Supermodels like Heidi Klum reportedly sip it to stay slim, while actress Megan Fox uses it to 'cleanse out' her system. But you don't need to be rich and famous to get hold of it; you can find it in your local healthfood store.
Yes, the latest celebrity must-have is the cheap and decidedly unglamorous apple cider vinegar (AVC for short)-a type of vinegar with a brownish-gold colour made by fermenting apple juice. It's been around for centuries, but has been making a bit of a comeback of late as a health tonic amidst claims that it can combat everything from acne to diabetes to the flu. Klum even says she merely has to sniff the stuff to knock food cravings on the head.
But what's the real story on ACV? Is there any evidence to show it's useful for more than just dressing salads? Here's a roundup of the research on ACV as a health remedy.
The good news
Anyone taking ACV for weight loss will be pleased to know there's some evidence to support its supposed size-shrinking properties. In a study carried out in Japan, obese volunteers all of a similar size and weight were randomly split into three groups and given a 500-mL daily drink containing either 15 mL of ACV, 30 mL of ACV or no ACV. After about three months, the researchers found that body weight, body mass index (BMI), waist size and visceral fat (the fat that accumulates around the organs) were all significantly lower in the two vinegar groups than in the placebo group. Levels of triglycerides-a type of fat in the blood linked to heart disease-were also lower in the vinegar drinkers.
As energy intake, meal content and physical activity levels were not significantly different among the three groups during the study, the researchers concluded that the vinegar was responsible for the beneficial effects. Still, the amount of weight loss wasn't much-around 1-2 kg (2-4 lb) (Biosci Biotechnol Biochem, 2009; 73: 1837-43).
There's also evidence to suggest that AVC may help control food cravings. A small Swedish study found that those who ate a piece of bread along with small amounts of vinegar felt fuller and more satisfied than those who ate the bread on its own. The researchers didn't say what type of vinegar they were using, but noted that its satiating effects were directly related to its content of acetic acid-the key component in all types of vinegar responsible for that distinctive sour taste and pungent smell. They found that the volunteers given the largest amounts of vinegar, and so the highest levels of acetic acid, reported feeling more full than the others (Eur J Clin Nutr, 2005; 59: 983-8).
Another study, presented at the 46th Annual Meeting of the American College of Nutrition at Kiawah Island, South Carolina, 22-25 September 2005, suggests that vinegar's apparent satiating effect can actually cut calorie intakes. It showed that people who drank a tonic containing ACV after breakfast consumed around 300 calories less over the rest of the day compared with when they drank a placebo drink not containing vinegar (DOC NEWS, 2006; 3: 7).
Besides helping with weight loss and hunger pangs, ACV appears to have a beneficial effect on blood sugar levels and so may be helpful for people with diabetes.
In a study by Arizona State University scientists, type 2 diabetics who took two tablespoons of ACV with a small amount of food (cheese) at bedtime saw a 4- to 6-per-cent drop in their blood glucose (sugar) levels come morning. Those who took a placebo (water plus cheese) saw their blood glucose levels drop by just 2 per cent (Diabetes Care, 2007; 30: 2814-5).
Another study involving healthy people, people with type 2 diabetes and those with signs of prediabetes (insulin resistance) found that taking ACV before high-carbohydrate meals boosted insulin sensitivity and reduced the spikes in insulin and glucose that are seen after meals. Those with prediabetic symptoms benefitted the most from the vinegar, cutting their blood glucose levels by nearly half (Diabetes Care, 2004; 27: 281-2).
Other research-albeit in animals so it may not apply to humans-suggests that ACV can increase HDL ('good') cholesterol and reduce levels of triglycerides-those potentially harmful blood fats-in diabetic rats (Pak J Biol Sci, 2008; 11: 2634-8). And in rats with high blood pressure, acetic acid-the main component of ACV-had a blood-pressure-lowering effect (Biosci Biotechnol Biochem, 2001; 65: 2690-4).
The bad news
Although this evidence is promising, there's not much more in the way of scientific 'proof' for ACV's supposed health benefits.
Supporters say that vinegar can treat all kinds of conditions like acne, allergies, flu, arthritis and constipation, but WDDTY couldn't find any scientific studies to support these claims. There also don't appear to be any studies comparing ACV with bog-standard vinegar, so we don't know whether ACV has beneficial properties beyond its acetic-acid content-the part found in all vinegars that's likely to be important based on the research so far.
Aside from the lack of evidence, there are also a few potential risks to consider. ACV is highly acidic, and one woman suffered 'burns' to her oesophagus after an ACV pill got stuck in her throat. Subsequent investigation into eight different ACV tablet products (conducted in the US) revealed that the acid contents and pH levels of the pills varied widely, and the product labelling was often inaccurate (J Am Diet Assoc, 2005; 105: 1141-4).
As for ACV in liquid form, taking it in small amounts diluted and with food appears to be safe-at least in the short run. However, there has been one report of someone who developed low potassium levels and weak bones (osteoporosis) after taking 250 mL of ACV daily for six years (Nephron, 1998; 80: 242-3). At this point, we just don't know whether there are any other long-term effects as the studies haven't been done.
Other negative effects could be caused by taking ACV in combination with certain drugs such as insulin, diuretics (water pills) and the heart drug digoxin.
There are so many health claims for this 'miracle' tonic, but most of them simply don't have any evidence backing them up. Although there are a few promising studies suggesting ACV may be useful as a slimming aid, any benefit is likely to be small.
One area where AVC may be of real value, however, is in helping people with type 2 diabetes who are not yet taking insulin and those who are 'prediabetic'. There is some encouraging research in this field but, as is often the case with natural remedies, there's still a lot more to be done before ACV can be recommended as an effective alternative.
For now, as we don't know the long-term health effects of ACV, rather than taking it religiously like some celebrities, it may be better to stick to using it as an occasional salad dressing (see box above) if you do want to give it a go.
Apple cider vinegar salad dressing
You will need:
240 mL olive oil
120 mL apple cider vinegar
1 teaspoon onion powder
2 tablespoons wholegrain or Dijon mustard
2-3 cloves garlic (minced)
1/2 teaspoon dried thyme
1/2 teaspoon dried basil
1 teaspoon salt.Combine all ingredients in a bowl and mix well before using. You can make it once a week and keep it in the fridge.
vol 23 no 9 December 2012