Acidophilus: benefits, dosage, side-effects

Find out all about acidophilus, including what it does, the benefits to taking it and how much you might need

What is acidophilus and what does it do?

Acidophilus is a type of ‘friendly’ bacteria in the lactobacillus family that helps ferment carbohydrates in foods and in particular lactose, the sugar found in milk.¹ 

Acidophilus lives in the gut, mouth and vagina. Sometimes, the natural balance of friendly bacteria in your body can be affected by illness or medication. But plenty of studies report that taking acidophilus, or another type of ‘good’ bacteria, may help restore the body’s natural equilibrium.² 

Acidophilus is available as a capsule, tablet, powder or vaginal suppository, and is also found in certain fermented foods such as live yogurt and kefir.

Benefits of acidophilus

Friendly bacteria, such as acidophilus, have been shown to help restore the balance of gut flora³ in a number of different ways:

• preventing ‘bad’ bacteria, like E-coli, from sticking to the gut lining
• secreting acids that decrease the pH of the gut, preventing the growth of unfriendly bacteria
• reducing inflammation triggered by unwelcome bacteria

At the moment, the science shows these actions may help the body in the following ways:

It may restore the natural balance of bacteria in the vagina

A 2014 Iranian study reported that friendly bacteria taken orally or as a pessary released acids inside the vagina that help maintain the pH at a healthy level, supressing the growth of bacteria that can cause problems such as thrush and UTIs.⁴

It can curb an over-active immune system

An over-active immune system can damage the body’s own cells and tissues, and is linked to a raised risk of allergic conditions such as childhood eczema. It’s thought to be caused by an imbalance in gut bacteria; a 2014 study by Canada’s McGill University reported that friendly bacteria may help rebalance and regulate the immune system’s over-activity, although more research is needed.⁵

It can ease diarrhoea

Various studies have looked at the benefits of taking friendly bacteria, such as acidophilus, to help diarrhoea. A 2016 review from the Cochrane Collaboration analysed 63 studies involving 8000 participants, and reported that the friendly bacteria worked in the gut to:

• suppress the germs causing diarrhoea
• help the body fight the infection

Scientists found a friendly bacteria, like one from the lactobacilli family, could shorten the length of a bout of diarrhoea by one day, although they called for more research into this effect.⁶

Dosage

How much acidophilus is safe to take?

Read the label carefully, as different products may contain different compositions and different amounts of acidophilus. But in general, taking too much friendly bacteria doesn’t appear to cause unwanted symptoms.⁷ Talk to your doctor before taking acidophilus if:

• your immune system is compromised – for example by HIV or medications such as corticosteroids or chemotherapy⁸

you have a lactose intolerance – some acidophilus products may contain lactose⁹

What are the side-effects of taking acidophilus?

Friendly bacteria is considered safe to take, but possible side-effects may include:

• bloating and gassiness
• constipation
• increased thirst¹⁰