Diet rich in nutrients is a feast for the eyes
Michelle Gelok
* Last Updated: March 30. 2009 8:30AM UAE / March 30. 2009 4:30AM GMT
Nutrients found in foods such as carrots, spinach, walnuts and kale have been shown to improve eye health.
While most of us wouldn’t think twice about wearing protection to shield our eyes from the harsh desert sun, few consider the foods we eat and their impact on the health of our peepers.
Science continues to show us that certain nutrients are needed by parts of the body to function properly and ward off disease. Calcium is known to boost bone health and prevent osteoporosis, and vitamin C can prevent scurvy. Based on new research, it seems that eye health is no exception. Studies show that nutrients play a role in maintaining healthy eyes and vision.
Vitamin A
Carrots have long been touted for their link to eye health, and for good reason. Carrots are rich in vitamin A, a nutrient that helps the retina function properly and is essential for general eye health. In fact, according to the World Health Organization, vitamin A deficiency is the leading cause of preventable blindness in children. A low level of this fat-soluble vitamin is also linked to night blindness. You can get a hefty dose of vitamin A from organ meats, orange root vegetables such as sweet potatoes and carrots, and green leafy vegetables including spinach and kale.
Omega-3 fatty acids
Omega-3 fatty acids, which are well known for their heart health benefits and anti-inflammatory properties, are beginning to make their mark when it comes to eye health. They have been shown to protect against age-related macular degeneration – a disease associated with ageing that affects the retina and is a leading cause of blindness in adults. In fact, a study published last year in the Archives of Ophthalmology reviewed data on more than 88,000 people and found that a high intake of omega-3 fatty acids was associated with a 38 per cent reduction in the risk of age-related macular degeneration. The same study also found that eating fish at least twice a week was associated with a 24 per cent lower risk of the condition. Other dietary sources rich in omega-3 acids include ground flaxseeds, walnuts and soybeans.
Lutein and zeaxanthin
Lutein and zeaxanthin are yellow pigments linked to eye health. These compounds act as antioxidants and are found in the lens and retina of the eye, protecting against both age-related macular degeneration and cataracts. One study found that people with the highest self-reported intake of foods rich in lutein and zeaxanthin were 35 per cent less likely to experience age-related macular degeneration. These pigments aren’t just found in the eyes; they are also found in food, which means it’s easy to stock up. You don’t have to look far to find rich dietary sources of lutein and zeaxanthin: spinach, kale, squash, green peas, broccoli and corn are full of such goodness.
Vitamin C
While vitamin C may be best known for its ability to fight off the common cold, it turns out it can offer some protection for your eyes as well. Research shows this powerful antioxidant may play an important role in the prevention of cataracts and age-related macular degeneration. A study published in the Archives of Ophthalmology found that people most likely to suffer from vision impairment lowered their risk by 25 per cent when treated with a high-dose vitamin C supplement that also included vitamin E, beta-carotene and zinc.
What’s more, preliminary animal studies have shown that long-term vitamin C supplementation may play a role in the prevention of diabetic retinopathy – a leading cause of blindness in diabetics. While these studies both used supplements, eating vitamin C-rich foods remains an easy way to meet your daily requirement, with the added benefit of other vitamins, minerals and fibre. The best dietary sources of vitamin C include papaya, red bell peppers, kiwi fruit and oranges.
Low glycemic index
When it comes to food, nutrients aren’t the only thing that may affect your risk for developing age-related eye diseases. A study published last year in The American Journal of Clinical Nutrition found that the glycemic index (GI), a measure of how carbohydrates impact blood glucose levels, heightened the risk. The study found that a diet rich in high GI foods was associated with a greater risk and increased severity of age-related macular degeneration. The health benefits of a low GI diet have been well documented, so the link to eye health isn’t surprising. High GI foods tend to be refined and processed, such as white bread, French fries and potato chips, whereas low GI foods tend to be higher in fibre, including oat bran, lentils, beans and barley.
Monday, March 30, 2009
Saturday, March 21, 2009
Red meat and blindness
Red meat and blindness
Red meat included things like roast beef, meatballs or lamb chops.
