Your daily fruit and veg intake discernibly dictates the colour of your face, new research has shown.
Scientists at the University of St Andrews in Scotland began by asking 35 students to complete questionnaires logging their average daily intake of fruit and vegetables. These individuals, the data show, consumed a modestly healthy 3.41 fruit and vegetable portions per day.
Next, at three and six week time-points, the students' faces and other skin areas were imaged, the colours analysed and the results compared with the diet records.
Changes in fruit and vegetable intake during the study period, the St Andrews team found, were reflected in skin colour changes in the participants. Specifically, changes were seen in colours corresponding to the carotenoid antioxidants with which vegetables and fruits are richly endowed.
But were these changes perceptible to a person, or merely to a sensitive camera? To find out, Ross Whitehead, the lead author on the study which is published this week in the journal PLoS One, showed a second group of volunteers pairs of images prepared from four faces.
These had been manipulated to add increasing amounts of yellow colouration to the skin over a series of 22 otherwise identical images of the same face. This colour difference would have corresponded to a variation in intake of 5.55 daily portions of fruits and vegetables.
The study participants were asked to rate pairs of images of the same face as more or less healthy. Initially they were shown faces at each end of the 22-face spectrum; if they chose correctly, faces progressively nearer to one another on the colour spectrum were presented.
The subjects could discriminate a colour difference equivalent to consuming 1.89 more, or fewer, portions of fruit and veg per day.
This ties in with what has already been observed in other human studies: people rate yellower faces as more healthy and given free rein to digitally manipulate photos of faces, most people add extra yellow, mimicking the effect of extra betacarotene, the orange chemical in carrots.
The results also resonate with what goes on in the natural world. Dietary antioxidants alter animal colours and this can be used by potential partners as a measure of an individual's health and likely mating prowess. Individuals with a good diet, healthy lifestyle and antioxidants to spare can afford to spend some on making their skins look a nice colour! Humans, it seems, are no different.
So, rather than a fake tan and a nose job, the way to pull, it appears, is instead to reach for your banana and a healthy helping of nuts...
I am surprised that an extra amount of yellowness is perceived as being healthy or more attractive. Yellow can be sallow skin or jaundice. Western caucasian culture perceives a healthy golden tan to be desirable, but thius is rooted in socio-economic reasons rather than dietary. On the opposite side of the argument, the Indian nation now spends millions of dollars a year on skin lightening cosmetics as a paler skin is perceived to be a sign of wealth and higher caste. This mimics the earlier historical times in Europe when pale skin meant good breeding and wealth - it was the poorer folk that had to work on the fland every day gaining a ruddy, tanned complexion.
There's probably a lot you can tell from just the face. People with hyper or hypothyroidism have very distinctive looks (see google images.) Cranial nerve damage can result in altered expressions, like a crooked smile, drooping eye lid. Parkinsons gives a mask like appearence. I think some forms of hyperlidemia cause yellowish fatty deposits in the face. cheryl j, Thu, 15th Mar 2012
The body images pandered to by the cosmetic industry are designed to bolster your self-image on a cultural and status score. They do not reflect scientific measurements of health. grizelda, Mon, 19th Mar 2012
Indeed; well said. chris, Mon, 19th Mar 2012