In the news:Lutein/Zeaxanthin May Bolster Memory in Older People with Cognitive Problems

Lutein & Zeaxanthin: Role in the Brain

Though there are hundreds of dietary carotenoids, the pigments found in red, yellow, orange, and dark green fruits and vegies, about six of them account for almost all the carotenoids found in our blood and brain tissue. Of these, lutein and zeaxanthin make up 66 - 77% of the total carotenoids present in the brain.

Here, lutein and zeaxanthin are thought to help protect brain tissue – particularly the brain’s fat content – due to their antioxidant and anti-inflammatory properties.

Studies exploring dietary intake of these carotenoids and cognitive health have generally shown a positive relationship. A higher intake of lutein and/or zeaxanthin, for example, has been tied to a lower risk of experiencing moderate-to-poor cognitive function.

Lutein, Zeaxanthin May Support Visual Memory & Learning

These findings led Australian university researchers to further examine the effects of lutein and zeaxanthin in older individuals with cognitive complaints living in the community.

In the newly published study(1), ninety volunteers aged 40–75 years received either 10 mg of lutein and 2 mg of zeaxanthin daily or a placebo for six months.

The participants were given a battery of computer-based cognitive tasks and questionnaires at the start and end of the study, and always at the same time of day, after eating the same breakfast, and without having consumed any caffeinated drink like coffee.

Compared to the placebo group, lutein and zeaxanthin supplementation was associated with greater improvements in tests measuring visual episodic memory and visual learning at the end of the 6-month period. No other significant differences in the performance on the other cognitive tests or questionnaires was seen.

The findings may be important because visual memory, especially, has been linked to cognitive decline in previous studies. In a 2-year study, for example, better visual memory was associated with a lower risk of cognitive deterioration up to 2 years later. In another investigation, poorer visual memory performance was linked to an increased risk of Alzheimer's disease up to 15 years later.

Visual episodic memory is the memory of everyday events. It’s the ability to recall things such as times, location geography, and associated emotions. In other words, it’s the collection of someone’s past personal experiences that happened at certain times and places.

According to the study authors, “further trials will be essential to clarify the potential benefits of lutein and zeaxanthin supplementation in diverse populations” over time.

While we await the results of future investigations into the cognitive effects of these carotenoids, there are plenty of reasons to consume lutein/zeaxanthin-rich diets.

First and foremost, lutein and zeaxanthin accumulate in the macula of the eye where they are thought to reduce oxidative stress and support eye health. Specifically, they buffer the damaging effects of blue light and protect underlying retinal cells. These carotenoids may also play a role in protecting against the effects of UV exposure on the skin.

As fat soluble nutrients, lutein and zeaxanthin are better absorbed when eaten with a meal containing some oil or fats. Plant sources of lutein such as raw spinach are moderately bioavailable, though cooking improves lutein absorption. Eggs are a very bioavailable source of both lutein and zeaxanthin, and corn is relatively high in zeaxanthin.

References

1. Lopresti AL, et al. The effects of lutein and zeaxanthin supplementation on cognitive function in adults with self-reported mild cognitive complaints: A randomized, double-blind, placebo-controlled study. Front. Nutr. Epub February 17, 2022.