Ask the doctors: Honey yogurt bacteria survive digestion

Dear Doctors: I just read that adding honey to yogurt is good for your gut microbiome. Is that true? I avoid added sugar, so I buy plain yogurt and have it with fresh berries. But I’m eating the yogurt to support my gut microbiome. How does the honey help? How much do you need?

Dear Reader: When you eat yogurt, which is a live culture, you’re adding to the diversity of the vast and complex communities of bacteria, yeasts and fungi that make their home in our intestines. It’s a smart move because these trillions of microbes, now collectively referred to as the gut microbiome, play key roles in our physical, mental and emotional well-being.

To reach the gut alive, microorganisms must survive a trio of hostile environments: the mouth, stomach and intestines. Each is equipped with enzymes that aid in the digestion and absorption of nutrients. However, these same enzymes, particularly those in the stomach and intestines, reduce the viability of the live bacteria contained in yogurt. This led researchers at the University of Illinois to wonder if honey, which is often paired with yogurt in the Mediterranean diet, might have a protective effect.

In the first of three studies, the researchers recreated the chemical composition of saliva, stomach acid and intestinal bile in a series of petri dishes. They then simulated the digestion of B. animalis, which is the microbe contained in yogurt. They found that the addition of honey had a significant protective effect on the yogurt microbe during the intestinal phase of digestion. Of the four types of honey they tested – clover, buckwheat, orange blossom and alfalfa – clover honey had the best outcome.

The next step was to test these results in a real-world setting. A group of 66 healthy adults was asked to eat one serving of commercial-grade yogurt mixed with 21 grams (about 1 tablespoon) of clover honey each day for two weeks. After a month off to clear their systems, they were then asked to eat a serving of plain yogurt each day for two weeks. Analysis of stool samples showed the clover honey had the same protective effect on the beneficial bacteria in the yogurt that had been observed in the laboratory experiment. A small third study found that the addition of sugar to the servings of yogurt did not protect the bacteria from being degraded by the digestive enzymes.

The researchers also asked the study participants to track their bowel movements and to fill out questionnaires about their mood, cognition and general sense of well-being. The responses revealed that the enhanced survival of B. animalis during digestion did not translate into improvements in mood, cognition or general health. However, four weeks may be too short a period of time for those types of improvements to become evident.

The takeaway here is that, yes, it appears that honey can help the bacteria in yogurt reach their destination in the large intestine. But honey is an added sugar, which must also be taken into account.

Send your questions to askthedoctors@mednet.ucla.edu.