by Lewis Chang, PhD
It has been suggested that oxidative stress contributes to the pathogenesis of Parkinson’s disease (PD), an age-related neurodegenerative disorder of the central nervous system affecting movement. As antioxidants may offset oxidative stress and damage to neurons, scientists have been interested in whether antioxidant consumption would reduce the risk of PD.
Researchers from Karolinska Institutet (Stockholm, Sweden) and University of Southern California (Los Angeles, CA) set out to investigate the association between antioxidant intake and PD risk later in life in two groups of individuals: the Swedish Mammography Cohort which included 38,937 women born between 1914 and 1948 and the Cohort of Swedish Men which included 45,837 men born between 1918 and 1952.
The study began in 1997 when researchers assessed the habitual intake of dietary antioxidants of these individuals using a food frequency questionnaire tailored to the Swedish diet. Information from the questionnaire was used to calculate intake of β-carotene, vitamin C, and vitamin E, as well as total antioxidant capacity (TAC). All participants were followed from 1997 until date of PD diagnosis, death, or end of study follow-up in 2014. The average follow-up period was 14.9 years.
The investigators found that an increase in dietary intake of β-carotene was associated with a lower risk of PD in both women and men. Dietary intake of vitamin E was inversely associated with PD risk in women (borderline significant) but not in men. TAC was not associated with PD risk.1
At first glance, dietary antioxidants appear to be more protective for women. However, women in general have a lower risk of PD than men, and estrogen hormones have been suggested to protect against PD. As for why individual antioxidants but not TAC were associated with PD risk, it may be due to the limited precision of the TAC surrogate measure in reflecting the true antioxidant capacity.
These study results suggest a potential role for dietary β-carotene and vitamin E in PD risk reduction. However, the dietary assessment was only conducted at one time point and thus may not reflect long-term dietary antioxidant intake in these individuals. Additional studies with serial measurements are needed to confirm the observed association.
Why is this Clinically Relevant?
- β-carotene and vitamin E from dietary sources may potentially be protective against the development of PD
- Good sources of β-carotene include yellow, orange, red and green leafy vegetables and fruits
- Good sources of vitamin E include nuts, seeds, vegetable oils, and green leafy vegetables
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References
1. Yang F, Wolk A, Hakansson N, Pederson NL, Wirdefeldt K. Dietary antioxidants and risk of Parkinson’s disease in two population-based cohorts. Mov Disord. 2017;32(11): 1631-1636.
