Catching Up with Carotenoids

Im currently in New Englandhome to some of the finest autumnal displays off carotenoidswhere the first day of the New Developments in Carotenoid Research conference at the Jean Mayer Human Nutrition Research Center (HNRC) at Tufts University, Boston, has just wrapped. It was an interesting and highly technical day focused mainly on beta-carotene, including presentations from several global carotenoid scientists on such topics as: vitamin A deficiencys role in childhood blindness, disease and morbidity; the genetics of beta-carotene metabolism in the body; the challenges in using plasma carotenoid levels as markers of fruit and vegetable intake; the possible effect of higher beta-carotene-to-vitamin-A equivalence on dietary vitamin A requirements; the nutritional relevance of beta-carotene as a source of vitamin A; techniques for measuring vitamin A activity from beta-carotene; filling dietary gaps and beta-carotene bioavailability and conversion.

Also included in the opening program was a summary of recent conclusions from the 2009 Hohenheim Consensus meeting, where carotenoid experts discussed 17 pressing carotenoid health questions, resulting in formulated consensus answers. In short, the scientists reached a consensus that not only is beta-carotene is a safe source of vitamin A intake, but also the provitamin A function of beta-carotene is essential to achieve vitamin A intake recommendations.

Among the messages I took away, the dietary vitamin A intake in the United States and other developed countries is mostly from preformed vitamin A, whereas underdeveloped countries rely far more on dietary intake of carotenoids, which then relies on a conversion in the body that has proven less than efficient. However, low vitamin A status is linked to increased expression of genes that increase the ability to convert beta-carotene to retinol. In the end, it appears vitamin A fortification solutions are needed, especially for certain underdeveloped areas of the world, including parts of Africa and India. Golden Rice, genetically modified for high beta-carotene content, is a current consideration. According to Alfred Sommer, MD, university distinguished professor at Johns Hopkins University and keynote speaker today, this fortified rice offers improved beta-carotene to vitamin A conversion. Also, it has become evident to many researchers that the production of vitamin A in the body from dietary intake of beta-carotene is not as efficient as once thought, so entities such as the Institute of Medicine (IOM) have changed their estimated bioconversion rate to reflect the lower production, which demonstrates expectations of research on dietary beta-carotene and vitamin A levels need to be equally altered, as do assessments of dietary intakes in the field and recommendation concerning beta-carotene/vitamin A-containing foods. Also interesting was the different conversion factors (amount of beta-carotene require to produce one unit of retinol) of foods. Carrots and spinach were bested considerably by spirulina and the aforementioned Golden Rice.

The day closed with a series of presentations on condition-specific human research on beta-carotene, including the effects of beta-carotene supplementation on cognitive performance, and the effect of beta-carotene and other carotenoids on sun protection. In addition to specific results, the approach to the human clinical study of carotenoids, carotenoid-rich foods and carotenoid supplementation on health endpoints may need to take a more personalized approach, according to Susan Mayne, Ph.D., professor of epidemiology and division head of chronic disease epidemiology at Yale School of Public Health. She reviewed the challenges encountered by research into the health effects of carotenoidsAre the researched benefits form the carotenoids alone or from the complex whole matrix of the plant source? Ultimately, she suggested trials focus on intervention in populations with low carotenoid status to bring them into more adequate status. With accurate skin assessment of carotenoids available, enabling researchers to gather a population of low carotenoid status, this approach just might make sense.

The final presentation should be of interest to manufacturers and formulators, as Bruno Leuenberger, Ph.D., a formulation and applications scientist at DSM, which sponsored the conference, discussed carotenoid bioavailability as it relates to formulation of nutritional health products. He explained high-end formulation technology for carotenoids includes two steps: micronization (nano-grinding, emulsification, solvents, etc.) of the carotenoid in a protective colloid-dominant matrix; and the drying of this dispersion in a spray tower using a flow agent introduced during drying.  This results in beadlets (~300m) that contribute to a formulations good powder-handling abilities, stability in supplement and food applications, and bioavailability.

Tomorrow, the conference will turn to information on lycopene, lutein and zeaxanthin, which will provide even more color on the current science on carotenoids. Check back tomorrow afternoon for my final report on this informative carotenoid-focused event.

Read about Day Two here .