Lutein-fortified milk passes bioavailability test: Study
The fortified milk product could raise blood levels of lutein to the top end of the reference ranges in the US and European populations, according to results of a human study published in the Journal of Nutritional Biochemistry.
Researchers from Madrid’s Hospital Universitario Puerta de Hierro report that these raised blood levels are relevant for different health benefits, including eye health.
“The present results support the suitability of fermented milk as a carrier of lutein esters and the efficacy of this food-based approach to improve the status of lutein in control subjects,” wrote lead author Fernando Granado-Lorencio.
“Overall, the present approach and the information provided may be relevant in the design and evaluation of the nutritional and health effects of novel, potentially functional, food products.”
Lutein, a nutrient found in various foods including green leafy vegetables and egg yolk, has a ten-year history in the dietary supplement market as a nutrient to reduce the risk of age related macular degeneration (ADM).
The global lutein market is set to hit $124.5 million (€93 million) in 2013, according to a 2007 report from Frost & Sullivan, with skin health offering a major new avenue for the carotenoid.
According to the report, manufacturers need to address this growing maturity in dietary supplements by identifying new and potentially lucrative application segments that offer opportunities for the continued growth of the lutein market.
Study details
The new study looked at a new delivery method for the nutrient. Granado-Lorencio and his co-workers prepared fermented milk fortified with a lutein ester mix (Cognis).
Twenty-four volunteers were recruited and randomised to consume the fortified fermented milk a low lutein dose (equivalent to about 4 mg free lutein/100 ml) and a high lutein dose (about 8 mg free lutein/100 ml). A single dose study and a multiple dose study for 14 days were performed.
Consumption of the milk resulted in increases in the blood levels of lutein, with the higher dose milk raising levels more than the lower dose.
“Our results show that the regular consumption of lutein ester-fortified fermented milk, at the level of fortification and consumption used (ca. 4–8 mg/day), may increase the serum levels of lutein above the 90 percentile of the reference ranges in the US and European populations (greater than 0.50 micromoles/L),” wrote the researchers.
Furthermore, using an in vitro approach, the researchers showed that very little hydrolysis of the lutein esters occurred. Their in vitro model simulated gastrointestinal conditions and showed that hydrolysis of the nutrient to be in the order of about 15 per cent, regardless of the dose used.
In vitro, lutein ester hydrolysis was incomplete regardless of the amount initially present. Free lutein released was higher using the high-dose fermented milk, but the percentage of hydrolysis was similar at both levels of fortification. In the micellar phase, the percentage of free and total lutein was not different according to the dose.
“Our data […] support an in vivo dose-dependent effect as well as the usefulness of in vitro models to provide relevant information to predict in vivo responses,” added Granado-Lorencio and his co-workers.
Source: Journal of Nutritional Biochemistry Published online ahead of print, “Lutein bioavailability from lutein ester-fortified fermented milk: in vivo and in vitro study”Authors: F. Granado-Lorencio, C. Herrero-Barbudo, B. Olmedilla-Alonso, I. Blanco-Navarro, B. Perez-Sacristan
