Celebrities like Gwyneth Paltrow and Beyonce reportedly start their morning with a glass of warm lemon water for health purposes, according to True Lemon.

Many health and fitness enthusiasts drink hot lemon water upon waking to cleanse the system, stimulate digestive enzymes and possibly even assist with weight loss. But the trendy daily 'healthy' habit could cause enamel erosion.

"Lemon juice is a popular drink in the morning, but unfortunately it is highly acidic (with a pH between 2 and 3) and therefore can contribute to enamel erosion or tooth wear over time," says an expert from the British Dental Association, according to Huffington Post U.K.

Erosion is the loss of tooth enamel, caused by acid attack. When the enamel is worn away, it exposes the underlying dentin, which is more yellow in color than enamel, which may lead to painful sensitivity.

Acidic food and drinks can cause enamel erosion. Lemon juice is highly acidic, so over time, routine consumption of lemon juice will erode enamel. Not only is erosion making teeth appear hollowed and yellowed, but it may also make teeth sensitive to hot and cold food.

"The temperature of the water can exacerbate this effect because erosion is more severe at higher temperatures," Professor Damien Walmsley, the British Dental Association’s scientific adviser said.

"Studies also suggest that the incidence of this type of tooth wear, particularly among children and adolescents, is more prevalent than in the past."

But Dr. Christine Skordelese, a cosmetic and biomimetic dentist, told Marie Claire, "As long as you're not sucking on lemons all day long, having fresh lemon water is good for you. It actually helps prevent disease."

She did agree that it can strip the enamel off over time, but said that lemon water is better than drinking coffee with milk, which can lead to cavities. She also said that an actual lemon fruit is better than bottled lemon juice.