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5 Medications that Should Not be Taken with Dairy

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5 Medications that Should Not be Taken with Dairy

Dairy products are a fundamental part of the American diet, with an average annual consumption of nearly 667 pounds. However, it is important to recognize that dairy can interact negatively with certain medications. While dairy can be considered a healthy food choice, its interactions with medications can be significant–and potentially detrimental.

Polyvalent cations, like calcium, in dairy products can bind to certain medications in the stomach or affect the acidity of the stomach. This could impact the efficacy of the medication and compromise treatment outcomes for patients. In this article, we will explore five common medications that should not be taken with dairy and how functional medicine practitioners can advise their patients on managing these interactions.


Understanding Drug-Nutrient Interactions

Drug-nutrient interactions generally occur when nutrients in food affect the absorption, metabolism, and even effectiveness of medications. Also termed pharmacokinetics, these interactions can occur with various foods, including dairy products, and can have implications for patient outcomes.

Certain nutrients in food can bind to medications in the gastrointestinal tract, reducing their absorption into the bloodstream. The calcium in dairy products can bind to medications, such as tetracyclines and fluoroquinolones. Some medications require a specific pH level for optimal absorption. Foods that affect stomach acidity, such as dairy products, can therefore impact the absorption of these medications.

Some foods contain substances that can induce or inhibit the enzymes responsible for metabolizing drugs in the liver–one of the most famous being the CYP450 system in the liver. This can lead to changes in the concentration of the drug in the body, potentially affecting its effectiveness or causing adverse effects. An example of a drug-nutrient interaction in the context of enzyme metabolism is warfarin and Vitamin K.

The Role of Dairy in Drug Interactions

Dairy products, such as animal-based milk, cheese, and yogurt, are known for their rich fat and nutrient content, including calcium, phosphorus, and magnesium. While these nutrients are required for overall health, they can also interact with certain medications, posing a threat to medication efficacy.

A primary mechanism by which dairy products interfere with medication is through the presence of calcium. Calcium can bind to certain drugs, forming insoluble complexes that are challenging for the body to absorb. This process can significantly reduce the absorption of these medications, leading to decreased effectiveness.

In addition to calcium, other minerals found in dairy products, such as sodium, magnesium, and zinc, can also interfere with medication absorption. These minerals can compete with drugs for absorption, leading to reduced bioavailability of the medication.

Tetracycline Antibiotics

Tetracyclines are a class of antibiotics used to treat bacterial infections like acne and pneumonia. These medications should not be taken at the same time as dairy products due to the interaction between tetracyclines and calcium found in dairy. Calcium in dairy products can bind to tetracyclines in the stomach. This can lead to lower concentrations of the drug in the bloodstream and potentially compromise its ability to fight off the current infection.

To minimize the impact of dairy on the absorption of tetracyclines, patients should be advised to take these medications at least two hours before or four hours after consuming dairy products. This timing allows for the medication to be absorbed properly before any dairy products are consumed, reducing the likelihood of the calcium in dairy interfering with the antibiotic. Beyond calcium found in dairy, patients taking tetracyclines should exercise the same level of caution with aluminum, iron, and magnesium, often found in multivitamins and antacids.

Fluoroquinolone Antibiotics

Fluoroquinolones are a class of antibiotics used to treat respiratory and urinary tract infections. Like tetracyclines, fluoroquinolones should not be taken with dairy products and separated by at least two hours before and four hours after dairy due to a similar interaction with calcium.

If patients do not adhere to the dosing recommendations for both tetracyclines and fluoroquinolones, it can result in decreased effectiveness of the antibiotic, leading to prolonged infections, recurrent episodes, or the development of antibiotic-resistant bacteria. This can have long-term consequences for patients–particularly those with underlying health conditions or compromised immune systems–because when they get an infection, they may need more potent antibiotics and/or extended treatment durations. 

Thyroid Medications

Medications like levothyroxine and Armour Thyroid are commonly used to treat hypothyroidism, a condition marked by an underactive thyroid gland that does not produce enough thyroid hormone to meet the body’s needs. 

Calcium, present in dairy products and supplements, can interfere with the absorption of thyroid medications in the gut. Studies have shown that when co-administered, calcium can bind to levothyroxine, decreasing absorption by up to 25% and increasing the chance of persistent symptoms such as fatigue, weight gain, and depressed mood.

