Zarabi, RD, CDN, of Lenox Hill Hospital/Northwell Health Katz Institute for Women's Health in New York City, said the research should not be a green light to start popping pecans all day long.

"It is always a challenge correlating results of a dietary study to isolated ingredients such as pecans as demonstrated in this study since we don't eat in silos," she told 番茄社区.

"This study, like most that measure food intake, fails to account for the other nutrients consumed throughout the day," noted Zarabi, who was not involved with the study. "How do we know the lipid levels were not influenced by other fat sources that are high in omega 3 fatty acids, or fiber that is known to improve the risk of cardiovascular disease?

"In science we must always ask, is it causation or association," Zarabi said. "Although I do believe pecans and most nuts are chock-full of healthy fats we need for brain development and protect against heart disease, it is not the green light to be popping nuts all day. Most finger foods are addictive, and if salted, enhance flavor, so portion control becomes an issue. Too much of any healthy food still contains calories and fat, so we need to limit nuts to appropriate serving size and replace any saturated fat sources with unsaturated ones, such as pecans or other nuts."

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