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UNLOCKING BETTER HEALTH WITH rTG FISH OIL

by Dr Nina Bailey BSc (Hons), MSc, PhD, RNutr

With so many fish oil products available, from budget-friendly standard oils to highly concentrated, choosing an effective fish oil can be both confusing and challenging. What really matters is not just taking fish oil, but how much omega-3 EPA and DHA you take, absorb and use.

For omega-3s to ‘work’, they must be digested, absorbed, and successfully delivered to your cells. The form, purity, strength and dose of your supplement all affect how well it supports your health. Re-esterified triglyceride (rTG) fish oil is considered the gold standard, but even here, quality can vary.  

Here’s how we optimise dosing to ensure you get the maximum benefits, and why the form and grade of our fish oils matter to us just as much as the dose.
 

why dose and form matter

Natural fish oil contains around one-third as EPA and DHA, along with additional fats, cholesterol and impurities that can both limit absorption and counteract benefits.(1)  Low‑concentration oils may appear as value for money but are in fact far less effective at raising omega-3 levels. Since the main goal of taking a fish oil supplement is to raise omega-3 levels, it becomes easier to understand why choosing the right product is essential.
 

Research shows that meaningful health benefits usually occur once your Omega-3 Index reaches 8% or higher.(2,3) The Omega-3 Index measures the amount of EPA and DHA in your red blood cell membranes and reflects your long-term omega-3 status. If you are not regularly consuming EPA and DHA, your levels will be low. Since a fish oil’s impact on omega-3 levels varies with dosage, the most reliable way to determine an individualised dose is through an Omega-3 Index test. 

This is because achieving the optimal 8% target typically requires a minimum of 1,000mg (as rTG omega-3) per day, and often a higher dose, depending on your baseline omega-3 status and body weight.(4,5)
 

Sadly, many standard fish oils don’t provide enough EPA and DHA per serving to reach this target. In addition, the omegas-3 in fish oils are available in several forms, including natural triglyceride (TG), ethyl ester (EE), and re-esterified triglyceride (rTG).
 

While concentration is important, the form of omega-3 in the product will affect how well they are digested, absorbed, and raise omega 3 levels. Concentrated rTG consistently raises omega‑3 levels more effectively than the other forms, even at the same dose.(6)

How we create high-strength fish oil 

To concentrate EPA and DHA, fish oil is broken down to allow the removal of unwanted fats, cholesterol, and harmful contaminants. The concentrated omega‑3s are temporarily converted into EEs and some companies stop at this stage, choosing to sell fish oils in the EE form.

However, while EE products are pure and concentrated, they are not efficiently absorbed. To solve this, we take it a step further by taking EE and rebuilding the natural triglyceride structure of the fatty acids, restoring them to the form found in fish. This process, of producing rTG fish oil, combined with multiple purification steps, removes nearly all toxins and impurities to create a product that is pure, stable, and highly absorbable.

WHY rTG ABSORBS BETTER

The body’s primary fat digesting enzyme (lipase) easily breaks down the fats in TG and rTG oils. In contrast, the fats in EE oils require a different enzyme that is produced in much smaller amounts, making EE fats 10–50 times less efficiently digested than rTG fats. Additionally, because EE oils lack part of the original natural triglyceride structure, they must be taken with a fatty meal. The addition of dietary fat provides the missing component that allows them to be absorbed properly.

In contrast, rTG fish oil delivers superior absorption even without additional dietary fat. In fact, studies show rTG fish oils are about 1.4× better absorbed than EE oils — meaning you achieve higher omega‑3 levels with a smaller dose.(7)
 

NOT ALL rTG OILS ARE EQUAL

Producing true rTG oil requires multiple steps to fully rebuild the triglyceride structure, adding each fatty acid one at a time. However, producing concentrated oil that is 100% rTG is difficult and expensive. Many products labeled ‘rTG’ contain significant amounts of less‑absorbable forms or may be ‘spiked’ with cheaper ethyl esters to increase the omega‑3 content on the label.(8)

Our rTG oils reach as high as 80% true rTG, meaning most of the oil has been fully re-esterified back to the rTG form, offering exceptional purity, stability, and absorption. This ensures your body can use every milligram, helping you reach and maintain optimal omega‑3 levels more effectively.

The Takeaway

Not all omega‑3 supplements are equal. Our rTG fish oils are highly concentrated, purified, and designed for maximum bioavailability, and at doses to give you the best support to optimise your health.

REFERENCES

1.    Mason, R. P., et al. Omega-3 fatty acid fish oil dietary supplements contain saturated fats and oxidized lipids that may interfere with their intended biological benefits. Biochem Biophys Res Commun. 2017 Jan 29;483(1):425-429. https://www.sciencedirect.com/science/article/pii/S0006291X16321878


2.    Maki, K. C. Long-chain omega-3 fatty acid bioavailability: Implications for understanding the effects of supplementation on heart disease risk. J Nutr. 2018 Nov 1;148(11):1701-1703. https://pubmed.ncbi.nlm.nih.gov/30383282/


3.    He, K. et al. The effect of n-3 polyunsaturated fatty acid supplementation on cognitive function outcomes in the elderly depends on the baseline omega-3 index. Food Funct. 2023 Oct 30;14(21):9506-9517. https://pubmed.ncbi.nlm.nih.gov/37840364/


4.    Flock, M. R., Skulas-Ray, A. C., et al. Determinants of erythrocyte omega-3 fatty acid content in response to fish oil supplementation: a dose-response randomized controlled trial. J Am Heart Assoc. 2013;2(6):e000513. https://pubmed.ncbi.nlm.nih.gov/24252845/


5.    Schuchardt, J. P., et al. Incorporation of EPA and DHA into plasma phospholipids in response to different omega-3 fatty acid formulations—a comparative bioavailability study of fish oil vs. krill oil. Lipids Health Dis. 2011 Aug 22;10:145. https://pubmed.ncbi.nlm.nih.gov/21854650/


6.    Neubronner J et al. Enhanced increase of omega-3 index in response to long-term n-3 fatty acid supplementation from triacylglycerides versus ethyl esters. Eur J Clin Nutr. 2011 Feb;65(2):247-54.https://pubmed.ncbi.nlm.nih.gov/21063431/


7.    Walker, M. K., et al. Predicting the effects of supplemental EPA and DHA on the omega-3 index. Am J Clin Nutr. 2019 Oct 1;110(4):1034-1040. https://pubmed.ncbi.nlm.nih.gov/31396625/


8.    Minton, S. T., et al. Comparative membrane incorporation of omega-3 fish oil triglyceride preparations differing by degree of re-esterification: A sixteen-week randomized intervention trial. PLoS One. 2023 Jan 27;18(1):e0265462. https://pubmed.ncbi.nlm.nih.gov/36706088/

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We are here to help

Our expert nutritionists and in-house medic are here to answer your questions and advise about supplementation, dosing and contraindications. Do you have a question about one of our products or have a specific health goal in mind?

FREE 15-MINUTE CONSULT

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