Is macular pigment a biomarker for dementia?

Ophthamic-homepage-header-1It is well established that reduced macular pigment optical density is a sign that AMD is developing, but can it also show a change in mental cognition? Recent studies are showing that macular pigment is related to poor cognition, which shows potential for macular pigment as a non-invasive biomarker.

Several studies have been conducted, and continue to be, in to the link between the macular and incidences of Alzheimer’s disease. A recently published French study shows promise for detecting a decline in cognitive function via macular pigment, which we’ve explored below. It is still early days though, conversley, a study in 2013 dismissed the link between AMD and dementia or Alzheimer’s for example.

Are plasma carotenoids and lutein inversely associated with dementia risk?

A the recent French study observed at 1092 older participants without dementia over a 10 year period. Of these people 199 dementia cases were recorded and 132 had Alzheimer’s disease. After removing socioeconomic variables, only higher lutein concentration was associated with a decreased risk of dementia. This study suggests that maintaining a high concentration of lutein, in respect to plasma lipids, moderately decreased risk of dementia and Alzheimer’s disease.

It is recommended that intake of lutein, through diet or supplementation, is increased to protect against AMD or slow progression, but studies like this are also associating it with brain health.

Poor vision and Alzheimer’s

Another study by the Waterford Institute of Technology, observed a significant association between macular pigment levels and cognitive performance in those with low macular pigment or early AMD. The research found that patients with Alzheimer’s had lower cognition but also “considerably poorer” vision compared to the same people of their age without Alzheimer’s. The study also found these people had a significant lack of lutein, zeaxanthin and meso-zeaxanthin.

They used supplementation rich in carotenoids which did see patients experience improved vision as their macular pigment increased.

These studies show a link that is promising for detecting dementia, and this may become something that people are screened for during their eye examinations. Studies of paediatric brains show that 60% of the brain tissue is lutein, but lutein is only found in 12% of the carotenoids in our diet. This shows a need to increase lutein levels throughout our lives to protect macular pigment and potentially cognition.

The link to macular pigment offers potential as a non-invasive clinical biomarker for cognitive health, making it a more effective approach than measuring serum concentrations of lutein and zeaxanthin.

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