Eye Syndrome (DES) has become not only a significant quality-of-life issue but
has shown itself to be a very real disease process. Whether it's called
Dysfunctional Tear Syndrome, Chronic Dry Eye, or Dry Eye Disease, it's a
condition whereby the anterior surface of the eye is not properly maintained
and/or the patient is experiencing an uncomfortable feeling in his or her eyes.
For many years, the logical "treatment" for this
condition 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 will require more than just "adding moisture" to resolve this problem.
New methods of treatment include enhanced artificial tears, punctal plugs, lipid
layer and tear quality enhancements and epithelial surface treatments. In the
past few years a new approach to resolving this condition has included oral
nutritional supplementation. Here we'll look at the facts and fiction
surrounding the oral treatment of DE
fats for eye health
Essential Fatty Acids (EFAs) are involved in
producing energy in our bodies from food substances, and moving that energy
through our systems. They govern growth, vitality and mental state. They connect
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. EFAs play a part in almost every function of our body.
Humans do not produce fatty acids, so we must get them from our diet. The EFAs
we will address are here Omega-6 and Omega-3.
Strike a balance
Omega-6 fatty acids are the most plentiful in the
U.S. diet. They are in most 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 almost all cold-water fish. A proper balance of these fatty
acids is essential to good health. The Institute of Medicine (www.iom.edu)
recommends a daily intake ratio of 4:1 � four times as many Omega-6 fatty acids
as Omega-3. It's currently estimated that the average American diet maintains
From fat to prostaglandins
problem with trans fats
are trans fatty acids and where do they come from? A fatty acid molecule
consists of a chain of carbon atoms in carbon-carbon double bonds with hydrogen
atoms attached. In nature, most unsaturated fatty acids are cis fatty
acids. This means that the hydrogen atoms are on the same side of the double
carbon bond. In trans fatty acids, the two hydrogen atoms are on opposite sides
of the double bond, giving them a sharper, almost spiked, texture. Trans double
bonds can occur in nature as the result of fermentation in grazing animals.
People eat them in the form of meat and dairy products. Trans double bonds are
also formed during the hydrogenation of either vegetable or fish oils. French
fries, donuts, cookies, chips and other snack foods are high in trans fatty
of hydrogenating oils is to harden them to improve
their "spreadability," feel, baking qualities, and
especially to extend shelf life. To hydrogenate oil,
manufacturers use hydrogen gas under pressure in the
presence of metal catalysts to heat it to a high
temperature (248-410�F) for six to eight hours.
However, since this process will likely destroy all
of the double bonds of the fatty acids, it is
stopped prematurely (thus creating a
partially-hydrogenated product). The result is a
complex mixture of compounds, including trans fatty
acids. These trans fatty acids are linked to
increased risk of cancer, increased inflammation,
accelerated aging, obstruction of immunity and
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. They allow vital nutrients to
enter the cell and force destructive free radical debris out. Second, nutrient
co-factors like Vitamin C, Vitamin B6, zinc and magnesium help our bodies
produce enzymes that convert dietary Omega-6 and Omega-3 fatty acids into three
types of prostaglandins. The prosta-glandins (PGE1, PGE2 and PGE3) are site
►PGE1 prostaglandins reduce inflammation and inhibit blood clotting. They are
also capable of reducing pain, swelling and redness associated with
inflammation, particularly in mucosal tissues, including the eyes. Only Omega-6
fatty acids can produce this particular prostaglandin.
►PGE2 prostaglandins can also only be produced by Omega-6 fatty acids. These
pro-inflammatory prostaglandins constrict blood vessels, increase body
temperature and encourage blood clotting. These events are lifesaving when the
body suffers a wound or injury. Without PGE2s, a person could bleed to death
from the slightest of cuts, or succumb to a viral or bacterial attack. However,
in excess, this type of prostaglandin is harmful because it sets up a chronic
inflammatory condition in the body.
►PGE3 prostaglandins are available from Omega-3 fatty acids. Omega-3s,
particularly docosahexaenoic acid (DHA), keep brain cells healthy and also keep
the rods and cones in our retinas supple and working properly. The Omega-3 fatty
acid, eicosapentaenoic acid (EPA), also plays an important anti-inflammatory
role. When necessary, it blocks the release of Omega-6 arachidonic acid, which
is necessary for the production of pro-inflammatory PGE2.
Without sufficient Omega-3s in the diet, chronic
inflammation can become a problem, one that's now linked to many degenerative
diseases of the eye, including macular degeneration, glaucoma and diabetic
retinopathy. As with all dietary intake, a proper balance of EFAs is the key to
good health. Most scientists agree that a diet including cold-water fish two or
three times a week, or EPA/DHA supplementation, helps maintain the proper
balance of EFAs (Women of childbearing age and children should check local
mercury warnings for fish).
that Omega-6 fatty acids metabolize to the site-specific anti-inflammatory
eicosanoid, prostaglandin E1 (PGE1). Literature suggests these particular
prostaglandins reduce ocular surface inflammation, as well as the inflammatory
process associated with meibomianitis and reduced lacrimal gland aqueous output.
