Research into the bioavailability of carotenoids lutein and zeaxanthin has confirmed that bioavailability is very much dependent on formulations used, with starch blends performing better than alginate.
The randomised, double-blind, cross-over study published in the European Journal of Nutrition, found lutein availability was 1.8-fold and 1.3-fold higher, respectively, for starch formulations than for alginate.
“Although case-control studies suggest a combined dose of 6mg of lutein and zeaxanthin per day for reducing the risk of AMD, the average North American ingests only 1–2 mg of lutein daily from their diet,” said the researchers from DSM, Kemin and KGK Synergise, which are all involved in carotenoids.
“This may lead to a deﬁcit of these important carotenoids. With the dramatic increase in age-related eye diseases, it becomes very important to more thoroughly understand the issues associated with the bioavailability of lutein and zeaxanthin supplement formulations and their potential impact upon target populations.”
The study featured 48 healthy subjects who were given a single dose of 20mg of lutein from either of the two formulations and lutein was measured in the plasma at several time intervals.
After a wash out period of 28 days the study was repeated with the alternative formulation, with starch performing more potently.
The control plasma samples were analysed at least 4 times/day during the study as described in. In addition, the method was regularly checked for accuracy and precision (±15 %) by participation in inter-laboratory studies organised by the National Institute of Standard and Technologies (NIST, Gaithersburg, Maryland, US).