These beauty smoothies really work
If you drink smoothies containing lots of carrot juice, orange juice and other sources of carotenoids, within a couple of weeks your skin will become a colour that most people find attractive. Psychologists at the University of Nottingham Malaysia Campus announced this in PLoS One.
Carotenoids such as lycopene [structural formula shown above] and alpha- and beta-carotene [structural formulae shown below] protect the skin. After being absorbed from food they accumulate in the skin where they inhibit aging processes. As a result, the colour of the skin changes too. In 2011 Scottish psychologists showed that people with relatively high amounts of carotenoids in their skin are more attractive than people with low levels of carotenoids in their skin.
Most research on the effect of carotenoids on skin colour has been done using supplements. The researchers wanted to know whether ordinary foods that contain carotenoids have the same effect on the skin. That's why they did an experiment with 81 students. Half of the students drank a 250 ml smoothie every day for six weeks and the other half just drank water.
The researchers varied the composition of the smoothies. The composition is shown below. Click on the figure for a larger version. The researchers also added a small amount of fat – in the form of cream of palm oil – to boost the absorption of the carotenoids.
The smoothies provided an average of 25 mg carotenoids per day, as the table above shows. Click on the figure for a larger version. The carotenoids consisted of 80 percent beta-carotene, 15 percent alpha-carotene and 5 percent lycopene.
Within a couple of weeks the subjects' face skin had become a little yellower and redder. The red colouring was probably largely due to the effect of the lycopene. The effect remained visible after supplementation stopped.
Week 0: before supplementation; week 1-7: supplementation; week 8-9: no supplementation anymore.
Broken blue line: water group; solid orange line: smoothie group.
The researchers hope that their findings will encourage people to eat more healthily. "Appearance provides a powerful motivation for improved health behaviors", they wrote. "Intervention with a carotenoid-rich fruit smoothie may represent a viable mechanism for increasing fruit and vegetable intake, though this should take place as part of a healthy and balanced diet."
PLoS One. 2015 Jul 17;10(7):e0133445.
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