There are 3 nutritionally significant omega-3 fats: 18-carbon alphalinolenic acid (ALA), 20-carbon eicosapentaenoic acid (EPA) and 22-carbon docosahexaenoic acid (DHA).
While carbon chain length varies, all omega-3 fatty acids share a unique basic shape, making them perfectly suited for their metabolic functions.
One important function is as part of cell membrane structure. Another very important role for DHA is for vision. DHA is a key component of the retina, making DHA very important for fetal development.
It’s also a critical part of brain tissue, and plays a role in neurotransmitter activity. EPA is involved with immune function and gene expression.
Recommended Dietary Allowances for Omega-3 Fats
NOTE: Adequate Intake is a combined value for the 3 key omega-3 fats in our food: alphalinolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)
Which Foods Have Omega-3 Fats?
Plant foods naturally high in omega-3 fats contain only the ALA form. EPA and DHA are found in animal foods like fish.
Many processed foods are now fortified with omega-3. Since there’s no official RDA for omega-3 fats, these foods do not have to list the amount or type of omega-3 added, although some do provide this information. Foods that may be fortified with omega-3 include:
Prepared foods like smoothies
In most cases, the added omega-3 is plant-sourced ALA. Algal-sourced DHA may be used, and is currently added to infant formulas.
What Happens If You Don’t Get Enough Omega-3 Fats?
Deficient intake of omega-3 is hard to define, as there is no official RDA.
While research has not identified clear omega-3 deficiency symptoms yet, numerous diseases have been associated with poor omega-3 intake, especially low intake of fish.
Risk for cardiovascular disease, sudden cardiac death, stroke and immune function are all linked to low omega-3 intake. Research on dementia and lung disease suggest a preventative role for omega-3, and there is evidence that omega-3 intake by pregnant and nursing women impacts fetal and infant brain and eye development.