By Dr. Mercola
Humans evolved with a staple source of the essential omega-3 fat docosahexaenoic acid (DHA) in their diets, namely seafood.
Animal based omega-3 fats are considered essential because they cannot be synthesized in appropriate quantities by your body and must be supplied through your diet.
The introduction of high-quality, easily digested nutrients from seafood into the human diet coincided with the rapid expansion of grey matter in the cerebral cortex -- a defining characteristic of the modern human brain.
The DHA molecule has unique structural properties that provide optimal conditions for a wide range of cell membrane functions, and grey matter is a particularly membrane-rich tissue.
There's no doubt you need omega-3 fat for proper brain function. In fact, mounting evidence suggests that deficiency in this essential fat may lead to brain degeneration. According to a recent article published in the journal Nutrients1:
"An emerging body of research is exploring a unique role for DHA in neurodevelopment and the prevention of neuropsychiatric and neurodegenerative disorders."
Plant-Based versus Animal-Based Omega-3 Fats
Before we go any further, it's important to recognize that animal-based omega-3 fat is not interchangeable with plant-based sources of omega-3. And while you do need both in your diet, animal-based omega-3 fats are particularly important for your brain health.
Dietary fish and marine oil supplements such as krill oil are a direct source of EPA and DHA. Plants, on the other hand, contain the parent omega-3, alpha-linolenic acid (ALA), which can be converted into eicosapentanoic acid (EPA) and docosahexanoic acid (DHA). However, as stated in the featured article, this conversion is ineffective in general, and appears to get progressively more ineffective with age:
"Unlike the photosynthetic cells in algae and higher plants, mammalian cells lack the specific enzymes required for the de novo synthesis of alpha-linolenic acid (ALA), the precursor for all omega-3 fatty acid syntheses. Endogenous synthesis of DHA from ALA in humans is much lower and more limited than previously assumed.
... [A]fter much intense research, the 1989 NATO Advanced Research Workshop on dietary n-3 and n-6 fatty acids on biological effects and nutritional essentiality, agreed by consensus that n-3 fatty acids generally: (1) have anti-inflammatory properties; (2) lower serum triglycerides and cholesterol; and (3) decrease thrombosis and platelet aggregation. Therefore administration was recommended as beneficial in cardiovascular disease, hypertension and rheumatoid arthritis.
Since then, however, there has been a wealth of evidence to support the notion that the omega-3 fatty acids are not bioequivalent and that the longer chain EPA and DHA are much more important than their precursor ALA." [Emphasis mine]
The reason why EPA/DHA are more important is because although ALA (that you get from plant sources) is an essential nutrient, the conversion of ALA to EPA and DHA is typically severely impaired by inhibition of delta 6 desaturase; an enzyme necessary for the conversion. Elevated insulin levels impair this enzyme, and over 80 percent of the U.S. population has elevated insulin levels, so chances are high that you'll be part of this significant majority... Therefore, you want to make sure you get the bulk of your omega-3 from animal sources, not plant sources, to make sure you won't develop a deficiency.
DHA: One of the Most Important Nutrients for Brain Function
Sixty percent of your brain is fat. DHA alone makes up about 15 percent to 20 percent of your brain's cerebral cortex, as well as 30 percent to 60 percent of your retina, making it an essential nutrient for both brain and eye health.
It's found in high levels in your neurons; the cells of your central nervous system, where it provides structural support. When your omega-3 intake is inadequate, your nerve cells become stiff as the missing omega-3 fats are substituted with cholesterol and omega-6 instead. Once your nerve cells become rigid, proper neurotransmission from cell to cell and within cells become compromised.
The influence of omega-3 fat on physical and mental health has been the subject of intense research over the last four decades, and there's compelling evidence that animal-based omega-3 fats can help reduce the symptoms of a variety of psychiatric illnesses and degenerative brain disorders. For example, low DHA levels have been linked to:
- Memory loss
- Alzheimer's disease
- Bipolar (manic-depressive) disorder
EPA: Of Particular Importance for Depression...
The EPA found in animal-based omega-3 also plays a very significant role in the signaling within nerve cells, and it has been suggested that normalizing communications within nerve cells may be an important factor for alleviating depressive symptoms. Additionally, EPA can lower the levels of three important immune chemicals; all of which are elevated in depression:
- Tumor necrosis factor alpha (TNFa)
- Interleukin 1 beta (IL-1ß)
- Prostaglandin E2
DHA Found to Significantly Improve Cognition in the Elderly
In more recent years, researchers discovered that DHA is a precursor for a newly identified signaling molecule called protectin. (When found in your central nervous system it's referred to as neuroprotectin, or NPD1.) This molecule is synthesized in response to oxidative stress.
As explained in the featured article:
"NPD1 induces nerve regeneration, reduce leukocyte infiltration and maintains homeostasis through ageing by reducing pro-apoptotic and pro-inflammatory signaling. NPDI is induced by oxidative stress and protects retinal and neuronal cells from oxidative stress-induced apoptosis. Many mechanisms have been implicated, including suppression of the IL-1β induced stimulation of COX.
The discovery of NPD1 offers new therapeutic opportunities for a range of neurodegenerative conditions, such as Alzheimer's disease. It also provides an exciting potential for DHA in helping to delay or minimize the "normal" cognitive decline during ageing."
This is great news, as it's becoming quite clear that degenerative conditions can be not only prevented but also reversed. For example, in one study, 485 elderly volunteers suffering from memory deficits saw significant improvement after taking 900 mg of DHA per day for 24 weeks, compared with controls.2 Another study found significant improvement in verbal fluency scores after taking 800 mg of DHA per day for four months compared with placebo3. Furthermore, memory and rate of learning were significantly improved when DHA was combined with 12 mg of lutein per day.
