BLOG: Carotenoid supplements may benefit those at risk for Alzheimer’s

I came across an interesting story in the New York Times the other day, seemingly unrelated to the topic of this blog, blue light. The story outlined the results of a recent study on the cost of caring for someone with one of the three leading causes of death for older Americans: heart disease, cancer, and dementia.

The first two often require expensive drugs, surgeries and hospitalizations. The third, dementia, has no effective treatment. However, the surprising answer to the research was that dementia was by far the most expensive to care for.

The numbers were pretty staggering. For patients with heart disease or cancer, the 5-year cost for patients on Medicare was about the same for each, averaging about $175,000. For patients with dementia, the amount was $287,000. For each of these diseases, Medicare picked up about $100,000 in costs. But the average out-of-pocket cost for caring for patients with dementia was more than 80% higher than for patients without dementia. The reason for the added cost was for care givers, which are not covered under Medicare.

The take-home message was that dementia can be a financially devastating disease for both the patient and their families. The number of people with dementia is expected to skyrocket as the Baby Boomers age.

However, the number of people developing dementia-related disease, such as Alzheimer’s, will still be dwarfed by the number developing age-related macular degeneration. Individuals with intermediate to advanced AMD also need care givers, a financial burden that is not covered by Medicare. It turns out these two diseases of aging are related and, as in any epidemic, preventive measures are needed.

Last year, the Macular Pigment Research Group (Waterford, Ireland) published two studies in the Journal of Alzheimer’s Disease. In their first study, it was confirmed that patients with Alzheimer’s disease (AD) have less macular pigment, lower serum concentrations of the macular carotenoids, poorer vision as measured by best corrected visual acuity and contrast sensitivity, and a higher incidence of AMD when compared to control subjects.

In their second study, the group confirmed that for subjects with AD, supplementation with all three macular carotenoids – lutein, zeaxanthin and meso-zeaxanthin – increased macular pigment levels, increased circulating macular carotenoid serum levels and improved vision.

The researchers state, and it is important to note, that the findings of the first study and the results of the second study are not attributable to an inability of those with AD to respond to carotenoid intake. The disease does not affect carotenoid absorption and transport to target tissue. The reason for lower macular pigment and associated serum and vision levels is simply due to dietary intake. Those with AD have poorer dietary habits; they do not eat as many carotenoid-containing foods as those without the disease.

Now, of course, it is important to remember that AD is multifactorial. Age and genetics are likely the two strongest risk factors for developing the disease. However, evidence also points to the fact that as a rich network of blood vessels supplies our brains, conditions that damage these vessels including high blood pressure, diabetes, high cholesterol, heart disease and stroke are also contributing factors for developing AD.

Those at risk of developing AD are counseled to maintain a healthy lifestyle that includes a proper diet. Studies show that the average American diet lacks the amount of carotenoids necessary to support healthy eyes. In other words, if we are not eating what is necessary to support macular pigment levels, we are also not eating what is necessary to control the systemic conditions that contribute to the development of AD.

The second study also confirmed the hypothesis that carotenoid supplementation will likely not improve cognitive function in patients with AD or controls.

From their study: “The rationale whereby antioxidants are important for cognition rests on their ability to prevent or attenuate oxidative damage, as opposed to tissue repair. In other words, there is a biologically plausible rationale, supported by emerging evidence, that antioxidant intake is protective for cognition, but the notion that established cognitive impairment could be reversed by supplementation with antioxidants is less probable.”

Lutein and zeaxanthin are found in brain tissue, and it is thought that they enhance gap-junctional communication. The second study ends by stating the need for future studies on the effects of macular carotenoid supplementation to preserve cognition for those at risk of AD or with early disease.

As it has been borne out that macular carotenoid supplementation attenuates blue light damage playing a protective role in AMD, is it too early to start recommending them for those at risk of AD? From the New York Times piece outlining the devastating financial burden placed on families caring for patients with AD, it seems to me that this would be inexpensive insurance. The question is whether the coverage will pay-off.

References:

Kolata G. Costs for dementia care far exceeding other diseases, study finds. New York Times. October 26, 2015.

Nolan JM, et al. J Alzheimers D. 2014;42(4):1191-202. doi: 10.3233/JAD-140507.

Nolan JM, et al. J Alzheimers D. 2015;44(4):1157-1169. doi: 10.3233/JAD-142265.