“Eating too much red meat can raise the risk of going blind by half,” the Daily Mail reported. It said that research has shown that eating red meat at least 10 times a week makes people 50% more likely to develop age-related macular degeneration (AMD), than those who eat it less than five times a week. The newspaper said that eating chicken however, appears to protect against the condition. It quotes the Royal College of Ophthalmology, as saying: “The evidence is still not strong enough to merit any advice to the public.”
This reliable study followed 5,600 middle-aged men and women for 13 years. The opposing effects of chicken and red meat are puzzling. The researchers say that they took into account several known major risk factors for AMD, such as smoking. They admit however, that rather than directly raising the risk of AMD, red meat consumption could actually be a marker for other lifestyle factors that are having the damaging effect. Meanwhile, there is no evidence that eating chicken protects against the disease. The researchers say that more research is needed.
Where did the story come from?
Dr Elaine E-W. T. Chong from the Centre for Eye Research Australia at the University of Melbourne carried out this research with colleagues. The study was supported by awards from the National Health and Medical Research Council, the Ophthalmic Research Institute of Australia and others bodies. The study was published in the American Journal of Epidemiology, a peer-reviewed medical journal.
What kind of scientific study was this?
The researchers say that age-related macular degeneration (AMD) is the leading cause of severe vision loss in people aged 50 years or older in the developed world. AMD is an eye condition that causes the gradual loss of central vision (the ability to see what is directly in front of you). It occurs when the part of the eye responsible for central vision (the macula) is unable to function as effectively as it used to. There are two types of AMD, dry and wet, and two defined stages, early and late. Early AMD is characterised by yellow deposits and changes in retinal pigmentation, and is thought to indicate an unhealthy retina. This is thought to progress to late AMD, which is more severe and can be either dry or wet in type. Dry AMD involves thinning (atrophy) of the retina, while wet AMD involves leaking of fluid exudates. The scar tissue from both types destroys central vision.
Risk factors for AMD are known to include age, family history and smoking. Smoking is the only modifiable risk factor consistently found in previous studies. In this cohort study, the researchers wanted to see if meat consumption was linked to AMD and if it could be considered a risk factor.
The researchers obtained their data from a large study called the Melbourne Collaborative Cohort Study. This was a prospective cohort study of 41,528 Melbourne residents (17,049 men) between the ages of 40 and 69 when they were recruited between 1990 and 1994. During follow-up between 2003 and 2006, all the participants had eye examinations, and retinal photographs of both eyes were taken. These were graded in a standardised way by doctors who received additional training in the process. The extent of agreement between graders was tested statistically to ensure that the diagnoses were reliable.
When they enrolled, the participants completed a 121-item food frequency questionnaire, which asked about their eating habits. There were 18 questions relating to fresh red meat, processed red meat, and chicken. Red meat included things like roast beef, meatballs or lamb chops. The researchers also asked about demographic and lifestyle factors, including age, sex, smoking status and country of birth. Height, weight and blood pressure were directly measured.
From the 41,000 people enrolled in the Melbourne Collaborative Cohort Study, 6,734 participated in the eye study. The participants were excluded for various reasons. For example, a large number in the original cohort were the wrong age for the eye study; some had left the state (Victoria) before the examination in 2003, and some left or died during follow-up. Others were excluded if they had extreme high-energy diets or were likely to have changed diet over the 10 years since the start, or had missing data. This left 5,604 participants for analysis.
The analysis was done by statistical modelling. The modelling was adjusted for the participants’ age, sex, smoking (current, past, never) and energy intake. The researchers also had data to allow them to test for a range other potential risk factors that could have interfered with the result. They modelled a range of potential ‘confounders’ (vitamin C, vitamin E, b-carotene, zinc, lutein/zeaxanthin, trans-unsaturated fatty acids, omega-3 fatty acids, saturated fat, cholesterol, total fat, alcohol, vegetable intake, fish intake, supplement use, education, body mass index, and protein intake at baseline). Only body mass index and zinc, protein, and vitamin intake were adjusted for in the final model.
What were the results of the study?
The researchers report that 1,680 cases of early AMD and 77 cases of late AMD were found from the digital macular photographs of both eyes at follow-up.
Higher red meat intake was found to be positively associated with early AMD, even after the various potential confounders were taken into account. The researchers say that someone who ate red meat 10 times a week was 1.47 times more likely to have early AMD than a person who ate it less than five times a week (OR 1.47; 95% confidence interval: 1.21 to 1.79; P for trend < 0.001.
