Why purple carrots as opposed to orange for eyes?
Did you ever listen to your granny when you were a young whippersnapper and she used to tell you that eating up all your carrots would help you see in the dark? No? Well perhaps you should have as there may just be some truth in this old wives tale! Carrots are extremely rich in the carotenoids α- and β-carotene which are converted into Vitamin A in the body. Vitamin A is beneficial for the eyes and interestingly for night vision in particular.
But now, how many of you have come across a purple carrot? Do you know that carrots started off purple? And it turns out we perhaps shouldn’t have been so hasty in switching to the orange variety! Purple carrots are little nutrient powerhouses it seems – together with the β-carotene content we’d expect of a carrot, there are quite a few added extras in there too.
What are the extra eye-boosting components of purple carrots?
So, first we have the presence of another group of antioxidants called anthocyanins which is what gives these carrots their distinctive purple colour. As with carotenoids, anthocyanins are thought to be beneficial for many aspects of your health including the cardiovascular system and age-related disorders of the eyes1 such as macular degeneration or cataracts.
Other purple fruits including bilberries, blackcurrants and blueberries have traditionally been used to support the health of the eyes too, and a lot of this is thought to be down to this very ingredient. So, could purple carrots be the next big thing?
Plus, there’s more! Purple carrots have another thing going for them – they’re also rich in another carotenoid called lutein (not to mention boasting much larger amounts than their orange cousins), and guess what? Lutein and eyes go way back.
Not only is lutein an additional carotenoid to add to the list of beneficial components of purple carrots, research also suggests that the bio-availability of lutein from vegetables is up to five times higher than that of β-carotene!2 This is impressive, especially as we already know that the bioavailability of the β-carotene from regular carrot juice is good to start with.3
Lutein and Macular degeneration
Now, let’s talk lutein. A pivotal study back in 1994 was one of the first to show that a higher dietary intake of carotenoids was associated with a lower risk of age-related macular degeneration4. When split into 5 groups ranking in order of their carotenoid consumption, the group with the largest intake versus that with the lowest had a 43% lower risk of developing the degenerative eye condition! Further to this already impressive result, the specific carotenoids lutein and zeaxanthin were most strongly associated with the reduced risk4.
So, these results are quite something. And what better way to up your intake? How about by adding some Purple Carrot Juice to your already veggie-packed diet (I hope).
In 2004, a randomized control trial was carried out on participants who had already developed aged-related macular degeneration.6 Lutein was given to half the participants, and results showed a significant improvement in this group in comparison to the control group. This benefit was apparent with both taking lutein alone, and in combination with other nutrients (as you would expect when consuming lutein naturally through food for example). Lutein as a treatment for people already suffering from eye conditions needs to be subject to more research but these results are certainly intriguing.
Lutein and Cataracts
Much like disease and death in general, incidences of cataracts has been linked to poor nutrition7 and further to this, it’s now thought that deficiencies in specific eye-friendly carotenoids, lutein and zeaxanthin, are of particular relevance.8
A small study in 2003 showed that treatment with 15mg of lutein for 2 years actually helped to improve visual performance scores in participants with cataracts.9 This was in comparison to other control groups who were treated with vitamin E or a placebo instead. The control groups saw no improvement, but instead, a trend towards deterioration of their eye health.
A more recent, large-scale study following women long-term, split their participants into 5 groups ranking in order of their intake of carotenoids. Women with the highest carotenoid intake, versus those with the lowest, had a 32% lower incidence rate of cataracts.10 However, as much as this indicates that dietary intake of carotenoids seems protective, it was hard to adjust for other aspects of the partipants’ diets in the case of this study. So a woman who eats lots of purple carrots may also partake in some other eye-boosting pastimes! This is known as confounding factors and they should ideally be adjusted for.
So, to sum up, although more evidence is still needed, (especially in terms of lutein as a treatment for eye problems) the research out there supporting purple carrots in helping to maintain and support eye health is looking pretty good! It looks like adding in Biotta’s Purple Carrot Juice to an already healthy lifestyle may just offer some protection to those eyes of yours – worth a try!
1. Zafra-Stone, S. et al Berry anthocyanins as novel antioxidants in human health and disease prevention. Mol Nutr Food Res. 2007, 51(6), (675-683)
2. van het Hof, K.H. et al. Bioavailability of lutein from vegetables is times higher than that of β-carotene. Am J Clin Nutr. 1999, 70(2), p261-268
3.Müller, H., Bub, A., Watzl, B. et al. Plasma concentrations of carotenoids in healthy volunteers after intervention with carotenoid-rich foods. Eur J Nutr 1999, 38(1): (35-44).
4. Seddon, J.M. Dietary carotenoids, vitamins A, C and E and advanced age-related macular degeneration. Eye Disease Case Control Study Group. 1994, 272(18), (1413-1420)
5. SanGiovanni, J.P. The relationship of dietary carotenoids and vitamin A, E and C intake with age-related macular degeneration in a case control study: AREDS Report No.22. Arch Ophthalmol. 2007, 125(9), (1225-1232)
6. Richer, S, et al. Double-masked, placebo-controlled, randomized trial of lutein and antioxidant supplementation in the intervention of atrophic age-related macular degeneration: the Veterans LAST study (Lutein Antioxidant Supplementation Trial)". Optometry. 2004, 75 (4): 216–30
7. Das, B.N.; Thompson, J.R.; Patel, R.; Rosenthal, A.R. The prevalence of age-related cataracts in the Asian community of Leicester: A community based study. Eye, 1990, 4, 723–726
8. Abdel-Aal, E.M. et al. Dietary sources of lutein and zeanthin carotenoids and their role in eye health. Nutrients. 2013, 5(4), 1169-1185
9. Olmedilla, B. Et al. Lutein, but not alpha-tocopherol supplementation improves visual function in patients with age-related cataracts: a 2-y double blind, placebo-controlled pilot study. Nutrition. 2003, 19(1), 21-24
10. Moeller, S.M. et al. Associations between age-related nuclear cataract and lutein and zeaxanthin in the diet and serum in the Carotenoids in the Age-Related Eye Disease Study, an Ancillary Study of the Women's Health Initiative. Arch Ophthalmol. 2008, 126 (3): 354–64.