February 3, 2022, Sioux Falls, SD: Two pivotal studies showcasing the Omega-3 Index were recently published in the journal Prostaglandins, Leukotrienes and Essential Fatty Acids (PLEFA). The first discussed the relationship between the Omega-3 Index and red blood cell (RBC) distribution width (a measure of cellular integrity) and the second explored the relationship between the Omega-3 Index and a balanced immune system.
Both studies observed benefits associated with higher blood levels of omega-3s (EPA+DHA) in healthy people, which helps provide support for establishing Dietary Reference Intakes (DRIs) for healthy people. EPA and DHA.
The omega-3 content of erythrocyte membranes, i.e. the omega-3 index, is a stable biomarker of the long-term intake of omega-3 EPA and DHA. And fatty acids sequestered in red blood cell membranes have been known for decades to contribute to structural integrity and affect signaling pathways.
The deformability of RBC cells (i.
“We used red blood cell distribution width (RDW), measured routinely in hematology labs, as the biomarker of interest, as it is a standard way to assess the size heterogeneity of cells. red blood cells, which is related to the proper deformability of the cell membrane,” said Michael McBurney, PhD, FCNS-SCN, FASN, lead author of this paper, and consultant scientist with the Fatty Acid Research Institute (FARI).
“Although the RDW is used clinically to diagnose anemia, it has recently been shown to also predict the risk of death from several diseases – namely, cardiovascular, SARS-COV-2, sepsis, lung disease and cancer. . Instead of sick people, however, we chose to study healthy people. Why?” he said. “Because we wanted to determine if red blood cell EPA+DHA levels were associated with red blood cell structure and function in non-disease states.”
The researchers in this study did indeed find a relationship. In 25,485 people with no signs of inflammation or anemia, a higher Omega-3 Index was still significantly associated with a lower (i.e., better) RDW. And while their observation does not prove that omega-3 fatty acids lower RDW, it does strengthen the case for establishing DRIs for EPA+DHA in a healthy population.
The second study delved deeper into the relationship between the Omega-3 Index and the immune system. The human immune system is made up of innate and adaptive components. The innate component consists of cells that engulf injured and diseased human cells and bacteria that have invaded the body. This digestive action of innate immune cells such as neutrophils (N) and natural killer cells prevents enzymes and acids from being released by dead or dying cells that can damage adjacent healthy cells.
The adaptive system, on the other hand, is made up of memory cells, i.e. lymphocytes (L) or T and B cells, with the learned ability to attack cells expressing certain markers, for example those infected by viruses. Cells forming tissues and organs, as well as immune cells, can release signaling molecules, e.g. stimulate the creation of new immune cells).
The neutrophil to lymphocyte ratio (NLR) measures the balance between the innate and adaptive immune system. The NLR is also a biomarker of systemic inflammation and, like the RDW, predicts a higher risk of death from many chronic diseases. A normal NLR is around 1 to 3, with a score above 6 indicating mild stress and above 9 indicating severe illness.
“As previously stated, DRIs are for the general healthy population only. Since one of our long-term goals at FARI is to generate scientific support for EPA+EPA DRIs, we also limited this study to healthy individuals. In other words, excluding people with active inflammation [C-reactive protein (CRP) > 3mg/L – the threshold for acute inflammation] we tried to minimize the risks for critics to claim that our findings were related to the disease,” McBurney explained.
In this study of 28,871 healthy, non-inflamed individuals, researchers observed inverse associations between the Omega-3 Index and the NLR, i.e. the higher the Omega-3 Index, the more the NLR is weak. This was especially evident in people with an Omega-3 Index below 6.6% (an ideal Omega-3 Index is considered to be 8% or higher). In these people, the NLR clearly increased when the Omega-3 index fell; but above an index of 6.6%, the NLR remained relatively stable.
McBurney pointed out that the relationship observed in healthy people suggests that blood levels of EPA + DHA play a role in maintaining a quiescent and balanced immune system, and therefore provides evidence for a relationship between the nutrients. and structure/function in healthy people. However, even when people with evidence of chronic inflammation (ie, CRP > 3 mg/L) were included, the relationship still held.
“The NLR paper may be particularly important because most nutritional immunity studies measure circulating levels of inflammatory molecules, i.e. markers of inflammation, making these findings related to disease,” McBurney said, adding, “This is a report of association between nutrient status and cell-based immune function/balance in healthy people.
“These two reports associating a high omega-3 index with low (i.e. healthier) levels of two new biomarkers – RDW and NLR – help us understand a little better why omega-3 fatty acids are good for us,” said William S. Harris, PhD, FASN, lead author of both studies and president of FARI.