Similar trends towards increasing prevalence of early AMD were seen among people with higher intakes of fresh and processed red meat separately. There was no significant difference in the rates of late AMD.
Eating chicken had an opposite effect. The chances of late AMD was significantly less for those who ate chicken three and a half times a week or more compared with those who ate it less than one-and-a-half times a week (OR 0.43, 95% confidence interval: 0.20 to 0.91; P for trend = 0.007).
What interpretations did the researchers draw from these results?
The researchers say their findings suggest that intakes of specific meats may have different effects on the risk of AMD. They say that these meats could be a target for lifestyle changes.
What does the NHS Knowledge Service make of this study?
Investigating new risk factors for major causes of blindness is clearly important and, given the limited epidemiologic data so far on the links between meat consumption and AMD, this study is a step forward. Limitations noted by the researchers include:
The small number of people with late AMD (77) means that the researchers were unable to examine the effect of eating red meat on the two sub-types, wet and dry AMD, separately. If eating meat only increased the incidence of one type of AMD, the overall effect would have been reduced.
Diets were only assessed once at the beginning of the study. Although people who had extreme variation in their diets were excluded, it is still possible that consumption of meat over the participants’ lifetimes is not accurately reflected in the one-off measurement.
The researchers adjusted for known potential lifestyle confounders that could also contribute to the rates of AMD. However, they do raise the possibility that meat intake could be a proxy for other risk factors or for other unknown substances that are associated with AMD. In the same way chicken intake may be associated with a particular lifestyle that is protective against AMD.
‘Residual confounding’ due to inaccurately measured or unmeasured risk factors is always a problem for observational studies such as this, and it may have contributed to some of the difference between groups.
The authors mention that an association between red meat consumption and AMD is biologically plausible, which makes this link more robust. However, they also caution that other cohort studies need to confirm this link.
Red meat included things like roast beef, meatballs or lamb chops.
“Eating too much red meat can raise the risk of going blind by half,” the Daily Mail reported. It said that research has shown that eating red meat at least 10 times a week makes people 50% more likely to develop age-related macular degeneration (AMD), than those who eat it less than five times a week. The newspaper said that eating chicken however, appears to protect against the condition. It quotes the Royal College of Ophthalmology, as saying: “The evidence is still not strong enough to merit any advice to the public.”
This reliable study followed 5,600 middle-aged men and women for 13 years. The opposing effects of chicken and red meat are puzzling. The researchers say that they took into account several known major risk factors for AMD, such as smoking. They admit however, that rather than directly raising the risk of AMD, red meat consumption could actually be a marker for other lifestyle factors that are having the damaging effect. Meanwhile, there is no evidence that eating chicken protects against the disease. The researchers say that more research is needed.
Where did the story come from?
Dr Elaine E-W. T. Chong from the Centre for Eye Research Australia at the University of Melbourne carried out this research with colleagues. The study was supported by awards from the National Health and Medical Research Council, the Ophthalmic Research Institute of Australia and others bodies. The study was published in the American Journal of Epidemiology, a peer-reviewed medical journal.
What kind of scientific study was this?
The researchers say that age-related macular degeneration (AMD) is the leading cause of severe vision loss in people aged 50 years or older in the developed world. AMD is an eye condition that causes the gradual loss of central vision (the ability to see what is directly in front of you). It occurs when the part of the eye responsible for central vision (the macula) is unable to function as effectively as it used to. There are two types of AMD, dry and wet, and two defined stages, early and late. Early AMD is characterised by yellow deposits and changes in retinal pigmentation, and is thought to indicate an unhealthy retina. This is thought to progress to late AMD, which is more severe and can be either dry or wet in type. Dry AMD involves thinning (atrophy) of the retina, while wet AMD involves leaking of fluid exudates. The scar tissue from both types destroys central vision.
Risk factors for AMD are known to include age, family history and smoking. Smoking is the only modifiable risk factor consistently found in previous studies. In this cohort study, the researchers wanted to see if meat consumption was linked to AMD and if it could be considered a risk factor.
The researchers obtained their data from a large study called the Melbourne Collaborative Cohort Study. This was a prospective cohort study of 41,528 Melbourne residents (17,049 men) between the ages of 40 and 69 when they were recruited between 1990 and 1994. During follow-up between 2003 and 2006, all the participants had eye examinations, and retinal photographs of both eyes were taken. These were graded in a standardised way by doctors who received additional training in the process. The extent of agreement between graders was tested statistically to ensure that the diagnoses were reliable.
