Vinegar, and in particular apple cider vinegar, has been linked to a number of positive health effects, as is the case with many nutrients and foods. Such foods are often labelled as "superfoods". In recent years, vinegar has been hailed and promoted for its weight loss properties. Is there some truth in these claims? Can vinegar help weight loss?
What is the apple cider vinegar diet?
Many diets are marketed as quick fixes to weight loss. In previous blogs, we have discussed the alkaline diet, vegan/vegetarian diet, and ketogenic diet. Here we will discuss the apple cider vinegar diet. Apple cider vinegar, and vinegar in general, has been used for medicinal purposes for centuries. Apple cider vinegar comes from apples that have been crushed, distilled, and then fermented. It can be consumed in small quantities or taken as a supplement, the usual way is to take 1-3 tablespoons before or with meals. The active compound in apple cider vinegar is believed to be acetic acid (and, if this is the active compound, any type of vinegar would have the same effects). It also contains a number of polyphenols.
What is apple cider vinegar supposed to do?
Various forms of vinegar have been used for their presumed healing properties. It was claimed that vinegar improves strength, “detoxificaties the body” (whatever that may mean), as well as heals wounds, fevers, sores, and even scurvy, and it was also claimed to be an antibiotic. Most of those claims we know are not true. More recently the claims have been the effects on weight loss as well as glucose control. In this blog we focus on weight loss only. There is some evidence that it modifies glucose responses to meals but whether this also exerts a health benefit for healthy individuals with normal glucose control is a question that is still open (maybe a topic for a future blog). Here we look at the evidence that vinegar can help weight loss.
Vinegar has been claimed to improve strength, detoxify the body, heal wounds and fevers, as well as be an antibiotic.
Studies that show a possible effect of vinegar
Several studies in obese rats and mice suggest that acetic acid can prevent fat deposition and improve their metabolism. Of course, this does not mean that effect also translates to weight loss in humans. Studies in humans are much less convincing. There are few studies and most of them relatively small. The results are also mixed.
In one Japanese study published in 2009, 175 obese individuals were randomly assigned to three groups of similar body weight, body mass index (BMI), and waist circumference (1). During a 12-week treatment period, the subjects in each group ingested 500ml daily of a beverage containing either 1 tablespoon of vinegar (15 ml; 750 mg acetic acid), 2 tablespoons (30 ml of vinegar; 1500 mg acetic acid), or no vinegar (placebo). There were small reductions in body weight (1-2kg), BMI, visceral fat area, waist circumference, and serum triglyceride levels in both vinegar intake groups compared with the placebo group. Four weeks after the intervention, weights returned to normal.
Some have suggested a reduced food intake with the addition of vinegar and one study found that vinegar consumption promoted feeling fuller after eating. This seems a positive outcome and maybe an explanation for the weight loss in the study discussed above. However, when reading the study more carefully it becomes clear that it did so by causing nausea. Few people would consume something that makes them nauseous for longer periods of time, so the sustainability should be seriously questioned.
A more recent study randomly assigned 39 subjects to follow a restricted calorie diet with apple cider vinegar or a restricted calorie diet without apple cider vinegar for 12 weeks (2). While both groups lost weight, the apple cider vinegar group lost a little more. The effects were quite small and short-term.
Studies that show no effect of vinegar
There are a number of other studies that show no effects of vinegar on body weight or health parameters. These studies usually get no attention at all in the media and we also know that such studies are more difficult to get published (publication bias). However, the findings are just as important. A meta-analysis could only find 13 studies performed on humans that were eligible for inclusion (3). And the studies that were included were not all specifically looking at effects on weight loss, many were interested in other outcomes.
Of the 13 studies 10 were clinical trials (RCTs) and three studies were non-randomized interventional studies. When the authors performed a risk-of-bias assessment the studies were judged to be of low quality. Most studies had no sample size calculations prior to conducting the studies and no considerations of power and almost all studies were single blinded, and it was also difficult to find a suitable “placebo”. So the hype of apple cider vinegar (or vinegar in general) and weight loss is based on minimal evidence and the evidence that is available is relatively low quality.
Studies showing no effect of vinegar on body weight or health parameters get very little attention in the media.
What can we conclude about vinegar?
The scientific evidence that vinegar consumption (whether of the apple cider variety or not) is an effective way to lose weight long term is not compelling. It is questionable whether the practice is sustainable, especially in individuals where it causes side effects. Could there be any negative effects of taking daily doses of vinegar. Some have argued that it could damage tooth enamel or have effects on potassium concentrations. But that evidence isn’t that strong either in my opinion. This conclusion was shared by the meta analysis in 2020 that concluded that the side effects and negative consequences when ingested in the amounts suggested and if ingested according to recommendations was minimal (3).
If you really want to lose weight, paying attention to overall energy intake and physical activity are still the key factors. Finding ways that reduce intake but make it sustainable and solutions will therefore be highly individual. There is no simple zero-effort cure that works for everyone. If something is advertised as such, alarm bells should be ringing.
There is no simple zero-effort cure that works for everyone. If something is advertised as such, alarm bless should be ringing.
Reference
Kondo, T, Kishi M, Fishimi T, Ugajin S, Kaga T. Vinegar Intake Reduces Body Weight, Body Fat Mass, and Serum Triglyceride Levels in Obese Japanese Subjects, Bioscience, Biotechnology, and Biochemistry 73:8, 1837-1843, 2009.
Khezri SS, Saidpour A, Hosseinzadeh N, Amiri Z. Beneficial effects of Apple Cider Vinegar on weight management, Visceral Adiposity Index and lipid profile in overweight or obese subjects receiving restricted calorie diet: A randomized clinical trial,. Journal of Functional Foods 43, 95-102, 2018.
Launholt TL, Kristiansen CB, Hjorth P. Safety and side effects of apple vinegar intake and its effect on metabolic parameters and body weight: a systematic review. Eur J Nutr 59(6): 2273-2289, 2020.
