Kicking off my series of articles exposing the myths about eating fish, I want to address the loudest justification I hear for harvesting our watery friends: Omega-3s.
Here's the highlight reel of this article: Omega-3s from fish or fish oil don't help and often harm the health conditions they are allegedly great for; omega-3 intake is a scam isn't that important in the scheme of your whole entire diet; and most vegans probably require less omega-3 intake than non-vegans.
I believe the fundamental reason to not consume fish or fish oil is compassion; but it can be really challenging to extend compassion to other creatures when you're seriously struggling with your own health. Fatty fish is rich in omega-3 fatty acids. Omega-3s have a lot of positive press. Some of it is warranted. These fats are powerful, (literally) essential, and lots of stuff goes wrong when we don't eat enough of them! In my clinical practice, I find that most people are generally not eating enough total fat, let alone enough of these essential omega-3s. But does that mean that eating fish is the answer to major health issues? Or any health issues?
Unfortunately, no. The underlying uselessness of eating fish and taking fish oil for any condition is clear in the context of three big truths that we really need to talk about: Fish doesn't improve heart health. It doesn't prevent dementia. And it isn't even anti-inflammatory.
As a science-based nutritionist, sometimes I need to see some biochem pathways and clinical studies to really believe something. This article is especially for those of you (and me) whose values are more based around logic than feelings, or if your mind needs some science to change its thinking. This is a big topic, so be prepared to put on your science hats and thinking caps.
To keep it simple, remember this: omega-3, fish, and fish oil are three different things.
Omega 3 Fatty Acids 101
Omega-3 essential fatty acids are superstars. They're "essential" because the human body can't make them itself and needs them for survival. They're "fatty acids" because they are -- uh, fats. And they are "omega-3" because of their molecular structure.
There are six omega-3 fatty acids in the human diet, and they are metabolised through a series of enzymatic reactions. The two most researched and talked-about omega-3s are EPA and DHA. Plants mostly contain alpha-LNA. It takes a lot of effort for the human body to convert alpha-LNA and other omega-3s into the allegedly super-active EPA and DHA, but it can do it! Fish fat contains concentrated amounts of EPA and DHA, so it's kind of a "short-cut" to boost your omega-3s by eating fish or taking fish oil...
Some Quick Highlights of Omega-3 Fatty Acids:
Influence mood and behaviour
Limit inflammation throughout the body
Facilitate cellular messaging
Influence the immune system
Essential for growth and function of the brain
Obviously these fats are great for our health. "Eat more fish" is a common recommendation and fish oil is a frequent prescription from almost all nutritionists, naturopaths and doctors; and if you believe it'll help relieve your serious condition, of course you'd be tempted to take that advice. Well, don't. Here's why eating fish or taking fish oil is a well-meaning but ultimately useless treatment:
Fish Doesn't Help Heart Health
Omega-3s have been held up as a frontline nutritional therapy to reduce or even reserve cardiovascular disease. Sorry but this has got to be the biggest fish-eater scam of all time. While in vitro and animal tests show that omega-3s (specifically EPA) can influence the underlying mechanisms that we believe are behind heart diseases and strokes, quality real-world studies show that fish oil supplements and eating more fish doesn't do jack.
Evidence shows that eating fish or taking fish oil supplements:
Does NOT decrease the risk of having a stroke 
Has NO affect on hospital admission rates for heart failure 
Does NOT benefit abnormal heart rhythms 
Does NOT decrease the risk of having a heart attack 
In 2018, a Cochrane review  performed "the most extensive systematic assessment of effects of omega-3 fats on cardiovascular health to date" and found that:
Moderate- and high-quality evidence suggests that increasing EPA and DHA has little or no effect on mortality or cardiovascular health (evidence mainly from supplement trials). Previous suggestions of benefits from EPA and DHA supplements appear to spring from trials with higher risk of bias. 
Translation: the only decent studies on fish and fish oil have shown that they have barely any impact on cardiovascular health, and the trials from the past that everyone is touting as evidence are totally bogus.
The underlying mechanisms behind cardiovascular disease are inflammation, damage to blood vessels (driven by high blood pressure and oxidative stress), and high cholesterol. Omega-3 fatty acids have been shown to influence all of those mechanisms, but they are only one part of a much larger diet, in a much larger biosystem -- your body! If the rest of your diet is packed full of vegetables, fruits, nuts, seeds, whole grains and legumes (i.e. sources of alpha-LNA), then chances are your systemic inflammation will be low, blood pressure will be chill, and cholesterol will be in total balance.
