Dietary antioxidants may be less protective with Parkinson’s: Study
Nutrients to prevent frailty in older adults appear less effective for patients
A diet rich in antioxidants — such as vitamins A, C, E, and selenium and zinc — may help most older adults counter becoming frail, but its benefits are less certain for people with Parkinson’s disease, a study drawing on U.S. data suggests.
Findings indicate that the disease’s complex nature “may modulate the impact of dietary antioxidants on frailty … [and] underscore the need for a nuanced, disease-specific approach to understanding the role of dietary antioxidants … particularly in the context of neurodegenerative conditions like [Parkinson’s disease],” the researchers wrote.
The study, “Examining the relationship between CDAI and frailty and its manifestation in Parkinson’s disease: a cross-sectional study,” was published in Frontiers in Nutrition by a team of researchers in China.
Antioxidants, plentiful in vegetables and fruits, help protect cells from damage
Antioxidants, including vitamins A, C, and E and the minerals selenium and zinc, are plentiful in vegetables and fruits and are reported to help protect cells from damage. As a result, they’re widely touted as a way of slowing the aging process and lowering its associated risks, like frailty and dementia.
While adhering to a healthy diet rich in whole grains, fruits, vegetables, and nuts appears to reduce the risk of Parkinson’s, it’s less clear how getting more antioxidants from foods can keep patients from becoming frail or more vulnerable to health stressors with aging. Frailty is common among people with Parkinson’s and considered a risk factor for the disease.
Researchers drew on data covering 21,354 adults, with a mean age of 57.8, who took part in the National Health and Nutrition Examination Survey, a long-term U.S. study of health and nutritional status. Researchers also included 268 adults with Parkinson’s, with a mean age of 61. No study participant was younger than age 40.
Among general population adults, 15,382 did not have frailty while 5,972 were considered frail based on an index that considers symptoms, functional limitations like handgrip strength, and coexisting conditions or comorbidities. Those in the frailty group were older on average (61.5 vs. 56.7 years) and more likely to be female (60.3% vs. 51.2%). They also were more likely to smoke (60.2% vs. 45.3%).
Compared with frail individuals, the other adults a had higher dietary intake of certain nutrients, including vitamins A, C, and E, as well as zinc, selenium, and carotenoids — the pigments that confer many fruits and vegetables their yellow, orange, or red color.
Frailty was more common among Parkinson’s patients than for the general population (61.6% vs. 28%). Of the 268 patients, 165 found to be frail. These people also were significantly more likely to smoke (57.2% vs. 37.9%) and to have comorbidities, such as high blood pressure and diabetes. Their diet also included less of vitamin E relative to patients without frailty.
Dietary antioxidants tied to lower frailty risk for general US population
In the general population, higher composite dietary antioxidant index (CDAI) scores, which reflect higher intakes of six antioxidants — vitamins A, C and E, zinc, selenium, and carotenoids — were linked to a lower risk of becoming frail.
“This large nationally representative study provides novel evidence linking higher dietary antioxidant intake to lower frailty risk in the general US population aged 40 and older,” the scientists wrote. “All studied antioxidants (vitamins A, C, E, zinc, selenium, and carotenoids) showed protective effects against frailty.”
Each unit increase in CDAI reduced the likelihood of frailty by 3.7%. Higher intake of vitamin C was associated with a lower risk up to 161.53 milligrams (mg), after which the risk increased again. For selenium, that threshold was 109.99 micrograms.
For people with Parkinson’s, however, the benefits of antioxidants were less clear. Only vitamin C (threshold, 52.45  mg) and zinc (9.35  mg) showed significant effects on reducing frailty.
“These findings highlight population-specific differences in the role of dietary antioxidants in frailty and suggest the need for personalized nutritional strategies in [Parkinson’s] frailty management,” the researchers concluded.
Among the study’s limitations, the researchers noted that dietary intake was assessed using 24-hour recalls, “which may not capture long-term or usual intake patterns.” Follow-up data to analyze how frailty changes over time also were lacking.
About the Author
