Does taking omega-3 help you stay healthy for longer?
Omega-3 likely has benefits, but for whom and from which source varies considerably. The most concrete benefit has been demonstrated for flaxseed in relation to cardiovascular risk factors; for the heart and brain effects of fish fatty acids, the evidence is mixed or preliminary.
Omega-3 fatty acids are widely discussed, but the evidence varies considerably depending on the health goal in question. Starting with the heart: historical research pointed to protection against cardiovascular disease, but more recent studies in broad Western populations show mixed results. Ethnicity and baseline intake turn out to play a major role. People who already eat a lot of fish may be starting from a different position than someone following a Western diet.
For the brain: there are indications that omega-3 can slow cognitive decline, but the evidence is limited and context-dependent. Dosage and how well your body absorbs the fatty acids make a clear difference. Definitive conclusions cannot yet be drawn here. Walnuts, which contain plant-based omega-3, are also linked to better cognitive health in older adults, but this evidence too is preliminary.
An interesting finding concerns sleep: people with higher blood levels of omega-3 less often slept nine hours or more per night. This sounds positive, because sleeping too long is associated with poorer health. However, this was measured at a single point in time in nearly 19,000 people, without it being possible to establish cause and effect.
Flaxseed, which contains plant-based omega-3, has the most concrete evidence of all the sources covered in this overview: 30 grams of ground flaxseed daily for at least twelve weeks demonstrably lowers blood pressure and improves fat levels and blood sugar, particularly in people at elevated risk. Whether this actually prevents diseases such as a heart attack or diabetes has not been proven.
The ratio of omega-6 to omega-3 in the typical Western diet runs as high as 10:1 or more, while a ratio of around 4:1 is considered favourable. Getting more omega-3 therefore makes sense primarily as a correction for an imbalanced ratio. How you do this, whether through fish, flaxseed or supplements, makes a biological difference: fish fatty acids such as EPA and DHA work differently from plant-based omega-3.
Claims based on reviews, a pooled cohort study (~19,000 participants) and observational/associative research. No large direct RCTs with "staying healthy for longer" as an endpoint. Causality has therefore not been established for most claims.