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10 Years of Omega-3 Science: From Then to Now: Page 2 of 2

10 Years of Omega-3 Science: From Then to Now: Page 2 of 2

Photo © iStockphoto.com/SherSor

In the Body

In the past 10 years, studies have been carried out to better characterize the distribution of omega-3 LCPUFA in the body. Once ingested, the fates of EPA and DHA are quite distinct, displaying different kinetics in the incorporation into different, but overlapping, pools of lipids in distinct cell types. 

Detailed studies of tissue distribution in rats have confirmed that the distribution of individual PUFA species varies tremendously between tissues, with extremes for DHA levels being 78-fold higher in brain compared to adipose tissue, and for EPA being 780-fold higher in testes than in adipose tissue. Surprisingly, skeletal muscle may contain the largest pool of DHA.

Marked inter-individual differences in people have furthermore been documented in studies carried out in the past few years that aim to stratify people based on their omega-3 status. 

Risk stratification based on PUFA membrane composition has become a very promising line of research for prediction of disease risk, especially with respect to non-communicable and lifestyle-related chronic illnesses that are afflicting billions of citizens today. On average, marked increases in blood levels of EPA and DHA can be achieved after several weeks of sustained daily intake. A period of three months of supplementation seems to be an acceptable period to adjust a low and insufficient level to one corresponding to a level that is correlated with significant reduction in risk for chronic inflammatory disease. 

 

Testing for Fatty Acid Levels

Given large inter-individual responses to changes in omega-3 LCPUFA intake, the only way to confirm absorption and membrane incorporation (and compliance in case of intervention studies) is by testing actual fatty acid levels in the body. The approach that has been developed in recent years is by measuring the sum of EPA and DHA as percentage of fatty acids esterified in the red blood cell membrane phospholipids (or similar approaches). Interestingly, this “omega-3 index” shows good predictive value for high and low risk for a variety of disorders that afflict mankind, in particular those that have a chronic low-grade inflammatory component.

Several layers of regulation ultimately define tissue content of omega-3 LCPUFA. A few factors that have been shown to be important are the absolute amounts of daily ingested omega-3 LCPUFA, the efficiency of fat digestion, the regulatory feedback of highly unsaturated fatty acids on the enzymes that convert ALA into EPA and DHA, and the actual usage of omega-3 LCPUFA. The latter includes the non-enzymatic turnover of PUFA (for example by oxidation) and by enzymatic pathways (used for energy generation and conversion into lipid mediators after release from membrane phospholipids). 

How the levels of EPA and DHA in distinct lipid pools relate to health and disease is still difficult to understand since the body is extremely complex and given the difficulty in taking samples from most organs to address this relationship in human intervention trials.

 

The Modern Omega-3 Supply

Relatively few food products contain substantial levels of omega-3 LCPUFA, nearly all originating from the marine food chain. Over the past 10 years, a wealth of knowledge has become available of the presence and capacity in many distinct organisms to biosynthesize EPA and DHA. 

Ten years ago, the biotechnological application of using the bacterial polyketide synthase mode of producing EPA and DHA was developed. Now, the capacity to produce omega-3 LCPUFA has been expanded to higher plants, in which omega-3 LCPUFA, such a stearidonic acid and DHA, can be produced. 

Land-based omega-3 LCPUFA production is a tremendous biotechnological accomplishment, completely changing the nature of evolutionary biology of humans from this decade into the far future. Critical in achieving this was the science in overcoming product-mediated inhibition of gene expression of the many heterologous expressed enzymes needed to reproduce a functional biosynthetic pathway for omega-3 LCPUFA production in higher plants, from which seed oils can be obtained at industrially relevant levels. If this can be accomplished, there is no end to imagining what science will be able to achieve in the next decade. 

 

Author's Note: I regret that it has been impossible to highlight a more complete spectrum of scientific discoveries and advancements of the past 10 years. References that support the mentioned scientific developments can be obtained from the author via e-mail at [email protected]. More information on the role of polyunsaturated fatty acids in health can be found at Fats of Life (www.fatsoflife.com).

 

Also read:

Omega-3 Discoveries: New Lipids, New Benefits

2016 Omega-3 Science Update

2016 Omega-3 Market Update: Fish Oil, Krill Oil, Astaxanthin, and More

Widespread Omega-3 Usage Could Save €12.9 Billion in Annual EU Healthcare Costs, Study Suggests

 

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