Dr. Grossman’s Blog

Lutein May Help Visual Contrast Sensitivity for Computer Users

Lutein is known to be an essential nutrient in helping prevent the onset of macular degeneration. Researchers now believe that lutein may also help protect against the detrimental effects of long-term computer display light exposure.

A study published in the British Journal of Nutrition indicates that improvements in the eye’s sensitivity to contrast on a computer screen were observed following 12 weeks of supplementation with lutein.

Scientists at the Peking University in China studied 37 healthy individuals aged 22 to 30 who had long-term computer display light exposure. Participants were randomly assigned to one of three groups: one group was given placebos, one group was given 6 milligrams of lutein daily, and one group was given 12 milligrams of lutein daily.

Levels of serum lutein and visual performance indices such as visual acuity, contrast sensitivity and glare sensitivity were measured at the beginning of the study and again at 12 weeks.

After 12 weeks researchers found an increase in blood levels of lutein in both lutein groups. The study authors noted: “Visual function in healthy subjects who received the lutein supplement improved, especially in contrast sensitivity, suggesting that a higher intake of lutein may have beneficial effects on the visual performance.”

Lutein can be found in green leafy vegetables and egg yolks. Learn about food sources for nutrients important to good eye health, including lutein.

Read other studies about the benefits of lutein for good eye health

SOURCE: “A 12-week lutein supplementation improves visual function in Chinese people with long-term computer display light exposure”, Ma, et al, British Journal of Nutrition, Published online by Cambridge University Press 19 Feb 2009 doi:10.1017/S0007114508163000.

A team of Harvard researchers found that women who took a combination of folic acid and vitamins B6 and B12 had a 35% to 40% lower risk of developing age related macular degeneration (AMD) than women who took a placebo.

A group of 5442 female health care professionals 40 years or older (of whom 5205 did not have a diagnosis of AMD at the beginning of the study) received either a combination of folic acid/B6/B12 or a placebo.

After more than seven years of treatment and follow-up, 137 women were diagnosed with AMD.  Of these 137:

• 55 had been taking the supplements; 82 had been taking the placebo.
• 70 had ‘visually significant AMD’, including 26 who had been taking the supplements and 44 who had been taking the placebo.

Researchers concluded that daily supplementation with folic acid, pyridoxine (vitamin B6), and cyanocobalamin (vitamin B12) may reduce the risk of AMD.

Learn about good food sources for nutrients such as folic acid and vitamin B

Find nutritional products and supplements to supply folic acid and vitamin B

SOURCE:  “Folic Acid, Pyridoxine, and Cyanocobalamin Combination Treatment and Age-Related Macular Degeneration in Women”, Christen et al, Arch Intern Med. 2009;169(4):335-341.

University of Liverpool scientists claim that macular degeneration could be reduced by up to 20% by increasing the amount of fruit, vegetables and nuts in the diet.

Age-related macular degeneration (AMD) is a leading cause of blindness, as individuals gradually lose their central vision due to the failure of cells in the macula (the light sensitive membrane at the center of the retina).

Professor Ian Grierson, Head of Ophthalmology at the University of Liverpool, said: “Poor eating habits have a huge impact on health in general and the health of your eyes is no exception. Eye problems such as AMD, cataract and even glaucoma can all be affected by what we eat. But a relatively minor change in diet – adding a little more fruit into our meals – can make a profound difference and can keep eye diseases like AMD at bay for up to 20% longer.

“There are of course other risk factors related to AMD such as age, light exposure, smoking and being overweight. But if we can improve the kind of food that we eat, we could dramatically reduce the number of people who may suffer from eye diseases in the future.”

Grierson recommends incorporating fruits and nuts as minor additions to what we already eat, such as peaches with ham or ginger with melon.  He believes this will help slow down or even prevent the degeneration process by increasing micronutrient, vitamin and antioxidant intake in the diet.

Learn more about food sources for nutrients important to eye health

SOURCE:  “Diet Could Reduce Onset Of Eye Disease By 20%”, University of Liverpool (2009, February 18),  http://www.liv.ac.uk/news/press_releases/2009/02/Diet-could-reduce-onset-of-eye-disease.htm

Fresh-cut fruits is one of the fastest growing food categories in U.S. supermarkets, but what effect does processing and storage have on the nutritional value of the fruit?

Surprisingly, an international team of scientists has found that cutting and packaging fruit had almost no affect on the main antioxidants.

Their report, published in the Journal of Agricultural & Food Chemistry, shows that fresh-cut fruit retains vitamin C and other healthful antioxidants after days on the shelf.

