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Conference highlights expanding benefits of carotenoids
Presenters discussed their positive effect on ocular as well as systemic health.
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The Macular Carotenoid Conference, held in Cambridge, England, hosted research presentations that focused primarily on the carotenoids found in the human eye and brain: lutein, zeaxanthin and mesozeaxanthin. Program topics ranged from genetic engineering and food source alteration for carotenoid-poor diets around the world to inflammatory marker influences of carotenoids in chronic diseases such as dementia, Alzheimer’s disease and age-related macular degeneration.
Nearly all of the research and presentations pointed toward the importance of maintaining carotenoid levels in the serum, eye and brain throughout life. The densitometer, which uses heterochromatic flicker photometry, has been used to measure carotenoids in the macula in most research for the past 20 years. The technology was developed at Brown University and is distributed by Macular Metrics. The macular pigment measurements from this device are now used in many studies as a biomarker for carotenoid changes in brain tissue in vivo.
One of the research presentations highlighted a new objective technology from Heidelberg Engineering that can provide macular pigment measurements comparable to the current densitometer measurements considered standard today.
Macular pigment research
Much of the research presented at this conference followed a common theme: macular pigment is important, and increasing macular pigment correlates with increased vision and performance, while a lack of or decreasing level of carotenoids correlates with cognitive decline and chronic diseases such as AMD, glaucoma and Alzheimer’s disease.
This mirrors positive results found in the Age-Related Eye Disease Study 2 in the U.S. regarding the benefits of lutein and zeaxanthin in macular degeneration patients, particularly those individuals whose diets are deficient in these carotenoids. It was noted that, while dietary recommendations range in various countries from 6 mg to 12 mg, most humans ingest only 2 mg daily through food sources. Nearly all of the researchers and scientists in attendance felt that the dietary amount of carotenoids consumed by individuals in most countries was below the amounts desired and that a minimum dietary intake should be established for carotenoids.
Health, vision benefits of carotenoids
Antonio Martinez, PhD, from Universidad de Seville, Spain, said it is reasonable to expect health benefits from carotenoids due to their chemical properties that absorb light and affect permeability of membranes and because of the antioxidant properties of their electron-rich backbones. Further evidence demonstrates that carotenoids are found in human diets and blood plasma and in high levels in human breast milk, specifically, colostrum, responsible for its unique yellowish color.
Martinez also said it is sensible to advise the consumption of carotenoid-containing foods due to the expected and measured health benefits. He noted that the highest concentrations of carotenoids are found in the skin and peels of fruits and other plants, which are often discarded.
In a particularly interesting study, University of Georgia researchers (Bovier et al.) presented data showing that suboptimal health and stress levels of students at the school were higher in those in a placebo trial vs. a group supplemented with carotenoids. These researchers are also responsible for the “baseball players” study (Hammond et al.) highlighted in Sports Illustrated June 15, 2015, concluding that baseball players supplemented with carotenoids show improved vision and eye-hand coordination measurements.
John Nolan, PhD, presented data from his Central Retinal Enrichment Supplementation Trial, a 12-month study of more than 300 individuals that found statistically significant improvements in vision performance when subjects were supplemented with a formulation of 10 mg mesozeaxanthin, 10 mg lutein and 2 mg zeaxanthin. Contrast sensitivity, macular pigment volume, blood serum levels and cognitive function were measured.
Nolan’s findings confirm what I see in clinical practice when prescribing carotenoids for vision improvement and prevention. Most often, patients report improved vision that can be measured by instrumentation we have in the office such as contrast sensitivity and microperimetry.
Macular pigment, Alzheimer’s, cognitive function
An entire day was devoted to the benefits of increasing carotenoid levels in the human brain.
The incidence of Alzheimer’s disease (AD) is predicted to triple by 2051, and no new pharmaceuticals have been released in 10 years. Risk of AD increases with hypertension, dyslipidemia, diabetes, obesity and smoking. Exercise and preventive measures will be necessary to reduce the number of patients developing AD.
A study from Aston University showed that nutritional deficiencies were common among those patients developing AD. Vitamins C, A and E, along with carotenoids lutein, zeaxanthin, beta-cryptoxanthin, lycopene and alpha-carotene were found to be deficient in those with developing AD.
An in vitro study showed mechanisms for LDL lipid oxidation that disrupt tight junctions and cytokine secretion, which forms critical stages for dementia and AD in the brain. The researchers concluded that possibly decreasing cholesterol in mid-life could be helpful.
