Live yogurt cultures have properties that improve digestion of lactose.
Lactose maldigestion is common in adults
Lactose is a natural sugar found in milk and other dairy products. It can be broken down in the small intestine by the enzyme lactase into glucose and galactose, two simpler sugars that are readily absorbed into the bloodstream.
After weaning, our ability to digest lactose declines because we produce less lactase. Difficulty in digesting lactose due to this normal reduction in lactase production/activity is known as lactose maldigestion.
Undigested lactose reaching the colon is broken down by the resident microbiota, resulting in the production of short-chain fatty acids (SCFAs) and gases. In most people, this maldigestion produces no noticeable symptoms.
When lactose maldigestion gives rise to symptoms such as bloating, cramps, diarrhoea, and flatulence, this is called lactose intolerance.
Self-diagnosis of lactose intolerance is common, but it is often incorrect and in fact very few people have confirmed clinical lactose intolerance.
People with lactose intolerance may eat moderate amounts of dairy products without experiencing significant symptoms
Dairy products are widely recognised as an important part of a healthy diet as they are a source of several nutrients. Dairy products are particularly important for providing calcium, for which it is difficult to achieve the recommended daily intake from a dairy-free diet without supplements.
It is therefore important that dairy products are part of everyone’s diet, including people with lactose maldigestion or intolerance.
People with lactose intolerance or lactose maldigestion can generally tolerate up to 12 g (~0.4 ounces) of lactose (equivalent to about one glass of milk or 240 g/~8 ounces of natural yogurt), particularly when consumed as part of a meal, with no or minor symptoms.
There is some evidence that a daily intake of 24 g (~0.8 ounces) of lactose can be tolerated if it is distributed throughout the day and consumed with other foods.
Since dairy products vary in the amount of lactose they contain, the amount of lactose ingested depends upon the type and quantity of dairy products consumed. In particular, a reduced level of lactose is found in yogurt containing the two active bacterial cultures L. delbrueckii subsp. bulgaricus and S. thermophilus.
Yogurt may improve lactose digestion
The live bacteria L. delbrueckii subsp. bulgaricus and S. thermophilus produce lactase which breaks down some of the lactose in yogurt.
- The bacteria survive their passage through the gut and the bacterial lactase helps further with digestion of lactose in the small intestine.
- Unlike milk, yogurt’s semi-solid state benefits lactose digestion by slowing transit through the gut.
- Several studies show that yogurt with live active cultures may significantly enhance lactose digestion and reduce symptoms of intolerance in people with lactose maldigestion.
“Yogurt consumption is recommended by health authorities as part of a healthy balanced diet, even for people with lactose maldigestion or intolerance. In fact, yogurt containing live active cultures may improve lactose digestion and reduce symptoms of intolerance in people with lactose maldigestion.” – Professor Bob Hutkins
Yogurt is recommended by health authorities for people with lactose maldigestion
The European Food Safety Authority (EFSA) has approved the claim that yogurt improves digestion of lactose.
- The EFSA’s conclusions were based on 13 studies showing that consumption of live cultures in yogurt improved digestion of lactose in yogurt among people with lactose maldigestion.
- To qualify for this claim, yogurt must contain at least 108 CFU live starter bacteria (L. bulgaricus and S. thermophilus) per gram of yogurt, and therefore fresh yogurt is best. Ultra-high temperature (UHT) yogurt or yogurt labelled ‘long-life’ has been heat-treated and this process kills the beneficial bacteria.
Several medical organisations recommend that people with lactose maldigestion – including those with lactose intolerance – consume yogurt as part of a balanced diet.
“The live bacteria in yogurt survive passage through the gut. The lactase they produce breaks down some of the lactose in yogurt and this allows people suffering from lactose maldigestion/ intolerance to gain the nutritional benefits of yogurt and of other dairy products as well.” – Professor Naïma Lahbabi-Amrani
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