A metallic taste in the mouth is one of the most common ketosis symptoms. It usually affects those on low-carb and ketogenic diets. However, it may also be a sign of oral bacteria buildup, infections or exposure to certain chemicals. If you're on a diet, though, ketosis is most likely the culprit.
As your body enters ketosis, you may experience the so-called keto flu. A common symptom is bad breath, which may be accompanied by a funny taste in the mouth.
However, ketosis isn't always the culprit. Tooth decay, oral bacteria buildup, dehydration and diabetic ketoacidosis may cause these symptoms, too.
What Is Ketosis?
Ketogenic diets are known for their beneficial effects on metabolic health. These eating plans are low in carbs, high in fat and moderate in protein — and require no calorie counting. The downside is that they're quite restrictive and limit your food choices. Additionally, their safety is subject to debate.
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According to a review published in the Indian Journal of Medical Research in November 2018, the ketogenic diet has been proven effective for weight loss and diabetes management. Furthermore, it may improve blood lipids and glycemic control. A potential drawback is the risk of nutrient deficiencies resulting from low intakes of fruits, vegetables, whole grains and other foods.
Most versions of this diet plan limit carbs to 50 grams per day, as noted in the above review. Under normal circumstances, your body converts carbs to glucose — its primary source of fuel. If you cut down on carbs, your liver begins to produce ketone bodies for energy. When ketone bodies reach high levels in the blood and urine, your body enters ketosis, a metabolic state in which it burns stored fat.
Have you ever heard of the so-called keto flu? This condition describes a number of symptoms that kick in as your body enters ketosis. Some dieters experience a metallic taste in the mouth, bad breath, constipation, weakness, low energy and other unpleasant side effects. Your breath may have a fruity odor because of the acetone (a type of ketone body) eliminated through the lungs.
Ketosis Symptoms: What to Expect
A fruity breath, or acetone breath, is one of the hallmarks of ketosis. This side effect may also occur during fasting, as reported in a June 2017 review in the Journal of Breath Research.
Diabetic ketoacidosis, a complication of diabetes characterized by elevated ketone bodies in the blood, may give your breath a sweet smell, too. You may also notice a sweet or metallic taste in the mouth.
Ketosis and diabetic ketoacidosis are quite similar. The latter, though, occurs only in people with diabetes and results from extremely low ketone body concentrations. If left untreated, it can be fatal.
While in ketosis, you may feel less hungry than usual. According to a November 2014 research paper published in Obesity Reviews, ketogenic diets suppress appetite, making it easier to reduce total food intake.
Read more: The Benefits of Ketosis
Ketosis symptoms may also include enhanced mental focus and improved brain function. As the experts at Stanford Health Care note, ketone bodies account for about 30 percent of the energy supplied to the brain after three days of ketosis — and 70 percent after four days. In fact, this dietary plan is studied for its role in the prevention and treatment of Alzheimer's disease.
Each person experiences ketosis differently. Some dieters report fatigue, low energy, mood swings and diminished physical performance. Others feel energized and healthier overall. Certain supplements, such as medium-chain triglycerides (MCTs), may improve your symptoms and help you get into ketosis faster.
Other Causes of a Metallic Taste
There are many factors other than ketosis that may cause a metallic taste in the mouth. For example, antibiotics, antidepressants and other medications can have this side effect, according to the Cleveland Clinic. Sometimes, poor oral hygiene is the culprit.
Whether you're on a diet or eating like usual, it's crucial to take proper care of your teeth and gums. Common dental problems, such as tooth decay, may cause bad breath and a funny taste in your mouth, among other symptoms.
Juice fasting, for instance, can affect your teeth in the long run. As the American Dental Association points out, acidic beverages like soda, lemon juice, orange juice and sports drinks may cause tooth erosion, leading to oral bacteria buildup and infections or cavities. As a result, you may experience a metallic taste and bad breath.
Read more: 10 Healthy Habits That Are Destroying Your Teeth
Many times, these symptoms are related to what you eat and drink. They may also result from upper respiratory infections, exposure to lead or mercury and the use of certain dietary supplements, as reported by the Cleveland Clinic. Luckily, you can address these issues through simple lifestyle changes.
What to Do About It
The first step to getting rid of that bad taste in your mouth is to determine what caused it in the first place. Was it your diet? Did you take antibiotics or iron supplements?
If you're on the keto diet, this symptom won't go away anytime soon. However, you can use mints and sugar-free chewing gum to freshen your breath.
Sugarless gum might even help you stick to your diet and keep your appetite in check, according to a small study published in Physiology & Behavior in May 2016. Subjects who chewed gum reported less hunger and ate fewer snacks three hours after lunch. Another small study, which appeared in the journal Applied Physiology, Nutrition and Metabolism in April 2015, suggests that chewing gum may increase energy expenditure, helping you burn more calories throughout the day.
However, these studies were quite small and more research is needed to confirm their findings. To stay safe, choose a brand of chewing gum that contains no sugar, titanium dioxide and artificial sweeteners. A growing number of manufacturers are now offering stevia chewing gum and other similar products containing natural ingredients.
Take the time to brush and floss your teeth after every meal. Avoid tobacco, alcohol, spicy foods and other products that may cause dry mouth.
Drink plenty of fluids and eat high-water foods to stay hydrated, especially if you're on the keto diet. This low-carb diet plan may leave you dehydrated, according to a review published in the October-December 2017 edition of the Journal of Postgraduate Medicine. Dehydration may cause dry mouth, which in turn, can lead to bad breath and affect your sense of taste.
If you don't notice any improvements, see your doctor to determine the exact cause and discuss your treatment options.
- IJMR: "Ketogenic Diets: Boon or Bane?"
- Harvard.edu: "What Is Keto Flu?"
- Journal of Breath Research: "Breath Acetone as a Potential Marker in Clinical Practice"
- Mayo Clinic: "Diabetic Ketoacidosis"
- European Medicines Agency: "EMA Confirms Recommendations to Minimise Ketoacidosis Risk With SGLT2 Inhibitors for Diabetes"
- Obesity Reviews: "Do Ketogenic Diets Really Suppress Appetite? a Systematic Review and Meta‐Analysis"
- Science Direct: "The Ketogenic Diet as a Potential Treatment and Prevention Strategy for Alzheimer's Disease"
- Journal of Nutrition and Metabolism: "The Effect of Medium Chain Triglycerides on Time to Nutritional Ketosis and Symptoms of Keto-Induction in Healthy Adults: A Randomised Controlled Clinical Trial"
- Cleveland Clinic: "Common Causes for a Metallic Taste in Your Mouth"
- NHS Inform: "Tooth Decay"
- American Dental Association: "Erosion: What You Eat and Drink Can Impact Teeth"
- Physiology & Behavior: "Short-Term Effects of Chewing Gum on Satiety and Afternoon Snack Intake in Healthy Weight and Obese Women"
- Applied Physiology, Nutrition and Metabolism: "Chewing Gum Increases Energy Expenditure Before and After Controlled Breakfasts"
- American Dental Association: "Limiting the Effects of Dry Mouth"
- NCBI: "Ketogenic Diet in Endocrine Disorders: Current Perspectives"
- Cleveland Clinic: "Sour Taste in Your Mouth? Here Are the 7 Most Common Causes"