Most Americans who have heard of lutein have heard of it in connection with eyesight — macular health, the carotenoid in leafy greens, the thing in the eye vitamins at the pharmacy. The cognitive research is less widely known and more interesting than the eye angle suggests.
They Do Not Stop at the Retina
Lutein and zeaxanthin are dietary carotenoids the body cannot manufacture. They concentrate in the macula, which is the familiar part. They also accumulate in brain tissue, and measurements of retinal carotenoid density have been found to correlate with levels in the brain — which is what made them worth studying cognitively in the first place.
The Twelve-Month Trial
Published in Frontiers in Aging Neuroscience in 2017. Older adults took 12 mg daily of combined lutein and zeaxanthin for twelve months, against placebo. 51 participants were analyzable, with a mean age of 73.7 years.
- Complex attention improved significantly against placebo (p < 0.02)
- Cognitive flexibility also improved (p < 0.04)
Two features make this unusually relevant to anyone over sixty-five. It ran for a full year rather than a few weeks, and it was conducted in adults in their seventies rather than in undergraduates. Most cognitive supplement research can claim neither. Read the paper
Where Marigold Comes In
Marigold flowers are the standard commercial source of both carotenoids — which is why "Marigold Extract" appears on supplement labels where you might have expected to see lutein named directly. They are the same subject.
You Can Also Just Eat Them
Kale, spinach, collard greens and other dark leafy vegetables are the richest dietary sources. Egg yolks contribute a form that is well absorbed. Corn and orange peppers supply useful amounts. Both carotenoids are fat-soluble, which means a salad eaten with some olive oil delivers more than the same salad eaten dry.
Average American intake runs well below the 12 mg used in the trial above, which is the gap a supplement is intended to close. Food first remains the sensible default.
Reading This Honestly
One twelve-month trial in 51 people reporting improvement in two cognitive domains is a promising finding, not a settled one. What makes it worth including in a formula aimed at adults over fifty is that it was run in the right people for the right length of time — which is a lower bar than it ought to be, and one most ingredient research fails to clear.
See the Full Ingredient Guide → ← More Articles