People turning to apple cider vinegar tonics as a homeopathic remedy to kick a cold or lose weight might want to consult a doctor before making it part of their routine.
Apple cider vinegar beverages, often called fire cider or switchel, date to the Colonial era when the drinks were created to replace nonpotable water. For decades, the beverage faded from view, but more recently it has been popularized by celebrities like Katy Perry and natural health proponents, who see the tonic as a trendy cure-all for everything from acne to hangovers.
From sparkling switchel to probiotic tonics, brands like Bragg, CideRoad and Pepsi's KeVita, among others, have jumped in and offered up their own take on the drink.
"Homeopathic types of remedies probably have some merit," said Ken Harris, managing partner at Cadent Consulting Group. He noted that the beverages are part of an effort to "contemporize home remedies" and appeal to a consumer who is seeking healthier alternatives.
But the acidic treatment could do more harm than good, said Dr. Fatima Cody Stanford, an obesity medicine physician at Massachusetts General Hospital and Harvard Medical School.
"There's no regulated formulation," Stanford told CNBC. She said if the cider is not diluted properly, tooth erosion and ulcers in the stomach, esophagus and intestines can occur, not to mention burning of skin.
However, the majority of the beverages on the market contain only one to two tablespoons of apple cider vinegar. It is usually mixed with water and sweeteners or spices to make the drink more palatable. Stanford's own apple cider vinegar recipe, which she uses as an energy booster, is usually diluted in at least 8 ounces of warm water.
New Jersey-based CideRoad's switchel contains about a tablespoon of apple cider vinegar in its 14-ounce bottles and is mixed with ginger, water and natural sweeteners like maple syrup and cane sugar, according to the company's founder and CEO, Kevin Duffy.