I read an interesting interview a while ago. Among other things it mentions that &quot;The beta-carotene that is produced synthetically is a single isomer -- a very straight molecule called &quot;all-trans&quot; beta-carotene. Beta-carotene that is found in nature frequently consists of both the straight &quot;all-trans&quot; molecule and a variety of bent molecules that contain what are called &quot;cis&quot; double bonds.&quot;<p><a href="http:&#x2F;&#x2F;drpasswater.com&#x2F;nutrition_library&#x2F;carotenoids_interview.html" rel="nofollow">http:&#x2F;&#x2F;drpasswater.com&#x2F;nutrition_library&#x2F;carotenoids_intervi...</a>