Antioxidants intake may improve brain health and reduce risk of dementia

USA: The levels of blood lutein + zeaxanthin and β-cryptoxanthin, two types of carotenoids, are inversely related to incident all-cause dementia, states a study published in the journal of Neurology.

Alzheimer's disease (AD) and subtypes of dementia, is a major factors in older people's impairment and long-term institutionalization. Consuming antioxidants in the diet, such as β-carotene and vitamins A, C, and E may help prevent oxidative DNA damage by lowering reactive oxygen species, according to epidemiologic research.

"The first study to examine dementia risk in this way on a national scale was this one. An individual's description of the kind of foods they often eat may not be a good indicator of the actual antioxidant content. The results of food comparison studies for the onset of dementia have been inconsistent, and this basic fact may help to explain why", the researchers said.

They studied the relationships between these nutritional biomarkers and incident dementia from all causes and that caused by Alzheimer's disease (AD) in middle-aged and older US individuals.

For this objective, the authors identified incident dementia cases for up to 26 years using data from 7,283 participants in the third National Health and Nutrition Examination Survey (NHANES 1988-1994), combining that data with Centers for Medicare & Medicaid Services records. Participants ages ranged from 45 to 90 at baseline, and the average follow-up was 16 to 17 years. Participants underwent a medical examination, a blood test, and an interview, and they were dementia-free at baseline.

Findings included:

• In models that were adjusted for lifestyle (per SD, HR 0.93) and socioeconomic level (HR 0.92), serum lutein+zeaxanthin was linked to a lower risk of dementia from all causes in adults 65 and older.
• In age- and gender-adjusted models of individuals 45 and older (per SD, HR 0.86) and 65 and older (HR 0.86), serum beta-cryptoxanthin demonstrated an inverse connection with all-cause dementia. This link was also observed in a model with socioeconomic status adjustment (HR 0.89), but it was weaker in later models.
• In fully adjusted models, no relationships were discovered for lycopene, alpha-carotene, beta-carotene, or vitamins A, C, or E. Inhibitory interactions between vitamin A and beta-carotene, alpha-carotene and vitamin A, vitamin E and lycopene, and lycopene and beta-carotene were observed, indicating that one antioxidant may be beneficial at reduced levels of the other.

"With or without antioxidant supplementation, a balanced diet high in carotenoids and antioxidants from dark leafy greens and orange-pigmented fruits may lower the incidence of dementia", added the authors.

The researchers concluded that the two carotenoids lutein+zeaxanthin and beta-cryptoxanthin may be the most significant for potentially safeguarding the brain. To determine the precise amount of antioxidants required to support good aging and brain health, more research is required, they wrote.

REFERENCE

Beydoun MA, et al "Association of serum antioxidant vitamins and carotenoids with incident Alzheimer disease and all-cause dementia among U.S. adults" Neurology 2022; DOI: 10.1212/WNL.0000000000200289.