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Omega-3 Fats

Story at-a-glance -

  • A recent analysis found regular consumption of fish and other omega-3- rich foods may lower your risk of a fatal heart attack (myocardial infarction) by about 10 percent
  • Omega-3s EPA and DHA from marine animal and plant sources are NOT interchangeable
  • Plant sources that contain omega-3 ALA do not provide the same benefits as theomega-3s you find in marine sources

How Good Fats Prevent Heart Disease

July 11, 2016 | 236,561 views
| Available in EspañolDisponible en Español

By Dr. Mercola

Omega-3 fats — specifically EPA and DHA — are essential to your overall health, including your heart health.

A recent analysis of 19 studies confirms that regular consumption of fish and other omega-3 rich foods, including certain plant-based sources, may lower your risk of a fatal heart attack (myocardial infarction) by about 10 percent.1,2,3

This effect held true even after accounting for confounding factors like age, sex, ethnicity, diabetes and use of aspirin or cholesterol-lowering drugs.

According to senior study author Dr. Dariush Mozaffarian, "Our results lend support to the importance of fish and omega-3 consumption as part of a healthy diet." Other studies have found even more significant effects.

One large Italian trial found that heart attack survivors who took 1 gram of omega-3 fat each day for three years had a 50 percent reduced chance of sudden cardiac death.4

Health Benefits of Omega-3 Fat

Omega-3 fats benefit your cardiovascular health in several ways. In addition to lowering your blood pressure and triglyceride concentrations and improving endothelial function (a major factor in promoting the growth of new blood vessels), research has demonstrated omega-3s are:

  • Antiarrhythmic: counteracting or preventing cardiac arrhythmia
  • Antithrombotic: tending to prevent thrombosis (a blood clot within a blood vessel)
  • Antiatherosclerotic: preventing fatty deposits and fibrosis of the inner layer of your arteries from forming
  • Anti-inflammatory: counteracting inflammation (heat, pain, swelling, etc.)

Researchers are also attributing a number of other health benefits to omega-3 fat, including:


Healthier, stronger bones

Improved mood regulation

Reduced risk of Parkinson's disease

Reduced risk of death from ALL causes

Protecting your tissues and organs from inflammation

Brain and eye development in babies, and preventing premature delivery

Reduced risk of Alzheimer's disease

Delayed progression to psychosis among patients at high risk for schizophrenia

Protection against osteoarthritis and rheumatoid arthritis (RA)5,6, 7

Protection against metabolic syndrome,8 including obesity, fatty liver9 and type 2 diabetes (by reducing inflammation and blood sugar)

Improvements in premenstrual syndrome (PMS) and dysmenorrhea10

Lowered risk for other neurological/cognitive dysfunction, including: memory loss, brain aging, learning disorders and ADHD,11 autism and dyslexia12

Reduced risk of Crohn's disease

Reduced risk of colon cancer13

Reduced risk of kidney disease14

Reduced risk of autoimmune disorders, such as lupus and nephropathy

Not All Omega-3s Are Made the Same

It's crucial to understand that not all omega-3 fats are created equal. There are two areas of confusion about omega-3s that I will attempt to clarify here:

  • Marine animal- versus plant-based omega-3 (docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) versus alpha-linolenic acid (ALA))
  • The difference between fish- and krill-based omega-3 (triglyceride-bound omega-3s versus phospholipid-bound omega-3s)

For starters, omega-3 fats can be obtained from both marine animal and plant sources, but contrary to popular belief, they are simply NOT interchangeable.

In recent years, a "myth" of sorts has sprung up, where people who avoid animal foods believe they can simply consume plant-based omega-3 ALA to meet their needs. But this isn't true and the science doesn't support this assertion.

Omega-3s EPA/DHA are essential polyunsaturated fats your body needs for a variety of functions, including digestion, muscle activity, blood clotting, visual acuity, memory and learning, and basic cell division and function of cell receptors.

Omega-3s EPA/DHA are considered "essential" fats as your body cannot make them and, hence, you must get them from your diet. Omega-3 ALA on the other hand is quite ubiquitous in the diet and therefore there is no real need to supplement.

