Do Seniors Need to Supplement DHA for Vision Health?

mackerel contains DHADocosahexaenoic acid or DHA is a naturally-occurring chemical, so why might seniors need to supplement it? Our bodies create small amounts of this omega-3 fatty acid. DHA from the diet, such as seafood, also counts. Docosahexaenoic acid is crucial to brain development in infants, and it is found in large quantities in the brain and retina. Researchers have found that consuming extra DHA can fight eye disease. How much docosahexaenoic acid do you need to get these effects? Can you get enough through your diet, or do you need to supplement DHA for optimum health?

DHA Overview

A long-chain omega-3 fatty acid, DHA is found in every cell in the human body. DHA is a crucial structural component of your brain, skin, and eyes. Up to twenty-five percent of the fat in the human brain is docosahexaenoic acid.1

The retina is technically brain tissue. DHA makes up as much as 60% of the total polyunsaturated fatty acids (PUFAs) in the retina.

A pregnant woman’s body uses docosahexaenoic acid to help build the baby’s brain and retina. Breast milk contains the omega-3 fatty acids the infant needs. Baby formula is fortified with DHA to support brain and eye development.

Research on DHA, the Eyes and the Brain

Macular Degeneration: Seniors who eat at least one serving of fatty fish per week cut advanced wet macular degeneration risk in half in a large study.2 A meta-study found that subjects who ate the most omega-3s had a 38% lower risk compared to those who ate the least.3

Neuroprotection: Brain synapses contain a very high concentration of docosahexaenoic acid. DHA is crucial for communication between the nerves.4

Anti-inflammatory: Neuroprotectins are proteins that form connective tissue between brain cells. Docosahexaenoic acid has an anti-inflammatory effect on neuroprotectins.5

Cellular Energy: DHA regulates important enzymes that provide energy to the cells, especially the brain.6

Alzheimer’s Disease: A study found that seniors who ate at least one serving of fish per week had a 60% lower risk of Alzheimer’s Disease.7 Taking plant-based oils reduced the risk of getting early-onset Alzheimer’s Disease in genetically vulnerable people (APOE4 gene).8 Alzheimer’s Disease patients have significantly less docosahexaenoic acid in the hippocampus, responsible for short-term memory. 9

How Much Docosahexaenoic Acid

The body does not generate enough docosahexaenoic acid for optimum health. Extra DHA needs to be ingested. Mainstream health authorities typically recommend that adults get 250-500 mg of omega-3 fatty acids per day.10 However, researchers have found that eating or supplementing 650 mg of DHA is optimal. Unfortunately, adults in the United States get an average of only 100-200 mg of docosahexaenoic acid per day through their food.11

Food Sources of DHA

Fatty fish is an excellent source of DHA. Tuna, salmon, oysters, halibut, herring, mackerel, and anchovies are easy to find in any grocery store. Fresh fish is more flavorful. Canned fish is more economical and nutritionally equivalent to fresh. Fish packed in oil retains more of the omega-3 fatty acids.12 A tablespoon of cod liver oil contains 2,664 mg of omega-3 fatty acids.

Vegetarians may lean on flaxseeds, chia seeds, walnuts, and soybeans. These foods are rich in omega-3 fatty acids, mostly ALA. The body converts ALA into docosahexaenoic acid, but only in tiny amounts. Vegetarians may be low in DHA, even if they eat those foods. The body converts less than 1% of ALA into DHA.

Algae is rich in DHA, but it is not a common food in the Standard American Diet. Fatty fish get their DHA from eating algae. Vegetarians and vegans looking for a valid plant-based source of DHA can turn to algae supplements.

DHA Supplements

The most common form of DHA supplementation for adults is fish oils. Fatty fish oil is typically packaged in soft gels or capsules. Belching may produce an unpleasant fishy taste. Thus, some fish oil supplements add a flavor such as lemon. Cod liver oil by the spoonful is sufficient, but not tasty and may cause acid reflux in some people.

Seafood can be contaminated by heavy metals. Look for fish oil supplements that guarantee purity. The fish oil should be in a dark bottle to protect it against the effect of exposure to light. It should be processed at low heat. High heat can make the fish oil unhealthy to ingest. Smaller the fish, such as mackerel and sardines, have fewer impurities than large fish. Favoring smaller fish helps preserve the survival of large fish in the ocean.

Excessive fish oil supplements can thin the blood. People taking blood thinners must be cautious. Follow package directions and consult your doctor.

Krill oil is another option to get DHA. Krill oil comes from tiny shrimp and contains EPA and DHA, plus astaxanthin. Astaxanthin is a champion eye-protecting nutrient. It can cross the blood/brain barrier to deliver antioxidants directly to neural tissue to the brain, supports the retina, helps boost the immune system, and even reduces the risk of certain cancers.

Algae supplements provide omega-3 fatty acids, including DHA. Certified vegan formulas are available.

For health-related issues such as macular degeneration or even dementia, recommended dosages can increase as follows: 1,000 mg – 4,000 mg per day for prevention and maintenance. 4,000 mg – 6,000 mg per day for depression.


Seniors are vulnerable to eye disease and other effects of aging. Even one serving of fish per week helps protect the eyes and brain. For optimum health, take omega-3 fatty acid supplements that are rich in DHA, derived from oily fish, krill, or algae.

  1. Biochimie. 2011 Jan;93(1):7-12. doi: 10.1016/j.biochi.2010.05.005. Epub 2010 May 15 “Docosahexaenoic acid (DHA) and the developing central nervous system (CNS) – Implications for dietary recommendations” by Guesnet P, Alessandri JM.
  2. Augood C, et al. Oily fish consumption, dietary docosahexaenoic acid and eicosapentaenoic acid intakes, and associations with neovascular age-related macular degeneration. Am J Clin Nutr 88:398-406, 2008.
  3. Chong, E. Archives of Ophthalmology, June 2008; vol 126: pp 826-833. News release, Journal of the American Medical Association.
  4. Postepy Hig Med Dosw (Online). 2011 Jun 2;65:314-27. J Neurochem. 2007 May;101(3):577-99.
  5. Litman BJ, Niu SL, Polozova A, Mitchell DC. The role of docosahexaenoic acid containing phospholipids in modulating G protein-coupled signaling pathways: visual transduction. J Mol Neurosci. 2001 Apr;16(2-3):237-42
  6. Turner N, Else PL, Hulbert AJ. Docosahexaenoic acid (DHA) content of membranes determines molecular activity of the sodium pump: implications for disease states and metabolism. Naturwissenschaften. 2003 Nov;90(11):521-3.
  7. Ann Neurol. 1997 Nov;42(5):776-82.
  8. ibid
  9. Morris MC, Evans DA, Tangney CC, Bienias JL, Wilson RS. Fish consumption and cognitive decline with age in a large community study. Arch Neurol.2005 Dec;62(12):1849-53.
  10. Dietary Guidelines for Americans 2010, U.S. Department of Agriculture, U.S. Department of Health and Human Services
  11. Kris-Etherton PM, Taylor DS, Yu-Poth S, et al. Polyunsaturated fatty acids in the food chain in the United States. Am J Clin Nutr. 2000 Jan;71(1 Suppl):179S-88S