The Phospholipid Brain-DHA Advantage

Dr. Rhonda Patrick here. Today we're going to discuss the similarities and differences between krill oil and fish oil. Omega-3 fatty acids, including eicosapentaenoic acid, also known as EPA, and docosahexaenoic acid, also known as DHA, are extremely important for human physiology. In fact, because fish oil is already one of my most favorite supplements, it's been really hard for me to entertain the notion that there may be something even more awesome out there. Omega-3 fatty acids are essential fatty acids that are required by the human body. They must be obtained by diet because our bodies are unable to make them. In fact, data from the National Center for Health Statistics has shown that omega-3 fatty acids are one of the top dietary factors that influence early mortality.

But before we dive into a comparison between krill oil and fish oil, let's go over a few of the established benefits of omega-3 fatty acids. Supplementation with EPA and DHA has been shown to lower all-cause mortality. It's been shown to slow the attrition of telomeres, which are a biological marker for aging. It's been shown to delay brain aging by helping the brain repair damage, as well as delay brain atrophy. It lowers inflammation, which causes tissue damage, as well as plays a role in cancer.

It increases HDL and lowers triglycerides, and it plays a very important role in cell membrane fluidity, which is critical for neurons because the important function of neurotransmitters depend on cell membrane fluidity, including neurotransmitters like norepinephrine, which play a role in focus and attention. So whether or not we're talking about mortality or the awesome effects on delaying brain aging, omega-3 fatty acids are pretty great. But that's not what this video is about. We'll dive into those mechanisms in another video. Let's get back to the context of this video and compare the similarities and differences between krill oil and fish oil. There are a few key characteristics that distinguish krill oil from fish oil that may influence the way you supplement.

The omega-3 fatty acids found in krill oil are more bioavailable. The variety of DHA found in krill oil is preferred by the brain, and krill oil contains a unique antioxidant that's not found in fish oil. What's important to understand about fish oil is that it is usually modified by a process known as molecular distillation, which allows for the concentration of EPA and DHA omega-3 fatty acids and allows for the removal of any contaminants such as mercury. This process of molecular distillation involves taking the omega-3 fatty acids, which are in triglyceride form, meaning 3 fatty acids bound to a glycerol backbone, and converting Turning it into an ethyl ester form, which involves removing that glycerol backbone and replacing it with an ethanol backbone.

After the process of molecular distillation, the omega-3 fatty acids can be re-esterified into their triglyceride form. However, most fish oil supplements on the market contain the omega-3 fatty acids in their ethyl ester form, which is unfortunate because that's less bioavailable than the omega-3 fatty acids found in triglyceride form. The omega-3 fatty acids found in krill oil are mostly in phospholipids, Such as phosphatidylcholine, phosphatidylserine, and phosphatidylethylamine. Phospholipids contain a, a fat-soluble diacylglyceride and a water-soluble phosphate group that's attached to an organic molecule, such as choline or serine or ethylamine.

What's important to understand is that the omega-3 fatty acids in phospholipids are more bioavailable than the omega-3 fatty acids in triglycerides. Omega-3 bioavailability is heavily influenced by how it's absorbed in the small intestine. In order to be absorbed in the small intestine, EPA and DHA from fish oil, whether in triglyceride or ethyl ester form, must first be cleaved by pancreatic lipases, which are enzymes that cleave triglycerides, into their free omega-3 fatty acid form, which means they're no longer bound to a glycerol or ethanol backbone. The omega-3 fatty acids found in krill oil can also be cleaved by another class of enzymes known as phospholipases, which cleave phospholipids.

However, it's important to note that phospholipids don't necessarily have to be cleaved because they can also form micelles and can be absorbed in their intact form. Ethyl esters are very poor substrates for pancreatic lipases, and for that reason, they're not absorbed very well in the small intestine. Omega-3 fatty acids found in triglycerides are more bioavailable than those in ethyl ester form. However, they are not more bioavailable than those found in phospholipid form for 2 reasons. The first reason is because The gastric lipases in the stomach can break down omega-3 fatty acids and triglycerides. This is not the case for phospholipids. And the second reason is because phospholipids don't necessarily have to be broken down in the small intestine.

They can be absorbed in their intact form. There's evidence demonstrating that the omega-3 fatty acids from krill oil in phospholipid form is more bioavailable than fish oil. Mice that were given identical doses of EPA and DHA in either phospholipid triglyceride, or ethyl ester form had EPA and DHA plasma concentrations that were highest from those in phospholipid form, followed by triglyceride form, and then lastly by ethyl ester form. In line with this, humans that were given doses of krill oil 38% lower than those of fish oil had the same levels of EPA and DHA in plasma as those given fish oil, despite the fact that they were given a much lower dose.