Plant-based omega-3 has 18 carbons whereas marine-based omega-3s have between 20 and 22. They all have their first double-bond in the third position — hence the name "omega-3." However, as you will see below, the difference in the length of the carbon chain makes a significant difference.

This is where the distinction between long-chain and short-chain omega-3s comes from. EPA and DHA are long-chain fatty acids and ALA is a short-chain fatty acid.

Although your body can convert some of the ALA found in plants to the DHA found in marine oils, it is very rare for it to be more than 5 percent and typically found to be 1 to 3 percent, or even less. This is an insufficient amount to have any significant benefit.

Animal- Versus Plant-Based Omega-3

Here's a rundown of the core differences between marine-animal and plant-based omega-3s:15,16,17,18,19

Marine animal-based omega-3

Sources: Fatty fish (such as salmon, anchovies, sardines and herring), fish and krill oils.

Primary omega-3 content: DHA: a long-chain polyunsaturated fatty acid (PUFA) consisting of 22 carbons, and EPA: a long-chain polyunsaturated fatty acid consisting of 20 carbons.

Long-chain fatty acids EPA and DHA are more readily available to your body.

Your body also seems to have a significant capacity to synthesize another omega-3 fat, docosapentaenoic acid (DPA), most likely by elongating  EPA.

Biological effects: DHA and EPA are structural elements with many biological effects, most notably anti-inflammatory activity and communication within the cell and between cells.

More than 90 percent of the omega-3 fat found in brain tissue is DHA; as much as 30 percent of the fatty mass of the prefrontal cortex is DHA and the development of a normal brain in a fetus is absolutely dependent on the availability of DHA.

All other omega-3 fats are found only in trace amounts, including ALA, regardless of how much ALA you consume.20

Plant-based omega-3

Sources: Certain plants, such as flaxseed, flaxseed oil, chia seeds, nuts (especially walnuts) and leafy greens.

Primary omega-3 content: ALA is a short-chain fatty acid consisting of 18 carbons; it's conversion to long-chain fatty acids is very poor, around 1 to 3 percent.

ALA is a precursor to EPA and DHA. However, enzymes are required to elongate and de-saturate the shorter 18 carbon ALA into long-chained omega-3. In most people,  this doesn't work very well and hence the conversion rate is very small.

Typically, less than 1 percent of ALA is converted to EPA/DHA. Some studies have found the conversion rate to be as low as 0.1 to 0.5 percent.21 Your conversion is also dependent on having adequate levels of other vitamins and minerals.

So, while a tiny amount of the ALA you consume can be converted by your body into long-chain omega-3, it's a highly inefficient strategy and nowhere near as helpful as supplying EPA/DHA directly from marine sources.

Biological effects: Source of energy (fat).

Key Difference: ALA Is a Source of Energy Whereas EPA and DHA Are Structural Elements

According to Nils Hoem, Ph.D., a leading scientist in omega-3 phospholipids whom I recently interviewed, when you look at the uptake and distribution of EPA and DHA you see something rather strange.

After eating a meal of salmon or taking a krill or fish oil, the fatty acid level in your plasma (blood) will remain elevated for more than three days afterward. "Your body works on its distribution, redistribution and re-redistribution for three days. That's hardly consistent with being "just food," he says.  

On the other hand, the short-chain omega-3s (ALA) are rapidly absorbed, peaking a couple of hours after ingestion. Within 10 hours, they're gone. This suggests your body is using them very differently.

According to Hoem, the short-chain fatty acids are simply food — they're a source of energy — while the long-chain fatty acids, those with 20 and more carbons, especially EPA and DHA, are structural elements. So EPA and DHA are not just "food;" they're elements that actually make up your cells, and those are two completely different functions. To learn more about this, please keep your eye out for Hoem's interview, which is scheduled to run shortly.

EPA and DHA are extensively distributed throughout your body, including your heart and brain. In fact, research shows there are specific transporters in your blood-brain barrier, the placenta (in pregnant women), and likely also in your liver, which transport these molecules in a very precise way into the cell membranes where they belong.

