In a study of healthy, middle-aged adults, consumption of one apple a day for four weeks lowered blood levels of a substance linked to hardening of the arteries by 40 percent.
Taking capsules containing polyphenols, a type of antioxidant found in apples, had a similar, but not as large, effect.
The study, funded by an apple industry group, found that the apples lowered blood levels of oxidized LDL - low-density lipoprotein, the "bad" cholesterol. When LDL cholesterol interacts with free radicals to become oxidized, the cholesterol is more likely to promote inflammation and cause tissue damage.
The difference was similar to that found between people with normal coronary arteries versus those with coronary artery disease.
The study is published online in the Journal of Functional Foods and will appear in a future print edition.
The researchers described daily apple consumption as significantly more effective at lowering oxidized LDL than other antioxidants studied, including the spice-based compound curcumin, green tea and tomato extract.
For the study, the researchers recruited nonsmoking healthy adults between the ages of 40 and 60 who had a history of eating apples less than twice a month and who didn't take supplements
containing polyphenols or other plant-based concentrates.
In all, 16 participants ate a large Red or Golden Delicious apple daily for four weeks; 17 took capsules containing 194 milligrams of polyphenols a day for four weeks; and 18 took a placebo containing no polyphenols. The researchers found no effect on oxidized LDLs in those taking the placebo.
The study also found eating apples had some effects on antioxidants in saliva, which has implications for dental health. The researchers hope to follow up on that finding in a future study.
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