⏱ 3 min read
Fats are not just an energy reserve: they form the membranes of every cell, wrap the nervous system, and give rise to signaling molecules. And like the other families, many important lipids are made from precursors through elongation and desaturation pathways. The most relevant case for supplementation is that of omega-3s.
The plant-based omega-3, alpha-linolenic acid (ALA) —found in flaxseed, chia, and walnuts—, is a precursor that the body can elongate and desaturate to produce the long-chain omega-3s EPA and DHA, the ones that concentrate the cardiovascular and neuronal benefits. The problem is efficiency: in humans, conversion of ALA to EPA is low and conversion of ALA to DHA is even lower, often only a small percentage.
That low conversion rate explains why relying only on plant ALA rarely suffices to reach optimal DHA levels. The enzymes responsible —the delta-6 and delta-5 desaturases and the elongases— are slow, compete with omega-6 metabolism (very abundant in the modern diet, which worsens the bottleneck), and vary with genetics, sex, and age. That is why oily fish and, for plant-based diets, algae oil —which provide preformed EPA and DHA— are the most reliable sources, bypassing the inefficient conversion.
When the body makes fat from scratch —for example, from an excess of carbohydrates— it starts from a common precursor: acetyl-CoA, the same molecule that fuels energy metabolism. Both fatty acids and cholesterol are built from it, and steroid hormones, vitamin D, and bile salts in turn derive from cholesterol. It is an example of how a single central precursor branches toward very different destinations depending on metabolic signals.
Cell membranes are made largely of phospholipids, and building them requires specific precursors such as choline (for phosphatidylcholine) and others such as serine and inositol. This connection links the world of lipids with that of acetylcholine and brain function, and explains why choline sources such as citicoline or alpha-GPC provide substrate both for the neurotransmitter and for the repair of neuronal membranes.
Educational information, not medical advice.