The Difference Between Fish- and Krill-Based Omega-3

Total Video Length: 05:40

The next area of confusion relates to the different types of marine-based omega-3. Fish and krill are two sources that provide both EPA and DHA. However, there are important differences between these two marine sources of omega-3s. One of the most important differences between fish and krill oil is the fact that krill oil is bound to phospholipids.

Fatty acids are water insoluble, so they cannot be transported directly in their free form in your blood — they require "packaging" into lipoprotein vehicles. Most fatty acids are typically bound to esters, which do not travel efficiently in your bloodstream. The phospholipids in krill oil seem to be partially different in this regard.

  • Fish oil is bound to triglycerides and methyl esters
  • Krill oil is bound to triglycerides and phospholipids

Phospholipids are also one of the principal compounds in high-density lipoproteins (HDL), which you want more of, and by allowing your cells to maintain structural integrity, phospholipids help your cells function properly. (You can learn more about this in the video above.)

There's also a synthetic form of marine omega-3, which is bound to ethyl esters. This is simply a fatty acid that has been sliced off from its triglyceride source and then ethylated with ethanol. Pharmaceutical omega-3 supplements are typically made this way, and research shows ethyl esters, unless taken in conjunction with a meal, may simply pass through your body without being absorbed whatsoever.

Other Advantages of Krill Oil Over Fish Oil

Research also shows krill oil has a number of other advantages over fish oil, including the following:

Higher potency

Studies have shown that krill oil is more potent than fish oil. This means you need far less of it than fish oil, as confirmed by a 2011 study published in the journal Lipids.22 Researchers gave subjects less than 63 percent as much krill-based EPA/DHA as the fish oil group, yet both groups showed equivalent blood levels — meaning the krill was more potent.

Contains phosphatidylcholine

When you consume fish oil, your liver has to attach it to phosphatidylcholine in order for it to be utilized by your body. Krill oil already contains phosphatidylcholine, which is another reason for its more efficient cellular uptake. Phosphatidylcholine is composed partly of choline, the precursor for the vital neurotransmitter acetylcholine, which sends nerve signals to your brain, and for trimethylglycine, which protects your liver.

Choline is important to brain development, learning and memory. In fact, choline plays a vital role in fetal and infant brain development, so it is particularly important if you are pregnant or nursing.

Resists oxidation

Fish oil is quite prone to oxidation, and oxidation leads to the formation of free radicals. Consuming free radicals further increases your need for antioxidants. Fish oil is very low in antioxidants whereas krill oil contains astaxanthin — probably the most potent antioxidant in nature — which is why krill oil is so stable and resistant to oxidation.


Fish are very prone to mercury and other heavy metal contamination, courtesy of widespread water pollution. Antarctic krill is not prone to this contamination. Not only are they fished from cleaner waters, but since krill is at the bottom of the food chain, it feeds on phytoplankton and not other contaminated fish.

Although processed fish oil can be purified, it requires extensive additional damaging processing to do so, unlike krill, which is not contaminated from the start and requires no additional processing to achieve high purity levels.

Environmentally sustainable

Krill is far more sustainable than fish because it's the largest marine biomass in the world, making krill fishing one of the most sustainable practices on the planet. Krill fishing is also carefully regulated, and only less than 1 percent of the total krill biomass in the areas where the fishery is allowed (designated as "Area 48" in the Southern Ocean) is caught each year.

The krill population is monitored by the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR). The Marine Stewardship Council (MSC) certifies that krill fishing is carried out in compliance with strict sustainability criteria to avoid overfishing. For more information, please read my 2009 article that goes into the sustainability aspects of krill harvesting in greater depth.

Superior metabolic influence

Researchers have found that krill oil is vastly superior to fish oil when it comes to having a beneficial influence on your genetic expression and metabolism. Genes have "switches" that can be flipped on and off, which control virtually every biochemical process in your body, and nutrients like omega-3 fats control those switches.

Fatty acids help to direct metabolic processes such as glucose production, lipid synthesis, cellular energy, oxidation and dozens of others. We now know that various types and sources of omega-3 fat affect liver tissue differently, which is what a 2011 study23  in Frontiers in Genetics was designed to examine.

