Q&A: Lutein delivery systems

Lutein and zeaxanthin, two closely related xanthophylls, are becoming known as important factors in eye health through numerous trials and clinical studies. They act as a barrier to the macula protecting it against blue light and accordingly from light-induced oxidative damage and can be helpful in decreasing the risk of age-related macular degeneration (AMD), which is a major cause of irreversible blindness in the Western world. At a recent congress on "Lutein and its benefits in eye health" held in Schloss Hohenkammer (Munich, Germany) OTEurope spoke with Dr Wolfgang Schalch, principal scientist, Human Nutrition and Health at DSM Nutritional Products about his presentation on 'Critical parameters for lutein delivery systems' and the Actilease system.

Please could you describe the delivery system Actilease manufactured by DSM Nutritional Products?Actilease is a patented technology for the formulation of xanthophylls that basically provides two advantages. Firstly, it protects the lipid soluble xanthophyll from oxidative damage. These substances are sensitive to light and oxygen. Protection is achieved by embedding the xanthophyll particles in a protective starch-based colloidal system that has been developed by the R&D Centre Forms of DSM. The result of this protection is greater stability of Actilease xanthophylls and consequently their longer shelf life. Secondly, there is the bioavailability aspect, which is very important as different people have varying diets as well as absorption and transportation rates so the Actilease xanthophylls must be and are bioavailable. This is achieved because the xanthophylls in Actilease are present as very tiny particles that can be readily dispersed in water: This dispersion in water and gastric juice is a vital pre-requisite for the substance to be transported into the blood circulation. To sum up Actilease is a beadlet technology that is patented for the formulation of lipophilic agents. These beadlets contain micro-particles of xanthophylls of superior bioavailability encapsulated and stabilized in a protective matrix.

What problems did you encounter when designing the delivery system?The most important thing to consider is the protective colloid. If you use pork-based gelatine then this is not kosher and is not accepted by some subjects. This problem is also present when fish is used. In using certain proteins you can encounter allergy risks and then the product must be labelled as potentially allergenic. We found that the most uniform protective colloid we could use is probably modified food starch, which can also be used for subjects requiring kosher products.

Could you elaborate on any comparative studies with other products?In my presentation, I have shown an example of initial in vitro experiments and supplementation studies in rats, which demonstrated striking differences in dissolution behaviour and bioavailability between several lutein preparations. Out of them, two lutein products were selected and further evaluated in a human study: Actilease lutein and alginate formulated lutein. In the study, subjects were first given one product and then, after 28 days, they were swapped to the other product. It was found that Actilease lutein elicited higher plasma responses (i.e., the average plasma concentrations of lutein were higher when the subjects had consumed Actilease lutein) and it was concluded that this system has the superior oral bioavailability when compared to the other test product, the alginate-based lutein.

In your presentation you described a study on monkeys that, among other things, examined the blue-light vulnerability when diets are devoid of lutein. Could you elaborate on this a little?This was a unique opportunity because we collaborated with the Oregon National Primate Research Centre, and they have a lot of different monkeys available to study. They had Rhesus monkeys available that had been fed on a carotenoid-free diet since birth and even conception because the mothers of those monkeys were already on this feed. The consequence was that these monkeys did not have any xanthophylls in the blood and they did not have the yellow spot in the retina, which is called the macula lutea. Therefore, this was the perfect way to analyse how supplementation with lutein and zeaxanthin would affect blue-light vulnerability. This study has been published on-line before print in Investigative Ophthalmology & Vision Science and the abstract can be viewed by clicking here

What do you believe the future holds for lutein?Originally, lutein was thought to be mainly important for risk reduction of AMD and diseases of the retina, which is targeted at patients older than 55 or 65. However, we are presently also targeting the application of xanthophylls for younger, healthy subjects to improve visual performance, such as in twilight hours. Basis for this are recently conducted studies that demonstrated that xanthophyll supplementation improved the resistance to glare, shortened photostress-recovery time and enhanced the quality of the image on the retina. Particularly this latter characteristic may be relevant for patients that have undergone refractive surgery (such as LASIK).

If you are interested in learning more about this please contact Dr Schalch by E-mail: Wolfgang.schalch@dsm.comAlso, we will be featuring further information from this congress in an upcoming issue of OTEurope.