Omega-3 fats actively regulate the biological processes that determine how much and how we age. A diet rich in their sources, possibly combined with targeted supplementation at “longevity” dosages, is a promising strategy to protect our health and cognitive capital over the years.
Omega-3s play important structural and functional roles in the human body. The three main representatives of this family of nutrients are alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).
The first is the Omega-3 typical of plant-based foods; it is abundant, for example, in walnuts and flaxseeds. EPA and DHA, on the other hand, are the so-called marine Omega-3s, abundant in fatty fish (such as sardines, anchovies, salmon and mackerel) and in fish, krill and microalgae oils.
Although ALA is the precursor of the other two, the efficiency with which it is converted into EPA and DHA is extremely low. Some studies suggest that only 0.2% of dietary ALA is converted into EPA, and an even smaller 0.05% is converted into DHA.
In women these percentages appear to be higher than in men, but still insufficient to easily meet daily EPA and DHA requirements through ALA intake alone.
For this reason, even though only ALA meets the definition of an essential nutrient (which therefore must necessarily be obtained through diet), EPA and DHA are in practice also considered essential, and it is advisable to obtain them preformed through foods or dietary supplements.
In the human body, Omega-3s are found mainly as phospholipids in membranes, whose fluidity and function they influence, or as triglycerides in fat stores. Their structural role underlies their impact on health and longevity.
Omega-3, pillars of longevity
Scientific interest in Omega-3s in longevity medicine stems from research showing that people with higher levels of these fats in their blood have a 15%-18% lower risk of dying from any cause.
This protective effect appears to depend primarily on the ability of EPA and DHA to counteract inflammaging, i.e., the low-grade, silent but harmful chronic inflammation that, by damaging tissues and organs, is one of the main drivers of aging.
Marine-derived Omega-3s act as powerful regulators of this phenomenon. In addition to counteracting excess Omega-6 (fats that are equally essential, but often pro-inflammatory and too abundant in the modern diet), they promote the production of molecules that switch off inflammation (resolvins, protectins and maresins), helping to prevent it from becoming chronic.
Furthermore, Omega-3s have been associated with the maintenance of telomeres (the protective ends of chromosomes that tend to shorten with aging) and with slowing molecular biological clocks, modifying DNA without altering the sequence of the genes it contains, through a phenomenon known as methylation.
At the clinical level, the scientific literature suggests, for example, that the anti-inflammatory properties of Omega-3s slow the degradation of joint cartilage in conditions such as osteoarthritis, improving mobility and reducing reliance on painkillers. But the role of these fats as promoters not only of longevity, but of healthy longevity, also depends on other factors.
Indeed, adequate Omega-3 intake has been associated with improved muscle strength and stimulation of protein synthesis, suggesting interesting potential in countering sarcopenia — the loss of muscle mass and strength that, with advancing age, represents a primary risk to independence.
In addition, EPA and DHA help keep triglyceride levels and blood pressure within normal ranges, significantly reducing cardiovascular risk. At the same time, ALA protects the heart and arteries, helping to keep cholesterol levels normal as well.
Finally, Omega-3s are also recognized allies of good eye function. But their benefits are not evident only at the physical level: by promoting brain health, they also help support cognitive and psychological wellbeing.
The role of DHA in brain longevity
Indeed, after adipose tissue, the brain is the organ richest in fat in the human body: more than 50-60% of its weight is in the form of lipids, and 35% of its fats correspond to Omega-3.
DHA is the absolute protagonist, accounting for more than 90% of total Omega-3s in the brain and 10-20% of its entire fat mass. It is a fundamental component of neuronal membranes, and its presence is particularly relevant in gray matter, the part of the brain where information is processed.
By shaping the structure of neuronal membranes, Omega-3s facilitate signal exchange and nerve transmission; they also increase neurotransmitter release. These functions are joined by important neuroprotective effects:
- prevention of cell damage caused by oxidative stress due to the presence of reactive oxygen species;
- regulation of signals leading to programmed cell death, which is consequently inhibited.
Studies analyzing the practical implications of these actions have linked adequate Omega-3 intake to a roughly 20% reduction in the risk of dementia and cognitive decline. This effect is dose-dependent: it is estimated that every 0.1 g/day increase in EPA and DHA reduces the risk of cognitive decline by 8%-9.9%.
Studies conducted on healthy adults with an average age over 76 have linked higher blood Omega-3 levels to better memory, faster information-processing speed, and greater brain volume in specific brain regions (the entorhinal cortex and total white matter).
In patients with mild cognitive decline, DHA supplementation has been associated with significant benefits in preserving hippocampal volume and memory functions. And in individuals without cognitive problems but with coronary artery disease, high doses of EPA and DHA (over 3 grams per day) have been associated with a two-and-a-half-year slowing of cognitive aging.
An interesting finding concerns carriers of the APOE*E4 gene, a genetic risk factor for Alzheimer's disease: these individuals appear to particularly benefit from DHA supplementation, especially if started before the onset of symptoms.
Moreover, maintaining high blood Omega-3 levels seems to be an effective strategy for psychological balance, capable of preserving not only memory but also emotional stability. Even late-life depression, often underestimated, may benefit from an adequate Omega-3 intake, which appears to help counteract the associated inflammatory processes.
It is important to keep in mind, however, that the effectiveness of Omega-3s can be influenced by other nutrients. For example, it appears that having an adequate amount of B vitamins available is a necessary requirement for these fats to exert their beneficial effects on cognitive abilities.
How much Omega-3 for longevity?
The amount of Omega-3 to take depends on the benefit one wishes to achieve. To support good heart function, 250 mg per day of EPA+DHA is enough, while 2 or 3 g are needed to control triglycerides and blood pressure, respectively. And while there are no established dosages against inflammation-related disorders, we know that 250 mg per day of DHA is needed for eye health and to maintain normal brain function.
Research on brain longevity points to higher dosages. Dose-response analyses indicate that maximum efficacy for overall cognitive function is achieved within a range of 1000 to 2500 mg per day. More specifically:
- for short-term memory and visuospatial functions, it is suggested to exceed 1000 mg/day;
- for overall cognitive abilities, peak efficacy is observed around 1500 mg/day;
- for episodic memory (the part of long-term memory that allows us to remember the “what,” “where” and “when” of an event), benefits initially appear to decrease before increasing again at higher doses.
To date, research seems to leave little room for doubt: taking Omega-3s has positive effects on the body, is well tolerated and carries no significant risks. The fundamental basis remains a diet rich in oily fish, considered the optimal source for ensuring a steady supply of EPA and DHA, but personalized supplementation represents a valuable tool in situations of deficiency or increased need, for the elderly and for people living alone.
In addition to classic fish oil, options such as cod liver oil, krill oil and microalgae oils are available, also suitable for those following vegetarian or vegan diets.
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