It compared the livers of mice fed krill oil to those fed fish oil by looking at the gene expression triggered by each. Although both fish oil and krill oil contain omega-3s, they differ greatly in how they affect the genes controlling your metabolism. Krill oil:

  • Enhances glucose metabolism in your liver, whereas fish oil does not
  • Promotes lipid metabolism; fish oil does not
  • Helps regulate the mitochondrial respiratory chain; fish oil does not
  • Decreases cholesterol synthesis, whereas fish oil increases it

So krill will help lower your triglyceride and cholesterol levels and increase your energy production, whereas fish oil does neither. Last year, an Italian study24,25 confirmed that krill oil helps improve lipid and glucose metabolism and mitochondrial function, which may help protect against hepatic steatosis (fatty liver disease) caused by an unhealthy diet (such as diets high in unhealthy fats).

By stimulating certain mitochondrial metabolic pathways, including fatty acid oxidation, respiratory chain complexes and the Krebs cycle, krill oil helps restore healthy mitochondrial energy metabolism.

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Butter Is Not Linked to Heart Disease

Besides omega-3 fats, you might have heard some of the good news about saturated animal fats like butter and lard being far healthier than previously believed. Recent research has again acquitted butter, finding it does NOT increase your risk for heart disease.26 As reported by STAT:27

"Researchers combined the data from nine studies looking at the relationship of butter consumption with various health outcomes. They found that eating butter didn't significantly change people's incidence of cardiovascular disease, coronary heart disease or stroke.

The study did find a small link between butter and overall mortality — each daily tablespoon of butter was linked to a 1 percent increase in mortality risk. On the other hand, the same amount of butter was associated with a 4 percent lower risk of diabetes."

Butter, as you probably know, has long been demonized for being high in saturated fat. But as butter consumption declined, being replaced instead by processed vegetable oils that were thought to be healthier for the heart, heart disease rates actually increased.

Today, we recognize that trans fats are far more harmful to your heart than saturated animal fats ever were, and butter is again gaining favor. An interesting article in The Atlantic28 dating back to 2012 describes the history behind the misguided advice to avoid saturated fats, and "how Procter & Gamble convinced people to forgo butter and lard for cheap, factory-made oils loaded with trans fat."

Citizen Petition to Lift Interstate Ban on Raw Butter

In related news, the Farm-to-Consumer Legal Defense Fund and Organic Pastures Dairy Company have organized a citizen's petition to lift the interstate ban on raw butter. According to the Food and Drug Administration (FDA), it has the authority to ban sale of raw butter under its power to regulate communicable disease — a claim Pete Kennedy, attorney for Farm-to-Consumer Legal Defense Fund, says is "not only ridiculous but illegal as well." As noted in a recent article announcing the petition:29

"FDA's assertion of this power in banning raw butter is dubious for two reasons: first, the ban violates the Federal Food and Drug Cosmetic Act (FFDCA); and second, FDA is trying to prohibit a food in interstate commerce that has little or no record of making anyone sick.

FDA's butter ban is illegal according to a statute in the FFDCA that governs standards of identity for food. Standards of identity are requirements prescribing what a food product must contain to be marketed under a certain name in interstate commerce.

For instance, the standard of identity for milk in final package form requires that it be pasteurized or ultrapasteurized and that it contain not less than 8 ¼ percent non-fat milk solids and not less than 3 ¼ percent milkfat. FDA's long-held position is that the pasteurization requirement can be part of the standard of identity. Standards of identity are intended to promote honesty and fair dealing for the benefit of consumers.

Congress has given FDA power to issue regulations establishing standard of identity requirements for most foods, but there are exceptions and one of those is butter.

The FFDCA specifically prohibits FDA from establishing a standard of identity for butter; Congress has passed a law defining butter that serves as a standard of identity for the product. That definition does not require butter to be pasteurized. The petition asks FDA to obey the law and abide by the statutory standard of identity for butter."

To help, I encourage you to make a donation to the Farm-to-Consumer Legal Defense Fund. If you're not already a member, you may also consider becoming one.

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