Purpose
"Eye healthy food" has become a commonly used phrase, but what does it mean to the typical consumer who may have eye disease? Typically, it suggests foods that are high in specific nutrients, such as lutein, beta-carotene, or vitamin A, but many processed food products high in these desirable nutrients may also have unhealthy nutrients such as sugar, sodium, saturated fat, and cholesterol. We devised a quantitative method to certify foods as "eye-healthy" based on their total nutrient content, serving size, and preparation method. In addition to certification of nutritional content, this method also provides a numerical score that can be used statistically to compare foods and preparation methods with respect to relative eye health.
Methods
Data were acquired from the United States Department of Agriculture's R25 food database. Using peer-reviewed ocular health studies as a guide, 24 "eye healthy" nutrients and 4 "eye unhealthy" nutrients were identified for each food. After exclusion of foods with missing nutrient data, 3652 foods in 24 categories were used. Each nutrient was self-weighted for content based on a 100-gram-weight assay, further weighted based on a heuristic analysis of their relative contribution to ocular health, and then adjusted for serving size. Two equations were generated to produce a "Healthy Index" and an "Unhealthy Index" for each food product. A Chebyshev polynomial equation based on the nutrient content was then used to define an "Eye Q Score" from 0 to 200. An Eye Q score >100 indicates an eye-healthy food product, with higher scores indicating increasingly beneficial foods.
Results
The index statistics for 7 of the 24 food categories are shown in the Table 1. Typical Eye Q score examples are shown in Table 2.
Conclusions
Unless both the healthy and unhealthy nutrient content of foods are considered, it is impossible to certify the eye health of any given food. This is particularly important for processed foods that have complex recipes or are artificially fortified. Some foods not generally considered as eye healthy have high Eye Q scores, while foods that are high in lutein or beta carotene may actually have poor Eye Q scores due to undesirable nutrients such as added sodium or sugar.
Keywords: 618 nutritional factors •
424 antioxidants •
592 metabolism