It's true that the typical American diet is
overloaded with Omega-6 linoleic acid (LA) from vegetable oils such as
sunflower, safflower, corn, cottonseed and soybean oils, which are added to
nearly all processed foods. Many pantries are far too full of processed
crackers, chips and baked goods � and thus 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 Omega-6 linoleic
acid. It's found in sources such as black currant seed oil, borage oil and
evening primrose oil. This compound is necessary to metabolize Omega-6 fatty
acid to the series one anti-inflammatory PGE1s, which are associated with
healthy mucosal tissue and tear film. On the other hand, the human body cannot
metabolize Omega-3 fatty acids to these specific anti-inflammatory
patients is a challenging task because many may not be
aware of their nutritional balance. While a qualified
nutritionist should make complete recommendations of
nutritional supplements, you can offer them valuable
information about treating chronic eye disease. Review
the various companies that supply eye-related
nutritional products and look at their rationale. Be
sure their ingredients are backed by qualified research
studies. Most likely you'll be making a "recommendation"
for a nutritional supplement, rather than "prescribing"
it, but the patients will value your opinion as an
When I encounter
patients with a likely dry eye condition, I briefly
discuss the anatomy of the tear layer and explain why
they are experiencing their symptoms. I then discuss the
product I am recommending and my rationale for doing so.
I give them a brochure from the manufacturer and let
them consider the process. I also let them know that it
will likely be effective within 30 days but that they
will need to continue to take the supplement as long as
their symptoms persist. Many patients have called in
within two weeks to say that they can already feel a
difference! This is good for my practice, for my
patients and for my bottom line.
Metabolization is the key
Most Omega-6 fatty acids are consumed in
(polyunsaturated) vegetable oils as linoleic acid (LA). Excessive intake of LA
is unhealthy, because it can promote inflammation if 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). DGLA also blocks,
when appropriate, the pro-inflammatory arachidonic acid (AA) conversion.
Sources of EFAs
Flaxseed oil does not include any GLA, so the
body's ability to utilize it is totally dependent on the unpredictable delta 6
enzymatic conversion of its LA to GLA. As an Omega-3 fatty acid, flax does not
contain EPA/DHA; therefore it's totally dependent on the enzymatic conversion of
its high-content alpha-linolenic-acid (ALA) to EPA/DHA, which is required to
produce the series three anti-inflammatory prostaglandins.
All fatty acids compete for the same metabolic
desaturase, so for good health, we should consume fewer trans fat Omega-6s and
more GLA Omega-6s and DHA/EPA Omega-3s.
Put supplements to work
The body requires all of the EFAs for optimal
health. They are particularly important for dry eye patients because PGE1s from
Omega-6 interrupt the inflammatory loop associated with chronic DES. The PGE1s
also increase the anti-inflammatory immunosuppressive effects of cyclosporine.
So if you choose to use a cyclosporine agent to treat DES, an oral supplement
will serve to enhance this action.
A good nutritional supplement should address many
of the underlying inflammatory processes associated with DES. Studies suggest
oral administration of specific Omega-6 EFAs that contain sufficient amounts of
GLA 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's
the most unstable of the EFA oils and it does not contain GLA. Flax stability
issues keep it from easily converting to GLA, which it must do to produce PGE1.
It To the Streets
Here are some
tips for applying this knowledge to your patients:
all patients will present with symptoms of dry eyes.
Discuss dry eye with those who either mention dry
eyes as one of their symptoms or who fit the likely
demographic. This latter group consists of:
who work in a dry environment (many offices,
airplanes, air conditioning)
over 40 years of age
who have had (or are considering) LASIK surgery
who have lid abnormalities that might disrupt the tear film
who work on computers on a regular basis
who are using systemic medications (antihistamines, psychotropics, HRT,
who have chronic disease (Sjogrens, lupus, rheumatoid arthritis, diabetes)
contact lens wearers who can't wear lenses as long as they would like.
►Pharmaceutical-grade cold-water fish oil, as a source of Omega-3 EPA/DHA, is
germane to a good formulation. It serves as a metabolic gateway boost to the
downstream conversion of the Omega-3 to the anti-inflammatory PGE3. Peer
reviewed literature suggests Vitamin E, specifically gamma tocopherols, that
stabilizes EFAs and inhibits COX2 enzyme activity to prevent oxidation.
►Experts suggest curcumin to appropriately block Omega-6 and Omega-3 fatty acids
from metabolizing to the pro-inflammatory PGE2 and IL1. Curcu-min is a natural
COX2 in- hibitor with similar chemical properties to ibuprofens (NSAIDs). But
curcumin doesn't inhibit production of the COX1 enzyme that's necessary to
protect the stomach lining. The first sign of an adverse response can be severe
►Vitamin C, as ascorbic acid and fat-soluble ascorbyl palmitate, best modulates
PGE1 synthesis due to the extended half- life of the fat-soluble vitamin C over
water-soluble ascorbic acid. This vitamin C combination also enhances the
production of IgE concentrates in tears, the first line of basophil and mast
cell defense against invading pathogens and allergens that frequently cause dry
►Studies also recommend lactoferrin to increase the level of iron-binding
proteins to better inhibit viral and bacterial infections and to balance other
tear lipocalins (the family of proteins that transport small hydrophobic
molecules), which modulate the surface tension of the tear film and contact lens
comfort. Neutrophils, the first line of defense against infection, located in
the tear film, produce lactoferrin. Neutrophil apoptosis signals the macrophage
to clean up debris from wounds, including surgically-induced wounds, such as in
In looking for a tear-specific formula for oral
administration, be sure to look for nutrient co-factors necessary to address DES
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 DES, as well as enhance and restore
function to the glands involved in all three layers of the tear film.
Find the lucky combination
Treating idiopathic dysfunctional tear film with
oral nutritional supplements can be an effective method to resolve this
frustrating and uncomfortable condition in our patients. While it's worthwhile
to uncover the cause of the condition, using the right combination of
ingredients can work regardless of the causative factors. And your patients will
be glad you did.
offers on-site consultations and seminars on CVS to
eyecare professionals through his company, Corporate Vision Consulting, He also
has a private practice in Carlsbad, Calif. He can be reached at