Metabolic health

Odd-chain saturated fatty acid index

OCFA index, C15:0 and C17:0

Included in Complete.

Researchers use this index to track dairy fat.

This index combines saturated fats with an odd number of carbons, mainly pentadecanoic acid (C15:0) and heptadecanoic acid (C17:0). It's calculated from your individual results, with formulas that vary by lab, and is studied as a marker of dairy fat intake.

Dairy is a main source, and your body adds some too.

Odd-chain fats are made by microbes in the stomachs of cows and other ruminant animals, so they appear in milk fat and, to a smaller degree, in beef and lamb. Pentadecanoic acid tracks dairy intake more closely than heptadecanoic acid.

The body can also make some, partly from compounds produced by gut bacteria. In observational studies, higher levels have been linked with lower risk of type 2 diabetes, while results for heart disease are inconsistent. These studies can't show cause and effect.

It's partly a dairy marker and partly made by your own body.

Questions

What does a higher odd-chain SFA index mean?

It often reflects more dairy fat in your diet, especially from higher-fat dairy foods. Because the body also makes these fats, the index is an imperfect measure of intake, and it's best read with your eating habits and other results.

Should I eat more dairy to raise it?

Research hasn't shown that raising this index improves health. The links with lower disease risk come from observational studies, so diet changes are worth talking through with a clinician or in your 1:1 longevity coaching.

Sources and references