When it comes to fish oil, more is not better


The benefits of fish oil supplementation have been grossly overstated

Article summary:

  • Most of the studies showing fish oil benefits are short-term, lasting less than one year
  • The only fish oil study lasting more than four years showed an increase in heart disease and sudden death
  • Fish oil is highly unstable and vulnerable to oxidative damage
  • There’s no evidence that healthy people benefit from fish oil supplementation
  • Taking several grams of fish oil per day may be hazardous to your health

A new study was recently published showing that 3 grams per day of fish oil in patients with metabolic syndrome increased LDL levels and insulin resistance [1].

Unfortunately, I don’t read Portuguese so I can’t review the full-text. But this study isn’t alone in highlighting the potential risks of high-dose fish oil supplementation. Chris Masterjohn’s latest article on essential fatty acids, Precious yet Perilous [2], makes a compelling argument that fish oil supplementation – especially over the long-term – is not only not beneficial, but may be harmful.

This may come as a surprise to you, with all of the current media hoopla about the benefits of fish oil supplementation. Yet the vast majority of the studies done that have shown a benefit have been short-term, lasting less than one year. The only trial lasting more than four years, the DART 2 trial, showed that fish oil capsules actually increase the risk of heart disease and sudden death [3].

A 2004 Cochrane meta-analysis of trials lasting longer than six months suggests that the cardiovascular benefits of fish oil have been dramatically over-stated [4]. They analyzed 79 trials overall, and pooled data from 48 trials that met their criteria. The only effect that could be distinguished from chance was a reduced risk of heart failure. Fish oil provided no reduction in total or cardiovascular mortality.

Too much fish oil can wreak havoc in your body

Omega-3 fatty acids are highly vulnerable to oxidative damage. When fat particles oxidize, they break down into smaller compounds, like malondialdehyde (MDA), that are dangerous because they damage proteins, DNA, and other important cellular structures.

A study by Mata et al demonstrated that oxidative damage increases as intake of omega-3 fat increases]. The results of this study were summarized in the Perfect Health Diet [6], by Paul and Shou-Ching Jaminet:


Notice the clear increase in TBARS (a measure of oxidative damage of the LDL particle) with omega-3 fat. It’s important to note that this was only a 5-week trial. If it had gone on for longer than that, it’s likely the oxidative damage caused by omega-3 fats would have been even worse. This isn’t surprising if you understand the chemical composition of fats. Polyunsaturated fats (PUFA) are highly vulnerable to oxidative damage because they’re the only fatty acids that have two or more double bonds, and it’s the carbon that lies between the double bonds that is vulnerable to oxidation (as shown in the figure below):



Another thing worth noting, if you haven’t already, is that intake of saturated and monounsaturated fats does not increase oxidative damage by a significant amount. This is illustrated in both the table and the diagram above: saturated fats have no double bonds, which means they are well protected against oxidation. MUFA is slightly more vulnerable, since it does have one double bond, but not nearly as much as PUFA which has several double-bonds.

A randomized, double blind, placebo-controlled trial likewise showed that 6 grams per day of fish oil increased lipid peroxides and MDA in healthy men [7], regardless of whether they were supplemented with 900 IU of vitamin E. And consumption of fresh, non-oxidized DHA and EPA has been shown to increase markers of oxidative stress in rats [8].

Fish oil not as beneficial as commonly believed

To be fair, at least one review suggests that fish oil supplementation is beneficial in the short and even intermediate term. A recent meta-analysis of 11 trials lasting more than one year found that fish oil reduced the relative risk of cardiovascular death by 13 percent and the relative risk of death from any cause by 8 percent.

But the effect seen in this review was mostly due to the GISSI and DART-1 trials. They found that fish oil may prevent arrhythmia in patients with chronic heart failure and patients who have recently survived a heart attack .

However, there is no evidence that people other than those with arrhythmia and chronic heart failure benefit from taking fish oil or that doses higher than one gram of omega-3 fatty acids per day provide any benefit over smaller doses. And then there’s the rather disturbing result of the DART-2 trial, the only fish oil study lasting more than four years, showing an increase in heart disease and sudden death.