In a study on a possible connection between AD and AMD, Nolan and colleagues, as reported in the Journal of Alzheimer’s Disease, found that AD and AMD patients shared decreased visual acuity, decreased serum carotenoids and macular pigment.
Researchers from Tufts University found macular pigment related to cognitive function in the elderly in a study published in Age & Aging in 2014 (Vishwanathan et al.).
In 2014, a paper published in Neurology (Nelles et al.) showed that plasma levels of HDL and carotenoids are lower in AD patients with vascular comorbidities.
Maastricht University researchers presented data that showed inflammation markers FD, CF5, 3a, B and the final sC5b-9 in the serum were significantly reduced after lutein supplementation.
Kerry Gelb, OD, a conference attendee, commented: “Because there will probably not be an AREDS3, practitioners have to start connecting the dots for their patients. Supplementation of important nutrients, including macular carotenoids, along with diet and exercise, are essential for a person’s long-term brain and eye health.”
Macular pigment, AMD, glaucoma
Macular pigment has been shown in several studies to be reduced in patients with AMD. Specifically, several studies have shown that there is a central dip in macular pigment in most patients when tested with heterochromatic flicker photometry. In addition, this central dip has been shown to improve with supplementation of carotenoids. The specific 10:10:2 carotenoid formulation (10 mg lutein, 10 mg mesozeaxanthin and 2 mg zeaxanthin in MacuHealth, by MacuHealth LLC), has been shown to improve vision, contrast sensitivity and photorecovery times in patients with early AMD, according to Akuffo and colleagues and Sabour-Pickett and colleagues.
The specific binding proteins for the three macular carotenoids have been identified, and speaker Paul S. Bernstein, MD, PhD, theorized that the conversion of lutein to mesozeaxanthin occurs in the retinal pigment epithelium in chickens through an enzymatic process. His research in chicken eggs found that mesozeaxanthin is formed without the need for light (the chicken eggs were incubated in the dark).
In another presentation, Michael Tolentino, MD, a Primary Care Optometry News Editorial board member, reported that several patients with wet AMD in his Orlando, Fla., practice who wanted to defer injections or take supplements in conjunction with injections were given MacuHealth twice daily. He measured improvements in visual acuity and resolution of subretinal/intraretinal fluid on optical coherence tomography.
Tolentino said: “While the results are presented as a case series, the response of these patients was equivalent to the typical response obtained after a course of anti-VEGF injections. Furthermore, MacuHealth worked synergistically with injections in patients previously unresponsive to injections.
“I speculate that the potent antioxidative properties of these three carotenoids diminished the stimulus for VEGF upregulation,” he added. “This supplement shows promise as a method for diminishing initiation and frequency of injections in patients with exudative AMD.”
James Loughman, DipOpt, FAOI, PhD, Dublin Institute of Technology, in his lecture, Structural, Functional and Macular Pigment Response to Carotenoid Supplementation in Glaucoma Subjects, presented information that correlated glaucoma ganglion cell complex loss with macular pigment deficiencies in glaucoma patients. All patients who had ganglion cell loss showed reductions in macular pigment levels.
He feels the next phase of research should be supplementation of carotenoids to improve macular pigment to prevent such ganglion cell loss in patients with glaucoma.
Murray Fingeret, OD, a PCON Editorial board member, commented in a July 2015 email: “The issue of central loss is not a new one.... but this looks at it in a different way and comes to similar conclusions.”
- References:
- Akuffo KO, et al. Eye. 2015;29:902-912. doi: 10.1038/eye.2015.64.
- Bovier ET, et al. Nutrients. 2013;5(3):750-757. doi: 10.3390/nu5030750.
- Feeny J, et al. Age & Ageing. 2014;43(2):271-275. doi: 10.1093/ageing/aft210.
- Hammond Jr. BR, et al. Am J Clin Nutr. 2012;96(5):1207S-1213S. doi: 10.3945/ajcn.112.034876.
- Nelles G, et al. Neurology. 2014;82(10):Suppl. P3.205.
- Nolan JM, et al. J Alzheimer’s Dis. 2015;44:1157-1169. doi: 10.3233/JAD-142265.
- Sabour-Pickett S, et al. Retina. 2014;34(9):1757-1766. doi: 10.1097/IAE.0000000000000174.
- For more information:
- David W. Nelson, OD, MBA, is in a private group practice in Madison, Wis. He can be reached at amoptbddwn@aol.com.
Disclosure: Nelsons reports he is a consultant for MacuHealth LLC. Tolentino reports no financial disclosures.