Carotenoids in carrots, oranges and tomatoes protect against dementia
Red, orange and dark green vegetables and fruits contain substances that can protect the brain from aging processes and help prevent dementia. Epidemiologists at Harvard University conclude this from an epidemiological study in which fifty thousand women participated.

Carotenoids & the brain

In vitro studies suggest that carotenoids inhibit plaque formation in brain cells. [J Agric Food Chem. 2011 Dec 14;59(23):12691-6.] Those plaques accumulate when you age, and can kill brain cells. Neurologists find them in large amounts in the brains of people with Alzheimer's and other types of dementia.Carotenoids are found in red, orange, yellow and dark green vegetables. They have an antioxidant effect and activate mechanisms in cells that normally become active during periods of fasting and physical activity.
The researchers followed a group of 49693 women from 1984 to 2012. In 1984, the average age of the women was 48.

Between 1984 and 2006, the researchers measured how many carotenoids the women received through regular foods. In 2012, they surveyed the women using a questionnaire that gerontologists use to try to determine whether the elderly may be suffering from dementia.

The more carotenoids the women had consumed daily between 1984 and 2006, the less likely they were to score low in 2012. The figure below is not complete. Click on it for a full version.

Thus, carotenoids such as beta-carotene, lutein, zeaxanthin, beta-cryptoxanthin and lycopene were shown to protect against detrimental cognitive aging processes.Beta carotene is present in carrots, lutein in leafy vegetables such as spinach, while beta cryptoxanthin and lycopene are present in relatively high concentrations in oranges and tomatoes, respectively.
"This prospective study supports a potential beneficial role of long-term intake of multiple carotenoids in maintaining late-life cognitive function in women", the researchers summarize. "Our findings most strongly support benefits of lycopene, beta-cryptoxanthin, and lutein + zeaxanthin. However, beneficial roles for other individual carotenoids could not be excluded owing to strongly intercorrelated intakes."

"Because increasing intakes of carotenoids is a promising and relatively simple means of maintaining brain health, further research is warranted to establish the optimal combination and intakes of carotenoids for the prevention of cognitive decline in populations worldwide."
J Nutr 2020;150:1871-9.