Cataracts

Cataracts develop when damage to the protein of the lens of the eye clouds the lens and impairs vision.

Most people who live long enough will develop cataracts.1 Cataracts are more likely to occur in those who smoke, have diabetes, or are exposed to excessive sunlight. All of these factors lead to oxidative damage. Oxidative damage to the lens of the eye appears to cause cataracts in animals2 and people.3

It is unlikely that any nutritional supplements or herbs can reverse existing cataracts.

Checklist for Cataracts

Rating Nutritional Supplements Herbs
2Stars Vitamin B2
Vitamin C		  
1Star Beta-carotene
Carotenoids
Lutein
Quercetin
Vitamin B3
Vitamin E		 Bilberry
See also:  Homeopathic Remedies for Cataracts
3Stars Reliable and relatively consistent scientific data showing a substantial health benefit.
2Stars Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.
1Star An herb is primarily supported by traditional use, or the herb or supplement has little scientific support and/or minimal health benefit.

What are the symptoms of cataracts? Cataracts usually develop slowly without any pain or redness of the eye. The most common symptoms of a cataract are fuzzy or blurred vision, increasing need for light when reading or doing other close work, visual disturbances caused by bright lights (e.g., sunlight, car headlights), faded color perception, poor night vision, and frequent need to change eyeglass or contact lens prescriptions. A cataract will not spread from one eye to the other, although many people develop cataracts in both eyes.

How is it treated? In the beginning stages, the use of magnifying lenses, stronger eyeglasses, and brighter lighting may compensate for the vision problems caused by cataracts. Once vision is no longer adequate for daily activities, a doctor may recommend surgery to remove the clouded lens and replace it with a clear artificial lens. In many people, the lens capsule remaining in the eye after surgery eventually turns cloudy, causing additional loss of vision.

Lifestyle changes that may be helpful: Obese men are significantly more likely to develop a cataract than are men of normal body weight.4 To date, most,5 6 7 8 but not all,9 10 population studies have found an increased risk of cataracts as body mass increases.

Nutritional supplements that may be helpful: People with low blood levels of antioxidants and those who eat few antioxidant-rich fruits and vegetables have been reported to be at high risk for cataracts.11 12

Vitamin B2 and vitamin B3 are needed to protect glutathione, an important antioxidant in the eye. Vitamin B2 deficiency has been linked to cataracts.13 14 Older people taking 3 mg of vitamin B2 and 40 mg of vitamin B3 per day were partly protected against cataracts in one trial.15 However, the intake of vitamin B2 in China is relatively low, and it is not clear whether supplementation would help prevent cataracts in populations where vitamin B2 intake is higher.

The major antioxidants in the lens of the eye are vitamin C16 and glutathione (a molecule composed of three amino acids).17 Vitamin C is needed to activate vitamin E,18 which in turn activates glutathione. Both nutrients are important for healthy vision. People who take multivitamins or any supplements containing vitamins C or E for more than 10 years have been reported to have a 60% lower risk of forming a cataract.19

Vitamin C levels in the eye decrease with age.20 However, supplementing with vitamin C prevents this decrease21 and has been linked to a lower risk of developing cataracts.22 23 Healthy people are more likely to take vitamin C and vitamin E supplements than those with cataracts according to some,24 but not all,25 studies. Dietary vitamin C intake has not been consistently associated with protection from cataracts.26 27 Nonetheless, because people who supplement with vitamin C have developed far fewer cataracts in some research,28 29 doctors often recommend 500 to 1,000 mg of vitamin C supplementation as part of a cataract prevention program. The difference between successful and unsuccessful trials may be tied to the length of time people actually supplement with vitamin C. In one preliminary study, people taking vitamin C for at least ten years showed a dramatic reduction in cataract risk, but those taking vitamin C for less than ten years showed no evidence of protection at all.30

Low blood levels of vitamin E have been linked to increased risk of forming cataracts.31 32 Dietary vitamin E intake has not been consistently associated with protection from cataracts.33 34 Vitamin E supplements have been reported to protect against cataracts in animals35 and people,36 though the evidence remains inconsistent.37 In one trial, people who took vitamin E supplements had less than half the risk of developing cataracts, compared with others in the five-year study.38 Doctors typically recommend 400 IU of vitamin E per day as prevention. Smaller amounts (approximately 50 IU per day) have been proven in double-blind research to provide no protection.39

Some,40 but not all,41 studies have reported that people eating more foods rich in beta-carotene had a lower the risk of developing cataracts. Supplementation with synthetic beta-carotene has not been found to reduce the risk of cataract formation.42 It remains unclear whether natural beta-carotene from food or supplements would protect the eye or whether beta-carotene in food is merely a marker for other protective factors in fruits and vegetables high in beta-carotene.

People who eat a lot of spinach and kale, which are high in lutein and zeaxanthin, carotenoids similar to beta-carotene, have been reported to be at low risk for cataracts.43 44 Lutein, zeaxanthin, and beta-carotene offer the promise of protection because they are antioxidants. It is quite possible, however, that lutein is more important than beta-carotene, because lutein is found in the lens of the eye, while beta-carotene is not.45 In one preliminary study, lutein and zeaxanthin were the only carotenoids associated with protection from cataracts.46 People with the highest intake of lutein and zeaxanthin were half as likely to develop cataracts as those with the lowest intake.