So all of this data suggests that the bioavailability of omega-3 fatty acids is higher in krill oil because of the phospholipid form than that of, of fish oil in either triglyceride or ethyl ester form. The concentrations of EPA and DHA in plasma cholesterol are not necessarily indicative of their concentration in other cell types. So let's take a closer look at the transport mechanisms of these omega-3 fatty acids into different tissues. Starting with my personal favorite, the brain. DHA is the most abundant fatty acid in the brain, making up between 10 to 20% of the brain's total lipid composition, which is about 60% by dry weight.

Despite the fact that DHA is abundant in the brain, the mechanisms by which it's transported across the blood-brain barrier have remained unclear for some time. That is, until recently. As it turns out, something called DHA lysophosphatidylcholine is the preferred source of DHA by the brain. But what is DHA lysophosphatidylcholine? Well, it's a byproduct of DHA in phosphatidylcholine after it's cleaved by lipases either in the intestine or in the bloodstream. Because krill oil is a rich source of phosphatidylcholine, this implies that it would also be a good source of DHA lysophosphatidylcholine, whereas fish oil would not. Studies have shown that DHA lysophosphatidylcholine accumulates by tenfold higher amounts in the brains of developing rats compared to DHA in free fatty acid form.

And this is not species-specific, as similar results have been found in the brains of developing piglets. So what is the mechanism? Why does the brain prefer DHA lysophosphatidylcholine? A Nature paper published in May 2014 identified a specialized DHA transporter called MFSD2A that transports DHA lysophosphatidylcholine across the blood-brain barrier. Mice that were engineered to lack this transporter had 60% less DHA in their brain compared to controlled mice. This was only specific to the brain, as DHA levels in the heart and in the liver were the same as in controlled mice. There is an exception.

Red blood cells also prefer DHA lysophosphatidylcholine over DHA in free fatty acid form, which is not surprising because the DHA concentration in red blood cells tightly correlates to the actual DHA levels in the brain. One other unique aspect of krill oil is that it contains astaxanthin. Astaxanthin is a carotenoid that sequesters singlet oxygen, Which is produced by UV radiation. It is also a potent antioxidant against peroxyl radicals. Both singlet oxygen and peroxyl radicals damage DNA, lipids, and proteins inside of your cell, all of which lead to diseases of aging. Astaxanthin is one of the carotenoids that is easily absorbed by the human bloodstream. It also has an amphipathic structure, which means it has a both fat and water soluble portion.

And for that reason, it can accumulate in cell membranes. This is a good thing because DHA, which is very prone to oxidation, also accumulates in cell membranes where it plays an important role in cell membrane fluidity. Other antioxidants such as glutathione are produced in the soluble portion of the cell and do not accumulate in cell membranes. For this reason, getting a little astaxanthin with your omega-3 fatty acids may be a good way to protect your DHA as well as other polyunsaturated fatty acids, which are prone to oxidation, which accumulate in cell membranes. In addition, astaxanthin has benefits all on its own.

In clinical trials using astaxanthin for supplementation, it's been shown that supplementing with astaxanthin is able to lower inflammation, decrease DNA damage, including oxidation, and increase HDL. These mechanisms are all very relevant to degenerative diseases such as cancer, cardiovascular disease, diabetes, and neurodegenerative diseases. To summarize, krill oil beats fish oil from many different perspectives. The EPA and DHA present in krill oil are more bioavailable as a consequence to phospholipids. Perhaps the most compelling reason that krill oil is superior to fish oil is because krill oil is a great source of DHA phosphatidylcholine, the preferred source of DHA for the brain.

Additionally, krill oil comes with an added bonus of having astaxanthin, a carotenoid that seems to play a role in fighting off diseases of aging. One last novel feature of krill oil is that it also is a great source of other phospholipids such as phosphatidylserine and phosphatidylethanolamine. Both phosphatidylserine and phosphatidylethanolamine accumulate in mitochondrial membranes as well as cell membranes, and they have been shown to decrease in concentration in cell membranes and mitochondrial membranes with age. In fact, their decrease in concentration has been shown to play a role in neurodegenerative diseases such as Parkinson's disease and Alzheimer's disease. So naturally the next question is, how much krill oil does Rhonda supplement with? And the answer is, it's up for debate.

I have no idea. I personally take a lot of omega-3 and I'm currently supplementing with both fish oil in triglyceride form and krill oil. I'm Dr. Rhonda Patrick, and until next time, thanks for listening and for watching.