Best True Health
Welcome at » Eye Vision

Hydroxytyrosol is thought to be the main antioxidant compound in olive fruit, and it is believed to play a significant role in many of the health benefits attributed to olive oil. Previous research has linked the compound to cardiovascular benefits, typically reductions in LDL or “bad” cholesterol. Data has also suggested the compound may boost eye health and reduce the risk of macular degeneration.

Spanish researchers reported these results in the British Journal of Nutrition. Twenty-two healthy volunteers between 20 and 45 years of age and with a BMI between 18 and 33 kg/m2 were recruited. Volunteers were randomly assigned to receive 10 to 15 grams per day of hydroxytyrosol-enriched sunflower oil or non-enriched sunflower oil for three weeks. The former provided a daily hydroxytyrosol dose of between 45 and 50 mg. After the initial three week period, volunteers had two weeks of no intervention before crossing over to receive the other intervention.

Results showed no changes in total, LDL, or HDL-cholesterol between the groups. However, consumption of the hydroxytyrosol-enriched sunflower oil produced significant reductions in oxidized LDL from 79.8 units per liter at the start of the study to 64.1 U/l after three weeks, compared to an increase from 72.7 to 86.4 U/l during the control phase. Furthermore, the activity of arylesterase increased from 235.2 to 448.9 U/l during the hydroxytyrosol phase, compared with an increase from 204.1 to 310.3 U/l during the control phase.

The researchers reported that although hydroxytyrosol-enriched sunflower oil did not significantly reduce LDL-cholesterol or increase HDL-cholesterol, it acted as a functional food by increasing arylesterase activity and reducing oxidized LDL. Oxidized LDL is believed to be a major player in promoting atherosclerosis (the build-up of fatty plaques in arteries) and general cardiovascular disease. Based on these results, dietary sources of hydroxytyrosol appear to be capable of reducing certain risk factors associated with coronary artery disease.

Vazquez-Velasco M, et al. Effects of hydroxytyrosol-enriched sunflower oil consumption on CVD risk factors. 2010. Br J Nutr.

Age-Related Macular Degeneration (AMD) is the most common cause of vision loss in developed countries. This degenerative eye disease causes damage to the macula (central retina) of the eye, impairing central vision. People affected by AMD have difficulty reading, driving and performing activities that require clear central vision. Many factors contribute to the development of AMD, including aging, genetics, diet, and smoking. The macula is a yellow oval-shaped pigmented area located near the center of the retina. Structures within the macula are specialized to provide high-acuity vision. Lutein and zeaxanthin are found in high concentrations here, giving the macula its yellow color. This protective layer, known as macular pigment, filters harmful high-energy blue wavelengths of light preventing damage to the retina, cones, and rods.

Numerous published studies have previously reported a link to intakes of lutein and zeaxanthin and AMD risk; however, the research has been mostly inconsistent. In this newly published prospective study, researchers used two decades of data involving more than 100,000 participants from the Nurses’ Health Study and the Health Professionals Follow-up Study. All participants were aged 50 years or older and were free of diagnosed AMD, diabetes mellitus, cardiovascular disease, and cancer (except non-melanoma skin cancer) at baseline. The researcher’s analyzed carotenoid intake based on dietary food frequency questionnaires at baseline and follow-up, and then calculated predicted plasma carotenoid scores. The results of this study found that participants with the highest average plasma lutein and zeaxanthin levels had a 40% reduced risk of developing advanced AMD compared to those with the lowest average levels. “Lutein and zeaxanthin form macular pigments that may protect against AMD by reducing oxidative stress, absorbing blue light, and stabilizing cell membranes,” the authors explain.

Dark green leafy vegetables are the primary dietary sources of lutein and zeaxanthin, but they are also found in some other colorful fruits and vegetables. Average dietary intake in the U.S. is only about 1-3 mg/day, far below the amount most studies indicate as a minimum needed to decrease risk of AMD. “Because other carotenoids may also have a protective role, a public health strategy of increasing the consumption of a wide variety of fruits and vegetables rich in carotenoids could be most beneficial and is compatible with current dietary guidelines,” the authors concluded.

JAMA Ophthalmol. 2015;133(12):1415-1424.

Studies revealed that the majority of the pediatric population may fall short of recommended dietary intakes of omega-3 fatty acids.

According to NHMRC Nutrient Reference Values for Australia and New Zealand, the daily Adequate Intake of essential fatty acids and omega-3 fats such as DHA/EPA/DPA is 55mg/day for children aged 4-8 years of age. However estimates of actual dietary intake of these beneficial fatty acids are limited in children.

