Long-term Vitamin C intake and also a combination of antioxidants lower the risk of nuclear cataract, the most common kind, in older people: results of the Blue Mountains Eye Study.

November 30, 2009

  Researchers at the Department of Ophthalmology, Centre for Vision Research, at the University of Sydney in Australia note that oxidative stress (we take antioxidants to prevent this) is implicated in the formation of cataracts and that long-term intake of antioxidants may offer protection against cataract production. They investigated relations between antioxidant nutrient intakes measured at baseline (the very start of the study) and the 10-year incidence of age-related cataract.
     During the years 1992 through 1994 the researchers recruited 3654 people 49 years of age or older into the study. Of these persons, 2464 (67.4%) participants were followed for either 5 or 10 years after the start of the study. At each examination, lens photography was performed and questionnaires were administered, including a 145-item semi quantitative food-frequency questionnaire. Antioxidants, including beta-carotene, zinc, and vitamins A, C, and E, were assessed. Cataract was assessed at each examination from lens photographs with the use of the Wisconsin Cataract Grading System. Nuclear cataract was defined for opacity greater than standard 3. Cortical cataract was defined as cortical opacity >or= 5% of the total lens area, and posterior subcapsular (PSC) cataract was defined as the presence of any such opacity.
     Participants in the highest 20% of total intake (diet + supplements) of vitamin C had a reduced risk of incident nuclear cataract by 45%. An above-median intake of combined antioxidants (vitamins C and E, beta-carotene, and zinc) was associated with a reduced risk of incident nuclear cataract by 49%. Antioxidant intake was not associated with incident cortical or PSC cataract.  The researchers conclude that a higher intake of vitamin C or the combined intake of antioxidants had long-term protective associations against the development of nuclear cataract in this older population. The study is published in the June 2008 issue of the American Journal of Clinical Nutrition.

Cataract patients have much lower levels of Vitamin C in their blood than individuals with healthy eyes

     Dietary antioxidant vitamins, in particular vitamin C, could play a role in preventing the onset or progression of age-related visual impairment. In this study the test group included 50 cataract patients, while the control cataract-free group members were selected among medical staff and patients' companions after age matching with the test group. The mean plasma ascorbic acid level in the cataract group was much lower than the level in the cataract-free control group. This study revealed that the plasma ascorbic acid level in cataract patients is lower than in normal individuals. Antioxidant vitamins, in particular vitamin C can help with the prevention of cataracts, which is a major health service burden in many countries. The study is published in the February 2009 issue of the journal Current Eye Research/
Vitamin C reduces the risk of cataract

     A very large study from Japan shows that high intake of Vitamin C helps prevent cataracts. The study followed 35,186 people between the ages of 45-64 for five years. It found that men consuming the most Vitamin C cut their risk of developing a cataract by 35% vs. those with the lowest intake. Women reduced their risk by 41% (highest vs. lowest intake); it’s interesting to note that women who reduced their risk by 40% had a higher Vitamin C intake than men who reduced their risk by a third – both groups consumed far more than the RDA. The study is published in the January 30th, 2007 issue of the European Journal of Nutrition.
Long-term intake of Vitamin C or C with E, Beta-Carotene and Zinc reduces the risk of cataract
     Free radical damage is implicated in the formation of cataracts. Long-term intake of antioxidants may therefore protect us from developing cataracts. To test the theory 2464 individuals at least 49 years of age were followed for 10 years as part of the Blue Mountains Eye Study. The lens of their eyes was photographed at predetermined intervals and their diet was followed for antioxidant content.
     Participants with the highest intake of Vitamin C when adding diet and supplementation had a 45% drop in the risk of developing nuclear cataracts. A higher intake of Vitamins C, and E, Beta-Carotene, and Zinc reduced the risk of developing nuclear cataracts by 49%. The study is published in the June 2008 issue of The American Journal of Clinical Nutrition.
Lutein + Zeaxanthin along with Vitamins C and E and the mineral Zinc preserve vision in sick eyes
     Researchers from the Queen’s University Centre of Vision and Vascular Science and the Waterford Institute of Technology reported that a supplement containing high amounts of the carotenoids Lutein and Zeaxanthin in addition to the antioxidant nutrients zinc and vitamins C and E, helped preserve macular pigments in patients with age related macular degeneration (AMD), retarding the progression of early to late stage disease. Macular degeneration is the leading cause of vision loss among older individuals.
     433 subjects with early stage macular degeneration received the nutritional supplement or a placebo. The subjects, whose average age was 77 upon enrollment, were followed from October, 2004 to March, 2008. While participants who received the placebo experienced a steady decline in protective macular pigments, these pigments were preserved in those who received Lutein and Zeaxanthin. The researchers state that “Late AMD causes severe sight loss and has a huge economic impact both in terms of the effects of sight loss itself and in terms of the expensive treatments that are needed to deal with the condition.” “These findings are important because this is the first randomized controlled clinical trial to document a beneficial effect through improved function and maintained macular pigments” they note. The research is available on the Queen’s University Centre of Vision and Vascular Science website.
Vitamin C with Vitamin E supplements protect from senile mental decline

     Researchers examined the data from the Canadian Study of Health and Aging: a population based investigation following individuals over 65 years of age for 5 years. The participants were given the Modified Mini Mental State test to determine signs of dementia at the beginning of the study. The 894 people with no sign of dementia at the start of the study were followed closely to assess the protective effects of antioxidant supplements. Individuals reporting a combined use of Vitamin C with Vitamin E supplements and/or Multivitamin use at the start of the study were significantly less likely to experience significant cognitive decline during a 5-year follow up period, cutting their risk in half. Any antioxidant supplement use had some protective value. The study is published in the April 2005 issue of the journal Dementia and Geriatric Cognitive Disorders.
Vitamin C and Vitamin E taken together very protective against Alzheimer's disease

     Researchers have found that Vitamin C and Vitamin E protect the aging brain - but only if taken together and at a sufficient strength. Researchers at Johns Hopkins University in Maryland examined data on 4,740 people at or over the age of 65. The researchers found that taking a daily supplement of Vitamin C at 500mg a day or greater along with Vitamin E at 400 IU a day or greater, when taken in combination, decreased the likelihood of developing signs of Alzheimer's disease by 78% in the general public. Those not taking the combination or taking lower dosages did not have protection. The study is published in the journal Archives of Neurology a journal of the American Medical Association.