The credibility of the effects of functional food products and consumers' willingness to purchase/willingness to pay- review.

The credibility aspect of any food product is important in order to find and keep consumers, which is especially true for functional foods. Market success of these products depends mostly on the credibility of their beneficial effects on health. The aim of this literature review was to identify aspects that make the positive health effect of a functional product credible for consumers. Based on the established connection between purchase intention and credibility, articles have been collected, summarized and restructured. Research papers have been analyzed through a two-step selection process. From 1724 studies, 54 were selected to discuss the above mentioned topics. It has been found that most of the studies focus on the credibility of health claims, while those exploring the connection between different kinds of product attributes and the credibility aspect of functional food products are rare. It is believed that other features can significantly affect this aspect and it is strategically important to know these factors influencing credibility. The literature analysis showed that willingness to purchase functional products is influenced by sensory and non-sensory-characteristics of the product, while willingness to pay is affected for example by consumers' trust in functional foods. On the issue of what influences the credibility of the health benefits of functional products, ambiguous information was found. While one of the most important factors influencing acceptance of functional foods is credibility of information, other researchers' results show no direct significant relationship between credibility of health claims and willingness to purchase. Credibility of health effect is also influenced by the base product and the carrier ingredient, the source of information, the product design and cultural roots of a country.