This is such a helpful “de-hype without dismissing” piece. I love how you walk readers from the shelf-level marketing claim (“phospholipid DHA/krill oil = better brain delivery”) to what the biology and kinetics actually suggest: once ingested, DHA is extensively digested and repackaged, cycling through multiple lipid pools, so the form on the label is unlikely to map cleanly onto brain delivery the way consumers are led to believe. 
Your framing around MFSD2A/LPC-DHA is also the right kind of nuance: the transporter story is real and foundational in development, but extrapolating that to “therefore krill oil is superior for aging brains (especially APOE4)” is a leap that needs stronger human outcome evidence, particularly given the mixed/null cognitive RCT landscape and replication data challenging formulation superiority in brain DHA content. 
Clinically, the most actionable takeaway is your “context first” message: omega-3s may be a meaningful supportive lever, especially for APOE4 carriers, but they’re most plausible as part of an anti-inflammatory dietary pattern (fiber-rich, plant-forward, metabolically healthier milieu), not as a shortcut layered onto a Western pattern. The supplement aisle is getting bigger; your post helps people get smarter.
The supplement aisle has reached almost comical proportions — as if physiology were a simple input-output machine where adding a molecule guarantees delivery to the target tissue.
In reality, biology is much more about context, transport, and system state. I appreciate the pushback against the “capsule solves everything” narrative.
I'm the spousal support/researcher for my 4/4 husband, 73yo. We've been eating a whole foods vegan diet since 1990. We tested our Omega 3s and made the jump to taking a good quality fish oil a couple of years ago and it improved. After reading about this topic we're exploring next steps. I don't think we can bring ourselves to eating fish after decades. On what basis do I choose a new supplement for him? Thanks. (note: we also exercise and generally live a healthy lifestyle)
Dear Sheila, thank you for your note. I generally do not make clinical recommendations on social media. My goal is to discuss these topics so we are better informed when we make decisions. In general, I am a proponent of a healthy dietary pattern as opposed to a single ingredient. A healthy pattern does not have to contain fish. There are plant based sources of omega3s. Supplements can help in certain individuals but we need to be mindful that their effects are limited compared to Whole Foods. I hope this is helpful to you as you make your own decision.
Thank you for your response. I respect your choice to not make recommendations. The two plant-based sources of Omega3s we take daily are flax seeds & walnuts. I'm not sure if we take enough or if they can penetrate the blood brain barrier. I'll keep reading. Thanks.
Thank you for this evidence-based, thoughtful piece. As a physician in the longevity space, I hear a lot about omega-3 for health and longevity. The cardiac trials have mostly been null. You point at something similar for dementia and cognitive trials. For those who are not ApoE4 carriers, would you say omega-3 has even less benefit?
This is such a helpful “de-hype without dismissing” piece. I love how you walk readers from the shelf-level marketing claim (“phospholipid DHA/krill oil = better brain delivery”) to what the biology and kinetics actually suggest: once ingested, DHA is extensively digested and repackaged, cycling through multiple lipid pools, so the form on the label is unlikely to map cleanly onto brain delivery the way consumers are led to believe. 
Your framing around MFSD2A/LPC-DHA is also the right kind of nuance: the transporter story is real and foundational in development, but extrapolating that to “therefore krill oil is superior for aging brains (especially APOE4)” is a leap that needs stronger human outcome evidence, particularly given the mixed/null cognitive RCT landscape and replication data challenging formulation superiority in brain DHA content. 
Clinically, the most actionable takeaway is your “context first” message: omega-3s may be a meaningful supportive lever, especially for APOE4 carriers, but they’re most plausible as part of an anti-inflammatory dietary pattern (fiber-rich, plant-forward, metabolically healthier milieu), not as a shortcut layered onto a Western pattern. The supplement aisle is getting bigger; your post helps people get smarter.
Thank you for writing this.
The supplement aisle has reached almost comical proportions — as if physiology were a simple input-output machine where adding a molecule guarantees delivery to the target tissue.
In reality, biology is much more about context, transport, and system state. I appreciate the pushback against the “capsule solves everything” narrative.
I'm the spousal support/researcher for my 4/4 husband, 73yo. We've been eating a whole foods vegan diet since 1990. We tested our Omega 3s and made the jump to taking a good quality fish oil a couple of years ago and it improved. After reading about this topic we're exploring next steps. I don't think we can bring ourselves to eating fish after decades. On what basis do I choose a new supplement for him? Thanks. (note: we also exercise and generally live a healthy lifestyle)
https://www.pcrm.org/good-nutrition/nutrition-information/omega-3
Dear Sheila, thank you for your note. I generally do not make clinical recommendations on social media. My goal is to discuss these topics so we are better informed when we make decisions. In general, I am a proponent of a healthy dietary pattern as opposed to a single ingredient. A healthy pattern does not have to contain fish. There are plant based sources of omega3s. Supplements can help in certain individuals but we need to be mindful that their effects are limited compared to Whole Foods. I hope this is helpful to you as you make your own decision.
Thank you for your response. I respect your choice to not make recommendations. The two plant-based sources of Omega3s we take daily are flax seeds & walnuts. I'm not sure if we take enough or if they can penetrate the blood brain barrier. I'll keep reading. Thanks.
Thank you for this evidence-based, thoughtful piece. As a physician in the longevity space, I hear a lot about omega-3 for health and longevity. The cardiac trials have mostly been null. You point at something similar for dementia and cognitive trials. For those who are not ApoE4 carriers, would you say omega-3 has even less benefit?
We lack clinical efficacy and toxicity data to support an expensive supplement.
Also curious if you think the Lysophospholipid-DHA (LysoPL-DHA) version of omega 3 is supperior (https://pubmed.ncbi.nlm.nih.gov/39421371/)