By Dr. Mercola
Mounting research drives home the importance of animal-based omega-3 fats for heart health. After reviewing this topic carefully, I am now convinced that maintaining a healthy level of docosahexaenoic acid (DHA) may be one of the most important food priorities.
DHA is a 22 carbon omega-3 fat from seafood. Omega-3 fats can be obtained from both marine animal and plant sources, but contrary to popular belief, they are NOT interchangeable.
Alpha-linolenic acid (ALA), an 18-carbon omega-3 fat found in plants like flax and chia seeds does convert to DHA, but typically less than 1 to 3 percent, which is nowhere near the amount you need for brain and heart health.
While plant and animal omega-3 fats are important for health, the animal-based DHA is the one most strongly associated with heart health and other important health benefits.
Additionally, DHA through its electron cloud, has the ability to turn light directly into DC electric current, which is particularly important for establishing your biological clock and circadian rhythm.
DHA and EPA Protect Your Heart Health
Recent research suggests eating fatty 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 Taken AFTER a heart attack, omega-3 fats can also significantly improve your odds of survival.
One large 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 Another recent placebo controlled study5 found that high doses of omega-3 supplementation helps your heart heal after a heart attack.6,7,8,9,10
A total of 360 heart attack patients were divided into two groups. The treatment group took 4 grams of the prescription omega-3 fish oil called Lovaza. The placebo group received corn oil. After six months, the treatment group showed a 5.6 percent reduction in scarring of undamaged heart muscle.
Their hearts were also better able to pump blood compared to the controls. That said, it may be worth noting that corn oil is a terrible placebo. Placebos are supposed to be completely inert, like water. Corn oil is actually a harmful industrially processed GMO-contaminated omega-6 fat that clearly adversely affects your heart.
I don't say this to diminish the results, but it's been shown that prescription omega-3, due to it being a semi-synthetic form of marine omega-3 that is bound to ethyl esters,11 tends to have a poor absorption rate compared to natural triglyceride forms (such as fish oil or krill oil).12
Using a corn oil placebo could therefore make the drug appear more potent than it really is. According to Reuters:13
"Some people are better able to absorb and utilize fish oil, and those with the biggest increase in red blood cell levels of omega-3 levels had a 13 percent reduction in leftover blood in the left ventricle, compared to a 6 percent reduction for the fish oil group overall."
Animal-Based Omega-3 Benefits Heart Health in Many Ways
Animal-based omega-3 fats, especially DHA, benefit your cardiovascular health in a number of different ways, by:
✓ Lowering blood pressure
✓ Lowering triglyceride concentrations
✓ Improving endothelial function (which helps promote growth of new blood vessels)
✓ Counteracting or preventing cardiac arrhythmia
✓ Helping prevent thrombosis (a blood clot within a blood vessel)
✓ Preventing fatty deposits and fibrosis of the inner layer of your arteries
✓ Counteracting inflammation
Other Health Benefits of Omega-3 Fats
Your heart is by no means the only organ that needs omega-3s for optimal functioning. These healthy fats are also important for digestion, muscle activity, blood clotting, visual acuity, memory and learning, and basic cell division and function of cell receptors. For example, research suggests omega-3s are important for:
✓ Brain and eye development in babies, and preventing premature delivery
✓ Delaying progression to psychosis among patients at high risk for schizophrenia
✓ Protecting against osteoarthritis and rheumatoid arthritis (RA)14,15,16
✓ Protecting against metabolic syndrome,17 including obesity, fatty liver18 and type 2 diabetes (by reducing inflammation and blood sugar)
✓ Improvement in premenstrual syndrome (PMS) and dysmenorrhea19
✓ Lowering your risk for neurological/cognitive dysfunction, including: memory loss, brain aging, learning disorders and ADHD,20 autism and dyslexia21
✓ Reducing your risk of Crohn's disease
✓ Reducing your risk of colon cancer.22
Colon cancer patients who consumed a minimum of 0.3 grams of omega-3 from fish each day also reduced their risk of dying over the next decade by 41 percent23
✓ Reducing your risk of kidney disease24
✓ Reducing your risk of autoimmune disorders, such as lupus and nephropathy
There Are Crucial Differences Between Animal- and Plant-Based Omega-3s
As mentioned earlier, there are important differences between marine-animal and plant-based omega-3s:25,26,27,28,29
✓ Marine animal-based omega-3
• Primary omega-3 content: DHA and EPA, long-chained polyunsaturated fatty acids (PUFA) consisting of 22 and 20 carbons respectively, which your body can readily use.
• 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. DHA is especially important, as it is a component of every cell in your body.
More than 90 percent of the omega-3 fat found in brain tissue is DHA, making it very important for brain health. All other omega-3 fats are found only in trace amounts, including ALA, regardless of how much ALA you consume.30
EPA and DHA also likely play a role in helping your body properly utilize sunlight. They also have a profoundly important influence on mitochondrial health.
✓ Plant-based omega-3
• Sources: Certain plants, such as flaxseed, chia seeds, nuts (especially walnuts) and leafy greens.
• Primary omega-3 content: ALA: a shorter-chained PUFA consisting of 18 carbons. Plant-derived omega-3s are devoid of EPA/DHA.
ALA is a precursor to EPA and DHA. However, an enzyme is required to convert the shorter 18 carbon ALA into long-chained omega-3. In most people, this enzyme doesn't work very well and hence the conversion rate is exceptionally small.
Typically, less than 1 percent of the ALA is converted to DHA.31 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 DHA and EPA from marine sources.
• Biological effects: Source of energy (fat).
As you can see, ALA is primarily a source of energy, while 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. EPA and DHA are extensively distributed throughout your body, including your heart and brain, which is why deficiency is so detrimental to your brain and heart function.