A study in the Journal of Nutrition has published direct quantification of fatty acid intakes in 41 children aged 4-8 years.  Identical portions of all food and dietary supplements consumed over 3 days were collected. Duplicate samples were analyzed for calories, macronutrients, and fatty acids, including alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA).

Based on the dietary analysis, the children averaged 1,404 kcal energy intake per day, and their fatty acid intakes were at the following levels in mg/day: alpha-linolenic acid 1,611; EPA 38.4; DPA 26.3; and DHA 54.1.

Based on the US government recommended Dietary Reference Intakes (DRI), 61% of the children met the adequate intake for ALA, and only 22% met the recommended intake for DHA + EPA. These intakes were compared with recently established Australia/New Zealand recommendations for children, where only about half the children (51%) met suggested intakes for EPA + DPA + DHA.

The result of this study indicates a significant deficit in the actual intakes of polyunsaturated fatty acids, including DHA, among Canadian and Australian children when compared to recommended intakes. This deficit gap can be readily filled with an increased consumption of fish/seafood, foods (dairy products, breads, and others) that have been enriched with various delivery forms of omega-3 EFA, and the use of supplementation where necessary.

Source:
Madden SM et al; J Nutr. 2009 Mar; 139(3):528-32.

April 2012

 

It is estimated that 25% of the world’s population, and approximately 50% of pre-school children worldwide have anaemia.  50% of anaemia cases are due to iron deficiency.  Studies have shown that iron deficiency in infancy is related to poorer cognition in childhood.

Iron is an essential mineral that plays key function in oxygen transport and storage.  Iron deficiency is associated with fatigue, lethargy, impaired cognitive and motor function.  The risk factors of developing iron deficiency anaemia (IDA) include low iron intake, poor absorption of iron, and high iron demand particularly during infancy, growth spurts, adolescence, and pregnancy.  In observational studies anaemia and iron deficiency are associated with cognitive deficits, suggesting that iron supplementation may improve cognitive function.

A recent meta-analysis assessed whether iron supplementation improved cognitive functions including concentration, intelligence, memory, psychomotor skills and scholastic achievement.  Fourteen RCTs on iron supplementation in males and females aged 6 years and older were included in this analysis.

This analysis found that iron supplementation improved attention and concentration irrespective of baseline iron status.  In anaemic women and children, supplementation improved intelligence quotient (IQ) by 2.5 points, but had no effect on non-anaemic participants, or on memory, psychomotor skills or scholastic achievement.

Findings from this analysis provided evidence on the benefits of iron supplementation on cognitive function, however, further studies of at least one year’s duration with varying levels of baseline iron status and using well validated tests of cognition are needed to confirm and extend these results.

Source:
Falkingham et al. Nutrition Journal 2010, 9:4

April 2012

 

Korean Ginseng (Panax Ginseng) is an adaptogenic herb that has been used as potent energy tonic for thousands of years in Traditional Chinese Medicine. Modern clinical study has provided scientific evidence on its benefit in enhancing cognitive performance.

Although we do not yet fully understand the mechanism for many of Ginseng’s medicinal benefits, modern science using controlled clinical trials began to unravel scientific evidence on the health benefits of Ginseng supplementation.  Single doses of the traditional herbal treatment Panax ginseng have recently been shown to lower blood glucose levels and elicit cognitive improvements in healthy, overnight-fasted volunteers.

In a double-blind, placebo-controlled clinical trial, 27 healthy young adults completed a 10 minute “cognitive demand” test battery at baseline.  The 10 minute “cognitive demand” battery comprised a Serial Threes subtraction task (2 min); a Serial Sevens subtraction task (2 min); a Rapid Visual Information Processing task (5 min); and a “mental fatigue” visual analogue scale.

These young adults then consumed capsules containing either a Panax ginseng extract or a placebo, and 30 minutes later a drink containing glucose or placebo. A further 30 minutes later (i.e. 60 minutes post-baseline/capsules) they completed the “cognitive demand” battery six times in immediate succession.  The participants were divided into four groups: Placebo (0mg Ginseng/0 mg glucose); Ginseng (200mg Ginseng/0 mg glucose); Glucose (0 mg Ginseng/25 g glucose); or Ginseng/Glucose (200 mg Ginseng/25 g glucose).  Blood glucose levels were measured prior to the day’s treatment, and before and after the post-dose completions of the battery.

