Lutein Esters Provide Bioavailable Lutein

BACKGROUND: The bioavailability, or absorption, of nutrients is essential
for their ultimate use by the body. Lutein, an antioxidant carotenoid found
in kale and other foods, along with the carotenoid zeaxanthin, forms the
"macular pigment," which is crucial for normal vision. The macular pigment
may help filter out harmful blue wavelengths of light and may reduce free
radical damage. A lower macular pigment density is strongly associated with
age-related macular degeneration, the leading cause of blindness among
older men and women. Two principal forms of lutein -- lutein esters and
"free" (that is, unesterified or unbound) lutein -- are found in both foods
and over-the-counter dietary supplements.

RESEARCH: Researchers from the University of Illinois, Chicago, performed a
head-to-head comparison of the bioavailability of lutein esters and free
(unesterified) lutein. Using a randomized, crossover study design, they gave 8 women and 10 men a single dose of either lutein esters or free
lutein. The doses were calculated based on the volunteer's body weight and
on the all-trans lutein content of each formulation, so that the same
amount of all-trans lutein was delivered in each formulation. The free
lutein formulation was a crystalline suspension in safflower oil; the
lutein ester formulation was a powder; both formulations were packed into
gelatin capsules for administration. Blood samples were taken before
administration of the dose and at various intervals afterwards. The diet
was carefully controlled from two days prior until two days after the dose
was given.

RESULTS: The lutein ester supplement resulted in greater bioavailability of
lutein, compared with free lutein, in 14 of the 18 subjects. Overall,
lutein was 61.6 percent more bioavailable from the lutein ester formulation
than from the lutein formulation. In addition, lutein from the lutein ester
supplement was absorbed faster and resulted in higher blood levels of
lutein. During digestion, a normal process known as hydrolysis splits the
ester bond, allowing for absorption of lutein and assimilation into the
bloodstream, so it can reach tissues.

IMPLICATIONS: This study is consistent with other published research
showing that lutein esters are a source of bioavailable lutein. According
to the study results, hydrolysis of lutein esters is a very efficient
process and was not observed to impair or limit the bioavailability of
lutein from lutein esters. According to the scientists, other factors such
as the dissolution of a formulation seem to be important to the study's

Bowen, PE, Herbst-Espinosa SM, Hussain EA, et al, "Esterification does not
impair lutein bioavailability in humans," Journal of Nutrition, 2002; 132:3668-3673.

For the original abstract, visit:

Hide comments


  • Allowed HTML tags: <em> <strong> <blockquote> <br> <p>

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.