Apple cider vinegar: the bitter truth

Vinegar has a long history as a home remedy. If your mum made you sip a tablespoon of apple cider vinegar when you had an upset stomach, you’re not alone. Unfortunately, good evidence for any health benefits – either from sipping the stuff or taking a supplement – is hard to find.

Weight loss claims

Taking apple cider vinegar to aid weight loss has been the subject of several studies. One of the main theories is that vinegar acts as a natural appetite suppressant – so you eat less and can fit into your jeans again.

A frequently cited study is a 2009 trial in Japan involving 175 obese participants who were given daily doses of apple cider vinegar for 12-weeks. Compared with the placebo group, participants who took apple cider vinegar lost 1.6kg by the end of the trial.

However, a 2020 review in the European Journal of Nutrition found the health benefits of apple cider vinegar, including its effects on losing weight, couldn’t be determined due to a lack of high-quality research. It found most trials were small or conducted using lab animals.

One trial – involving humans – came to the conclusion it wasn’t appropriate to promote vinegar as an appetite suppressant as participants reported feeling nauseous.

Blood sugar claims

Several studies have investigated the effects of vinegar on blood glucose and insulin levels but they’ve had small numbers of participants.

One study involving 16 people with type 2 diabetes reported a reduction in glucose after adding vinegar to high-glycaemic carbohydrates (mashed potatoes and milk). However, this didn’t happen when vinegar was consumed with low-glycaemic carbs (wholegrain bread, lettuce and low-fat cheese).

The 2020 European Journal of Nutrition review concluded evidence was insufficient to make any firm conclusions about vinegar and blood sugar. More large-scale and long-term trials were needed before any definitive health claims could be made, the authors said.

Digestion claims

Unfortunately, evidence that apple cider vinegar can help with digestion is no better.

The vinegar’s been touted as beneficial for our gut microbiota. But so far, there’s nothing definitive to support taking more of it or splashing out on supplements.

On the downside, one study reported participants who took high doses (more than 4 tablespoons a day) experienced an increase in “adverse events”, such as frequent bowel movements and burping or flatulence.

Too much of the stuff can also damage your tooth enamel, as well as your oesophagus. That’s why it’s best to have with other foods (such as in your salad), rather than drink it neat.

What’s in it?

Apple cider vinegar, or apple vinegar, is made from fermented apple juice. Bacteria and yeast turn the fruit sugars into ethanol cider.

Then, in a second fermentation step, bacteria converts the ethanol (alcohol) into acetic acid. It’s the acetic acid that gets most of the attention in studies of the product’s supposed health benefits.

Apple cider vinegar often has a cloudy, brown colour due to being unstrained and containing strands of a material nicknamed “the mother” (a combination of proteins, enzymes and bacteria).