Moreover, research shows there are specific transporters in your blood-brain barrier, the placenta (in pregnant women) and likely also in your liver, which transport the EPA and DHA molecules in a very precise way into the cell membranes where they belong.
Why I Recommend Krill Oil Over Fish Oil
Fatty fish and fish oil have long been the go-to sources for animal-based omega-3 fat. Krill oil is a more recent source, and research suggests it has a number of benefits over fish and fish oil. One of the most important differences is that fish oil is bound to triglycerides and methyl esters while krill oil is bound to triglycerides and phospholipids.
Esters aren't efficiently absorbed whereas phospholipids are. The fact that krill oil is bound to phospholipids makes its EPA and DHA more bioavailable than fish oil. Phospholipids are in fact extremely important for life, as this membrane is required for everything that makes up a cell.
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.) Krill oil is also able to efficiently cross your blood-brain barrier to reach important brain structures.
In fish oil, the omega-3s are attached to triglycerides and esters that must be broken down in your gut to its base fatty acids of DHA and EPA. About 80 to 85 percent is simply eliminated in your intestine. Another reason for the superior bioavailability of krill oil has to do with the fact that it contains phosphatidyl choline (a precursor for the vital neurotransmitter acetylcholine).
When you consume fish oil, your liver has to attach it to phosphatidyl choline in order for it to be utilized by your body. Your liver can skip this step when you take krill oil, as the phosphatidyl choline is already in there.
Other Features That Make Krill Oil a Superior Choice
Please remember my primary recommendation for increasing your DHA levels is healthy seafood. However, if you are unable to do that for whatever reason and choose to use a supplement, then there are other considerations. Phospholipids are just the beginning. Studies have revealed krill oil differs from fish oil in a number of important ways. For example:
• 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.32 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.
• Krill oil has superior influence on your metabolism and genetic expression. 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 also help to direct metabolic processes such as glucose production, lipid synthesis, cellular energy, oxidation and dozens of others. 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.
Various types and sources of omega-3 fat affect liver tissue differently, which is what a 2011 study33 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: 34,35
◦ 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
Krill oil also resists oxidation, whereas fish oil is quite prone to oxidation, which in turn leads to the formation of free radicals — not what you're looking for when taking an omega-3 supplement! Fish oil is also low in antioxidants whereas krill oil contains astaxanthin, which is currently thought to be among the most potent antioxidants in nature. This is in large part what makes krill oil so stable and resistant to oxidation.
Last but not least, while fish are prone to all sorts of contamination, courtesy of water pollution, Antarctic krill are not prone to such contamination. Not only are they harvested from cleaner waters, but since krill are at the bottom of the food chain, they feed on phytoplankton, as opposed to other contaminated fish.
Krill are also far more sustainable than fish because they're the largest biomass in the world. Harvesting of krill is also carefully regulated, and only 1 to 2 percent of the total krill biomass is harvested each year.
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Dosing Suggestions and the Importance of Maintaining a Healthy Omega-3 to Omega-6 Balance
As you increase your intake of animal-based omega-3 fats, the EPA and DHA content in your red blood cells increase. As your omega-3 ratio increases in the cell, it "pushes out" omega-6 at a ratio of about 1 to 1. While you need some omega-6 fats, most people get FAR too much of it in their diet these days.
Consumption of soybean oil, which is almost exclusively omega-6, rose 1,000-fold between 1909 and 1999. Modern processing and refinement add to the problem as it damages the omega-6 fats. In my view, it's reasonable to assume this massive increase in damaged omega-6 oils has significantly contributed to our current epidemics of diabetes, heart disease, cancer and neurodegenerative diseases.
In terms of how much omega-3 fat you need, there's been a lack of reliable ways of measuring them. The best way to measure your omega-3 level is using an Omega-3 Index test, which measures the omega-3 in your red blood cells. Your index should ideally be above 8 percent. So to customize your dosage, get your level measured and then adjust your dosage until you reach this optimal level.
I believe the Omega-3 Index test can be an enormously important health screen, and it's commercially available. As with vitamin D, getting your level tested is really the best way to customize your dosage to ensure sufficiency, because requirements for omega-3 will vary depending on your lifestyle: your intake of fatty fish, for example, and your level of physical activity.
Athletes tend to burn off their omega-3 quite rapidly, as the DHA gets burned as fuel rather than being used as a structural component of their cell membranes. Hence they will need higher dosages.
That said, a general recommendation is to take about 2 grams of krill oil per day. With fatty fish, two to three servings a week may be sufficient. Keep in mind that not all fish contain EPA and DHA though! Only fatty fish caught in cold waters will have these fats. Good examples include wild-caught Alaskan Salmon, sardines and anchovies.
Setting the Record Straight on Plant- and Marine-Based Omega-3s
To recap, it's really important to realize that you cannot trade animal-based omega-3 for plant-based omega-3. Even if you take large amounts of plant-based omega-3 it simply will not provide you with the raw materials you need for health. This strategy doesn't work because your body cannot convert enough ALA into DHA and EPA.
Unfortunately, there are a lot of people who believe that. Even many health professionals have fallen for this misconception. If you're in this camp, I strongly urge you to reconsider. If you're an unwavering vegetarian and refuse to eat either fish or krill, you could potentially obtain some EPA and DHA from eating algae, although there are open questions about algae as a clean, healthy source.
Some vegans choose to use a marine-based DHA supplement extracted from algae. While this will certainly increase DHA levels, I believe it is far from ideal as it is highly concentrated, processed and unnatural. When we consume DHA from seafood it is accompanied by a wide variety of other long chain animal fats like EPA, but many others. Our body requires the balance of these fats in the proper ratios, and processed DHA from algae simply doesn't provide that.