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Lutein, derived from marigolds, is important for brain health as well as eye health. [Photo: Bigstock]

Lutein protects the brain as well as the eyes

You may know it as the nutrient that keeps your eyes healthy, but scientists are increasingly finding that lutein brings brain benefits as well.

Lutein is a member of the carotenoid family (like beta carotene). It is one of several plant pigments that humans acquire through the diet, primarily by eating leafy green vegetables, cruciferous vegetables such as broccoli, or egg yolks.

Decades of research show that it can help delay or prevent age related macular degeneration and this is why most people supplement with it.

The brain needs lutein

But new data from studies of primates, children, middle-aged people, and the elderly shows that the brain also needs lutein.

Data examining paediatric brain tissue suggest that 60% of the total carotenoids in the paediatric brain is lutein, even though lutein is only about 12% of the carotenoids in the average infant’s diet. This accumulation suggests that the brain has a preference for lutein.

There is scientific evidence to indicate that the density of the macular pigment may act as a biomarker of lutein in the brain. This has been seen even in those with Alzheimer’s and has helped researchers draw stronger links between eye health and brain health.

For instance, in a 2014 study older adults with higher levels of lutein and zeaxanthin (as measured through macular pigment density), had significantly better global cognition, verbal learning and fluency, recall, processing speed and perceptual speed than those with lower levels.

In a recent study, published in Frontiers in Aging Neuroscience, scientists from the University of Illinois found that consumption of lutein was linked to what the researchers called preservation of “crystallized intelligence” – essentially the ability to use the skills and knowledge one has acquired over a lifetime.

The researchers also reported that those with higher serum lutein levels also tended to have thicker grey matter in the parahippocampal cortex, a brain region that, like crystallized intelligence, is preserved in healthy aging.

A unique role

Most studies suggest that it is just lutein, not relatives like beta-carotene or lycopene, that are neuroprotective.

There is some evidence that the lutein/zeaxanthin combination may aid the brain by naming its processes more efficient. In a study of older adults those individuals with higher levels of both nutrients didn’t require as much brain activity to complete a cognitive task, while those with lower levels of these carotenoids required higher levels of brain activity to get it done.

In the main, however, it is higher levels of lutein that seem to be especially neuroprotective.

This is very new research so we can only speculate on lutein in the diet affects brain structure and function. It may be the antioxidant capacity of lutein that offers some neuroprotection. It is also possible, for instance, that that it plays an anti-inflammatory role or aids in cell-to-cell signalling – or something else which we don’t yet understand.

Most of us don’t get enough lutein from our diets – the average intake is just 1.6mg per day. There is no RDA for carotenoids such as lutein, zeaxanthin and beta-carotene, but eating five servings of fruits and vegetables each day, as currently recommended by the National Cancer and other health agencies, can provide 5-6mg of carotenoids, including lutein and zeaxanthin. A daily intake of 6mg of lutein and zeaxanthin is the level at which researchers report observable health benefits.