Eye diseases and vision loss are becoming more common in the United States as diabetes rates rise and the population ages. Many eye conditions worsen very slowly and have no noticeable symptoms in their early stages. For this reason, getting an annual eye exam is extremely important. But is there anything we can do to prevent eye disease from a nutritional perspective? Experts believe that there is such a thing as an “eye-healthy diet.” I interviewed Dr. Jeffrey Anshel, President of the Ocular Nutrition Society, and Dr. Elizabeth Johnson, a leading nutrition researcher, to get their views on the subject. Please listen to the full HealthyVision podcast here.
Some of the my favorite learning points from the show:
1. Which foods are healthy for the eyes? The human retina contains about 1000 times more concentrated carotenoids (found primarily in plant pigments) than any other part of the body. Our eyes use these pigments to protect themselves from the photo-damage of sunlight. Carotenoids (including beta-carotene, lycopene, lutein, and zeoxanthin) are found in highest concentrations in dark green, leafy and brightly colored vegetables. Egg yolks are also a good source of carotenoids. Interestingly, our retinas have a predilection for omega-3 fatty acids (found in fatty fish) to protect the eyes from UV radiation. My bottom line – the most eye-healthy meal on earth is probably a salmon salad Niçoise (see photo image above)!
2. Are carrots good for our eyes? While carrots can be part of healthy diet, choosing carrots as our primary source of vegetable intake may not be a good idea. Carrots contain beta-carotene, which competes with other carotenoids for transport molecules. Beta-carotene is a pretty good competitor and can “bump off” lutein and zeaxanthin from getting transported to the retina. Adults don’t process beta-carotene as well as kids do, so too many carrots may not be a great thing after all (especially as we get older)!
3. Should I take nutritional supplements for the eye? It’s always best to get your carotenoids from real food. However, some people (who take blood thinners for example) cannot eat dark green leafy vegetables because they also contain Vitamin K which can interfere with the medicines. For those who cannot get sufficient carotenoids from food, supplements may be beneficial.
4. What is the connection between obesity and chronic eye disease? While obesity is a risk factor for diabetes, and diabetes can cause chronic eye disease, there may be another problem at play. Carotenoids are fat soluble, and so they are preferentially stored in fat cells rather than remaining suspended in our blood stream. When we have larger fat stores, that fat may “mop up” the healthy vegetable carotenoids that we eat, without allowing them to be transported to the eyes to support retinal structures. Some researchers suggest that obese individuals may need to increase their carotenoid intake with supplements in order to prevent eye pigment deficiencies and potential macular degeneration. Losing body fat is also an important strategy of course.
Other questions answered in the podcast:
* How does cooking impact the nutritional value of fruits and veggies?
* Is there such a thing as over-supplementation (especially with Zinc)?
* How many veggies do I need to meet my daily carotenoid requirements?
* How do I know which vitamin supplements to trust?
I hope you enjoy the podcast – and redouble your efforts to eat a diet rich in fruits, veggies, fish and eggs and maintain a healthy weight. Remember that even though your mom may have told you that Bugs Bunny’s diet was best for your eye health, Popeye’s veggie of choice is even better for you!
The Biology of Omega-3 fatty acids: (Just a little science:)
When fish, flax-seeds or Brussels sprouts pass through the intestine, pancreatic enzymes transform the fat to free fatty acids. These acids are quickly taken up by the cells. Once in the cell, these fatty acids enter the mitochondria, endoplasmic reticulum and cytosol–places that you might recall because your mom helped you make a Cell sponge cake in 7th grade Biology.
In the cells, the Omega-3 fatty acids (ALA, DHA and EPA) exert their healthy influence in three major ways:
in the control of chemical messengers;
in the flux of ions—cell electricity;
in the smoothness and health of the cell membrane.
That’s enough about cells.
How do these (good) fats help our bodies?
Omega-3 fatty acids reduce Inflammation:
–Omega-3s get in the cellular (not phone) mix and end up competing with chemicals that cause inflammation—medical people say they antagonize bioactive mediators of inflammation.
–Newly-discovered by-products of Omega-3s are important in the resolution phase of inflammation. Biochem people call these chemicals, resolvins. All you have to remember here is this: to resolve (inflammation) is heart-healthy.
–When omega-3s are incorporated into the membranes of cells they do a lot of good: things like making the membrane more fluid and less sticky. For some reason, they even block genes that induce hardening of the arteries. (Genomic effects.)
Like swallows returning to San Juan Capistrano in the spring, Chia Pets begin appearing every December on late-night television and in the gift aisles of many stores. (Full disclaimer: I bought one for the Yankee Swap at Harvard Health Publication’s annual Christmas party.) Water these ceramic figures and they sprout a green “fur” from seeds embedded on the surface. Silly? Sure, that’s why they are such a hit. What you might not know is that the seeds may someday be a real gift for people with diabetes.
Chia seeds come from a plant formally known as Salvia hispanica, which is a member of the mint family. It gets its common name from the Aztec word “chian,” meaning oily, because the herb’s small, black seeds are rich in oils. It was a staple food for the Aztecs, and legend has it that their runners relied on chia seeds for fuel as they carried messages one hundred or more miles in a day. Chia seeds contain more healthy omega-3 fats and fiber than flax or other grain seeds. They are also a good source of protein and antioxidants. Read more »
We have know for some time that there are health benefits from drinking green tea. Research also shows that Omega 3 fatty acids have beneficial effects on a number of organs in the body, including the cardiovascular system, the brain, and even depression.
Dr. Fereidoon Shahidi, research professor in the Department of Biochemistry at Memorial University in Newfoundland, Canada, is hoping to show that green tea polyphenols, particularly epigallocatechin gallate (EGCG), may also prevent colon cancer and even have anti-viral effects when combined with certain Omega 3 fatty acids.
“We know from experience that green tea is not well absorbed by the body,” Dr. Shahidi said. “Our premise was to see if by adding something to it that has its own benefits, like Omega 3 fatty acids, we might get an entity that would have improved properties in terms of its absorption and health benefits,” he said. Read more »
Your doctor has just informed you that you have “hyperlipidemia” – or high cholesterol. She’s mentioning lipid-lowering drugs (statins), but you said you want to try some things on your own first. She agrees and will recheck your blood levels in three months. What are you going to do?
The advice is all over the map and your Google searches come up with various supplements and diets that are confusing and overwhelming. Here are some specific recommendations, based on evidence, that can help you lower your cholesterol. Read more »
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