FISH DOESN'T PREVENT DEMENTIA
The brain is chock-full of omega-3 fatty acids. These fats make up a large percentage of the structure of the brain, and are essential for its development, function, and protection against natural (and unnatural) ageing processes.
Most of a vegan's omega-3 is going to come from alpha-linolenic acid (alpha-LNA). This is then converted into other omega-3s, and eventually lands as EPA which is then converted into the "end of the line" omega-3, DHA. Getting there takes a few enzymatic reactions that require nutrient cofactors.
Our fish friends do the same thing. They eat algae that is rich in alpha-LNA, and convert it into DHA. Their fat contains high amounts of DHA.
DHA is great for human brain health. In fact, it makes up almost all omega-3 content of the brain; and omega-3 makes up almost 60% of all brain tissues. Remember, omega-3 and fish and fish oil are three different things.
Omega-3, particularly DHA, is needed for:
Mental and behavioural development
Creation and repair of new functional neurons
Limiting inflammation in the brain and nervous system
Facilitating communication between neurons
Creation and function of neurotransmitters
Regulating immune reactions in the brain
Helping the brain cope with ageing processes
Limiting the formation of beta-amyloid plaques that cause Alzheimer's disease
LOTS OF BRAIN STUFF!
But eating fish or taking fish oil:
Is NOT an effective treatment for Alzheimer's disease 
Does NOT improve cognitive performance in cognitively healthy older people 
Is NOT an effective treatment for dementia 
Does NOT prevent age-related brain changes and cognitive decline 
Does NOT improve children's neurodevelopment during breastfeeding 
High level meta-analyses and Cochrane Reviews have found that the evidence on fish and brain health is super inconsistent and based on poorly-designed studies. Because of these inconsistencies, it can't be concluded that fish helps the brain (even though every man and his dog think that it does).
Within these inconsistent findings, there are single studies that show a weak association between frequency of fish consumption and reduced risk of dementia  -- but remember that these studies are poorly designed and don't take into account other protective nutrients in the fish-eater's diet.
Rather than looking at a vegan diet vs pescatarian diet, studies usually compare two omnivore diets -- omnivores who eat fish, and omnivores who don't eat fish (but still eat other animals and their products). These studies don't consider any harmful factors found in the diets of omnivores who do not eat fish -- the people who happen to have a higher occurrence of dementia, and don't eat fish; nor do they consider the protective elements found in the omnivore-who-eats-fish's diet that aren't fishy.
Omnivores who eat fish tend to eat more vegetables, legumes and vegan sources of omega-3s than omnivores who don't eat fish, and it may be these (very vegan-friendly) elements that drive the reduction of risk . For example, vegan foods that contain lots of omega-3 fatty acids include chia seeds, flax seeds and walnuts - foods that are full of phytonutrients and fibre which have been directly proven to support cognition throughout the entire lifespan .
Also, check this out:
"Given that the first consequences of dementia on everyday living can appear three years before diagnosis, poor dietary habits could be a consequence rather than a cause of cognitive decline..." 
i.e. you can't draw a conclusions about diet and dementia by looking at what someone eats now. If Joe Schmo ate fish his whole adult life, developed dementia, stopped eating fish, finally got diagnosed, and then he participated in a study on fish and dementia risk -- well, the study might conclude that Joe Schmo got dementia because he didn't fish! But it'd be wrong!
What about fish oil? Surely a concentrated dose of DHA will boost brain health? The research suggests it's phooey. A Cochrane Review concluded that fish oil gives no improvement in cognitive function in older people , and other researchers emphasise that there is no single nutrient, including omega-3s in fish oil, that can protect against Alzheimer's disease (AD) and dementia:
This review has highlighted the lack of consistent evidence for the potential of nutraceuticals and pharmacotherapies to delay the progression of AD. Evidence for a single nutrient therapy is inconsistent. Therefore, it appears that the overall quality and composition of the diet also contribute to protection against AD and dementia.
(Thomas, et al., 2015) 
Translation: your entire diet is more important than your fish oil.
What kind of diet would have the quality and composition to possibly protect against Alzheimer's disease and dementia?
And maybe omega-3 isn't everything -- the lowest rates of validated instances of dementia and Alzheimer's disease in the world occur in remote India, where people eat a vegetarian diet rich in grains and beans . No fish.
Fish Doesn't Reduce Inflammation
This is one of the biggest shockers, I KNOW. In nutrition classes, we're taught that omega-3 fats are anti-inflammatory, that all other fats are inflammatory and in order to combat inflammation, you need to bump up omega-3 fats. Unfortunately, it's way more complicated than that.
