Lowering Diabetic Retinopathy Risk With Omega-3s

A major health concern for people with diabetes, particularly in middle age and beyond, is the possible development of diabetic retinopathy.

Diabetic retinopathy (DR) involves damage to the retina’s small blood vessels, a condition that may lead to blindness. It’s a leading cause of vision loss worldwide. Good blood sugar control, including a healthy diet and regular exercise, can prevent or delay retinopathy onset.

To lower the risk of DR as much as possible, research done by scientists in Barcelona suggests our healthy diet should include a couple servings of fatty fish every week. Fatty fish are rich in omega-3s, or long-chain polyunsaturated fatty acids (LC-PUFAs), and these fatty acids are a structural component of our eyes’ retinas.

The research participants with type 2 diabetes who met or exceeded the LC-PUFA baseline equaling at least two fatty seafood servings per week, showed “a 48 percent relatively reduced risk” of retinopathy. While this is far from a guarantee of DR immunity, it does help stack the deck in our eyes’ favor.

Marine vs Plant Omega-3s

Getting enough LC-PUFAs to benefit our eyes requires us to consume marine sources of omega-3 fats such as salmon, sardines, anchovies, and herring, or to take fish, or krill oil supplements.

Marine-based omega-3 is made primarily of two LC-PUFAs called DHA, and EPA. Both DHA and EPA serve as structural elements in our body, engage in anti-inflammatory activity, and aid communication in and between cells. They may even help us utilize sunlight. DHA, the longer of the two fatty acid chains, is found in every cell of our body, and accounts for over 90 percent of the omega-3 fat in our brain.

It’s important to realize that while plant-based omega-3 fats are also good for us, they are functionally different from marine-sourced omega-3s.

Plant-based omega-3s - found in flaxseed, nuts (especially walnuts), chia seeds, and leafy greens - contain no DHA, or EPA. The primary content of plant omega-3 is ALA, a precursor to both DHA and EPA. The body uses ALA largely as an energy source. Though ALA can be converted into DHA with the help of an enzyme, the conversion rate is very small—only about one percent of ALA is ever transformed into DHA.

This means that to enjoy the structural benefits of LC-PUFAs for eye health we need marine-sourced omega-3s in our diet.

Supplement Differences

The best source of marine omega-3 is two to three weekly servings of wild-caught, cold-water fatty seafood—but not everyone enjoys or can eat fish. For those who choose to get their LC-PUFAs with supplements, know that some supplement types are more bioavailable, or more readily absorbed by the body than others:

• Prescription omega-3 is a semi-synthetic form of marine omega-3, and is bound to compounds called ethyl esters. The ethyl esters make these supplements less absorbable than natural triglyceride forms such as fish oil, or krill oil.
• Fish oil is bound to triglycerides and methyl esters. Esters must be broken down in our digestive tract into the fatty acids DHA and EPA; a sizeable amount is lost in the process of elimination.
• Krill oil is bound to triglycerides and phospholipids. Phospholipids are readily absorbed by the body so the EPA, and DHA in krill oil is more bioavailable than with fish oil. The phospholipids in krill oil are also one of the main compounds in our HDL, the high-density lipoproteins that give our cells structural strength.

Marine-based omega-3 fats benefit heart health as well as eye health, and protect against the onset of metabolic syndrome and type 2 diabetes. The entire family will benefit by making fatty fish, or supplement substitutes, part of the weekly diet plan.

Sources: Science Daily; Mercola
Photo credit: Nithi Anand