In our last blog, we discussed the relationship between eye health and nutrition - specifically, between antioxidants and your macula. But there are many other ways in which nutrition and optometry interact. For example, did you know that your diet can also affect eye dryness?
The tear film in our eyes is made up three layers. The mucous layer is the innermost layer and coats surface of the eye. In the middle is the aqueous (or watery) layer, which is the thickest of the three. On the surface of the tear film is a thin, but very important oily layer. Oil floats on water, and so the oily layer is an important barrier between the tear film and the dry air in our environment. The oily layer of the tear film stops the watery layer from evaporating away. Patients with a thick, stable, healthy oily layer on the surface of their tear film almost never complain of dry eye symptoms.
The oily layer is produced by the meibomian glands in the eyelids. There are approximately 24 meibomian glands running vertically in each upper eyelid and 12 in each lower eyelid. These glands use Omega 3 fatty acids to produce the oily meibum, which is gently squeezed out into the tear film with each blink. Omega 3 is an essential fatty acid, which means that your body cannot produce it. If you don’t have it in your diet, you won’t have any for your meibomian glands to use. Then your tears are more likely to evaporate away, leaving you with symptoms of dry eyes.
The best dietary source of Omega 3 fatty acids is dark, oily fish such as salmon, mackerel, and sardines. We need to eat one portion of dark fish about 5 times per week in order to get the amount of Omega 3 fatty acid our body needs in order to maintain healthy Meibomian gland function. If you don’t eat that much fish, then you may wish to supplement your intake of Omega 3 fatty acids by taking fish oil supplements daily. We need 2000 to 3000 mg (that’s about one teaspoonful) per day. Be aware of two issues with Omega 3 fish oil supplements:
First, these types of fish swim in the oceans, and oceans can be polluted. In order to remove all the pollutants, the fish oil must be distilled. Distilling the fish oil turns it into a form that your gut will not recognize or absorb well. Turning the oil back into its natural form requires an extra step called transesterification, which is expensive. If you’ve wondered why the better products are more expensive, that’s why. The benefit to you is that fish oil in it’s natural, triglyceride form is better absorbed by up to 70%, so you’ll actually receive the benefit you’re hoping for when you take it.
Second, Omega 3 fatty acids have some blood-thinning properties, so it’s wise to discuss the choice to take fish oil supplements with your family doctor if you are already taking blood thinners.
While it is important to consciously include Omega 3 in your diet, we don’t recommend supplementing your intake of Omega 6 and Omega 9. Omega 6 and 9 come from seeds and grains and nuts, and since much of our beef and pork and poultry is grain fed, we get more than enough Omega 6 and 9 already in our North American diets. This is the main reason we believe it’s a good idea to consider grass-fed and grass-finished beef. When the cattle eats the grass, they also take in the bugs in the grass, which are a source of Omega 3 fatty acids to the cattle. It’s important that the cattle are finished on grass too, since the Omega 3 will only stay in their bodies for 1 or 2 days once they switch to a grain diet on their way to slaughter.
If you find yourself chronically suffering from dry eyes, it is likely that you need more Omega 3 fatty acids in your diet. If you have any other questions about how your nutritional habits affect your eye health, feel free to contact us at Doig Optometry at 403-333-3353. You’re always happy to help you “look” your best!