Many people take supplements to help with health conditions or improve their well-being. Vitamins, minerals, herbs, and probiotics are all types of supplements that may aid health (FDA, 2022).
You might even take a combination of supplements. But there are certain combinations that shouldn’t be taken.
Supplements might interact not only with each other, but also with medications you may be taking. That’s why knowing the potential interactions of supplements is important.
Supplement Combinations to Avoid
Supplements can have health benefits, but they may also have health risks. For example, sometimes the ingredients in certain supplements can alter lab tests or have negative effects during surgery (FDA, 2022).
The risks that may come with taking supplements can be increased if you take more than one supplement.
Here are some supplement combinations that you should talk to a healthcare provider about—and what you what you might need to do if you take both.
Magnesium and calcium
Magnesium is a mineral that is needed to help with hundreds of your body’s processes, including muscle and nerve function, blood sugar control, and blood pressure regulation.
It is found in food like green, leafy vegetables as well as in legumes, nuts, seeds, and whole grains. It is also available in a variety of supplement forms, though taking them might not be advised (MedlinePlus, 2021).
Having low levels of magnesium has been associated with heart disease, diabetes, and osteoporosis (brittle bones). Too-low levels of magnesium is rare, but it is more likely among those who (MedlinePlus, 2021):
Have alcoholism
Have a gastrointestinal disease or surgery that causes your body to not properly absorb nutrients Have type 2 diabetes Are older Calcium is another mineral important for bone health. It can be found in foods like milk, yogurt, and cheese. In the US, calcium is under-consumed by 30% of men and 60% of women (USDA, 2020).
A supplement may be called for if there is insufficient dietary intake of the mineral. Not getting enough calcium can lead to reduced bone strength and osteoporosis (NIH, 2022).
Taking both minerals together can result in a decreased absorption of magnesium if you take very high doses of calcium (2600mg daily).
It’s recommended that people at high risk for magnesium deficiency who take calcium supplements take the calcium at bedtime instead of during a meal.
That’s because taking the calcium supplement during a meal could negatively affect how much dietary magnesium is being taken in (NMD, 2022).
Vitamin C and copper
Vitamin C helps create collagen, a protein that helps your wounds heal. People take vitamin C supplements for various reasons, including to help fight infection, reduce pain after surgery, or lower blood pressure (NMD, 2022).
The mineral copper is involved in energy production and helps create your connective tissue, which gives structure to the body. People with cardiovascular disease may take copper supplements as they have been shown to help change blood lipid levels, lowering the risk for atherosclerotic cardiovascular disease. The supplement has also been used in Alzheimer’s disease since copper deficiency has been seen among those with the condition (NIH, 2021).
There is some evidence that taking high amounts of vitamin C (over 1,500mg) can reduce copper absorption. The finding was based on research completed among young men, and it is likely that it only affects people whose intake of copper is low (NMD, 2022).
Iron and green tea
Iron is a mineral that is an essential part of red blood cells that transfers oxygen from the lungs to the tissues. Iron supplements are typically recommended for people who have iron-deficiency anemia, cancer, and certain gastrointestinal disorders, as well as for those who are pregnant (NIH, 2022).