The results showed that both Panax ginseng and glucose enhanced performance of a mental arithmetic task, and ameliorated the increase in subjective feelings of mental fatigue experienced by participants during the later stages of the sustained, cognitively demanding task performance.  Accuracy of performing the Rapid Visual Information Processing task (RVIP) was also improved following the glucose load.  Panax ginseng caused a reduction in blood glucose levels 1 hour following consumption when ingested without glucose.

These results confirm that Panax ginseng may possess glucoregulatory properties and can enhance cognitive performance.

Source:
Reay JL etal; Journal of Psychopharmacology 2006; 20(6):771-81

Age-related macular degeneration (AMD) is the leading cause of severe visual loss in individuals over 50 years of age.  Previous studies suggest that high intakes of oily fish and antioxidant nutrients have been associated with a protective effect against AMD.

The Rotterdam Study is a prospective cohort study ongoing since 1990 in the city of Rotterdam in The Netherlands. The study targets cardiovascular, endocrine, hepatic, neurological, ophthalmic, psychiatric, dermatological, oncological, and respiratory diseases.  Recent study published in Archives of Ophthalmology investigated whether dietary nutrients can reduce the genetic risk of early age-related macular degeneration (AMD) conferred by the genetic variants CFH Y402H and LOC387715 A69S in a nested case-control study.

Researchers assessed dietary intake of 2167 individuals (>=55 years) from the population-based Rotterdam Study at risk of AMD, using a semiquantitative food frequency questionnaire and genetic variants were determined. Incident early AMD was determined at 3 follow-up visits (median follow-up, 8.6 years). The synergy index was used to evaluate biological interaction between risk factors; hazard ratios were calculated to estimate risk of early AMD in strata of nutrient intake and genotypes.

Five hundred seventeen participants developed early AMD. Significant synergy indices supported the possibility of biological interaction between CFH Y402H and zinc, β-carotene, lutein/zeaxanthin, and eicosapentaenoic/docosahexaenoic acid (EPA/DHA) and between LOC387715 A69S and zinc and EPA/DHA. Dietary intakes of zinc in the highest tertile, as well as high dietary intakes of β-carotene, lutein/zeaxanthin, and EPA/DHA, were associated with reduced risk of early AMD for the CFH Y402H genetic variant.  The highest intake of zinc and EPA/DHA reduced the risk for early AMD in people with LOC387715 A69S genetic variant.

High dietary intake of nutrients with antioxidant properties reduces the risk of early AMD in those at high genetic risk.  The study authors further suggested that clinicians should provide dietary advice to young susceptible individuals to postpone or prevent the vision-disabling consequences of AMD.

Source:
Ho L. et al; Arch Ophthalmol 2011 Jun; 129(6):758-66

A new study from Spain discusses the heart health potential of hydroxytyrosol, an olive extract possibly effective at reducing levels of oxidized LDL cholesterol.

In a recent study, supplementing with hydroxytyrosol – a polyphenolic compound extracted from olives – correlated with higher activity levels of the enzyme arylesterase, an antioxidant biomarker, and lower levels of oxidized LDL cholesterol. Oxidized LDL is believed to be a major player in promoting atherosclerosis (the build-up of fatty plaques in arteries) and general cardiovascular disease.

Hydroxytyrosol is thought to be the main antioxidant compound in olive fruit, and it is believed to play a significant role in many of the health benefits attributed to olive oil. Previous research has linked the compound to cardiovascular benefits, typically reductions in LDL or “bad” cholesterol.  Data has also suggested the compound may boost eye health and reduce the risk of macular degeneration.

Spanish researchers reported these most recent results in the British Journal of Nutrition.  Twenty-two healthy volunteers between 20 and 45 years of age and with a BMI between 18 and
33 kg/m2 were recruited. Volunteers were randomly assigned to receive 10 to 15 grams per day of hydroxytyrosol-enriched sunflower oil or non-enriched sunflower oil for three weeks. The former provided a daily hydroxytyrosol dose of between 45 and 50 mg. After the initial three week period, volunteers had two weeks of no intervention before crossing over to receive the other intervention.

Results showed no changes in total, LDL, or HDL-cholesterol between the groups. However, consumption of the hydroxytyrosol-enriched sunflower oil produced significant reductions in oxidised LDL from 79.8 units per liter at the start of the study to 64.1 U/l after three weeks, compared to an increase from 72.7 to 86.4 U/l during the control phase. Furthermore, the activity of arylesterase increased from 235.2 to 448.9 U/l during the hydroxytyrosol phase, compared with an increase from 204.1 to 310.3 U/l during the control phase.