Omega-3 fatty acids are said to be anti-inflammatory for three very science-heavy reasons:
Omega-3s are precursors for signalling molecules that result in other signalling molecules called "series 3 prostaglandins" -- these are hormone-like chemicals that balance inflammation. This process is controlled by immune cells.
Omega-3s can "crowd out" pro-inflammatory fats by taking their place in cell membranes. Within the membranes, omega-3s perform key roles in creating immune signals that help to regulate inflammation.
Omega-3s activate immune cells to "clean up" inflammation.
If that sounded way too complicated, here's the take-away: the anti-inflammatory actions of omega-3s are all associated with immune cells.
While animal tests suggest that omega-3 is a powerful anti-inflammatory in mice, the results don't translate to humans . Mice immune cells contain higher amounts of DHA to begin with, and readily suck up more; human immune cells aren't so keen on it.
"These key species-dependent differences may help explain why dietary fish oil, a rich source of DHA, has such a powerful beneficial impact on a variety of inflammatory conditions in mice, whereas human clinical trials have shown much more modest benefits, if any." 
But let's say for argument's sake that omega-3 is a powerful anti-inflammatory nutrient.
Remember that fish and fish oil are not just omega-3 fatty acids. Fish oil notoriously contains pollutants -- even those sold in the strictest markets . Do you know how fish oil is made? (Spoiler: it's not a clean process.)
As for whole fish, the fat profile of salmon contains only 13% omega-3s, with 30% saturated fat, 46% monounsaturated fats, and 13% omega-3s (with 7% other polyunsaturated fats like omega-6). Plus cholesterol. I'm not saying that these other fats are "bad", but they sure aren't anti-inflammatory. In fact, in isolation they are definitely pro-inflammatory . Fish is also packed full of crude protein, heavy metals, contaminants and pollutants -- major sources of inflammation! If omega-3 is a powerful anti-inflammatory in humans, it's unlikely that a measly 13% omega-3 in salmon could do much in the face of all these other inflammatory factors.
This could explain why fish and fish oil are evidentially useless when it comes to treating inflammation-driven disease:
Fish or fish oil:
Does NOT help to maintain remission in Chron's disease 
Does NOT reduce osteoarthritis pain and barely makes a dent on rheumatoid arthritis symptoms 
Does NOT improve eczema - in fact, it makes it worse and higher consumption leads to a greater risk, possibly because "unrecognized active agents in fish might have counteracted the benefit of marine-origin n-3 PUFAs in eczema" 
If you're still certain that omega-3 is a nutrient you need, there is good news -- plant-based sources of omega-3 fats (which admittedly also contain other pro-inflammatory fats) are packed full of other powerful anti-inflammatory nutrients like vitamin C, vitamin E tocopherols, carotenoids, and fibre that will help the omega-3 content to have any effect on your inflammation. Nothing works in isolation.
So why does fish take centre stage in anti-inflammatory diets like the Mediterranean diet? It has nothing to do with its alleged anti-inflammatory actions. Fish is just there to displace other protein sources that are more inflammatory -- red meat, chicken, turkey, pork etc. By switching these land animals for fish, the total inflammatory potential of a meal is reduced. A grilled fish fillet is less inflammatory than a steak. But you know what reduces inflammation even further? Cutting out the fish, too!
Ditch the fish!
EPA and DHA are the most researched types of omega-3s fatty acids. There are actually six omega-3 fatty acids. EPA and DHA are only found in high amounts in animal sources while the other types are more abundant in plants. Nutritionists and dieticians lament that the human body doesn't convert the other omega-3s into EPA and DHA very effectively, so the idea is that you need to eat fish (or other animal sources) to get enough of these two very active and well-researched omegas. But research has recently been coming out about the health impact of other omega-3s like DPA and alpha-LNA  .
Watch this space. I believe that over the next ten years we'll see a huge increase in research on the other four omega-3 fatty acids that are rich in plants and less-so in meat, demonstrating that they each have a fundamental role in human health. It'll become clear that EPA and DHA are "end of the line" omegas because they are actually the least important of all of the omega-3 essential fatty acids.
WAY TOO LONG, DIDN'T READ?
Vegan diets are naturally anti-inflammatory -- no need for extra omega-3 from fish or fish oil.
Vegan diets are rich in neuro-protective nutrients -- no need for extra omega-3 from fish or fish oil.
Vegan diets are the best diet for cardiovascular health - no need for extra! omega-3! from fish! or fish oil!
Don't worry about your omega-3s. There are more powerful and effective ways to control inflammation, protect the heart, and support your brain.
Some Light Reading:
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 Oops, there is no 28! Lucky I write the formatting rules for my blog, right?
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