Philip Calder, PhD, has studied the issue for years. Dr. Calder is a professor of nutritional immunology at the University of Southampton in the UK, who spoke with NutraIngredients-USA at the recent GOED Exchange meeting in Seattle.
Dr. Calder said that marketers of new and innovative ingredients can sometimes muddy the water when they promote faster uptake of EPA and DHA as an end in itself. And some chemists familiar with pharmaceutical parlance say dietary supplement marketers tend to use the term incorrectly anyway.
“I think what a lot of companies in the fish oil industry are really meaning is the level of EPA and DHA that appears in the blood or in the tissues,” Calder said. “People have focused on faster uptake in an acute setting. I don’t think that really matters if people are going to be taking a supplement on a regular basis, by which I mean daily.”
Why does bioavailability matter?
Bioavailability was not one of the first concerns with fish oil and other omega-3 supplements. Researchers had been able to show that supplementing with the oils, even the base 18:12 varieties, did in fact boost levels of the target chemicals in the blood. After all, nutritional oils like fish oils and other marine oils are one of the body’s energy sources, and so the digestive tract is preprogrammed to absorb them, so to speak. It’s not the same issue as it is with some highly tannic compounds, like many polyphenols, which the body actively resists absorbing.
Getting more EPA and DHA in tissues then became a question of just administering more fish oil, until a consumer would balk at the number of capsules involved. Some early research on omega-3 supplements at high doses had subjects swallowing ten or more capsules a day.
Dr. Calder said the real issue is whether new technologies could boost the overall level of EPA and DHA in the blood from a single dose.