It’s logical to assume the effects of oxidative damage would take a while to manifest, and would increase as time goes on. That’s likely the reason we see some benefit in short- and intermediate-term studies (as n-3 displace n-6 in the tissues), but a declining and even opposite effect in the longer-term DART-2 trial (as increased total PUFA intake causes more oxidative damage).

The danger of reductionist thinking in nutritional research

The current fish oil craze highlights the danger of isolated nutrient studies, which unfortunately is the focus of nutritional research today. Kuipers et al. eloquently described the risks of this approach in a recent paper. 

The fish oil fatty acids EPA and DHA (and their derivatives), vitamin D (1,25-dihydroxyvitamin D) and vitamin A (retinoic acid) are examples of nutrients that act in concert, while each of these has multiple actions(7,8).

Consequently, the criteria for establishing optimum nutrient intakes via randomized controlled trials (RCT) with single nutrients at a given dose and with a single end point have serious limitations. They are usually based upon poorly researched dose–response relationships, and typically ignore many possible nutrient interactions and metabolic interrelationships.

For instance, the adequate intake of linoleic acid (LA) to prevent LA deficiency depends on the concurrent intakes of α-linolenic acid (ALA), γ-LA and arachidonic acid (AA). Consequently, the nutritional balance on which our genome evolved is virtually impossible to determine using the reigning paradigm of ‘evidence-based medicine’ with RCT.

Interest in fish oil supplementation started with observations that the Inuit had almost no heart disease. It was assumed their high intake of marine oils produced this benefit. While this may be true, at least in part, what was overlooked is that the Inuit don’t consume marine oils in isolation. They eat them as part of a whole-food diet that also includes other nutrients which may help prevent the oxidative damage that otherwise occurs with such a high intake of fragile, n-3 PUFA.

It’s also important to note that there are many other traditional peoples, such as the Masai, the Tokelau, and the Kitavans, that are virtually free of heart disease but do not consume high amounts of marine oils. What these diets all share in common is not a large intake of omega-3 fats, but instead a complete absence of modern, refined foods.

Eat fish, not fish oil – cod liver oil excepted

That is why the best approach is to dramatically reduce intake of omega-6 fa , found in industrial seed oils and processed and refined foods, and then eat a nutrient-dense, whole-foods based diet that includes fatty fish, shellfish and organ meats. This mimics our ancestral diet and is the safest and most sane approach to meeting our omega-3 needs – which as Chris Masterjohn points out, are much lower than commonly assumed.

Some may ask why I continue to recommend fermented cod liver oil (FCLO), in light of everything I’ve shared in this article. There are a few reasons. First, I view FCLO as primarily a source of fat-soluble vitamins (A, D, K2 and E) – not EPA and DHA. Second, in the context of a nutrient-dense diet that excludes industrial seed oils and refined sugar, and is adequate in vitamin B6, biotin, calcium, magnesium and arachidonic acid, the risk of oxidative damage that may occur with 1 gram per day of cod liver oils is outweighed by the benefits of the fat-soluble vitamins.

So I still recommend eating fatty fish a couple times per week, and taking cod liver oil daily, presuming your diet is as I described above. What I don’t endorse is taking several grams per day of fish oil, especially for an extended period of time. Unfortunately this advice is becoming more and more common in the nutrition world.

More is not always better, despite our tendency to believe it is.

Article by Chris Kresser on October 25, 2010 @ 8:55 am In Food & Nutrition,Heart Disease.

Digestive Health Ann Arbor now offers a complete Metabolic Health Assessment.  It is extremely comprehensive and provides considerably more information about the current state of your health then most doctors will provide.  If you are interested in a very detailed assessment of your health, please click here for more information. (This assessment is covered by your health insurance).

