Are the best antioxidants identified to prevent age-related dementia?

New research shows that high levels of specific carotenoid antioxidants in the blood help prevent age-related dementia.

Researchers have found that people with high levels of lutein + zeaxanthin and beta-cryptoxanthin serum have decades of dementia decades later than their peers with low levels of these antioxidants.

Lutein and zeaxanthin are found in green leafy vegetables such as cabbage, spinach, broccoli and beans. Beta-cryptoxanthin is found in fruits such as oranges, papayas, mandarins and dates.

“Antioxidants can help protect the brain from oxidative stress, which can damage cells,” said the first author, May A. Baidon, PhD, MPH, in a press release from the National Institute on Aging (NIA).

“This is the first national representative study to analyze blood levels of antioxidants for the risk of mental disorders,” said Luigi Ferrucci, NIA’s scientific director. Medscape medical news.

“The results of a blood test may reflect current antioxidant levels, rather than a report on what foods a person eats regularly,” Ferrucci added.

The investigation was posted online today neurology.

Reduces the risk of dementia

The researchers tested the associations and interactions of vitamins A, C and E in serum, as well as general and individual serum carotenoids, and their interactions with Alzheimer’s disease (AD) and all-cause dementia.

The researchers analyzed data from 7,283 participants in the Third National Health and Nutrition Examination (NHANES III), who were initially at least 45 years old and had been observed for an average of 16–17 years.

They found that serum levels of lutein + zeaxanthin were associated with a reduced risk of dementia due to all causes in people aged 65 and older in lifestyle-adapted models.

An increase in each standard deviation (SD) for lutein + zeaxanthin (approximately 15.4 μmol / liter) is associated with a 7% decrease in the risk of dementia (risk factor). [HR] 0.93; 95% CI, 0.87 – 0.99, P = .037). This association has slowed down a bit since it was adapted to the socio-economic situation.

Serum levels of beta-cryptoxanthin showed a “strong” negative correlation with dementia caused by all causes in age- and sex-adjusted models.

For beta-cryptoxanthin, each increase in SD (approximately 8.6 μmol / liter) was associated with a 14% reduction in the risk of dementia in people aged 45 and older (HR, 0.86; 95% CI, 0.80–0.93). , P <.001) and 65 and older (HR, 0.86; 95% CI, 0.80 to 0.93, P = .001).

This link remained strong in models adapted to socio-demographic and socio-economic factors, but weakened in subsequent models.

No association for lycopene, alpha-carotene, beta-carotene or vitamins A, C or E was found in the fully adjusted models.

The researchers noted that the antagonistic interactions observed for vitamin A and alpha-carotene, vitamin A and beta-carotene, vitamin E and lycopene, lycopene and beta-carotene, suggest a lower level of predictive protective effects of one antioxidant than the other.

“This analysis of observational research has shown that the most important carotenoids that can potentially protect the brain are lutein + zeaxanthin and beta-cryptoxanthin. However, randomized controlled trials are needed to prove a causal link,” Ferrucci said.

“Experts do not yet know the daily level of antioxidant intake to promote healthy brain aging. More research is needed to determine the required level of antioxidant intake through diet and / or supplements to promote brain health and healthy aging.”

An important step forward

Babak Huoshmand, MD, PhD, MPH and Miia Kivipelto, MD, PhD, Karolinska Institutet, Stockholm, Sweden, said nutrition and dietary components are “potential targets” for reducing the risk of dementia, an “inconsistent conclusion” to date from observational studies.

The study “is an important step towards studying the complex relationship between antioxidants and dementia because it takes into account factors that may affect associations and considers interactions between different components.”

The findings add to the “difficulty” because they could lead to the hypothesis that blocking the oxidative damage of antioxidants may have a beneficial effect in preventing dementia.

However, clinical trials of antioxidant compounds have been largely “disappointing,” and a recent review by Cochrane found no evidence for the use of supplements to maintain cognitive function or prevent dementia, Hooshmand and Kiwipelto.

They add that the study promotes the belief that antioxidants do not act independently of each other or other factors, including socioeconomic status and lifestyle.

“Careful consideration of the evidence is required to understand how antioxidants affect the complex pathology of dementia because it is more visible than it is visible,” they conclude.

The study was supported in part by the Intramural Research Program of the National Institutes of Health and the National Institute on Aging. Beydun, Ferrucci and Hushmand will report in a related statement. Kiwipelto supported consulting advice for Combinostics, Roche and Biogen.

Neurology. Published online May 5, 2022. Annotation, Editorial

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