Higher Antioxidant Levels Linked to Lower Dementia Risk, Study Results Show

Individuals with higher levels of antioxidants in their blood may be less likely to develop dementia, according to the results of a study published online in Neurology, the medical journal of the American Academy of Neurology.¹

The results of the study showed that individuals with the highest level of the antioxidants lutein and zeaxanthin as well as beta-cryptoxanthin in their blood were less likely to develop dementia decades later than individuals with lower levels of antioxidants.¹

The 2 antioxidants, lutein and zeaxanthin, are found in green, leafy vegetables, including broccoli, kale, peas, and spinach, while beta-cryptoxanthin is found in fruits, including oranges, papaya, persimmons, and tangerines.¹

“Extending people’s cognitive functioning is an important public health challenge,” May Beydoun, PhD, MPH, of the National Institutes of Health's National Institute on Aging in Baltimore, Maryland, said in a statement.¹

“Antioxidants may help protect the brain from oxidative stress, which can cause cell damage. Further studies are needed to test whether adding these antioxidants can help protect the brain from dementia,” Beydoun said.¹

The 7283 participants were at least aged 45 years at the beginning of the study. The individuals had a physical exam, interview, and blood tests for antioxidant levels at the beginning of the study.¹

The study participants were followed for an average of 16 years to see if dementia developed.¹

The individuals were divided into 3 groups based on the levels of antioxidants in the blood. Investigators found that individuals with the highest amounts of lutein and zeaxanthin were less likely to develop dementia than those with lower levels.¹

Every standard deviation increased in lutein and zeaxanthin levels, approximately 15.4 micromols/liter, was associated with a 7% decrease in the risk of dementia. Additionally, for beta-cryptoxanthin, every standard deviation increase in levels, approximately 8.6 micromols/liter, was associated with a 14% reduced risk of dementia.¹

“It’s important to note that the effect of these antioxidants on the risk of dementia was reduced somewhat when we took into account other factors, such as education, income, and physical activity, so it’s possible that those factors may help explain the relationship between antioxidant levels and dementia,” Beydoun said.¹

One limitation of the study is that antioxidant levels were based on 1 measurement of blood levels and may not reflect the individuals’ levels over their whole lifetimes, investigators said.¹

The National Institute on Aging, which is part of the National Institutes of Health, supported the study.¹

The American Academy of Neurology is the largest association of neurologists and neuroscience professionals, with more than 38,000 members in the association, according to the statement.¹

There were an estimated 5 million adults over aged 65 years with dementia in 2014, and that is expected to rise to about 14 million individuals by 2026, according to the CDC.²

Signs and symptoms of dementia include issues with attention, communication, and memory.²

References

1. Higher antioxidant levels linked to lower dementia risk. EurekAlert. News release. May 4, 2022. Accessed May 5, 2022. https://www.eurekalert.org/news-releases/951218

2. Alzheimer's disease and healthy aging. CDC. Updated April 5, 2019. Accessed May 5, 2022. https://www.cdc.gov/aging/dementia/index.html