The flavonoid, quercetin may also help by blocking sorbitol accumulation in the eye.47 This may be especially helpful for people with diabetes, though no clinical trials have yet explored whether quercetin actually prevents diabetic cataracts.

Are there any side effects or interactions? Refer to the individual supplement for information about any side effects or interactions.

Herbs that may be helpful: Bilberry, a close relative of blueberry, is high in flavonoids called anthocyanosides.48 Anthocyanosides may protect both the lens and retina from oxidative damage. The potent antioxidant activity of anthocyanosides may make bilberry useful for reducing the risk of cataracts.49 50 Doctors sometimes recommend 240 to 480 mg per day of bilberry extract, capsules or tablets standardized to contain 25% anthocyanosides.

Are there any side effects or interactions? Refer to the individual herb for information about any side effects or interactions.

References:

1. Kahn HA, Leibowitz HM, Ganley JP, et al. The Framingham Eye Study: I. Outline and major prevalence findings. Am J Epidemiol 1977;106:17–32.

2. Schocket SS, Esterson J, Bradford B, et al. Induction of cataracts in mice by exposure to oxygen. Isr J Med Sci 1972;8:1596–601.

3. Palmquist B, Phillipson B, Barr P. Nuclear cataract and myopia during hyperbaric oxygen therapy. Br J Ophthalmol 1984;68:113–7.

4. Schaumberg DA, Glynn RJ, Christen WG, et al. Relations of body fat distribution and height with cataracts in men. Am J Clin Nutr 2000;72:1495–502.

5. Glynn RJ, Christen WG, Manson JE, et al. Body mass index. An independent predictor of cataract. Arch Ophthalmol 1995;113:1131–7.

6. Hankinson SE, Seddon JM, Colditz GA, et al. A prospective study of aspirin use and cataract extraction in women. Arch Ophthalmol 1993;111:503–8.

7. Hiller R, Podgor MJ, Sperduto RD, et al. A longitudinal study of body mass index and lens opacities. The Framingham Studies. Ophthalmology 1998;105:1244–50.

8. Tavani A, Negri E, La Vecchia C. Selected diseases and risk of cataract in women. A case-control study from northern Italy. Ann Epidemiol 1995;5:234–8.

9. Leske MC, Chylack LT Jr, Wu SY. The Lens Opacities Case-Control Study. Risk factors for cataract. Arch Ophthalmol 1991;109:244–51.

10. Mohan M, Sperduto RD, Angra SK, et al. India-US case-control study of age-related cataracts. India-US Case-Control Study Group. Arch Ophthalmol 1989;107:670–6. [published erratum appears in Arch Ophthalmol 1989;107:1288.]

11. Jacques PF, Chylack LT Jr. Epidemiologic evidence of a role for the antioxidant vitamins and carotenoids in cataract prevention. Am J Clin Nutr 1991;53:352S–5S.

12. Knekt P, Heliovaara M, Rissanen A, et al. Serum antioxidant vitamins and risk of cataract. BMJ 1992;305:1392–4.

13. Bhat KS. Nutritional status of thiamine, riboflavin and pyridoxine in cataract patients. Nutr Rep Internat 1987;36:685–92.

14. Prchal JT, Conrad ME, Skalka HW. Association of presenile cataracts with heterozygosity for galactosaemic states and with riboflavin deficiency. Lancet 1978; 1:12–3.

15. Sperduto RD, Hu TS, Milton RC, et al. The Linxian cataract studies. Arch Ophthalmol 1993;111:1246–53.

16. Taylor A, Jacques PF, Nadler D, et al. Relationship in humans between ascorbic acid consumption and levels of total and reduce ascorbic acid in lens, aqueous humor, and plasma. Curr Eye Res 1991;10:751–9.

17. Reddy VN. Glutathione and its function in the lens—an overview. Exp Eye Res 1990;150:771–8.

18. Packer JE, Slater TF, Wilson RL. Direct observation of a free radical interaction between vitamin E and vitamin C. Nature 1979;278:737–8.

19. Mares-Perlman JA, Lyle BJ, Klein R, et al. Vitamin supplement use and incident cataracts in a population-based study. Arch Ophthalmol 2000;118:1556–63.

20. Taylor A. Cataract: relationship between nutrition and oxidation. J Am Coll Nutr 1993;12:138–46 [review].

21. Taylor A, Jacques PF, Nadler D, et al. Relationship in humans between ascorbic acid consumption and levels of total and reduced ascorbic acid in lens, aqueous humor, and plasma. Curr Eye Res 1991;10:751–9.

22. Jacques PF, Chylack LT Jr. Epidemiologic evidence of a role for the antioxidant vitamins and carotenoids in cataract prevention. Am J Clin Nutr 1991;53:352S–5S.

23. Jacques PF, Chylack LT, McGandy RB, Hartz SC. Antioxidant status in persons with and without senile cataract. Arch Ophthalmol 1988;106:337–40.

