I was unable to access the OP's source, but I do want to point out there are several ω-3 polyunsaturated fatty acids with different nutrient characteristics. Thanks be to Chat G for banging this out, but I like many people have had this drilled in.
ALA (α-linolenic acid, 18:3 n-3) is an essential fatty acid. It's nutritional role is primarily as a precursor to the other ω-3 PUFAs, humans can elongate and desaturate ALA into longer-chain ω-3s (EPA, DPA, DHA), but the conversion efficiency is very limited (<5% to EPA, <1% to DHA for most people). ALA cannot be converted from EPA, DHA, or DPA. Sources are primarily plant oils (flaxseed, chia, walnuts, canola, soy). If this is your only source of ω-3 PUFAs, you're unhealthy.
EPA (eicosapentaenoic acid, 20:5 n-3) is (conditionally) essential. Its role is anti-inflammatory, a precursor for resolvins, cardiovascular protection, eye and brain signaling, and a precursor to DHA synthesis in limited amounts. Sources are marine foods (fatty fish: salmon, mackerel, sardines, anchovies).
DHA (docosahexaenoic acid, 22:6 n-3) is (conditionally) essential. Its role is as a major structural lipid in the retina, brain, and neural tissues, visual function, cognitive development, and neuronal membranes. Sources are marine foods (same as EPA) plus algae oils.
DPA (docosapentaenoic acid, 22:5 n-3) is an intermediate between EPA and DHA. Don't know. Sources are fish and red meat (esp. grass-fed ruminants).
In practice EPA, DHA, and DPA conversion from ALA is too inefficient, so direct dietary sources (fish, seafood, algal oil) are the meaningful way humans obtain enough EPA/DHA. That's why nutrition guidelines (WHO, FAO, NIH, EFSA) often treat EPA + DHA as conditionally essential, especially for infants (where DHA is critical for retina and brain development) and for populations with low fish intake.
Eat fish. As always, a balanced and diverse diet is a key requirement for health. For those who don't know, sardines are less fishy than tuna (hardly at all IMO), cheap, widely accessible, and pretty sure they have low mercury risk.
I was unable to access the OP's source, but I do want to point out there are several ω-3 polyunsaturated fatty acids with different nutrient characteristics. Thanks be to Chat G for banging this out, but I like many people have had this drilled in.
ALA (α-linolenic acid, 18:3 n-3) is an essential fatty acid. It's nutritional role is primarily as a precursor to the other ω-3 PUFAs, humans can elongate and desaturate ALA into longer-chain ω-3s (EPA, DPA, DHA), but the conversion efficiency is very limited (<5% to EPA, <1% to DHA for most people). ALA cannot be converted from EPA, DHA, or DPA. Sources are primarily plant oils (flaxseed, chia, walnuts, canola, soy). If this is your only source of ω-3 PUFAs, you're unhealthy.
EPA (eicosapentaenoic acid, 20:5 n-3) is (conditionally) essential. Its role is anti-inflammatory, a precursor for resolvins, cardiovascular protection, eye and brain signaling, and a precursor to DHA synthesis in limited amounts. Sources are marine foods (fatty fish: salmon, mackerel, sardines, anchovies).
DHA (docosahexaenoic acid, 22:6 n-3) is (conditionally) essential. Its role is as a major structural lipid in the retina, brain, and neural tissues, visual function, cognitive development, and neuronal membranes. Sources are marine foods (same as EPA) plus algae oils.
DPA (docosapentaenoic acid, 22:5 n-3) is an intermediate between EPA and DHA. Don't know. Sources are fish and red meat (esp. grass-fed ruminants).
In practice EPA, DHA, and DPA conversion from ALA is too inefficient, so direct dietary sources (fish, seafood, algal oil) are the meaningful way humans obtain enough EPA/DHA. That's why nutrition guidelines (WHO, FAO, NIH, EFSA) often treat EPA + DHA as conditionally essential, especially for infants (where DHA is critical for retina and brain development) and for populations with low fish intake.
Eat fish. As always, a balanced and diverse diet is a key requirement for health. For those who don't know, sardines are less fishy than tuna (hardly at all IMO), cheap, widely accessible, and pretty sure they have low mercury risk.