The researchers obtained pineapples, mangoes, cantaloupes, watermelons, strawberries and kiwifruits from wholesale commercial sources in California.  The fruit was taken to a laboratory at the University of California in Davis. Half of each lot was processed as fresh-cut and half left whole.

Both lots were refrigerated under identical conditions for nine days and then tested for nutrient content. Tests showed only small losses of antioxidant compounds in the cut fruit compared to fruit left whole. Levels of some antioxidants in fresh-cut mango and watermelon actually increased due to exposure to light.

In general, researchers found that fresh-cut fruits visually spoil before any significant nutrient loss occurs. 

Learn more about antioxidants

Read other articles about the benefits of antioxidants for good eye health

SOURCE:  Quality Changes and Nutrient Retention in Fresh-Cut versus Whole Fruits during Storage, Gil et al, J. Agric. Food Chem., 2006, 54 (12), pp 4284–4296.

Age-related macular degeneration (AMD) is the most prevalent cause of irreversible blindness in developed countries. Researchers have shown that high dietary intake of beta carotene, vitamins C and E, and zinc may substantially reduce the risk of AMD.

Scientists at the Erasmus Medical Centre in the Netherlands investigated whether regular dietary intake of antioxidants is associated with a lower risk of incident AMD.

Participants in the study included 7983 inhabitants aged 55 years or older in a middle-class suburb of Rotterdam, the Netherlands. A baseline home interview and a series of examinations at the study center were conducted from 1990 until 2004. Food intake was assessed with a food questionnaire, and participants were evaluated for incident AMD (defined as soft distinct drusen with pigment alterations, indistinct or reticular drusen, geographic atrophy, or choroidal neovascularization). Incident AMD occurred in 560 participants after follow-up exams (conducted 8 years later, on average).

Study results showed that participants who consumed vitamin E and zinc were less likely to have AMD.

An above-median consumption of all 4 nutrients studied (beta carotene, vitamin C, vitamin E, and zinc) was associated with a 35% reduced risk of AMD.

Learn more about macular degeneration (AMD)

Find excellent food sources for beta carotene, vitamin C, vitamin E and zinc

SOURCE: Dietary intake of antioxidants and risk of age-related macular degeneration, Leeuwen et al, JAMA, 2005 Dec 28;294 (24):3101-7.

Evidence continues to show that oxidative stress contributes to age-related maculopathy (ARM) and that consuming appropriate antioxidants such as zeaxanthin may protect against this condition. 

The term maculopathy is associated with diseases of the macula, an area at the center of the retina that is associated with highly sensitive, accurate vision.  Age-related macular degeneration (AMD) is an example of maculopathy.

A study published in the American Journal of Clinical Nutrition investigated the link between lower intakes of antioxidants and ARM.   828 healthy Irish participants between the ages of 20 and 60 years were analyzed for risk factors for ARM and dietary intake of relevant nutrients.

Researchers showed that several variables related to risk for ARM are associated with a relative lack of key nutrients in the diet.  They determined that the most important and universal risk factor for ARM is a lack of dietary zeaxanthin.

Zeaxanthin is one of the two carotenoids contained within the retina of the eye.  Ultraviolet radiation is absorbed by the lens, but visible or “blue” light penetrates to the retina, enabling us to see.  Along with lutein, zeaxanthin absorbs the potentially harmful effects of blue light.

How can you ensure you are consuming zeaxanthin?  Good dietary sources include green vegetables such as spinach, kale, turnip greens, collard greens, romaine lettuce, broccoli, zucchini, corn, garden peas and Brussels sprouts.

Read more about antioxidants and nutrient food sources for good eye health

Learn about natural zeaxanthin products

SOURCE:  O’Connell, et al, Diet and risk factors for age-related maculopathy, American Journal of Clinical Nutrition, Vol. 87, No. 3, 712-722, March 2008.

A study published in the American Journal of Clinical Nutrition found that eating one portion of omega-3 fatty acid-rich fish per week may reduce the risk of age-related macular degeneration (AMD) by over 50 percent.

2,275 people over 65 years of age participated in the EUREYE Study. They were given eye exams and completed a food frequency questionnaire.

Researchers found that oily fish was consumed less than once per week by 64% of the study population, once per week by 25%, and twice per week or more by 12%.

Those eating oily fish at least once per week had a 50% reduced risk of a type of AMD called neovascular AMD (NV-AMD), while those eating oily fish at least twice per week had a 58% reduced risk.

Good choices for fish rich in omega-3 fatty acids are cold water oily fish such as salmon, herring, mackerel, anchovies and sardines.

