CLINICAL

  NUTRITION

OMEGA-3S AND CAROTENOIDS

EFFICACY, CREATION AND VALUE FOR AMD

LAURIE CAPOGNA, O.D.

Q: WHICH IS THE MOST EFFECTIVE FORM OF OMEGA-3 SUPPLEMENTS: ETHYL ESTERS, (EE), TRIGLYCERIDES (TG) OR PHOSPHOLIPIDS?

A: Some studies show there may be less bioavailability and slower increase in omega-3 levels with EE supplements compared with TG. However, consuming omega-3 supplements in EE form with dietary fats from a meal can increase the absorption of the fatty acids, and long-term supplementation with EE omega-3s may lead to similar blood levels.

With regard to TG omega-3 supplements, there is some evidence to support greater bioavailability and faster absorption of this form. (Most liquid forms of omega-3s are in TG form, which is helpful for those who have trouble with pills.)

To date, there are a limited number of human studies comparing the efficacy of krill oil (phospholipids) vs. EE and TG forms of omega-3 supplements. However, early research suggests EPA and DHA may be absorbed better from krill oil vs. EE or TG forms of omega-3 supplements.

The verdict: Research products for their source of fish, type of fish oil and how the manufacturers establish quality control — scientific support for their products — to recommend the most effective supplement form.

Q: HOW ARE OMEGA-3 SUPPLEMENTS MADE?

A: When creating an omega-3 supplement, the DHA and EPA must be concentrated to levels greater than naturally found in fish. The steps to create them:

• In fish, DHA and EPA are attached to a glycerol backbone, which is removed, resulting in a free glycerol molecule and a free fatty acid (DHA or EPA).

• A process called molecular distillation results in an ethanol molecule being attached to each free fatty acid, allowing for the concentration of the omega-3s at lower temperatures and producing an EE omega-3 supplement.

• Enzymes are used to separate the ethanol molecule from the free fatty acid to create a TG omega-3 supplement. Glycerol is added back to the solution, and the enzymes work to attach the DHA and EPA onto the glycerol molecule.

Q: HOW IMPORTANT ARE LUTEIN AND ZEAXANTHIN REGARDING AMD?

A: A high dietary intake of carotenoids, especially lutein and zeaxanthin, is associated with a decreased risk of advanced AMD, report numerous studies.

Lutein and zeaxanthin must be obtained through diet and or supplementation. Dietary sources: leafy greens (especially kale), orange peppers and egg yolks. The average North American receives only 1 mg to 3 mg of lutein from diet and has a low macular pigment level. Thus, dietary counseling is important for maintaining a healthy retina.

It makes sense to prescribe a supplement containing both lutein and zeaxanthin for AMD patients. For patients who have AMD risk factors, such as smoking, I recommend supplementation as well.

Finally, consider measuring the macular pigment optical density of patients who have AMD risk factors or excessive blue light exposure, as it indicates who needs supplementation and dietary changes. Also, the measurements enable you to track the efficacy of your nutritional recommendations. OM

Questions are based on reader responses to an Optometric Management online survey, which closed on Dec. 20.

DR.CAPOGNA is is an active partner in Peninsula Vision Associates and operates a low vision clinic. In addition, she is a member of the Ocular Nutrition Society and co-author of “Eyefoods: A Food Plan for Healthy Eyes and Eyefoods for Kids: A Tasty Guide to Nutrition and Eye Health.” E-mail lcapogna@cogeco.ca, or send comments to optometricmanagement@gmail.com.