Food for Thought . . .

6/26/14

Can dinner really be delicious medicine for our eyes?

Recent studies have shown compelling evidence that specific nutrients support eye health.* When a vitamin or mineral is given as a supplement, are there the supporting micronutrients and enzymes required for optimal utilization of that supplement by our bodies? Is a nutrient more bioavailable and/or more beneficial to our health as a foodstuff than as a supplement? Are there unintended effects from supplements that are not present when the nutrient is derived from a food source?**

Visionary Kitchen - nutrients
Despite the many thought provoking questions, I personally take supplements as I feel it is difficult to acquire the nutrients strictly through food. Dietary preferences and requirements influence our everyday food choices as well as the quality of food available at our local grocery stores. Thoughtfully designed, well-sourced supplements have been shown to enhance eye health and general well being.
Here are some key nutritional principles which should be kept in mind to maximize the nutrient availability to our eyes and bodies from the foods that we eat:

1. Bioavailability: Vitamins A, D, E and K are fat soluble; the vitamin B-complex and vitamin C are water soluble. Dietary fats aid in the transport of fat soluble vitamins. Of particular importance to eye health are the fat soluble carotenoids in the vitamin A family, lutein and zeaxanthin. Carotenoids are the red, orange and yellow pigments found in fruit and vegetables such as kale, spinach, corn, apricots and orange bell peppers. To maximize their nutritional benefit, combine foods rich in carotenoids with a healthy source of fat such as olive oil, avocados or walnuts. Egg yolk contains the most bioavailable source of lutein and zeaxanthin and is preferentially deposited in the macula.

2. Nutrient Synergy: Nutrient synergy is the interaction of two or more nutrients that work together to achieve a greater effect than a single nutrient alone could. Foods have a vast array of micronutrients. We know that spinach contains a high level of lutein; however, we don’t know precisely how all the nutrients in spinach work together to promote eye health. Epidemiological studies show people who eat spinach have a lower risk for developing Age-related Macular Degeneration (AMD). Levels of lutein and zeaxanthin in the macula can be measured and low levels are a predictor for the risk of developing AMD.

3. Growing and Feeding Practices: The growing and feeding practices of the agriculture industry affect the nutrient profile and nutrient density of our food. Grass-fed versus corn-based animal husbandry, and wild versus farm-raised fish, alters the fatty acid profile. The amount of omega-3 fatty acids found in eggs varies depending upon the chicken’s diet. Ketchup from organically grown tomatoes contains nearly 50% more lycopene than from conventionally grown tomatoes. Choose quality ingredients whenever possible.

4. Cooking Techniques: Steaming, sautéing or pureeing will break down the plant cell walls increasing the body’s access to the lutein found in dark leafy greens. Cooking tomatoes will increase the availability of lycopene. Heat, however, diminishes the amount of vitamin C present. To maximize lutein and vitamin C, consume both fresh and cooked vegetable sources. Excessive heat and lengthy cooking times diminish vitamin content (mineral content will remain intact, however).

5. Whole Foods: Whole foods have benefits such as soluble and insoluble fiber which help to regulate blood sugar. Foods high in fiber have been shown to decrease total cholesterol, triglycerides and VLDL levels. Fiber supports gut health which is integral to nutrient absorption.

6. Select Eye Nutrient Dense Foods: Studies have highlighted lutein+zeaxanthin, the omega-3 fatty acids balanced with omega-6 fatty acids, the vitamin A family, the antioxidant vitamins C and E, as well as the mineral zinc. There a number of other nutrients that play a role in eye health including B vitamins, selenium and other plant based antioxidants. Knowing the food sources of these important nutrients will help you to make better food choices for eye health.

How does this sound for dinner tonight? Grilled wild salmon on a bed of lightly sautéed spinach with caramelized onions!

* AREDS 1, 2; LAST: Lutein Antioxidant Supplement Trial; ZVF: Zeaxanthin and Visual Function
** CARET: Carotene and Retinal Efficacy Trial

author-portraitSandra Young, OD
Author of the award winning Visionary Kitchen: A Cookbook for Eye Health
www.visionarykitchen.com

Beyond Eating Green

Beyond Eating Green

Spinach and kale aren’t the only things to watch in your diet. Eating low glycemic foods may slow the development and progression of AMD. The glycemic index measures how quickly carbohydrates get glucose (sugar) into the blood stream. People with diabetes will find this familiar. High glycemic foods like potatoes, white rice, processed foods like cakes and crackers and cereal raise the blood glucose level. Low glycemic foods include vegetables and beans.

from www.crossfithoboken.com
from www.crossfithoboken.com
Several years ago researchers at Tufts University found that mice fed a low glycemic diet developed fewer and less severe age-related lesions in the retina than mice fed the higher GI diet. When lesions like this develop after age 60 in humans, they are the earliest warning sign of age-related macular degeneration. Earlier studies in humans resulted in similar observations.

*Here are some tips from Harvard University for low-glycemic eating.

1. Eat a lot of non-starchy vegetables, beans, and fruits such as apples, pears, peaches, and berries. Even tropical fruits like bananas, mangoes, and papayas tend to have a lower glycemic index than typical desserts.

2. Eat grains in the least-processed state possible: “unbroken,” such as whole-kernel bread, brown rice, and whole barley, millet, and wheat berries; or traditionally processed, such as stone-ground bread, steel-cut oats, and natural granola or muesli breakfast cereals.

3. Limit white potatoes and refined-grain products, such as white breads and white pasta, to small side dishes.

4. Limit concentrated sweets – including high-calorie foods with a low glycemic index, such as ice cream – to occasional treats. Reduce fruit juice to no more than one-half cup a day. Completely eliminate sugar-sweetened drinks.

5. Eat a healthful type of protein, such as beans, fish, or skinless chicken, at most meals.

6. Choose foods with healthful fats, such as olive oil, nuts (almonds, walnuts, pecans), and avocados, but stick to moderate amounts. Limit saturated fats from dairy and other animal products. Completely eliminate partially hydrogenated fats (trans fats), which are in fast food and many packaged foods.

7. Have three meals and one or two snacks each day, and don’t skip breakfast.

8. Eat slowly and stop when full.

*Adapted from Ending the Food Fight, by David Ludwig with Suzanne Rostler (Houghton Mifflin, 2008)

Judi Delgado headshotJudith Delgado
Executive Director
Macular Degeneration Partnership