Dietitians point to food-first approach for probiotics and prebiotics

Dietitians say a healthy gut depends on both probiotics and prebiotics, two dietary components that play different roles in supporting digestion. Fortune reported that the balance of bacteria in the gastrointestinal tract is tied not only to digestion, but also to areas such as mood and immune function.

The gut contains a mix of helpful and harmful microbes, according to Fortune. The goal, nutrition experts told the publication, is to support the beneficial organisms so they can help keep potentially harmful microbes from gaining ground.

How probiotics and prebiotics differ

Probiotics are live microorganisms, including bacteria and yeasts, that occur in the body and can also be consumed through certain foods or supplements, Fortune reported. Prebiotics are different: They are fibers that humans do not digest, but that serve as food for beneficial gut bacteria.

Amy Bragagnini, a registered dietitian and national spokesperson for the Academy of Nutrition and Dietetics, told Fortune that prebiotics act as fuel for the microbiome because they can pass through the gastrointestinal tract without breaking down and feed healthy microbes.

Bragagnini said probiotics may provide benefits on their own, but a durable gut microbiome is better supported by getting both probiotics and prebiotics. In her view, probiotics do much of the digestive work, while prebiotics help sustain them.

Why the balance matters

Fortune reported that beneficial bacteria help limit the growth of pathogens that can contribute to inflammation. When the balance shifts away from helpful microbes, the body may have more trouble metabolizing certain nutrients and absorbing vitamins and minerals.

Gut health can affect more than regular digestion, Fortune reported. A 2020 review in BMJ Nutrition, Prevention & Health found that probiotics, with or without prebiotics, may help relieve symptoms of depression, while other research cited by Fortune linked gut microbes to immune support, including increased production of some antibodies.

Bragagnini told Fortune that illness, antibiotics or a diet heavy in processed foods can allow less helpful bacteria to become more dominant. She said possible signs of low probiotic levels can include sudden uncontrolled diarrhea, heavy gas, bloating and discomfort when no clear cause is known.

Food sources experts recommend

Meg Harrell, a registered nurse and nurse educator in Sanford, Florida, told Fortune that food is the best way to get probiotics and prebiotics. She said some products advertise added live microorganisms, but consumers may not know how much they contain.

Harrell pointed to fermented foods as probiotic sources, including:

• Yogurt
• Sauerkraut
• Tempeh
• Kefir
• Miso
• Kombucha
• Kimchi

Prebiotic foods are fiber-rich plant foods, but Fortune reported that the relevant fibers include galacto-oligosaccharides, fructo-oligosaccharides, oligofructose, chicory fiber and inulin. Harrell cited whole grains, bananas, green leafy vegetables, soybeans and onions as foods to look for.

Supplements and starting small

Bragagnini told Fortune that probiotic supplements can be a backup option for people who struggle to get enough through food. She said supplements are not regulated by the Food and Drug Administration and advised choosing brands with the UPC symbol as an added quality signal.

For people changing their diets, Bragagnini recommended assessing current fruit and vegetable intake first. If someone is eating only one or two servings a day, she told Fortune, aiming for at least five servings can be a practical first step.

Bragagnini also suggested working with a registered dietitian, particularly when adding unfamiliar foods. She told Fortune that trying one new recipe each week can make the change more manageable.

This story draws on original reporting from Fortune.