One of life’s great ironies is that the advancement of research often proves that, old wives tales notwithstanding, the sensible wisdom of old can be right on the money. The latest to be proven is the reason why we should be eating our spinach – a phrase many of us wouldn’t have heard since childhood when a parent weilded Popeye comics as an often ill-fated attempt to make us finish our greens. A recent study emerging from Japan has revealed that spinach may actually help protect our eyes from macular degeneration [1].
This study is significant as macular degeneration is the leading cause of sight loss for people over the age of 60. It occurs when the central portion of the light-sensitive retina, known as the macular, deteriorates. It’s affects an estimated 1 in 7 Australians over the age of 50, making it 4 times more prevalent than Dementia [2].
There are 2 forms of macular generation but the majority of sufferers fall victim to the ‘dry’ form. This is characterised by yellow drusen deposits in the macular which then lead to dimming or distortion, and eventually central blind spots as the condition advances [3].
The problem arises when macular pigment thins out and lets in types of light that can cause damage. One such type is the blue light which is encountered often in our modern, electronic-device rich lifestyle.
“Healthy macular maintains a yellow pigment that shields blue light. This might be compared to the macula having its own pair of sunglasses. This macular pigment is made up of three yellow carotenoids – specifically lutein, zeaxanthin and meso-zeaxanthin.
Towards the middle of the macula, zeaxanthin is more concentrated, reaching 75 percent. Away from the middle, the dominant component is lutein, with 65 percent or more of the total. Among all tissues, the macula contains the highest concentration of these carotenoids [Adams,1].”
What can happen when our consumption of carotenoids is low? The macular degenerates. This is commonly an age related issue, but it can also be seen among those with low levels of lutein and zeaxanthin in their diet [1].
Here’s where spinach comes in. Sometimes called the worlds healthiest vegetable, it is rich in carotenoids including the all too significant nutrients lutein and zeaxanthin [4].
The recent spinach study looked at 11 pairs of healthy eyes, all belonging to non-smokers. Over the course of 2 months, study participants consumed 75g of frozen spinach every day. This contained 10mg of lutein. The researchers found that the constant intake of lutein-spinach indicated some strong benefits for macular health. Over the course of the 2 month study, the macular pigment optical density and serum lutein concentrations both increased in participants. The researchers found that visual acuity actually improved in participants [5,1].
This echoes findings by another study hailing back to 2012. That double-blinded, randomised study took a larger sample of people over the age of 50. It found that macular pigment optical density increased significantly both in the group that received lutein supplements, and in the group that received lutein and zeaxanthin groups. The researchers stated that:
“There was a significant dose-response effect for lutein supplementation, and the changes in MPOD [macular pigment optical density] from baseline to 48 weeks were correlated negatively with baseline MPOD in all active treatment groups.
Among patients with early AMD [age-related macular degeneration], supplementation with lutein and zeaxanthin improved macular pigment, which played a causative role in boosting visual function and might prevent the progression of AMD [6].”
This adds to a growing body of knowledge linking green vegetables containing lutein and zeaxanthin to increased macular health [1]. Food, it seems, can be a powerful protector of health. Imagine that.
There’s a simple message in all of this: eat your spinach. It could help save your sight.
References
[1] Adams, C (2016), “Spinach helps protect eyes from macular degeneration,” Green Med Info, retrieved 1 June 2016
[2] Staff Writer (2012), “Macular Degeneration Facts and Figures,” Macular Degeneration Foundation, retrieved 1 June 2016
[3] Staff Writer (2016), “Age Related Macular Degeneration Overview,” Web MD retrieved 1 June 2016
[4] Rudrappa, U (2015), “Spinach,” Nutrition and You,” retrieved 1 June 2016
[5] Ozawa, Y, Nagai, N, Suzuki, M, Kurihara, T, Shinoda, H, Watanabe, M and Tsubota, K (2016), “Effects of Constant Intake of Lutein-rich Spinach on Macular Pigment Optical Density: A Pilot Study,” Nippon Ganka Gakkai Zasshi. 2016 Jan;120(1):41-8.
[6] Ma L1, Yan SF, Huang YM, Lu XR, Qian F, Pang HL, Xu XR, Zou ZY, Dong PC, Xiao X, Wang X, Sun TT, Dou HL, Lin XM. (2012), “Effect of lutein and zeaxanthin on macular pigment and visual function in patients with early age-related macular degeneration,” Journal of Ophthalmology, 2012 Nov;119(11):2290-7. doi: 10.1016/j.ophtha.2012.06.014. Epub 2012 Aug 1.
