A spoonful of sugar may help the medicine go down, but according to two new studies, a spoonful of honey might do something even better.
Adding one or two tablespoons of honey to a serving of unsweetened yogurt could boost the latter's probiotic powers, the new studies suggest, by helping beneficial bacteria from yogurt survive their odyssey into our digestive systems.
"We were interested in the culinary pairing of yogurt and honey, which is common in the Mediterranean diet, and how it impacts the gastrointestinal microbiome," says co-author Hannah Holscher, a nutrition scientist at the University of Illinois Urbana-Champaign.
The Mediterranean diet is associated with a suite of health benefits, commonly attributed to the presence of healthy fats from fish, olive oil, and nuts, as well as reduced emphasis on red meat.
Dairy doesn't play a big role overall, but there are exceptions – namely for cheese and yogurt. And dating back at least to the ancient Greek dairy product oxygala, many Mediterranean traditions employ honey as a yogurt sweetener.
Based on existing knowledge about yogurt and honey, Holscher and her colleagues wanted to see if honey is more than just a sweetener in this role.
Some types of yogurt are supplemented with probiotic bacterial strains such as Bifidobacterium animalis, a natural resident of many animals' gastrointestinal tracts – including ours – that previous research has linked with improved gastrointestinal health and immune function in humans.
Honey is famous for its antibacterial properties, but it's also a prebiotic; an agent that promotes the growth or activity of helpful microbes within the eater's body.
Given its potential for boosting beneficial bacteria, the researchers hoped to learn if honey might help those bacteria endure the dangers they face inside a human digestive system.
"The enzymes in our mouth, stomach, and intestines help with digestion and facilitate nutrient absorption, but they also reduce the viability of microbes," Holscher says.
"That's great when it's pathogens, but not necessarily when it comes to beneficial bacteria," she explains. "We wanted to see if honey could help probiotic bacteria survive in the gut."
In the first of two new studies, researchers conducted lab experiments to investigate how four honey varietals – alfalfa, buckwheat, clover, and orange blossom – affect the viability of B. animalis in yogurt amid simulated digestion.
They mixed yoghurt innoculated with the bactreria into one of the four honey varietals, and then allowed the bacteria to grow on petri dishes while being exposed to solutions simulating one of several fluids they might encounter in our guts: saliva, stomach acid, intestinal bile, and enzymes.
None of the four honey types showed a significant effect on the bacteria's survival in saliva or stomach acid, the researchers report, with outcomes similar to those of control groups, which featured yogurt mixed with sugar or water.
In solutions designed to mimic intestinal fluids, however, yogurt mixed with honey did seem to support the survival of beneficial bacteria. The effect was most pronounced with a clover varietal, the study found.
The researchers made their initial findings in a randomized, controlled crossover trial based on 62 healthy adult humans. They asked the participants to eat two different items for two weeks each: yoghurt with clover honey for one fortnight, and heat-treated yoghurt for the other.
A follow-up trial had 36 of these participants continue to a third round in the sequence, in which they ate yoghurt mixed with sugar.
Participants submitted stool samples as well as information about their bowel movements, and also filled out questionnaires and performed tasks to evaluate their mood, cognition, and overall well-being.
"Our findings showed that pairing honey with yogurt supported the survival of the yogurt's probiotic bacteria in the gut, so the lab study results did translate to real-world application in humans," Holscher says.
The study did not find changes in intestinal transit time, frequency of bowel movements, mood, or cognition. But that may simply reflect the general health of the participants, Holscher notes, and hardly precludes the need for further research.
It's worth noting honey is still sugar, with the associated health risks, and the study's authors are not suggesting a Winnie-the-Pooh approach.
"We found that one tablespoon of honey in a serving of yogurt helps support probiotic survival. However, we have to keep in mind that honey is an added sugar, and most Americans need to be cognizant of the amount of sugar in their diet to maintain a healthy body weight," Holscher says.
While there is substantial research pointing to the potential boon of probiotics, it's also worth mentioning probiotic supplements are not for everyone, and can pose dangers of their own.
In general, however, Holscher says this research hints at hidden wisdom behind the ancient tradition of mixing honey and yogurt.
"Adding a little bit of honey to unsweetened yogurt is a nice culinary pairing to incorporate into your menu rotation," she says.
The studies were published in The Journal of Nutrition.