Lutein and zeaxanthin supplementation improves measures of visual performance in healthy adults

At a Glance

A new study shows that supplementing with lutein and zeaxanthin—compounds contained naturally in green, leafy vegetables, such as kale and spinach—may improve measures of visual performance such as photostress recovery and the response to glare conditions. 

 Read more about this research below. 

Dietary carotenoids lutein and zeaxanthin are plant-derived pigments that concentrate in the inner layers of the macula region of the eye. The macular pigments act much like a sunscreen within the eye to protect the delicate tissues of the retina. It is well known that sufficient levels of these carotenoids reduce the risk of macular degeneration, a major cause of blindness in the elderly. Less is known of the benefits of supplementation of lutein and zeaxanthin in young, healthy adults. 

A new double-blind placebo controlled study published in Investigative Ophthalmology & Visual Science assessed the link between higher macular pigment optical density (MPOD) resulting from supplementation to improvements in glare disability, photostress recovery, and other measures of visual performance.   

The study included 115 young, healthy adults who either received a supplement containing a daily dosage of 10 mg of lutein and 2 mg zeaxanthin or a placebo over a one year supplementation period. Several measurements were collected at baseline and every 3 months: serum lutein and zeaxanthin, MPOD, photostress recovery, chromatic contrast and glare disability. MPOD is a measure of the amount of macular pigment present in the macular. Photostress recovery is a measure of how fast the eye recovers sight after being exposed to a flash of bright light. Chromatic contrast is the ability to discriminate an object from its colored surroundings. Glare disability is a measure of the amount of glaring light that can be tolerated before vision is significantly impaired. 

MPOD and serum lutein and zeaxanthin levels increased significantly in the treatment groups versus placebo. In the supplemented group, chromatic contrast and photostress recovery times improved significantly versus placebo during the study period. The researchers also found that improvement in glare disability was highly correlated to increased macular pigment density.  

The results of the current study demonstrate that lutein and zeaxanthin supplementation improves several measures of visual function in normal healthy individuals and adds to evidence from previous studies that increased MPOD results in improved visual performance. 

Hammond BR et al. A double-blind, placebo-controlled study on the effects of lutein and zeaxanthin on photostress recovery, glare disability, and chromatic contrast. Invest Ophthalmol Vis Sci. 2014 Dec 2;55(12):8583-9.

Multivitamin and Calcium Supplementation May Reduce Colorectal Cancer Risk

Here's more scientific evidence showing nutritional supplements may help in prevention of some cancers.

At a Glance—   A new meta-analysis has shown evidence in favor of a protective effect for dietary supplementation against the risk of colorectal cancer.
Read more about this research below.

Colorectal cancer is a major health concern, primarily in industrialized countries. Previous research has shown associations between some nutrients, such as calcium, and the risk of colorectal cancer. However, no systematic review or meta-analysis of prospective studies has focused on cancer risk and the use of dietary supplements specifically.  

In a new study published online in the International Journal of Cancer, researchers analyzed 24 studies examining the association between the use of supplements and risk of colon, rectal and colorectal cancer. This meta-analysis included original and peer-reviewed relevant studies published up until January 2013. 

The use of multivitamin supplements was associated with an 8% lower risk of colorectal cancer when compared to non-use of multivitamins. Subjects that used calcium supplements specifically had a 14% reduction in the risk of colorectal cancer compared to those who didn’t use calcium supplements. Inconsistent associations were found for colon cancer and colorectal cancer risk and other specific supplements, which included vitamins A, C, D, E and garlic. And, contrary to some recent concerns, no negative effect was found for folic acid.

The results of this meta-analysis suggest that in addition to other lifestyle factors, multivitamins and calcium supplements may have a beneficial effect on colorectal cancer risk. This research adds to the data from previous trials and cohort studies that have consistently shown that calcium supplementation may be beneficial in colorectal cancer prevention.

Heine-Bröring RC et al. Dietary supplement use and colorectal cancer risk: A systematic review and meta-analyses of prospective cohort studies  Int J Cancer. 2014 Oct 21. doi: 10.1002/ijc.29277. [Epub ahead of print]