Are “Superfoods” Really that Super?

You’ve probably heard of phytonutrients, those beneficial compounds in plant-based foods that help protect us against chronic diseases.  In particular, some foods, such as broccoli and blueberries, are so packed with these phytonutrients (such as polyphenols) that they’ve been dubbed “superfoods.”

New research out of Kingston University in London has challenged this notion, finding that most of these phytonutrients don’t even get absorbed from the digestive tract into the bloodstream.  So while they may benefit cells in the test tube, they can’t benefit our body’s cells if they don’t get absorbed.  This has been trumpeted with pithy news articles about “debunking exaggerated health claims and benefits” of phytonutrients.

Before you throw out the broccoli, and start scarfing down the Twinkies you’ve stockpiled since the demise of Hostess, keep a few points in mind:

  • This research was not actually done on people, but on a laboratory model simulating the intestinal wall.  There’s no guarantee that the absorption works the same way in humans; if it did, pharmaceutical companies could save gobs of time and money that they spend examining pharmacokinetics — how substances are actually absorbed and metabolized in living people.
  • The researchers say “some compounds may have a local effect in the gut itself…”  This is not trivial.  Much previous research has focused on the relationship between the health of the GI tract and the health of the rest of the body, and the interaction of stuff in our GI tract with GALT (gut-associated lymphatic tissue) influencing inflammation and immune signalling in distant parts of the body.
  • Epidemiological studies (looking at populations of real people) have shown that eating greater amounts and more variety of fruits and veggies leads to better health outcomes.  I’ll take that over a simulation experiment any day.
Always look beyond the headlines of health news and ask yourself, is this conclusion reasonable?  Does it concur with the rest of the evidence out there?  Is it taking all the variables into consideration?  This seems to be one case where researchers have leaped to conclusions once again.

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