24. Robertson JMD, Donner AP, Trevithick JR. Vitamin E intake and risk of cataracts in humans. Ann NY Acad Sci 1989;570:372–82.

25. Seddon JM, Christen WG, Manson JE, et al. The use of vitamin supplements and the risk of cataract among US male physicians. Am J Public Health 1994;84:788–92.

26. Lyle BJ, Mares-Perlman JA, Klein BE, et al. Antioxidant intake and risk of incident age-related nuclear cataracts in the Beaver Dam Eye Study. Am J Epidemiol 1999;149:801–9.

27. Chasan-Taber L, Willett WC, Seddon JM, et al. A prospective study of vitamin supplement intake and cataract extraction among U.S. women. Epidemiology 1999;10:679–84.

28. Robertson J McD, Donner AP, Trevithick JR. A possible role for vitamins C and E in cataract prevention. Am J Clin Nutr 1991;53:346S–51S.

29. Hankinson SE, Stampfer MJ, Seddon JM, et al. Nutrient intake and cataract extraction in women: a prospective study. BMJ 1992;305:335–9.

30. Jacques PF, Taylor A, Hankinson SE, et al. Long-term vitamin C supplement use and prevalence of early age-related lens opacities. Am J Clin Nutr 1997;66:911–6.

31. Rouhiainen P, Rouhiainen H, Salonen JT. Association between low plasma vitamin E concentration and progression of early cortical lens opacities. Am J Epidemiol 1996;144:496–500.

32. Lyle BJ, Mares-Perlman JA, Klein BE, et al. Serum carotenoids and tocopherols and incidence of age-related nuclear cataract. Am J Clin Nutr 1999;69:272–7.

33. Lyle BJ, Mares-Perlman JA, Klein BE, et al. Antioxidant intake and risk of incident age-related nuclear cataracts in the Beaver Dam Eye Study. Am J Epidemiol 1999;149:801–9.

34. Chasan-Taber L, Willett WC, Seddon JM, et al. A prospective study of vitamin supplement intake and cataract extraction among U.S. women. Epidemiology 1999;10:679–84.

35. Trevithick JR, Creighton MO, Ross WM, et al. Modelling cortical cataractogenesis: 2. In vitro effects on the lens of agents preventing glucose- and sorbitol-induced cataracts. Can J Ophthalmol 1981;16:32–8.

36. Robertson J McD, Donner AP, Trevithick JR. A possible role for vitamins C and E in cataract prevention. Am J Clin Nutr 1991;53:346S–51S.

37. Seddon JM, Christen WG, Manson JE, et al. The use of vitamin supplements and the risk of cataract among US male physicians. Am J Public Health 1994;84:788–92.

38. Leske MC, Chylack LT Jr, He Q, et al. Antioxidant vitamins and nuclear opacities. The Longitudinal Study of Cataract. Ophthalmology 1998;105:831–6.

39. Teikari JM, Virtamo J, Rautalahti M, et al. Long-term supplementation with alpha-tocopherol and beta-carotene and age-related cataract. Acta Ophthalmol Scand 1997;75:634–40.

40. Hankinson SE, Stampfer MJ, Seddon JM, et al. Nutrient intake and cataract extraction in women: a prospective study. BMJ 1992;305:335–9.

41. Chasan-Taber L, Willett WC, Seddon JM, et al. A prospective study of vitamin supplement intake and cataract extraction among U.S. women. Epidemiology 1999;10:679–84.

42. Teikari JM, Virtamo J, Rautalahti M, et al. Long-term supplementation with alpha-tocopherol and beta-carotene and age-related cataract. Acta Ophthalmol Scand 1997;75:634–40.

43. Hankinson SE, Stampfer MJ, Seddon JM, et al. Nutrient intake and cataract extraction in women: a prospective study. BMJ 1992;305:335–9.

44. Chasan-Taber L, Willett WC, Seddon JM, et al. A prospective study of carotenoid and vitamin A intakes and risk of cataract extraction in US women. Am J Clin Nutr 1999;70:509–16.

45. Yeum K-J, Taylor A, Tang G, Russell RM. Measurement of carotenoids, retinoids, and tocopherols in human lenses. Ophthalmol Vis Sci 1995;36:2756–61.

46. Lyle BJ, Mares-Perlman JA, Klein BE, et al. Antioxidant intake and risk of incident age-related nuclear cataracts in the Beaver Dam Eye Study. Am J Epidemiol 1999;149:801–9.

47. Varma SD, Mizuno A, Kinoshita JH. Diabetic cataracts and flavonoids. Science 1977;195:205.

48. Van Acker SA, van den Berg DJ, Tromp MN, et al. Structural aspects of antioxidant activity of flavonoids. Free Rad Biol Med1996; 20:331–42.

49. Salvayre R, Braquet P, et al. Comparison of the scavenger effect of bilberry anthocyanosides with various flavonoids. Proceed Intl Bioflavonoids Symposium, Munich, 1981, 437–42.

50. Bravetti G. Preventive medical treatment of senile cataract with vitamin E and anthocyanosides: clinical evaluation. Ann Ottamol Clin Ocul 1989;115:109.