When they enrolled, the participants completed a 121-item food frequency questionnaire, which asked about their eating habits. There were 18 questions relating to fresh red meat, processed red meat, and chicken. Red meat included things like roast beef, meatballs or lamb chops. The researchers also asked about demographic and lifestyle factors, including age, sex, smoking status and country of birth. Height, weight and blood pressure were directly measured.
From the 41,000 people enrolled in the Melbourne Collaborative Cohort Study, 6,734 participated in the eye study. The participants were excluded for various reasons. For example, a large number in the original cohort were the wrong age for the eye study; some had left the state (Victoria) before the examination in 2003, and some left or died during follow-up. Others were excluded if they had extreme high-energy diets or were likely to have changed diet over the 10 years since the start, or had missing data. This left 5,604 participants for analysis.
The analysis was done by statistical modelling. The modelling was adjusted for the participants’ age, sex, smoking (current, past, never) and energy intake. The researchers also had data to allow them to test for a range other potential risk factors that could have interfered with the result. They modelled a range of potential ‘confounders’ (vitamin C, vitamin E, b-carotene, zinc, lutein/zeaxanthin, trans-unsaturated fatty acids, omega-3 fatty acids, saturated fat, cholesterol, total fat, alcohol, vegetable intake, fish intake, supplement use, education, body mass index, and protein intake at baseline). Only body mass index and zinc, protein, and vitamin intake were adjusted for in the final model.
What were the results of the study?
The researchers report that 1,680 cases of early AMD and 77 cases of late AMD were found from the digital macular photographs of both eyes at follow-up.
Higher red meat intake was found to be positively associated with early AMD, even after the various potential confounders were taken into account. The researchers say that someone who ate red meat 10 times a week was 1.47 times more likely to have early AMD than a person who ate it less than five times a week (OR 1.47; 95% confidence interval: 1.21 to 1.79; P for trend < 0.001.
Similar trends towards increasing prevalence of early AMD were seen among people with higher intakes of fresh and processed red meat separately. There was no significant difference in the rates of late AMD.
Eating chicken had an opposite effect. The chances of late AMD was significantly less for those who ate chicken three and a half times a week or more compared with those who ate it less than one-and-a-half times a week (OR 0.43, 95% confidence interval: 0.20 to 0.91; P for trend = 0.007).
What interpretations did the researchers draw from these results?
The researchers say their findings suggest that intakes of specific meats may have different effects on the risk of AMD. They say that these meats could be a target for lifestyle changes.
What does the NHS Knowledge Service make of this study?
Investigating new risk factors for major causes of blindness is clearly important and, given the limited epidemiologic data so far on the links between meat consumption and AMD, this study is a step forward. Limitations noted by the researchers include:
The small number of people with late AMD (77) means that the researchers were unable to examine the effect of eating red meat on the two sub-types, wet and dry AMD, separately. If eating meat only increased the incidence of one type of AMD, the overall effect would have been reduced.
Diets were only assessed once at the beginning of the study. Although people who had extreme variation in their diets were excluded, it is still possible that consumption of meat over the participants’ lifetimes is not accurately reflected in the one-off measurement.
The researchers adjusted for known potential lifestyle confounders that could also contribute to the rates of AMD. However, they do raise the possibility that meat intake could be a proxy for other risk factors or for other unknown substances that are associated with AMD. In the same way chicken intake may be associated with a particular lifestyle that is protective against AMD.
‘Residual confounding’ due to inaccurately measured or unmeasured risk factors is always a problem for observational studies such as this, and it may have contributed to some of the difference between groups.
The authors mention that an association between red meat consumption and AMD is biologically plausible, which makes this link more robust. However, they also caution that other cohort studies need to confirm this link.
Saturday, March 14, 2009
Diet Could Reduce Onset of Eye Disease
University of Liverpool scientists claim that the degeneration of sight, caused by a common eye disease, 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 the leading cause of blindness in the UK, with 45% of those registered as blind suffering from the disease. The condition results in a gradual loss of central vision, due to the failure of cells in the macular – the light sensitive membrane at the centre of the retina. There is currently no cure for the more common ‘dry’ form of the disease, which is suffered by 90% of AMD patients.
