Losartan is a medication used to treat high blood pressure and reduce the risk of stroke in people with hypertension and left ventricular hypertrophy. Like all medications, losartan can interact with certain foods and supplements, potentially making it less effective or increasing side effects. Therefore, being aware of what foods to avoid while taking losartan is important.
What is losartan?
Losartan is an angiotensin II receptor blocker (ARB) that works by relaxing blood vessels to lower blood pressure. It prevents a hormone called angiotensin II from binding to receptors in blood vessels, which normally causes them to narrow. This helps maintain smooth blood flow.
In addition to treating hypertension, losartan may be used in people with type 2 diabetes to help protect their kidneys. It may also be used following a heart attack to prevent future cardiovascular events.
Some common brand names for losartan include Cozaar, Hyzaar, and Losartan Hydrochlorothiazide. Losartan may be prescribed as a standalone medication or combined with other blood pressure medications like hydrochlorothiazide as part of a treatment regimen.
How does losartan work?
Losartan works by blocking angiotensin II receptors found along blood vessel walls, preventing angiotensin II from binding to them. Angiotensin II is a hormone that causes blood vessels to constrict, increasing blood pressure.
When angiotensin II is unable to bind to its receptors, blood vessels remain relaxed and open, allowing blood to flow more smoothly. This reduces resistance in the circulatory system and lowers blood pressure.
Furthermore, losartan also inhibits the release of another hormone called aldosterone. Aldosterone signals the kidneys to retain salt and water, which also raises blood pressure. Therefore, losartan reduces blood volume and pressure through multiple mechanisms of action.
Losartan starts working within 1-2 hours after taking the first dose, but the maximum blood pressure-lowering effects may take 3-6 weeks. One dose of losartan persists for 24 hours.
Why should some foods be avoided with losartan?
Certain foods may interact with losartan and impact the drug’s effectiveness and absorption. Foods that are very high in potassium or magnesium can potentially cause dangerous electrolyte imbalances when combined with losartan.
Additionally, grapefruit juice contains compounds that interfere with enzymes needed to break down losartan in the digestive system. This slows the excretion of the drug from the body, leading to increased losartan levels in the bloodstream.
Foods that affect kidney function, like those high in phosphorus or protein, could also alter how efficiently losartan is eliminated from the body.
Potassium-rich foods to avoid
High potassium foods to avoid with losartan:
- Bananas
- Avocados
- Potatoes
- Tomatoes
- Orange juice
- Dried fruits like raisins and apricots
- Beans
- Dark leafy greens like spinach and kale
- Salmon
- Yogurt
Losartan can cause potassium levels to rise, so consuming high potassium foods in combination with the medication further increases this risk. Potassium acts as an electrolyte and plays a role in nerve signaling and muscle contractions, including the heart.
Too much potassium (a condition called hyperkalemia) can cause dangerous heart rhythm abnormalities. Seek immediate medical attention if muscle weakness, chest pain, or heart palpitations occur while taking losartan.
Grapefruit
All forms of grapefruit and grapefruit juice should be avoided with losartan. Grapefruit contains compounds called furanocoumarins that inhibit certain liver and gut enzymes needed to break down losartan in the body. This leads to higher concentrations of losartan in the bloodstream, intensifying its blood pressure lowering effects.
Grapefruit juice does not make losartan more effective, but rather increases the risk of side effects like fainting, dangerously low blood pressure, kidney failure, and hyperkalemia. Speak to a pharmacist or doctor about alternative citrus fruit juices that do not interact with losartan.
Licorice
Avoid consuming licorice while taking losartan. Licorice root contains a compound called glycyrrhizin which can cause fluid and electrolyte imbalances, including low potassium levels (hypokalemia). This may counteract the potassium-sparing effect of losartan and make the drug less effective for lowering blood pressure.
Look for licorice as an ingredient in teas, throat lozenges, extracts, and candies. It is sometimes found in dietary supplements promoted for heartburn, stomach ulcers, or adrenal fatigue.
Salt substitutes
Salt substitutes like NoSalt or Nu-Salt contain high amounts of potassium and should be avoided while taking losartan. Most salt substitutes replace some or all sodium chloride content with potassium chloride instead.
Excess potassium from these products further increases the risk of hyperkalemia posed by losartan. Stick to normal table salt or low-sodium sea salt as safer options.
Magnesium supplements
Avoid magnesium supplements while taking losartan unless cleared by a healthcare provider. Both magnesium and losartan can independently cause low blood pressure as side effects. Taking them together may result in an additive effect, severely lowering blood pressure.
Food sources of magnesium like dark leafy greens, nuts, seeds, and whole grains are likely okay in moderation. But consult a doctor about the safety of continuing magnesium supplements while on losartan.
Alcohol
Moderate to heavy alcohol consumption should be avoided with losartan due to increased risks of side effects. Alcohol and losartan both lower blood pressure on their own, so combining them can result in additive blood pressure lowering effects.
This could lead to potentially dangerous drops in blood pressure, causing symptoms like dizziness, fainting, blurred vision, nausea, dehydration, and electrolyte imbalances. It’s best to avoid drinking more than 1-2 alcoholic beverages per day while on losartan.
High protein foods
Protein-rich foods like meat, eggs, dairy, beans, and soy foods do not need to be restricted entirely. However, eating very large amounts of protein while on losartan may impair kidney function and reduce excretion of the drug from the body.
