Body & Fitness

How food affects medication

Be aware that what you eat may alter your medication.


Grapefruit and grapefruit juice can interfere with the way some enzymes in the digestive system process medications, both increasing and decreasing the effect of the drug. You need to be wary if you take statins to control cholesterol. Eating or drinking a large amount of grapefruit can react with statins, such as Lipitor, accelerating side effects. In severe cases, it may result in organ damage. Grapefruit can also have an impact on drugs prescribed for lowering blood pressure, as well as anti-malaria drugs containing quinine, some antihistamines and the anti-anxiety medication buspirone.

Dairy products

Calcium in dairy foods such as milk, cheese and yoghurt can affect the way some medicines are absorbed. In particular some antibiotics may be not be properly absorbed if you’ve just had a large milky drink or eaten lots of yoghurt. Some dairy products can also react with monoamine oxidase inhibitors (MAOIs); medication prescribed for depression. Strong, aged or processed cheeses (blue cheese, parmesan, brie or aged cheddar) are more likely to interact with these drugs as they are rich in a natural amino acid called tyramine. Tyramine can interact with a compound called selegiline, used in some drugs prescribed to treat Parkinson’s disease.


Chocolate is a natural mood booster. It stimulates the production of endorphins, the brain chemicals that produce feelings of pleasure. It also contains the chemical serotonin, which acts as an antidepressant. The darker the chocolate, the greater the effect. But if you have been prescribed MAOIs to treat depression, you need to be cautious. Eating a large amount of chocolate after taking an MAOI such as Nardil may cause a sharp rise in blood pressure. The caffeine in chocolate can also interact with stimulant drugs such as Ritalin, increasing their effect.

Marmite and Vegemite

If eaten in large quantities, these can react with MAOIs.

Pickled food, such as sauerkraut or herring

These can react with MAOIs. Cured meats such as salami can also react with MAOIs.


These nuts are great for you, thanks to the omega 3 fatty acids they contain. But they may affect your body’s ability to absorb levothyroxine, a drug commonly used to treat hypothyroidism.


Give licorice a miss if you are taking the drug digoxin (Lanoxin) for congestive heart failure or abnormal heart rhythms. Some forms of licorice may increase the risk of digoxin becoming toxic. It contains a sweetening substance called glycyrrhizin that can also reduce the effectiveness of some blood pressure drugs and diuretics.


Eating a lot of bananas and food rich in potassium, such as oranges and leafy greens, can increase levels of potassium. Taking ACE (angiotensin-converting enzyme) inhibitors such as Vasotec to control blood pressure or heart problems also raises potassium levels. Too much can cause palpitations or irregular heartbeat.

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