Krill oil may be better than fish oil for aging and brain health

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Krill oil supplements may promote healthy brain aging, according to new research. Xinhua/Liu Shiping via Getty Images
  • Researchers investigated the effects of krill oil on age-related neurodegeneration and Parkinson’s disease.
  • They found that krill oil can protect against many neurodegenerative processes in worms and human cell lines.
  • The researchers say that their findings warrant further preclinical and clinical research before it is widely recommended.

Marine oils like fish oil have been extensively researched for their health-promoting properties. Until now, however, krill oil has remained relatively understudied.

Krill oil has a high content of long-chain omega-3 fatty acids, antioxidants, and choline, an essential nutrient that aids healthy brain development and function.

One study found that dietary supplements of krill oil inhibited memory loss in mouse models of Alzheimer’s.

A review also suggested that the lipid nature of krill oil improves bioavailability and efficiency of absorption, making it more beneficial than other marine oils for inflammation and cognitive function.

Further study of krill oil could help develop dietary supplements and therapeutics that protect against neurodegeneration.

Recently, researchers studied the effects of krill oil on a roundworm model of Parkinson’s disease (PD).

They found that krill oil protected dopaminergic neurons from age-related degeneration and improved cognition. The degeneration of dopaminergic (DA) neurons is thought to play a key role in Parkinson’s.

“The study shows the potential of omega-3 fatty acids, choline, and antioxidants in slowing the age-related damage to neurons. However, it is important to repeat the studies in animal models, using appropriate controls. Furthermore, the [pretreated] krill oil may be more effective in animal models than natural krill oil.”
Dr. Papasani Subbaiah, professor at the Department of Medicine at the University of Illinois at Chicago, speaking to Medical News Today

The study was published in Aging.

The researchers chose to study roundworms as their aging processes are similar to those in humans. Previous research suggested that krill oil could increase the lifespan of these worms by four days. Their average lifespan is between 18-20 days.

In the current study, the researchers first measured the effects of krill oil on worm models of PD, characterized by DA neurons degrading over time.

Worms untreated with krill oil experienced deterioration of over 30% of dopaminergic neurons after six days. However, worms treated with krill experienced no reduction in DA neurons.

Buildups of proteins alpha-synuclein are also a key hallmark of PD. The researchers found that while controls had around 50 clumps of protein by day 6, those treated with krill oil only had 17.

PD is also known to affect movement. The researchers found that worms fed krill oil had significantly faster movement and higher activity levels than untreated worms.

They noted that worms with PD did not respond to krill oil, meaning that the oil likely works on key mechanisms underlying aging and PD.

Further experiments showed that krill oil also reduced senescence—the loss of cells’ ability to grow and divide. The researchers reported similar results from tests with human connective tissue cells.

More tests showed that krill oil led to a 6-fold decrease in oxidative stress in worms and improved their cognition. The researchers also found that krill oil promoted genetic activity known to promote healthy aging.

When asked how krill oil may differ from other marine oils in terms of neuroprotection, Dr. Subbaiah, who was not involved in the study, told MNT that krill oil has specific benefits, including the presence of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in the presence of phospholipids and not triglycerides, as in fish oil.

EPA and DHA have multiple benefits, including for immune function, cardiovascular function, and neuroprotection. Phospholipids improve tissue absorption and can cross the blood-brain barrier, whereas triglycerides cannot cross the blood-brain barrier.

One study found that pretreated krill oil can increase brain levels of EPA and DHA by 5-70 times more than untreated krill oil. Meanwhile, fish oil, whether treated or not, has no effect on brain levels of EPA or DHA.

Dr. James Giordano, Pellegrino Center professor of neurology and biochemistry at Georgetown University Medical Center, who was not involved in the study, also told MNT that phosphatidylcholine (a phospholipid in krill oil) “imparts both greater neuronal uptake, and direct membrane stabilizing effects within neuronal infrastructures.”

“This combination of improved bioavailability and membrane stabilization is important to promoting the anti-inflammatory, and anti-degenerative properties of many of the (omega-3) active ingredients found in krill oil.”
— Dr. James Giordano

“Taken together, these properties are useful to maintaining neuronal structural and functional integrity and reducing age-related inflammatory changes (known as inflammaging),” he added.

Krill oil’s benefits

Dr. Subbaiah noted that choline in krill oil is another benefit. Choline is a precursor to the neurotransmitter acetylcholine and is thus crucial for multiple neurological functions, such as regulating memory, mood, and muscle control.

Lastly, Dr. Subbaiah said that the presence of antioxidants like astaxanthin also makes krill oil beneficial. The potential benefits of astaxanthin include the following:

  • anticancer activity
  • antidiabetic effects
  • neuroprotective effects
  • promoting cardiovascular health
  • promoting ocular health
  • promoting skin health

Dr. Ali Mohebi, assistant researcher in neurology at the University of California San Francisco, who was not involved in the study, told MNT:

“These pieces of evidence suggest that while other marine oil compounds elevate various health markers such as blood pressure, cardiovascular function, etc., krill oil can be specifically beneficial in slowing down a range of neurodegenerative processes in the brain.”

The researchers concluded that krill oil might promote healthy aging in multiple ways, making it a good candidate for further preclinical and clinical explorations.

Dr. Mohebi noted that neurodegenerative conditions such as PD or Alzheimer’s progress gradually and that symptoms are only expressed in the later stages of the conditions. He noted, for example, that motor symptoms do not appear in PD until over 80% of DA neurons are dead.

“Any solution that would slow down the neurodegeneration process will significantly improve the quality of life of people more prone to developing such neurodegenerative disorders. The results of [this study] are promising as they suggest a dietary change that will potentially protect DA neurons against age-related degeneration,” he noted.

He added, however, that these findings do not mean that the public should start taking krill oil to treat neurodegeneration.

Should I take krill oil?

“Until the results are replicated by multiple groups across multiple species and finally tested in the human population, these or similar compounds should not be treated as medical knowledge. These basic science results inform future medical applications, and changing personal diets should only take place after consulting with medical doctors.”
— Dr. Ali Mohebi

When asked about the study’s limitations, Dr. Jordan Taylor, neurology section chief with the University of Michigan Health-West, who was not involved in the study, told MNT:

“While the findings are interesting, the study was completed with transgenic strains of C. elegans specifically created to produce elevated alpha-synuclein as a model of Parkinson’s disease. While this is generally a good model to study the degenerative effects of alpha-synuclein the results may not translate practically into humans.”

Dr. Subbaiah added that the main reason that marine oils, including fish oil and algal oil, do not significantly improve brain function is that they cannot cross the blood-brain barrier.

“The major reason that fish oil, algal oil, ethyl esters, and other currently available supplements do not improve brain function significantly is because of the blood-brain barrier, which requires the omega-3 in the form of phospholipids for transport into the brain.”
— Dr. Papasani Subbaiah

“It is important to note that even krill oil does not work well in whole animals because the omega-3 fatty acids in the krill oil are present in diacyl phospholipids, whereas the transporter in the blood-brain barrier requires the monoacyl (lyso) phospholipids,” Dr. Subbaiah said.

He added, however, that lysophospholipids can be generated by treating krill oil with a lipase. an enzyme that ‘digests’ fats.

“It is important not only to repeat these studies with animal models but also use other forms of omega-3 fatty acids as controls to show that the effects are specific for krill oil,” he concluded.