A higher intake of carotenoids lutein and zeaxanthin is associated with a reduced risk of AMD

At a Glance

New research covering two decades of prospective follow-up shows that an increased intake of lutein and zeaxanthin lowers the risk of advanced age-related macular degeneration (AMD)

 Read more about this research below. 

Age-Related Macular Degeneration (AMD) is the most common cause of vision loss in developed countries. This degenerative eye disease causes damage to the macula (central retina) of the eye, impairing central vision. People affected by AMD have difficulty reading, driving and performing activities that require clear central vision. Many factors contribute to the development of AMD, including aging, genetics, diet, and smoking.

The macula is a yellow oval-shaped pigmented area located near the center of the retina. Structures within the macula are specialized to provide high-acuity vision. Lutein and zeaxanthin are found in high concentrations here, giving the macula its yellow color. This protective layer, known as macular pigment, filters harmful high-energy blue wavelengths of light preventing damage to the retina, cones, and rods.

Numerous published studies have previously reported a link to intakes of lutein and zeaxanthin and AMD risk; however the research has been mostly inconsistent. In this newly published prospective study, researchers used two decades of data involving more than 100,000 participants from the Nurses’ Health Study and the Health Professionals Follow-up Study. All participants were aged 50 years or older and were free of diagnosed AMD, diabetes mellitus, cardiovascular disease, and cancer (except nonmelanoma skin cancer) at baseline.

The researcher’s analyzed carotenoid intake based on dietary food frequency questionnaires at baseline and follow-up, and then calculated predicted plasma carotenoid scores. The results of this study found that participants with the highest average plasma lutein and zeaxanthin levels had a 40% reduced risk of developing advanced AMD compared to those with the lowest average levels. "Lutein and zeaxanthin form macular pigments that may protect against AMD by reducing oxidative stress, absorbing blue light, and stabilizing cell membranes," the authors explain.

Dark green leafy vegetables are the primary dietary sources of lutein and zeaxanthin, but they are also found in some other colorful fruits and vegetables. Average dietary intake in the U.S. is only about 1-3 mg/day, far below the amount most studies indicate as a minimum needed to decrease risk of AMD. "Because other carotenoids may also have a protective role, a public health strategy of increasing the consumption of a wide variety of fruits and vegetables rich in carotenoids could be most beneficial and is compatible with current dietary guidelines," the authors conclude. 

 Juan Wu, MS; Eunyoung Cho, ScD; Walter C. Willett, MD, MPH, DrPH; Srinivas M. Sastry, MD, MPH; Debra A. Schaumberg, ScD, OD, MPH  Intakes of Lutein, Zeaxanthin, and Other Carotenoids and Age-Related Macular Degeneration During 2 Decades of Prospective Follow-up. JAMA Ophthalmol. Published online October 08, 2015. doi:10.1001/jamaophthalmol.2015.3590

Higher levels of carotenoids may reduce breast cancer risk

At a Glance

The results of a new large study indicate that women with higher plasma carotenoid levels have a reduced risk of breast cancer, and particularly the more aggressive tumors.

 Read more about this research below.

Carotenoids are among the nutrients needed for plant photosynthesis.  They are also the pigments in fruits and vegetables that provide  the yellow, orange and red colors. Of over 600 known dietary carotenoids, a-carotene, b-carotene, b-cryptoxanthin, lutein, zeaxanthin, and lycopene are the most prevalent in the US diet, comprising 90% of circulating carotenoids.  Current evidence suggests that carotenoids may reduce breast cancer risk, but at what stage they are most influential and in what tumor subtypes is less clear. 

In a recent large study published online in the American Journal of Clinical Nutrition, researchers examined the issues of timing of carotenoid exposure as well as associations by breast tumor subtypes. 

The study group included 32,826 women that participated in the Nurses’ Health study and donated blood samples in 1989-1990.  In 2000-2002, 18,743 of these women donated a second blood sample.  Women diagnosed with breast cancer between first and second blood collection, and those diagnosed with breast cancer within ten years of the second collection, were matched with control subjects.

After adjusting for several breast cancer risk factors, significant inverse associations were observed between a-carotene, b-carotene, lycopene, and total carotenoids and breast cancer risk with an overall 18–28% lower risk in the women with the highest blood levels compared to women with the lowest levels. The protective benefits of b-carotene and total carotenoids were more pronounced in leaner women (BMI < 30).  In addition, a-carotene, b-carotene, b-cryptoxanthin, and total carotenoids were associated with a 46% reduction in risk of the more aggressive types of cancer than recurred or caused death.

In this large prospective analysis with 20 y of follow up, women with the highest blood levels of carotenoids had a significant reduction in breast cancer risk, and particularly the more aggressive and lethal subtypes.

A Heather Eliassen et al.  Plasma carotenoids and risk of breast cancer over 20 y of follow-up. Am J Clin Nutr doi: 10.3945/ajcn.114.105080