Eat leafy greens to see clearly

 

Carotenoids are pigments present in fruits and vegetables. An interesting fact about carotenoids is that carotenoids exert their beneficial effects by traveling to and then concentrating in specific tissues in the body. For example, lycopene, a carotenoid found in tomatoes, travels to the prostate, where it has potent anti-cancer effects

Lutein and zeaxanthin, which are found in leafy greens like kale, travel to the central area of the retina (called the macula), and are the only known carotenoids located in the human visual system. Previous research has shown that these pigments are protective against age-related macular degeneration. Scientists now have evidence that these macular pigments also play important roles in visual performance.

Since our bodies can’t produce these pigments, levels of lutein and zeaxanthin in the retina depend on the amounts consumed in the diet. 

Light must pass through lutein and zeaxanthin before being transmitted to photoreceptor cells that will produce a message from the light to send to the brain. As light passes through, some short wavelength (blue) light is absorbed by the macular pigments. For this reason, there was a theory that macular pigments have a light-filtering function in vision.

An analysis of several studies on the subject of macular pigments and visual performance confirms this theory. The authors evaluated the evidence and concluded that lutein and zeaxanthin likely improve the following visual functions by acting as light filters:

  • Discomfort glare – For example, experiencing bright light after being in a dark room. The wavelengths that macular pigments are capable of absorbing produce the least discomfort, suggesting that macular pigments protect the eye from this overstimulation by filtering the light.
  • Disability glare – Subjects with higher levels of macular pigment show improved visibility of objects in the presence of glare.
  • Photostress recovery – Elevated macular pigment values decrease the time necessary to recover vision following exposure to bright light.
  • Contrast – Macular pigments increase visibility and edge definition of objects in the atmosphere, possibly by absorbing blue sky light.

Rich sources of lutein and zeaxanthin include kale, spinach, turnip greens, swiss chard, and collards.


Reference:

Stringham JM et al. The Influence of Dietary Lutein and Zeaxanthin on Visual Performance. Journal of Food Science 2009

 

High fat intake - especially saturated fat - is associated with macular degeneration

 

Age-related macular degeneration (AMD) is the leading cause of vision loss in Americans over 60 years of age. This disease involves cell death in the macula of the eye, which has a high density of cone cells and is responsible for central vision.1 

A recent study published in the Archives of Ophthalmology2 investigated the relationship between fat intake and the presence of intermediate AMD 4-7 years later in over 1700 women, and found that some fats may benefit eye health while others may be damaging.

Total fat.Women aged 50-75 who consumed the highest proportion of calories from fat (43%) had the greatest risk of AMD – 70% higher odds than those with the lowest proportion of calories from fat (21%). As the authors stated,

"High-fat diets might be a marker for diets that are poor in many micronutrients that could protect against age-related macular degeneration.”3

They then looked further into the associations between specific types of dietary fat and AMD.

Saturated fats are detrimental when it comes to heart disease and cancer, so these results are no surprise - saturated fats showed the greatest association with AMD – 60% increased odds of AMD in women who consumed the greatest amounts. Monounsaturated fats, which are present in nuts, seeds, and avocados, were associated with a lower prevalence of the disease.

The associations between polyunsaturated fats and AMD are more difficult to interpret – the authors reported that both omega-3 and omega-6 polyunsaturated fatty acids were associated with a two-fold risk of AMD. But don’t overreact and throw away your walnuts and flaxseeds - the intakes of omega-3 and -6 in this study were highly correlated to one another, making it difficult to discern the effects of one from the other. Also, a 12-year study in the American Journal of Clinical Nutrition last month found that people at high risk for AMD were less likely to develop the disease if they had a greater intake of omega-3 fats.4 The authors of the current study hypothesized that excessive omega-6 fatty acid intake may influence AMD by promoting inflammation that can contribute to retinal damage. Vegetable oils, processed foods, and animal products contain high levels of omega-6 fats – with that in mind, the authors also stress that the associations that they found likely do not represent effects of only the types of fat, but the cumulative effects of the all the compounds in the foods that contain each type of fat.3

The evidence is overwhelming that a Nutritarian diet-style, with raw seeds and nuts as the major fat source, and the high exposure to phytochemicals and carotenoids is the healthiest way to eat. Can you imagine all the personal medical tragedies that could be prevented?   It would sure put a lot of drug companies and doctors out of business.

 

References:

1. http://www.nlm.nih.gov/medlineplus/maculardegeneration.html

2. Parekh N et al. Association Between Dietary Fat Intake and Age-Related Macular Degeneration in the Carotenoids in Age-Related Eye Disease Study (CAREDS). An Ancillary Study of the Women's Health Initiative. Arch Ophthalmol. 2009;127(11):1483-1493.

3. http://www.medpagetoday.com/Ophthalmology/GeneralOphthalmology/16950

4. Sangiovanni JP et al. {omega}-3 Long-chain polyunsaturated fatty acid intake and 12-y incidence of neovascular age-related macular degeneration and central geographic atrophy: a prospective cohort study from the Age-Related Eye Disease Study. Am J Clin Nutr. 2009 Oct 7. [Epub ahead of print]

 

Statins May Weaken Eye Muscles

A new study in Ophthalmology claims statins, very popular cholesterol-lowing drugs, may cause rare eye disorders, like eyelid-droop, double-vision and weakening of the muscles that control eye movement. Researchers examined 256 cases where statins, such as Lipitor, Zocor and Crestor, were associated with eye-muscle disorders, of the cases, 62 patients reported no more eyelid-droop or double vision after they stopped taking the medication. Experts call this side-effect rare; Reuters investigates.

Statins might make drug companies a lot of money, but they come with a price. According to Dr. Fuhrman, other side-effects of statins include hepatitis, jaundice, liver problems, gastrointestinal complications, low platelet levels and anemia. And many doctors question whether statins even prevent heart attacks at all!

There’s a better way. A diet rich fruits and vegetables improves cholesterol and reverses heart disease.
 

Type-1 Diabetes: Control Blood Sugar, Save Eyes and Kidneys

According to Dr. Fuhrman, eating a vegetable-based diet can help type-1 diabetics reduce their insulin requirements and keep glucose levels under excellent control. Good thing! Because a new study in Diabetes Care reveals strict blood sugar control staves off diabetes-related eye and kidney disease; via Reuters.