Content accuracy and readability of dietary advice available on webpages: A systematic review of the evidence

Concerns have been raised regarding the quality of health information published on the World Wide Web, while studies accumulating similar evidence for nutrition-related information are scarce. The present review aimed to systematically accumulate and discuss the findings of studies evaluating the content quality of websites publishing nutrition-related information, based on the PRISMA statement.

Studies that have assessed the accuracy and readability of dietary advice published on websites/webpages were evaluated. The SPIDER framework was used for the systematic search of studies, and those that evaluated websites/webpages that did not contain nutritional information, were videos or social media, referred to health professionals, or contained information on a specific theme (e.g., dietary supplements), were excluded.

Twenty-nine studies were included in this review, assessing information, published mainly in English, on 18 different diet-related topics. Twenty of them classified websites and reported, also, results per category. Inconsistent information has been found on 16%-49.6% of websites, with this percentage rising to 54%-94% in the case of 'weight loss' information. Purely congruent with guidelines information was found on 18%-39.7% of websites. Commercial sites were inferior in terms of quality to the rest. The readability level was estimated as higher than the recommended in 9 out of 11 studies that assessed it.

Results of the present systematic review indicate that inaccurate and hard-to-read dietary advice is found on many websites, regardless of the dietary topic.