I did some internet search for blueberry-based health food, and found how messy their ingredient labels are. Only a few proper ones can be found.
First, as to bilberry, which I told you about last time, many of them do not indicate the content of anthocyanin or anthocyanidin. Moreover, a majority of them do not indicate even the amount of bilberry per pill. Next, lutein is often used in blueberry-based health food, and it is usually displayed as marigold extract. This is extracted from marigold flowers, which you know well, mainly from their stamens.
There are marigold extracts containing different amounts of lutein, such as 5%, 10%, and 20%, and an appropriate way of indication would be, for example, "marigold extract (containing 20% lutein)" or "marigold extract (containing lutein ○○ mg)". Another example I saw on the net several times is an indication as lutein ○○ mg, without writing as marigold extract. This is clearly a case where marigold extract and lutein are mixed up, falsely indicating a content greater than the actual content of lutein.
Both bilberry extract and marigold extract are very expensive. It is all the more reason to assess the product quality very carefully without being fooled by the apparent price. My next talk will be about astaxanthin.