Diluted vinegar is a traditional tonic for weight loss. Indeed, mention of this remedy is found as far back as 1825, when Brillat-Savarin wrote about its dangers. A British poet, Lord Byron had popularized the weight loss tonic and would reportedly go for days eating biscuits and potatoes soaked in vinegar. Popular ways to use the vinegar are to ingest several teaspoons prior to meals, or drinking it diluted in water at bedtime. Apple Cider Vinegar seems to have gained a particular following as it contains both vinegar (acetic acid) as well as the pectins from the apple cider (a type of soluble fibre).
Is it true?
Vinegar has been used since the times of the ancients. Wine, left undisturbed, will turn into vinegar (acetic acid). Indeed, the word has its origins from Latin vinum acer (sour wine). The ancients quickly discovered the versatility of this wondrous substance for cleaning. In a time before antibiotics, the antimicrobial properties of vinegar was often used by healers. Wounds would often be washed in wine and vinegar. Because of the antimicrobial properties, vinegar has also been used to preserve food (pickling). Saeurkraut and kimchi, on the other hand, use fermentation to produce lactic acid which is slightly different process.
As a beverage, the tangy sour taste of vinegar never really gained much popularity, although Cleopatra famously was rumoured to dissolve pearls in vinegar as a drink. However, it still retains fans as a condiment for French fries, in use in dressings (balsamic vinegar) and in making sushi rice (rice vinegar).
There are no long term data on the use of vinegar as a weight loss aid. However, smaller short term human studies have been done recently. One study published in 2004 was titled “Vinegar improves insulin sensitivity to a high-carbohydrate meal in subjects with insulin resistance or type 2 diabetes”. Vinegar was given to to insulin resistant as well as normal subjects before a high carbohydrate meal of orange juice and a bagel.
The effect of the vinegar is clear. In controls, but more strikingly in pre-diabetic people, vinegar lowers the subsequent glucose high after the bread as much as 34%. Additionally, the insulin spikes are significantly reduced. Since insulin is a driver of obesity and diabetes, this effect, similar to fibre may be very beneficial over the long term.
A follow up study in 2010 “Examination of the antiglycemic properties of vinegar in healthy adults.” looked in more detail about the vinegar effect. Two different doses were examined and it was found that 10grams (approximately 2 teaspoons) was just as effective as 20 grams. Taking the vinegar just before the meal was more effective than taking it 5 hours before meals.
Indeed, the effect has also been shown with rice. In “Glycemic index of single and mixed meal foods among common Japanese foods with white rice as a reference food”, authors found that vinegar lowered the glycemic index of white rice by almost 40%. Addition of other foods such as pickled vegetables and fermented soybeans (Natto) also significantly lowered the glycemic index of the rice. In a similar manner, substitution of pickled cucumber for fresh cucumber reduced the glycemic index of a test meal by 35%.
Potatoes, served cold and dressed with vinegar as a salad showed considerably lower glycemic index than regular potatoes. The cold storage may favour the development of resistant starch, and the vinegar adds to the benefits. Both glycemic and Insulin Index reduced by 43% and 31% respectively.
Another study “Vinegar Ingestion at Bedtime Moderates Waking Glucose Concentrations” looked at the benefits on the blood sugars. Participants were type 2 diabetic patients that were not on insulin. They were given the 2 tablespoons of apple cider vinegar at bedtime and morning blood sugars were measured. There was a measurable effect to lower blood sugars in well controlled type 2 diabetic patients, but the effect is relatively small.
The dose response curve of vinegar on blood insulin effect can also be measured. Dr. Ostman tested different doses of vinegar on a test meal of white bread (50g carbohydrate) and found that higher doses of vinegar can progressively lower insulin response.
What is important to realize is that the total amount of carbohydrate is the same in all cases. The vinegar is not merely displacing carbohydrate calories, but actually seems to exert a protective effect on the serum insulin response.
Satiety has also been measure in response to white bread and various doses of vinegar. The lowest satiety score was white bread alone. There was a progressive linear relationship between the satiety score and the amount of vinegar ingested. Another study showed that vinegar ingestion resulted in slightly lower caloric intake through the rest of the day (approx 200-275 calories less). This effect was also noted for peanut products. Interestingly, peanuts also resulted in a reduction of glycemic response by 55%.
How does acetic acid produce these beneficial effects? This is a matter of conjecture. It is postulated that the acid interferes with the digestion of starches. It is possible that it has its effect on inhibiting salivary amylase and therefore specifically interferes with carbohydrate absorption. Indeed, the effect on fats and proteins is negligible. The other major mechanism postulated is that vinegar reduces gastric emptying. There is conflicting data here, with at least one study showing a reduction of glucose response by 31% but no significant delayed gastric emptying.
Ultimately, however, it is far more important to realize that it does work rather than question how it works. The large Nurse’s Health Study showed a significant cardiovascular benefit with the use of oil and vinegar dressing. This was considered to be the effect of dietary alpha linolenic acid. However, Dr. F Hu points out that mayonnaise, which contains similar amounts of alpha linolenic acid does not appear to provide nearly the same cardiac protection. Perhaps the difference here is the consumption of vinegar. This is only an association study and cannot prove it, but certainly an interesting hypothesis given what else we know about vinegar.
What about safety? Brillat-Savarin had warned against the use of vinegar as a weight loss aid all those years ago. But, really. Come on. Vinegar has been consumed for thousands of years. There is just about no conceivable way that it is not safe for human consumption. Just don’t expect rapid weight loss with the use of vinegar. Even among its proponents, it will only cause mild decrease in weight.
Adding vinegar as a protective factor into our Hormonal Obesity Theory, we can see now that there are, in fact a number of dietary changes we can make to reduce the insulin levels. None of these is new. The use of fibre and vinegar in the battle of the bulge has long been discussed and has always been a part of folk remedies. Maybe we should look harder at the tried and true rather than the latest and greatest.
Continue here with Sugars 1 – Hormonal Obesity XXIX
Start here with Calories I – How Do We Gain Weight?
See the entire lecture – The Aetiology of Obesity 3/6 – Trial by Diet