If your brand of multivitamin also contains iron, avoid taking this product at the same time as antacids, bisphosphonates (for example, alendronate), levodopa, thyroid medications (for example, levothyroxine), or some antibiotics (for example, tetracyclines, quinolones such as ciprofloxacin).
Mixing Medications and Dietary Supplements Can Endanger Your Health. Dietary supplements may contain ingredients that can have strong effects in the body. Talk with a health care professional before taking supplements.
Some common vitamins and supplements can raise blood pressure or alter how blood pressure or other medications work. You should always seek the advice of a healthcare provider when considering taking any supplement, especially if you are taking medication to control blood pressure or blood-thinning medication.
A minimum of two hours is usually mandated, with some sources citing four to six hours as a minimum recommendation. For example, it is recommended that doses of calcium and levothyroxine be separated by at least four hours, because the former decreases the bioavailability of the latter.
The supplements may interfere with prescription medications you're taking, she says. The chemical interactions can be minor or dangerous. They can weaken your medications and make them less effective, or they might make your prescriptions more powerful.
Vitamins D, E and K
“Studies have shown that a person's absorption of Vitamin K may be reduced when other fat-soluble vitamins such as Vitamin E and Vitamin D are taken together,” says Dr. Chris Airey, M.D. “It's advised that you take these vitamins at least 2 hours apart to maximize your absorption.”
Combining multiple supplements or taking higher-than-recommended doses can increase the risk that they can cause harm, said Kitchin. "You really can't get toxic doses of nutrients through food, but you can absolutely get toxic doses through supplements," Kitchin said.
For most of your supplements—including your daily multivitamin—you should take them with your largest meal of the day, such as lunch or dinner.
If you have high blood pressure, you may want to avoid certain vitamins and supplements because they can further raise your blood pressure. Some of these vitamins and supplements include vitamin D, St. John's wort, ephedra, arnica, and sodium. Before you consider using any vitamins and supplements, talk with a doctor.
“Some scientific evidence suggests that diets with adequate magnesium may reduce the risk of high blood pressure (hypertension), a condition associated with many factors.
If You Take Mineral Supplements
Large doses of minerals can compete with each other to be absorbed. Don't use calcium, zinc, or magnesium supplements at the same time.
Constipation, diarrhea, or upset stomach may occur. These effects are usually temporary and may disappear as your body adjusts to this medication. If any of these effects last or get worse, tell your doctor or pharmacist promptly.
However, taking your supplements at night isn't a good practice because your digestion and metabolism slow down when you're asleep. This means that when you take vitamins at night, they are not absorbed as efficiently as during the day.
Can you take vitamin D and magnesium together? Yes. In fact, it's probably best to take both together. Because so many people have low magnesium levels, vitamin D supplements on their own aren't very helpful for a large portion of the population.
But if you're looking for a night of sound sleep and to maximize growth and repair, knowing the proper supplements and when to take them is vital. Magnesium, tryptophan, omega-3s, and vitamin B6 are all awesome additions to your nightly routine to help relax the body and lull you into the best sleep of your life.
So, get enough vitamin D—just take it in the morning or afternoon. At night, take supplements that support sleep quality and muscle relaxation, like magnesium and melatonin (which you'll find in soothing, sippable Bulletproof Sleep Collagen Protein).
Not so fast. Other experts caution against taking magnesium at the same time as other minerals. “It can interfere with absorption of other minerals, so if you take a multivitamin, calcium or zinc, take magnesium at a different time of day,” Cooperman warns.
Taking iron and calcium at the same time will cause less of the calcium to be absorbed in the intestine, because the two minerals compete with one another for absorption. If your vitamin supplement includes calcium, it would be good to take your fiber and iron in the morning and your vitamin supplement at night.
Anticonvulsants. The anticonvulsants phenobarbital and phenytoin (Dilantin, Phenytek) increase the breakdown of vitamin D and reduce calcium absorption. Atorvastatin (Lipitor). Taking vitamin D might affect the way your body processes this cholesterol drug.