Professor Ian Grierson, Head of Ophthalmology at the University, has produced a comprehensive cooking guide called ‘Fruit for Vision’, designed to add fruit and vegetables into everyday meals. The recipes will help AMD sufferers slow down the degeneration process by increasing micronutrient, vitamin and antioxidant intake in the diet. Non-sufferers can also use the book to add fruit, nuts and vegetables into each meal to protect against the disease.
Professor Grierson 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.”
Fruit for Vision is published by Indigo Creative Marketing and the Macular Disease Society. It provides easy recipes that incorporate fruit and nuts in to the diet without having to change lifestyle. The recipes suggest minor additions to what we already eat, such as peaches with ham or ginger with melon, rather than major dietary changes.
Source: Universities Of Liverpool
Age-related Macular Degeneration (AMD) is the leading cause of blindness in the UK, with 45% of those registered as blind suffering from the disease. The condition results in a gradual loss of central vision, due to the failure of cells in the macular – the light sensitive membrane at the centre of the retina. There is currently no cure for the more common ‘dry’ form of the disease, which is suffered by 90% of AMD patients.
Professor Ian Grierson, Head of Ophthalmology at the University, has produced a comprehensive cooking guide called ‘Fruit for Vision’, designed to add fruit and vegetables into everyday meals. The recipes will help AMD sufferers slow down the degeneration process by increasing micronutrient, vitamin and antioxidant intake in the diet. Non-sufferers can also use the book to add fruit, nuts and vegetables into each meal to protect against the disease.
Professor Grierson 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.”
Fruit for Vision is published by Indigo Creative Marketing and the Macular Disease Society. It provides easy recipes that incorporate fruit and nuts in to the diet without having to change lifestyle. The recipes suggest minor additions to what we already eat, such as peaches with ham or ginger with melon, rather than major dietary changes.
Source: Universities Of Liverpool
Saturday, March 7, 2009
Vitamins May Help Women Keep Their Eyesight
Vitamins May Help Women Keep Their Eyesight
(Ivanhoe Newswire) -- Vitamin supplements may be the key to preventing the most common cause of vision loss in older Americans.
A new study found women who took a combination of vitamins B6 and B12 and folic acid appeared to significantly decrease the risk of age-related macular degeneration (AMD). Although there are treatment options for severe cases of the eye disease, the only current known prevention method is to avoid smoking.
In a randomized, double-blind clinical trial involving 5,442 women age 40 and over, women who took supplements had a 34 percent lower risk of any AMD and 41 percent lower risk of visually significant AMD, which results in a visual acuity of 20/30 or worse.
The study's authors said their findings are the strongest evidence to date in support of a possible beneficial effect of folic acid and B vitamin supplements in AMD prevention. Since the benefits were observed in the early stages of the disease development, this appears to be the first identified way, other than not smoking to reduce the risk of AMD in women at an average risk.
"From a public health perspective, this is particularly important because persons with early AMD are at increased risk of developing advanced AMD, the leading cause of severe, irreversible vision loss in older Americans," the authors wrote.
SOURCE: Archives of Internal Medicine, 2009;169:335-341
(Ivanhoe Newswire) -- Vitamin supplements may be the key to preventing the most common cause of vision loss in older Americans.
A new study found women who took a combination of vitamins B6 and B12 and folic acid appeared to significantly decrease the risk of age-related macular degeneration (AMD). Although there are treatment options for severe cases of the eye disease, the only current known prevention method is to avoid smoking.
In a randomized, double-blind clinical trial involving 5,442 women age 40 and over, women who took supplements had a 34 percent lower risk of any AMD and 41 percent lower risk of visually significant AMD, which results in a visual acuity of 20/30 or worse.
The study's authors said their findings are the strongest evidence to date in support of a possible beneficial effect of folic acid and B vitamin supplements in AMD prevention. Since the benefits were observed in the early stages of the disease development, this appears to be the first identified way, other than not smoking to reduce the risk of AMD in women at an average risk.
"From a public health perspective, this is particularly important because persons with early AMD are at increased risk of developing advanced AMD, the leading cause of severe, irreversible vision loss in older Americans," the authors wrote.
SOURCE: Archives of Internal Medicine, 2009;169:335-341
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