Interestingly, research suggests that the unsaturated fatty acid composition of normal brain tissue is age-specific, which could imply that the older you get, the greater your need for animal-based omega-3 fat to prevent mental decline and brain degeneration. According to the featured article:
"The glycerophospholipids in the cerebral cortex of the normal ageing brain show steady increases in the concentration of DHA with corresponding reductions of AA [arachidonic acid, an omega-6 fat]. Svennerholm demonstrated4, in tissue samples from 11 brains from fetal to 82 years, that the percentages of AA and DHA methyl esters in cerebral cortex ethanolamine glycerophospholipids was roughly equal or 1:1 (16.5 percent AA and 16.1 percent DHA) in the one month old human infant, but by the 82nd year the percentage of DHA has more than doubled and increased in proportion to AA close to approximately 1:4 (10.3 percent AA and 33.9 percent DHA)."
How Much DHA Do YOU Need?
For clarity, let me point out that, as with most studies, very high dosages were used in the trials above, and the participants were elderly patients with memory loss and other degenerative conditions. This likely does not describe you, and hopefully, by taking proper precautions now, you won’t develop that kind of degeneration to begin with.
I prefer krill oil compared to all other animal-based omega-3’s, because while the metabolic effects of krill oil and fish oil are “essentially similar,” krill oil is as effective as fish oil despite the fact that it contains less EPA and DHA.5 This is because krill oil is absorbed up to 10-15 times as well as fish oil, due to its molecular composition.
Fish oil is in a triglyceride molecule that has to be broken down in your gut to its base fatty acids of DHA and EPA. About 80-85 percent is never absorbed and is eliminated in your intestine (this is why fish oil can cause you to experience burp back and why about half of all people cannot tolerate fish oil). Then once the fatty acids are absorbed into your blood stream, your liver has to attach it to phoshphatidyl choline for it to be used by your body.
The beauty of krill is that all of it is in the correct form in the original pill, so your body uses virtually 100 percent of it.
As a result, most people only need two to three 500 mg capsules of krill oil per day (each capsule typically contain about 50 mg of DHA and 90 mg of EPA).
What's the Best Source of Animal-Based Omega-3 Fat?
It is typically a wise practice to obtain most of your nutrients from the food you eat. However, animal-based omega-3's are one exception where I believe taking a supplement is very important, for a couple of reasons.
First, the food source of omega-3, which is fish and other seafood, is just not a safe option anymore. The vast majority of our fish supply is now so heavily contaminated with industrial pollutants and toxins like mercury, PCBs, heavy metals and radioactive poisons that I just can't recommend it any longer. Even the slow-to-react FDA and EPA have put out health advisories warning against certain fish and shellfish consumption for young children, women who are pregnant or may become pregnant, and nursing mothers...
The second major reason why a high-quality, animal-based omega-3 fat supplement is so important is because so many people are deficient. In fact, omega-3 deficiency is likely the sixth biggest killer of Americans, and may be a significant underlying factor of up to 96,000 premature deaths each year. In my view, krill oil is your best option when it comes to obtaining important high-quality animal-based omega-3 fats for the following reasons:
- Krill oil contains essential EPA and DHA in a double-chain phospholipid structure that makes it far more absorbable than the omega-3s in fish oil
- It also contains vitamin E, vitamin A, and vitamin D
- Krill oil naturally contains astaxanthin, a potent antioxidant. Research has shown the antioxidant potency of krill oil is, in terms of ORAC (Oxygen Radical Absorptance Capacity) values, 48 times more potent than fish oil. So with krill oil, you can ensure that you're getting the incredibly healthy yet highly perishable fats (EPA and DHA) without having to worry about oxidation issues
- Your risk of getting any mercury contamination is much lower than with fish oil as the krill are so small they don't have the chance to accumulate toxins before being harvested
More Tips for Maintaining Healthy Brain Function
More than 5 million Americans currently have Alzheimer's, and by 2050 that could increase to between 11 million and 16 million people in the United States alone. But neither dementia nor Alzheimer's are a normal part of aging! Truly, your memory and brain functioning do not have to decline simply because you are getting older. This is especially true if you make sure you supply your brain with the essential nutrients it needs to perform its job, namely DHA and EPA.
Aside from optimizing your omega-3 intake, ideally by taking a krill oil supplement, the following guidelines can also greatly increase your chances of avoiding any kind of cognitive decline:
- Eat a nutritious diet with plenty of vegetables, paying special attention to avoiding all forms of sugar, especially fructose. Experts are starting to look at memory problems like Alzheimer's as a form of brain starvation, and glucose metabolism appears to play an important role in the disease. It's already known that diabetics have four times the risk of developing Alzheimer's, and those with prediabetes have triple the risk.
- Avoid and remove mercury from your body. Dental amalgam fillings are one of the major sources of mercury, however you should be healthy prior to having them removed. Once you have adjusted to following the diet described in my Nutritional Plan, you can follow the mercury detox protocol and then find a biological dentist to have your amalgams removed. ONLY see a high-quality biologically trained dentist to remove your amalgams or your health could get ruined.
- Avoid aluminum, such as in antiperspirants, cookware, etc.
- Exercise for three to five hours per week. According to one study, the odds of developing Alzheimer's were nearly quadrupled in people who were less active during their leisure time, between the ages of 20 and 60, compared with their peers.
- Avoid flu vaccinations as they contain both mercury and aluminum!
- Wild blueberries, which have high anthocyanin and antioxidant content, are known to guard against Alzheimer's and other neurological diseases.
- Challenge your mind daily. Mental stimulation, such as traveling, learning to play an instrument or doing crossword puzzles, is associated with a decreased risk of Alzheimer's. Researchers suspect that mental challenge helps to build up your brain, making it less susceptible to the lesions associated with Alzheimer's disease.