What it is
Fat molecules have a long backbone of carbon atoms bound to hydrogen atoms. When a particular carbon is “saturated,” it forms a single bond with two other carbon atoms, and two hydrogen atoms. When consecutive carbons are “unsaturated,” they’re each only bound to a single hydrogen atom, allowing the neighboring carbon atoms to form a double bond with each other. This typically causes a bend in the carbon backbone.
Alpha-linolenic acid (ALA) is a polyunsaturated fat with three pairs of unsaturated carbons, and multiple bends in its carbon backbone. These bends in the carbon backbone make the fat molecules less likely to stack up in an orderly fashion, thus making ALA a liquid at room temperature.
What it does
ALA is considered an essential fatty acid, but it's primarily important because it can be converted to the two more important omega-3 fatty acids – EPA and DHA. However, the conversion of ALA to EPA and DHA is pretty inefficient. Only about 3-6% of ALA is converted to EPA, and only about 2-4% is converted to DHA.
ALA also competes with omega-6 linoleic acid (LA) for use by common enzymes that convert ALA to EPA and DHA, and LA to arachidonic acid. EPA and DHA are generally anti-inflammatory, and arachidonic acid is generally pro-inflammatory, so sufficient ALA intake may indirectly reduce general inflammation.
The recommended intake of ALA is 1.6 grams per day for men, and 1.1 grams per day for women.
Likelihood of tracking completeness: Very low
ALA is not a nutrient food manufacturers are required to disclose on nutrition labels. The vast majority of food manufacturers do not voluntarily list ALA content on nutrition labels, so most branded products in the MacroFactor database lack information on ALA. So, if you’d like to accurately track your ALA intake, you’ll need to make a point of mostly tracking “common foods,” which come from research-grade databases that have full nutrient reporting.
For more on when you can track using branded foods versus common foods when you’re trying to accurately monitor your intake of particular nutrients, you should check out this article.
Likelihood of insufficient intake: Low
Most adults in developed countries consume adequate amounts of ALA.
For more on nutrients with a greater likelihood of insufficient or excessive intake, you should check out this article.
Signs of deficiency/insufficiency
The earliest signs of insufficient omega-3 intake (including ALA) are dermatitis and rough, scaly patches of skin.
Flax seeds, chia seeds, hemp seeds, and walnuts (and products made from those nuts and seeds) are the best sources of ALA. Canola oil is also high in ALA.
If you’d like to learn more about micronutrients generally, there’s a five-part series on the MacroFactor website you might enjoy.