To avoid the interaction between thyroid medications and calcium, patients should be advised to take their medication on an empty stomach in the morning, at least 30 minutes to one hour before breakfast (yes, this includes coffee), and four hours before having any calcium-rich foods, like dairy. 


Bisphosphonates are a first-line class of medications for osteoporosis and other bone disorders. These medications work by slowing down the breakdown of bone and increasing bone density. When bisphosphonates are taken at the same time as calcium, calcium can bind to bisphosphonates, causing reduced effectiveness of the medication which can lead to a greater risk of bone fractures. 

Research shows that many patients with osteoporosis have insufficient calcium intake, so they are often recommended to take calcium supplements as a part of a comprehensive treatment regimen for their condition. Patients in this category are advised to take the bisphosphonate on an empty stomach, for at least 30 minutes before consuming calcium-rich antacids or foods–like dairy and calcium supplements. This timing allows for optimal absorption of bisphosphonates without interference from calcium or other nutrients.


Lithium is a medication commonly used to treat bipolar disorder, a mental health condition characterized by episodes of mania and depression. Dairy products, like cheese, can contain high levels of sodium. When taken together, this can affect the balance of sodium and lithium in the body, potentially playing a role in toxicity from serum lithium levels. 

To avoid an unwanted interaction, patients should be advised to maintain a consistent level of sodium in their diet. Patients should also be encouraged to stay hydrated and to monitor their lithium levels regularly to ensure they are within the therapeutic range.

General Tips for Managing Dairy Intake with Medication

Managing dairy intake while taking medications known to interact with dairy can be challenging, but with a multi-prong approach, patients can safely navigate these interactions. Here are some general recommendations to consider:

  1. Read Medication Labels: Patients should carefully read the labels of their medications to check for any warnings or instructions regarding dairy consumption. Some medications may contain dairy products as excipients, which are inactive ingredients used as fillers or binders.
  2. Timing of Medication: Patients should follow the recommended timing for taking their medications about dairy consumption.
  3. Consider Alternative Sources of Calcium: Since dairy is a major source of calcium, patients–especially those on tetracyclines, fluoroquinolones, bisphosphonates, and thyroid medications–should consider alternative sources of calcium in their diet, such as leafy green vegetables, nuts, seeds, and fortified foods. Calcium supplements may also be recommended for certain patient populations, like those diagnosed with osteoporosis.
  4. Monitor Symptoms: Patients should monitor for any changes in symptoms or side effects when consuming dairy products while taking medications. If they notice any adverse effects, they should inform their healthcare provider promptly.
  5. Maintain a Balanced Diet: Patients should consult their interdisciplinary healthcare team to implement a balanced diet that includes a variety of nutrient-rich foods. In the case of patients on lithium, an inconsistent diet may lead to potentially life-threatening lithium toxicity with symptoms including but not limited to nausea, diarrhea, tremors, confusion, and seizures.

Consulting Healthcare Professionals

When it comes to managing medications known to interact with dairy, such as tetracyclines, fluoroquinolones, thyroid medications, bisphosphonates, and lithium, consulting healthcare professionals is paramount to patient outcomes. These interactions can have significant implications for treatment regimens, making it essential for patients to seek guidance from their healthcare team before making any big additions or changes to their diet, medications, supplements, and lifestyle.

Healthcare professionals, including physicians, pharmacists, nurses, functional medicine practitioners, and dietitians, can work together on an interdisciplinary care team to help patients navigate these interactions. In particular, functional medicine practitioners can provide personalized advice, monitor for any adverse effects, and work with the patient to develop an individualized treatment plan that ensures safe yet effective health outcomes.


Key Takeaways

Dairy is and continues to be a beloved part of many people's diets. Managing medications that interact with dairy is crucial for ensuring optimal patient outcomes. Understanding the mechanisms behind these interactions, such as the binding of calcium and other minerals to certain medications, is essential to managing them effectively. Patients should ask questions, seek guidance from their multidisciplinary healthcare team, and carefully manage their diets to ensure that their medications are as effective as possible. By taking these steps, patients can maximize the benefits of their medications while minimizing risks to improve their overall health and well-being.

The information provided is not intended to be a substitute for professional medical advice. Always consult with your doctor or other qualified healthcare provider before taking any dietary supplement or making any changes to your diet or exercise routine.
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