Are prebiotic sodas good for gut health?

NEW YORK – The sodas come in fun flavours, such as Cherry Vanilla and Orange Cream, and carry an alluring claim: They are good for your gut.

That pitch has helped prebiotic soft drink brands like Poppi and Olipop stand out in the soda aisle.

The drinks contain prebiotics, or dietary fibres that cannot be digested by humans, but can feed the beneficial microbes that live in the gut, said associate professor of nutrition Hannah Holscher at the University of Illinois Urbana-Champaign.

Probiotic products, in comparison, contain live microbes themselves.

But nutrition experts say you do not need a special soda to reap those benefits. Many foods – such as garlic, onions, peas, beans, lentils, grains and some fruit – are naturally rich in prebiotic fibres.

“If you eat a high fibre diet, you’re taking care of your prebiotics pretty well,” said Dr Marion Nestle, an emeritus professor of nutrition, food studies and public health at New York University.

Inulin, the main prebiotic fibre used in these sodas, can be isolated from plants, such as agave or chicory root, said Dr Holscher, who has accepted travel and speaking fees from Beneo, a company that manufactures ingredients, including prebiotic fibres.

The amount of fibre in prebiotic beverages varies. A can of Orange Cream Poppi has 2g of dietary fibre, while a Strawberry Vanilla Olipop has 9g. US dietary guidelines recommend 28g of fibre for a 2,000 calorie-a-day diet, but most Americans fall far short of this goal.

It is best to get your fibre from a variety of foods like fruit, vegetables, whole grains, nuts and legumes because they are also rich in vitamins, minerals and beneficial compounds called phytochemicals that can be found only in plants, Dr Holscher said.

A medium apple, a cup of cooked broccoli and a cup of cooked steel-cut oatmeal each contains 5g of fibre. A half cup of lentils and a cup of raspberries each contains 8g.

These foods also provide multiple types of fibres – not just one or two, as you might find in sodas or other products with supplemental fibre. “It’s these complex mixtures of different fibres that support lots of different microbes” and general gut health, Dr Holscher said.

But, she added, foods or beverages with added fibres can help you meet your fibre goals. And some small studies have linked prebiotics, in supplements and added to foods, with a healthier gut lining, improved insulin sensitivity and increased feelings of fullness. They also suggest that prebiotics may be able to provide some relief from constipation.

That said, this evidence is mixed. Other studies have not found benefits of prebiotics.

A person typically needs at least 3g of prebiotic fibres to begin to see any benefits, and at least 12g of inulin are generally needed to relieve constipation, Dr Holscher said.

But there can also be downsides to fibre, especially if you increase your consumption too suddenly.

Inulin fibre can cause digestive discomfort, Dr Holscher said.

As little as 1g to 5g can cause mild flatulence, and larger doses may lead to bloating. Some people “can’t even look at a food product that contains inulin without getting gas and bloating”, she added, while others may experience no symptoms.

Inulin and other prebiotic fibres are considered Fodmaps, types of carbohydrates that can worsenirritable bowel syndrome (IBS) symptoms in some people. While these drinks typically have significantly less added sugar than a traditional soda, they still contain sugar – which might also exacerbate IBS symptoms, said Dr Sean Paul Spencer, a gastroenterologist and researcher at Stanford University.

The best way to nourish the microbiome, he said, is to eat whole foods and limit sugar, processed foods and emulsifiers, which may negatively affect it.

Poppi soda also contains apple cider vinegar, which some small studies suggest can help lower blood sugars when consumed before a meal.

But whether there is enough vinegar in a can of Poppi to have that effect is not clear, said professor of nutrition Carol Johnston at Arizona State University.

The company did not respond to a question about the amount of apple cider vinegar in its beverages.

Olipop is marketed as containing “botanicals”, with plant extracts such as calendula and nopal cactus listed among its ingredients.

Whether there are any benefits of these substances, Prof Johnston said: “Who knows?”

These ingredients have not been well studied.

Prebiotic sodas are not likely to harm your health, Dr Nestle said, but it is also not likely that they will be beneficial.

“Really, if people are concerned about their microbiome, they need to eat vegetables,” she said. “Vegetables would do wonders.” NYTIMES