I had an interesting conversation today with Lisa Hannam, the health editor of Glow magazine, based in Toronto Canada.
I explained the nutrient signaling hypothesis, a new model for the the inflammatory effects of food. The basic idea is that foods that encourage the growth of harmful microbes are recognized by the immune system and serve an early warning (pro-inflammatory) signaling function. On the flip side: foods that inhibit the growth of harmful microbes have evolved an anti-inflammatory immune signaling function.
Lisa Hannam asked me what the take home message would be for her readers. On reflection, I realized we should redefine what “empty calories” really means. Empty calories are, of course, the absence of nutritional value in junk food. In light of the nutrient signaling model, “empty calories” are better recognized as nothing but fuel for the growth of harmful bacteria. These foods are bad for us because they result in harmful changes to the microbiota. Many saturated fats and simple sugars fall in this category.
Healthy diets, resulting in healthy microbiota and a healthy immune system require food that counteracts the growth of harmful bugs. “Healthy” nutrients are generally foods with antimicrobial properties; these inihbit the growth of pathogens and pathobionts (opportunistic pathogens). Antimicrobial nutrients include omega-3 fatty acids, complex carbohydrates, and polyphenols in fruits and berries.
We need anti-microbial nutrients to discourage the overgrowth of harmful bacteria. Recent evidence suggests that nutrients with antimicrobial effects can also have prebiotic effects, stimulating beneficial bacterial growth. So, the best, healthiest, foods probably have both properties: inhibition of harmful microbes and (not coincidentally) fertilizer for the growth of beneficial bacteria. We might need a new term like antimicrobial prebiotic (AMP) or probiomic to describe this dualistic beneficial effect.
So eat with an eye towards both prebiotic and antimicrobial properties in your food! Luckily, many delicious foods have these properties including chocolate, red wine, broccoli, apples, citrus, and chile and curry spices!