Please call 734-726-0153 to schedule a free consultation and evaluation. At Digestive Health Ann Arbor we are known for providing professional and compassionate care. We strive to guide people towards a comprehensive and holistic healing strategy. Restoring your body to health will restore the quality of your life.

Concerned about Bone Health? Calcium Supplements may not be the answer….

Sometimes a healthy diet is not enough to keep our bodies healthy. Even with nutrient-dense foods, our bodies often require supplements. However, some of the most frequently recommended supplements are ineffective at best or dangerous at worst. Chris Kresser, integrative medical practitioner, argued in a recent article that Calcium supplements are not only unnecessary, but also harmful. The following newsletter will sum-up Kresser’s ideas and provide a road map for navigating true bone health.

Do Calcium supplements prevent osteoporosis?


There is little evidence that this is true. While many older women take products such as Viactiv and Caltrate to maintain bone health and prevent osteoporosis, there is no strong evidence to support the claim that these supplements work. In fact, a study conducted by the American Journal of Clinical Nutrition actually found that calcium supplements might even increase the rate of hip fractures in older women.

Calcium Supplements: Associated with Heart Disease



Though dietary intake of calcium protects against heart disease, supplemental calcium intake may actually increase it. A study published in the British Medical Journal (BMJ) of 24,000 men and women between 35-64 years found that users of calcium supplements actually increased their risk of heart attack during the 11-year study period by 139%.

Why do Calcium Supplements Correlate with Heart Disease?



It seems surprising that the same substance in moderately different forms would have such drastically different effects. Researchers suspect that high doses of calcium in the supplements may calcify the arteries, unlike calcium in food. When calcium builds up on the interior walls of the arteries, the arteries narrow which reduces the blood flow and leads to the manifestation of heart disease symptoms.

4 Other Risks: Calcium Kidney Stones, Prostate Cancer, Lead Contamination



1.      The Office of Dietary Supplements at the National Institutes of Health (NIH) lists increase prostate cancer risk and increase in kidney stones associated with excess calcium consumption.


2.      A Swedish study reported a higher risk of death among women with high calcium intakes.

3.      Extra calcium is not absorbed by the bones, but rather excreted in the urine, which increases the risk of calcium kidney stones.

4.      A Consumer Lab analysis found lead contamination and mislabeled supplement bottles.

Calcium Supplements: Hiding in Conventional Food


Just because you aren’t popping calcium supplement in pill form does not mean you are not at risk of over-exposure. Calcium supplements can be found in


1.      Orange juice

2.      breakfast cereals

3.      non-dairy milk

4.      bread

5.      instant oatmeal

6.      graham crackers

7.      multivitamins

3 Ways to Maintain Healthy Bones without Supplements

1. Get calcium from foods like:


- dairy products


- sardines

- salmon

- dark leafy greens

- bone broth

2. Get enough Vitamin D and Vitamin K2:


Both vitamins are necessary for the regulation of calcium metabolism.

3.Get enough Silica and Magnesium.

4. Weight-bearing exercise:


 helps strengthen bones.

Digestive Health Ann Arbor: We can help


Sufficient calcium intake is actually a question of absorption, not consumption.  Often we eat enough calcium-rich foods or take enough calcium supplements, but because of a digestive disorder or food allergy the calcium does not absorb properly. Crucial to bone health maintenance is digestive health maintenance. If you struggle with osteoporosis or general concerns about bone strength, Digestive Health Ann Arbor can build a strategic plan to getting your health back on track.

Please call 734-726-0153 to schedule a free consultation and evaluation. At Digestive Health Ann Arbor we are known for providing professional and compassionate care. We strive to guide people towards a comprehensive and holistic healing strategy. Restoring your body to health will restore the quality of your life.




[i] http://ods.od.nih.gov/factsheets/Calcium-HealthProfessional/

[ii] http://www.bmj.com/content/346/bmj.f228

[iii] http://ajcn.nutrition.org/content/94/1/5.full

[iv] [iv] https://www.consumerlab.com/results/print.asp?reviewid=calcium