“We knew from previous studies that carotene (provitamin A) absorption is enhanced with co-consumption of lipid. Avocados contain about 17% lipid,” said Dr Steve Schwartz of Ohio State University, which conducted the Hass Avocado Board funded research.
“A previous animal study observed that consuming unsaturated fats enhances activity of the enzyme that converts inactive provitamin A carotenes to vitamin A. This suggests that consuming avocados with a provitamin A rich food could enhance conversion,” he told NutraIngredients.
Two separate sets of 12 healthy men and women were recruited for two randomised, two-way crossover studies. The first study investigated whether fresh avocado, when eaten with high beta-carotene tomato sauce, would promote absorption of provitamin A carotenoids, and the conversion of these carotenoids to an active form of vitamin A.
The second study investigated the same outcome, but replaced high beta-carotene tomato sauce with raw carrots. For both studies, test meals were served for breakfast, with or without 150g (one) fresh avocado.
Avocado boosts carotene absorption
In the first study researchers found that compared to a tomato sauce meal without avocado, the addition of 150g avocado more than doubled (2.4 times) beta carotene absorption, and more than quadrupled (4.6 times) the conversion of provitamin A to vitamin A.
In the second study, compared to a raw carrot meal without avocado, the addition of avocado significantly increased beta-carotene absorption by 6.6 times, more than quadrupled (4.8 times) alpha-carotene absorption and significantly increased (12.6 times) the conversion of provitamin A to vitamin A.
Vitamin A is important for reproductive health and growth promotion; it helps support healthy skin, immune function and vision and has antioxidant properties. Provitamin A carotenoids, like alpha- and beta-carotene, impart the orange and yellow colours to many fruits and vegetables. The body converts these plant pigments into an active and usable form of vitamin A.
“The results of this study strengthens the current body of research on this topic and complement a previous study conducted in my lab that showed a similar enhancement in carotenoid absorption with one half of an avocado,” said Dr Schwartz.
Dr Schwartz said his team would be following up with additional research and analyses on the absorption and conversion of alpha-carotene (a provitamin A carotene found in carrots).
Source: The Journal of Nutrition
First published ahead of print June 4, 2014 (doi: 10.3945/jn.113.187674)
‘Avocado Consumption Enhances Human Postprandial Provitamin A Absorption and Conversion from a Novel High–b-Carotene Tomato Sauce and from Carrots’
Authors: Rachel E. Kopec, Jessica L. Cooperstone, Ralf M. Schweiggert, Gregory S. Young, Earl H. Harrison, David M. Francis, Steven K. Clinton, and Steven J. Schwartz