Lutein has recently gained a place of honor as one of the nutrients highly-respected researcher Bruce Ames, PhD deems a ”longevity vitamin” supporting the functions of longevity proteins that regulate cellular aging processes, and could therefore reduce risk for premature aging. Foods containing relatively high levels of this fat-soluble carotenoid antioxidant include paprika, spinach, dandelion greens, cayenne peppers, turnip tops, watercress, swiss chard, collards, mustard greens, chicory leaf, radicchio, kale, rhubarb, bilberries, plums, blackcurrants, avocadoes, pears, rosehips, kiwi fruit, gooseberries, grapes, apples, raspberries, strawberries, watermelon, oranges, peaches, redcurrants, cranberries, tangerines, egg yolks, and fish skin. Lutein is best absorbed in the presence of dietary fats and appears to compete with other carotenoids for absorption, so those concerned about maintaining adequate body levels may also wish to take a supplemental form (again, with some fat) in addition to eating plenty of the above sources.
Where lutein really shines is in the health and function of eyes (especially the retina and macula, so central to long-term vision), particularly considering the popularity of electronic devices that emit phototoxic blue-white light, for which lutein and zeaxanthin are effective filters. Healthy people given lutein and zeaxanthin and exposed to photo-optic stress showed better visual recovery and greater density of protective macular pigment compared to those receiving placebo. (In fact, exposing growing greens to blue light is a great way to trigger them to produce higher levels of protective pigments like lutein, zeaxanthin, carotenes, and chlorophyll!) Lutein and zeaxanthin are the only carotenoids that concentrate in the macula, and thus are indispensable against potential accumulation of macular damage during aging. Because lutein and zeaxanthin are functionally as well as chemically related, many studies are carried out using both of these xanthophyll-type carotenoids.
As in the retina, lutein and zeaxanthin are principal carotenoids in brains both young and elderly—perhaps not surprising, since eyes are one of the brain’s sensory extensions. Lutein comprises around 59% of total brain carotenoids in infants yet only 31% of those in adults, and brain levels decline significantly during the progression from normal function to mild cognitive impairment, suggesting that it might play a role in neurocognitive development and/or aging. Serum lutein levels were found to relate to better cognitive function in the general population as well as people in their 80s and 100s, and lutein supplementation significantly improved verbal fluency scores (one measure of cognition) in older women. Intelligence could be considered a specialized part of brain function, and higher serum lutein levels further relate to higher measures of intelligence as well as greater volume in the temporal region of the brain (associated with linguistic ability) close to the hippocampus (associated with memory, mood, and the stress response) in cognitively normal adults aged 65-75. Recent research has also explored lutein’s brain metabolome (study of lutein metabolites in brain function), and has discovered that lutein plays roles in the metabolism of brain lipids and neurotransmitters as well as maintaining cerebral energy and osmotic homeostasis—quite an array of activities there!
Lutein may also contribute to healthy cardiovascular function. In a study of healthy Chinese subjects, lutein supplementation increased the blood’s total antioxidant capacity while reducing levels of C-reactive protein, an early marker of inflammation, and in Chinese people not yet diagnosed with any heart disease, lutein supplementation reduced the thickness of areas of the coronary artery showing very early signs of potential atherosclerosis. In cells taken from patients with coronary disease, lutein lowered direct production as well as genetic expression of chemical messengers centrally associated with an inflammatory response, including interleukin-6 (IL-6), IL-1β, and tumor necrosis factor-α. IL-6 is an increasingly important predictive marker in cardiovascular disease, and among several carotenoids in this study, only higher levels of lutein and zeaxanthin correlated to lower levels of this cytokine in these patients.