Moderation is key, as excess protein puts strain on the kidneys. This could lead to a buildup of losartan and exacerbate side effects. Those with kidney disease should be especially cautious with protein intake while on losartan.
Pickled, cured, or smoked foods
A high intake of pickled, cured, or smoked foods containing nitrates/nitrites may interact with losartan. Nitrates and nitrites are converted to nitric oxide in the body, which causes blood vessel dilation similar to losartan.
Eating large amounts of these foods can enhance the blood pressure lowering effects of losartan, increasing the risk of low blood pressure, dizziness, and falls. Limit intake of items like pickled vegetables, cured meats, smoked fish, and processed lunch meats while taking losartan.
Cruciferous vegetables
Cruciferous vegetables like broccoli, cauliflower, Brussels sprouts, and cabbage contain compounds that may interfere with losartan metabolism. Known as goitrogens, these compounds disrupt the function of thyroid hormones.
Since thyroid hormones play a role in losartan elimination, high goitrogen intake can potentially increase losartan levels in the body and side effects. Those with thyroid issues should be especially mindful of cruciferous vegetable intake while on losartan.
Herbal supplements
Avoid taking herbal supplements without first consulting your healthcare provider. Many popular herbal remedies can interact with losartan and increase the risk of side effects. These include:
- St. John’s wort
- Gingko biloba
- Garlic
- Ginseng
- Green tea
- Ephedra
- Licorice
- Goldenseal
The compounds in these supplements may enhance the blood pressure lowering effect of losartan, cause fluid/electrolyte imbalances, or interfere with losartan metabolism and elimination.
When to avoid losartan altogether
Losartan should be avoided in certain situations due to safety concerns:
- Pregnancy – Losartan can harm the fetus and cause birth defects.
- Breastfeeding – Losartan passes into breast milk and should be avoided by nursing mothers.
- Kidney impairment – Losartan may further deteriorate kidney function in those with existing kidney disease.
- Hyperkalemia – Those with high potassium levels should not take losartan due to further increase in potassium.
- Heart block – Losartan can make this condition worse and is contraindicated.
Losartan is also not suitable for children under 6 years old. Use caution if you have liver disease, chronic diarrhea, or heart failure. Discuss these and any other medical conditions with your doctor before starting losartan.
Foods to eat more of
While some foods need to be limited with losartan, increasing certain foods in your diet may help enhance the drug’s effectiveness:
- Calcium-rich foods like milk, yogurt, cheese, tofu, and leafy greens can help lower blood pressure.
- Fiber-rich fruits, vegetables, and whole grains support heart health.
- Potassium-rich foods like sweet potatoes, coconut water, pistachios, and tomatoes are fine in moderation.
- Foods containing magnesium like almonds, bananas, oatmeal, and edamame are beneficial.
- Protein foods like poultry, eggs, fish, and legumes can be eaten in controlled portions.
- Foods containing omega-3s like walnuts, salmon, and chia seeds promote heart health.
Be sure to incorporate these foods into an overall healthy diet tailored to your nutritional needs and restrictions.
The bottom line
Certain foods and beverages can interact with losartan and increase the risk of side effects like low blood pressure, kidney problems, and electrolyte imbalances. High potassium foods, alcohol, licorice, grapefruit, cruciferous vegetables, and some herbal supplements are examples of items to avoid.
Speak to your healthcare provider about your diet to determine which foods to restrict. With some modifications, you can safely take losartan while continuing to eat a nutritious, well-balanced diet.
Frequently asked questions
Can I eat bananas while taking losartan?
Bananas are high in potassium, so they should be eaten only occasionally and in small amounts while taking losartan. Stick to about 1/3 of a banana per day or less to keep potassium levels in a safe range.
Is salt bad for losartan?
No, regular table salt and sea salt are fine with losartan. Only potassium-based salt substitutes need to be avoided. In fact, losartan’s diuretic effects can sometimes lower sodium levels too much, so salt intake may need to be increased while on this medication.
Can I drink coffee with losartan?
Yes, it is generally safe to drink coffee while taking losartan. Caffeine does not significantly interact with this medication. However, coffee can sometimes increase blood pressure on its own, so those with hypertension should limit intake to 1-2 cups per day.
What fast food can I eat with losartan?
Fast food is not off limits, but make healthy choices like grilled chicken sandwiches, salads, roasted veggie bowls, and yogurt parfaits. Avoid excessive sodium and limit fried items, bacon, and processed meats high in nitrates/nitrites. Be mindful of portion sizes as well.
Can I drink Ensure with losartan?
Nutritional supplements like Ensure are typically fine with losartan, but check with your pharmacist. Avoid Ensure products formulated with added potassium like Ensure High Protein Powder. Also, limit Ensure intake if you have kidney issues.
Conclusion
Losartan is an effective medication for lowering blood pressure and protecting kidney function. But certain foods and supplements can interact with losartan and increase the risk of side effects. It’s important to be aware of dietary restrictions and make appropriate meal modifications while taking this medication.
With guidance from your healthcare provider, you can safely take losartan while continuing to eat a nutritious diet rich in heart-healthy foods. Monitoring your symptoms and getting regular lab tests for potassium and kidney function are also important. This will help ensure losartan continues working effectively for your condition.
