Olive and coconut oils may improve the intestinal absorption of lutein, according to research in mice.
The research published in the journal Food Research International looked at the influence of dietary lipids on the bioavailability and antioxidant property of the carotenoid in lutein-deficient mice.
The Indian researchers administered 200 micromolars (μM) of lutein from marigold petals in either olive, coconut, groundnut, soybean, sunflower, rice bran, corn, palm or fish oil for a period of 15 days.
When compare to the micelle lutein-fed control group, plasma lutein levels were the highest in the olive oil (82%) and coconut oil (68%) group.
The scientists said: “Results revealed an affirmative correlation between triglycerides, low density lipoproteins and high density lipoprotein levels with plasma and tissue lutein levels, signifying their role in the transportation of newly absorbed lutein to target tissues.”
Lutein accumulation in the liver and the eye was also highest in the olive oil (120% liver and 117% eye) and coconut oil- (105% and 109%) groups, compared to the control.
“The outcome of this study may have implications in the nutritional and biomedical applications for choosing a suitable dietary lipid for improving lutein bioavailability to protect the eyes from progression of AMD [age-related macular degeneration] and cataract in the elderly population,” according to the study.
Depending on the oil
The intestinal lutein levels were higher than the control group by 167% for olive oil and 159% for coconut oil, followed by sunflower oil (140%), groundnut oil (123%), soybean oil (108%), rice bran oil (87%), fish oil (51%), and palm oil (36%).
"Intestinal absorption of lutein is ensured through three key limiting steps: (a) release from the food matrix and transfer into the mixed micelles during digestion in the small intestine; (b) uptake by the enterocytes [a cell of the intestinal lining] and (c) enterocyte transport and packaging into the chylomicrons [fat droplets] for secretion in the bloodstream via lymph."
The researchers said that these differences may be a result of the solubility and micellarization of lutein in the intestinal lumen due to enhanced activity of intestinal lipase, a protein that causes fat to break down into fatty acids.
“Further, lutein absorption may be influenced by the specific fatty acid in dietary lipids that in turn help in improved portal absorption and the triglyceride or cholesterol influx between the liver and peripheral tissues, which may sway the uptake and transport of lutein,” the researchers wrote.
Source: Food Research International
Published online ahead of print, doi: 10.1016/j.foodres.2014.06.034
“Dietary fatty acid determines the intestinal absorption of lutein in lutein deficient mice”
Authors: B. Nidhi, T. R. Ramaprasad, V. Baskaran