Two quite extraordinary antioxidants, most well known for their enhancement and protection of vision as we age, have been turning up other benefits in recent scientific research.
One group of researchers explored the theory that lutein and zeaxanthin are important for hearing, measuring an interesting correlation between auditory function and the amount of lutein and zeaxanthin accumulated in the retina. Various studies have also linked higher levels of lutein and zeaxanthin to healthy cognitive function in both young and older adults.
Naturally occurring antioxidants
Both zeaxanthin and lutein are xanthophylls (a type of carotenoid) essential for our vision and obtained through vegetables such as leafy greens, carrots and capsicums. These two xanthophylls are potent antioxidants that give the yellow, orange or red colour to a number of vegetables and spices, and even egg yolks.
Other foods containing zeaxanthin and lutein are basil and parsley, squash, celery, tomatoes (lutein), zucchini, sweet corn and spirulina (zeaxanthin). The activity of xanthophylls in plants is to modulate photosynthesis and the energy received from the sun. All carotenoids have antioxidant properties, and lutein and zeaxanthin are particularly important for the health and proper function of the eyes.
Proven benefits for eyesight
Lutein and zeaxanthin are yellow pigments that, when consumed through the diet, migrate to a specific part of the eye – the macula – which is a yellow spot in the retina at the back of the eye. This is where lutein and zeaxanthin are found in the highest concentrations in the body. The macula is what allows us that clear, high-colour vision in the centre of our line of sight, and helps protect the eyes from too much light and some of the sun’s damaging rays.
Numerous scientific studies over the past couple of decades have demonstrated the positive effects of lutein and zeaxanthin on eye health in the elderly, and in the prevention of age-related macular degeneration. The latest studies continue to confirm this and show that supplementation can be an effective way to increase your consumption of these two antioxidants.
A Turkish study published in 2017 found that lutein and zeaxanthin together modulate lipid metabolism and reduce inflammation of the retina caused by high fat diets, by increasing antioxidant enzyme activity in the retina.
A long-term study of older women in the US, also published in 2017, measured the change in levels of macular pigment following daily supplementation of lutein and zeaxanthin over a period of 14 years. Factors such as diet, lifestyle, and metabolic health were taken into account and controlled for how they may also affect macular pigment optical density (MPOD), and how they may interact with lutein and zeaxanthin supplementation. The results of the study suggest that supplementation is an effective way to increase the presence of macular pigments.
Both lutein and zeaxanthin, in combination and separately, have been shown in recent research to have positive benefits in other areas of health, including hearing and brain function.
Perhaps most interesting is the effect of these two compounds on cognitive function in both young and elderly adults. Not only do they appear to slow down age-related cognitive decline in older adults, but zeaxanthin and lutein in combination have also been shown to improve cognitive function (spatial memory, reasoning and attention) in young, healthy adults aged 18-30.
The Irish Longitudinal Study on Ageing has revealed that “higher plasma lutein and zeaxanthin were independently associated with…global cognition, memory, and executive function” in adults aged 50 and over, with the results warranting further study. Another finding was that higher levels of zeaxanthin, but not lutein, were “associated with better processing speed”.
Researchers have concluded that zeaxanthin and lutein “promote cognitive functioning in old age by enhancing neural efficiency” in a study published in the Journal of the International Neuropsychological Society in 2016. They measured the presence of both pigments in the macula and in blood serum and found a correlation with ‘blood-oxygen-level-dependent’ signalling in several areas of the brain.
Using neuroimaging, another group of researchers compared brain structure integrity in older adults with concentrations of lutein and zeaxanthin in the retina and blood serum. The study, published in the Archives of Clinical Neuropsychology, confirmed “previous findings that L&Z influence white matter integrity, particularly in regions vulnerable to age-related decline.”
Scientists at Georgia University (USA) conducted a study based on the theory that lutein and zeaxanthin are concentrated in both the eyes and the brain, and have an impact on auditory health. The study tested the hearing of young, healthy adults and compared the results to the levels of these antioxidant pigments in the macula. They found the correlation they were looking for, leading to the conclusion that sufficient intake of both lutein and zeaxanthin may have a positive effect on hearing integrity.
Both zeaxanthin and lutein are fat soluble (not water soluble) so if you’re trying to increase your uptake, be sure to consume them (as whole foods or supplements) along with healthy fats such as olive oil or fatty fish.
If you have concerns about deteriorating eyesight, or not getting enough of these nutrients through your diet, both are available in About Health’s Lester’s Oil®. Lester’s Oil® also contains other nutrients important for eye health (such as astaxanthin and omega-3 fatty acids) and for maintaining overall health as you age.