The researchers reported that although hydroxytyrosol-enriched sunflower oil did not significantly reduce LDL-cholesterol or increase HDL-cholesterol, it acted as a functional food by increasing
arylesterase activity and reducing oxidized LDL.  Based on these results, dietary sources of hydroxytyrosol appear to be capable of reducing certain risk factors associated with coronary artery disease.

Source:
Vazquez-Velasco M, et al. Br J Nutr; 11 May 2011; 105(10):1448-52.

26 May 2011

Age-related macular degeneration (AMD) is the leading cause of visual impairment and blindness in the developed world among people aged 65 years or older.  The Age-Related Eye Disease Study Group (AREDS) has found that high-dose vitamin supplementation may have a role in preventing the progression of Category 3 and 4 age-related maculopathy.

Oxidative damage has been implicated in the pathogenesis of AMD, secondary to the retina’s high consumption of oxygen, its high proportion of polyunsaturated fatty acids, and its exposure to visible light.  Over the last decade, nnumerous cross-sectional and cohort studies have investigated the role of antioxidant supplementation in preventing age-related maculopathy.  The largest randomised controlled trial, undertaken by the Age-Related Eye Disease Study (AREDS) Group, compared antioxidant and zinc supplementation to placebo.  The AREDS Group demonstrated a statistically significant odds reduction for the risk of progression to advanced AMD and reduction in the rate of at least moderated visual acuity loss with the use of tablets containing antioxidants plus zinc.

A recent study published in the New Zealand Medical Journal compared dietary antioxidant, zinc, and copper intakes of Australia, New Zealand, United Kingdom, and the United States to determine the difference between the actual and suggested AREDS intakes for these nutrients.  The total median intake of vitamins A, C, and E; zinc; and copper is analysed from the most recent nutrition data published by the four countries. Forty multivitamin brands and 32 individual nutrient brands were analysed.

Results from this study revealed that the median intakes of antioxidants, zinc, and copper were comparable across the four countries, but substantially lower than the AREDS-recommended intakes to reduce the risk of progression to advanced AMD.  Sixteen of the 40 multivitamin preparations contained all recommended nutrients. The study authors suggested that dietary supplementation is required to achieve the AREDS nutrient intake recommendations. This may be achieved by using any combination of multivitamin and individual supplement preparations available.

Source:
Aparna Raniga & Mark J Elder, Journal of the New Zealand Medical Association, 24-July-2009, Vol 122 No 1299

Healthy subjects with an average age of 23.9 were assigned to receive daily supplements of lutein (10 mg) and zeaxanthin (2 mg) for six months. The subjects’ eyes were then tested for the effects of glare as experienced in everyday situations, including being outdoors on bright days, lengthy sessions of looking at a computer monitor, and nighttime exposure to oncoming headlights.

Following six months of supplementation, the participant’s average macular pigment optical density (MPOD) increased significantly from the average value at the beginning of the study. MPOD is a measure of the eye’s ability to filter short-wave light.

After testing the subjects for their performance in visual tasks following glare, researchers concluded that four to six months of supplementation with lutein and zeaxanthin significantly reduced the detrimental effects of the exposure and improved visual performance.

Optom Vis Sci 2008 Feb;85(2):82-8

The journal Archives of Ophthalmology recently reported that having reduced plasma antioxidant levels and increased exposure to sunlight increases the risk of neovascular, or advanced age-related macular degeneration (AMD).

In a recent study (titled the European Eye Study), over 4,400 participants over age 65 were analyzed for the presence of macular degeneration. Their blood plasma was evaluated for vitamins C and E, the carotenoids lutein and zeaxanthin, and the mineral zinc. Each individual also completed a questionnaire regarding their typical exposure to sunlight. This was used to estimate blue light exposure from visible light, which is known to contribute to the development of macular degeneration.

Early stage macular degeneration was detected in 2,182 participants, and 101 had the advanced form of the disease. The research found no association between blue light exposure and early macular degeneration. However, among participants in the lowest quartile (25 percent) of serum vitamin C, zeaxanthin, vitamin E and zinc, exposure to blue light significantly increased the risk of advanced macular degeneration.

Arch Ophthalmol 2008 Oct;126(10):1396-403

globalwarming awareness2007