Nutrients will work synergistically when addressing dry eye syndrome

For many years, the logical treatment for dry eyes has been to attempt to supplement the tear film with additional lubrication. The science of lubrication has come a long way and now we realize that it is more than just “adding moisture” to resolve this problem. New methods of treatment have included enhanced artificial tears, punctum plugs, lipid layer enhancements, tear quality enhancements and epithelial surface treatments.

In the past few years a new approach to resolving this condition has included using oral supplementation. This article will look at the facts and fiction surrounding the oral treatment of dry eye syndrome.

EFA: Good fats for eye health

Jeffrey Anshel

Essential fatty acids (EFAs) are involved with producing life energy in our bodies from food substances and moving that energy throughout our systems. They hook up oxygen, electron transport and energy in the process of oxidation. EFAs are also important in oxygen transfer, hemoglobin production and control of nutrients through cell membranes. They are also key in preventing damage from hard fats because they are “anti-sticky” and tend to disperse them.

EFAs play a part in almost every function of our body. Humans do not produce fatty acids; therefore they must be obtained from the diet. Two essential fatty acids are omega-6 and omega-3.

Omega-6 plentiful in diet

Omega-6 fatty acids are the most plentiful in our diet. They are in almost everything we eat that contains fat, including meat, most seed oil, dairy products and eggs. Omega-3 fatty acids are available in many seed oils and nearly all cold-water fatty fish.

A proper balance of these fatty acids is essential to good health. The daily intake recommendation of the Institute of Medicine is 4:1 – four times as many omega-6 fatty acids as omega-3 fatty acids. It is currently estimated that the average American diet maintains a ratio of up to 25:1.

Fatty acids are stored in every cell membrane of our body. They have two primary functions: First, they ensure cellular fluidity, acting as sentinel gatekeepers for every cell, allowing vital nutrients to enter the cell and forcing destructive free radical debris out of the cells. Second, both omega-6 and omega-3 fatty acids can be converted into three different types of active molecules called prostaglandins. These prostaglandins, PGE1, PGE2 and PGE 3, are site specific.

Omega-6 reduces inflammation

It is suggested that omega-6 fatty acids metabolize to the site-specific anti-inflammatory ecosinoid, prostaglandin E1 (PGE1), which is believed to reduce ocular surface inflammation and the inflammatory process associated with meibomianitis and reduced lacrimal gland aqueous output.

The typical American diet is overloaded with omega-6 linoleic acid (LA) from vegetable oils such as sunflower, safflower, corn and soybean oils, which are added to nearly all processed foods. Many pantries are far too full of overly processed crackers, chips, cookies and cakes and the omega-6 oils that oxidize too quickly and become pro-inflammatories.

However, good health also depends on omega-6 gamma linolenic acid (GLA), which is a downstream metabolite of LA and is found in sources such a black currant seed oil, borage oil and evening primrose oil. This compound is a necessary component in the downstream metabolism of omega-6 fatty acid to PGE1, which is associated with healthy mucosal tissue and healthy tear film. The human body cannot metabolize omega-3 fatty acids to these specific anti-inflammatory prostaglandins.

Most omega-6 fatty acids are consumed in polyunsaturated vegetable oils as LA. Excessive intake of LA is unhealthy, because it can promote inflammation if it is not properly metabolized. In contrast, omega-6 fatty acids that are successfully metabolized or those that have the metabolic advantage of containing GLA reduce inflammation after further metabolizing to dihomo-gamma-linolenic acid (DGLA), which also blocks, when appropriate, the pro-inflammatory arachidonic acid conversion.

Omega-6 needs omega-3

Successful DGLA downstream metabolism of omega-6 to the anti-inflammatory PGE1 is secured by omega-3 EPA (preferably, fish oil) blockage of arachidonic acid if those particular omega-3 metabolites are present in the body. This could possibly explain the benefits attributed to omega-3 fatty acids.

Good health depends on omega-6 gamma linolenic acid, a downstream metabolite of linoleic acid. This compound is a necessary component in the downstream metabolism of omega-6 fatty acid to PGE1, which is associated with healthy mucosal tissue and healthy tear film. Image: Troyer E

Both omega-3 and omega-6 EFAs are “short-chain” acids and must metabolize to long-chain molecules to be effective in the body. However, this conversion is not guaranteed, and this is especially true for omega-3, where it is estimated that only 2% to 15% of the ingested material metabolizes completely to long-chain EFAs.

The body requires all of the essential fatty acids for optimal health. They are particularly important for the patient with dry eye, because PGE1s from omega-6 interrupt the inflammatory loop associated with chronic dry eye syndrome. The PGE1s also increase the anti-inflammatory immunomodulating effects of cyclosporine.

Oral supplement needs omega-6, GLA

A good nutritional supplement should address many of the underlying inflammatory processes associated with dry eye syndrome. Oral administration of specific omega-6 essential fatty acids that contain sufficient amounts of GLA are suggested to stimulate the natural production of PGE1.

Black currant seed oil is an excellent source of omega-6 GLA because it is more stable than either borage oil or evening primrose oil. Many anecdotal stories abound regarding the use of flax seed oil. However, it is the most unstable of the essential fatty acid oils, and it does not contain GLA. Flax stability issues keep it from easily converting to GLA, which is something it must do to produce PGE1.

In looking for a tear-specific formula for oral administration, be sure to look for nutrient cofactors necessary to address dry eye syndrome by physiologic rather than pharmacological means. These ingredients are designed to work synergistically rather than individually, and effectively address the inflammatory process responsible for most dry eye syndrome, as well as enhancing and restoring function to the glands involved in all three layers of the tear film.

Treating idiopathic dysfunctional tear film with oral nutritional supplements can be an effective method to resolve this frustrating and uncomfortable condition. While it is worthwhile to uncover the cause of the condition, using the right combination of ingredients can work regardless of the causative factors.

For more information:

• Jeffrey Anshel, OD, can be reached at Corporate Vision Consulting, 842 Arden Drive, Encinitas, CA 92024; phone/fax: (760) 944-1200; e-mail: eyedoc@adnc.com; Web site: www.cvconsulting.com. Dr. Anshel is president of the Optometric Nutrition Society: www.optometricnutritionsociety.org.