Read other research showing the benefits of omega-3 fatty acids for healthy vision

Learn more about natural omega-3 vision supplements

SOURCE: Augood, et al; Oily fish consumption, dietary docosahexaenoic acid and eicosapentaenoic acid intakes, and associations with neovascular age-related macular degeneration; Am. J. Clinical Nutrition, Vol. 88, No. 2, 398-406, August 2008.

Scientists have long known that our diets influence our risk of age-related macular degeneration (AMD).  High glycemic-index diets have now been identified as a risk factor for AMD by researchers from the University of Sydney and the University of Melbourne in Australia, and the National University of Singapore.

The glycemic index (GI) is a measure of the effects of carbohydrates on blood glucose levels.  Carbohydrates that break down rapidly during digestion releasing glucose rapidly into the bloodstream have a high GI; carbohydrates that break down slowly, releasing glucose gradually into the bloodstream, have a low GI.

Scientists examined the association between the dietary glycemic index and the incidence of AMD in the Blue Mountain Eye Study population.

During 1992–1994, 3654 people aged 49 years or older attended baseline examinations.  Of these, 2335 patients were reexamined after 5 years and 1952 were examined again after 10 years.  At each examination, lens photography was performed and food-frequency questionnaires were administered.  An Australian database was used to calculate the mean glycemic index.

Over 10 years, 208 of 1810 participants developed early AMD. After adjusting for age, smoking, and other risk factors, a higher mean dietary glycemic index was associated with an increased risk of early AMD. 

Conversely, a greater consumption of predominantly lower glycemic index foods was associated with a reduced risk of incident early AMD. No relation was observed with late AMD.

Researchers concluded that a high-glycemic-index diet is a risk factor for early AMD, but they also noted that low glycemic-index foods such as oatmeal may protect against early AMD.

Learn more about the glycemic index and use a free GI database to find the GI index of your favorite carbohydrates at this University of Sydney Glycemic Index web site

SOURCE:  Kaushik, et al, Dietary glycemic index and the risk of age-related macular degeneration,  American Journal of Clinical Nutrition, Vol. 88, No. 4, 1104-1110, October 2008.

Cataracts are the leading cause of blindness around the world.  Studies suggest that oxidation is responsible for much of the damage to the lens and that antioxidants might protect the lens against formation of cataract.

Scientists at the University of Sydney and the University of Melbourne in Australia have released their investigation of the relationship between antioxidant nutrient intakes and the incidence of age-related cataract.

During 1992–1994, 3654 people aged 49 years or older attended baseline examinations as part of the Blue Mountains Eye Study.  Of these, 2464 (67.4%) of the participants were evaluated again at either 5 years or 10 years.  At each examination, lens photography was performed and food-frequency questionnaires were administered.  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.

Participants whose total intake of vitamin C (diet as well as supplements) was in the top 20% of the group had a reduced risk of nuclear cataract.  An above-median intake of combined antioxidants (vitamins C and E, beta-carotene, and zinc) was also associated with a reduced risk of incident nuclear cataract. 

Study authors concluded that higher intakes of vitamin C or the combined intake of antioxidants had long-term protective associations against development of nuclear cataract in this older population.

Learn more about antioxidants and their importance for good eye health

Read more about cataracts

SOURCE:  Tan, et al, Antioxidant nutrient intake and the long-term incidence of age-related cataract: the Blue Mountains Eye Study,  American Journal of Clinical Nutrition, Vol. 87, No. 6, 1899-1905, June 2008.

Accumulated weight around the waist (abdominal fat) may be linked to an increased risk of age-related macular degeneration (AMD). AMD is the most common cause of loss of vision and blindness in adults.

A recent study published in the Archives of Ophthalmology examined the association between changes in the waist-to-hip ratio (a measure of abdominal obesity) and risk of AMD. A total of 12,515 people aged 45 to 64 were followed over six years.

Researchers found that a higher waist-to-hip ratio (WHR) was associated with elevated risk of AMD.

The good news is that study participants who reduced their WHR generally saw a reduction in risk of AMD. Overall, a 3 per cent or more decrease in WHR was associated with a 29 per cent reduced risk of AMD. The effect was greatest among those participants classified as obese: a decrease in WHR was associated with 59% lower odds of AMD.

Researchers concluded that middle-aged people who had a 3% or greater reduction in WHR over time were less likely to have AMD, particularly among those who were initially obese.

Learn more about Age-Related Macular Degeneration (AMD)

SOURCE: Peeters, et al. Changes in Abdominal Obesity and Age-Related Macular Degeneration: The Atherosclerosis Risk in Communities Study, Arch Ophthalmol. 2008;126(11):1554-1560