If you're one of those people who pop a handful of vitamins every day in hopes of improving your health, it's important to know that there are risks involved if you don't follow the proper guidelines. While vitamins can help fill nutrient gaps in your diet, certain vitamins should not be taken together in high doses due to negative interactions and harmful effects.
Specific vitamins and minerals should not be taken together due to negative interactions and harmful effects, especially in high doses.
To choose the right vitamins for health optimization, start with identifying which nutrients you may be deficient in through a blood test.
The more vitamins taken at once, the higher the risk of interactions between the supplements, which can lead to adverse effects, such as nausea, vomiting, or stomach upset.
If you are on any medication or you plan to take several supplements together, consult your healthcare provider or registered dietitian to prevent any potential negative effects.
In this article, we will explore which vitamin and mineral supplements should not be taken together and provide practical advice on the dos and don'ts of supplement use to help you make informed decisions about your health.
Which vitamins should be taken together?
Some vitamins should be taken together to work properly or to improve effectiveness. While certain nutrient combinations may enhance absorption or provide synergistic health benefits, it's important to note that a balanced and varied diet is still the best way to obtain all the necessary vitamins and minerals. Below, we list 6 vitamin combinations that are often recommended for optimal health.
Vitamin D and calcium
Vitamin D and calcium are two nutrients that work hand in hand. Vitamin D helps the body absorb calcium, and calcium is essential for strong bone health and teeth.
Vitamin E and selenium
Both vitamin E and selenium are powerful antioxidants that help protect cells from damage. Studies have shown that consuming these nutrients together may have a synergistic effect on reducing inflammation and decreasing the risk of chronic diseases, including cancer.
Vitamin D and K
In 2020, a meta-analysis of eight randomized controlled trials with 971 subjects concluded that vitamin D and K in combination could induce better effects on improving total bone mineral density.
Vitamin C and magnesium
Findings show that taking vitamin C together with magnesium has synergistic benefits, including enhancing the anti-cancer effects of vitamin C and helping in alleviating joint pain and osteoarthritis.
Vitamin D and magnesium
Because magnesium assists in the activation of vitamin D, scientists recommend taking them together. They work together to support bone health, immune function, and overall health. Additionally, magnesium helps improve vitamin D absorption and also reduces the risk of vitamin D toxicity.
Multivitamin and vitamin D
If your multivitamin does not contain vitamin D, doctors highly recommend adding it due to its many health benefits in optimizing body function and reducing the risks of chronic diseases.
What vitamins should not be taken together?
In general, you can take vitamins together safely as long as they are within recommended dosages and instructions. However, there are some vitamins and minerals that should not be taken in combination, with noted undesirable effects, especially in high doses.
Calcium and iron
Calcium can inhibit iron absorption, so it's recommended to avoid taking these supplements together to prevent the development of iron-deficiency anemia. If you need to take both, it's best to take them at different times of the day.
Calcium and magnesium
While somebody may take calcium and magnesium together, high doses of calcium decrease magnesium absorption, so it's best to avoid taking them together at the same time.
Vitamin C and copper
High doses of vitamin C can interfere with copper absorption, which may lead to copper deficiency, so it's best to avoid taking them together. Most recent findings even show that this combination may induce systemic oxidative stress and kidney injury. If you decide to take them together, consume both at different times of the day.
Vitamin C and iron
Vitamin C can enhance the absorption of iron, so people with hemochromatosis or other conditions where they have excess iron in their bodies should not take them together as it may lead to harmful reactions.
Vitamin A and vitamin E
While both are fine in adequate levels, taking high doses of vitamin A and E together is harmful. For example, excess vitamin A may accumulate in the liver, leading to liver toxicity and injury. While excessive vitamin E intake increases the risk of bleeding and interferes with blood clotting.
How to choose the right vitamins
Choosing the right vitamins can be overwhelming, with so many options available. The best way to start is to identify which nutrients you may be deficient in through a blood test. This will help you prioritize which vitamins to focus on.
Here are some practical tips for choosing the right vitamins:
- Talk to your healthcare provider or a registered dietitian to determine which vitamins you may need based on your health status, lifestyle, and dietary intake.
- Choose reputable brands with a track record of producing high-quality supplements.
- Look for vitamins that are third-party tested (e.g., NSF, USP, BSCG) for purity and potency to ensure they contain what they claim and are free of contaminants.
- Choose vitamins in forms that are most easily absorbed and utilized by your body, such as methylated B vitamins, chelated minerals, and vitamin D3.
- Consider the dosage and form of the vitamin. Some vitamins may be better absorbed in lower doses throughout the day, while others may be best taken in a single dose.
Can you take too many vitamins?
It's important to be mindful of potential vitamin interactions. Some interactions may lead to decreased absorption or other negative effects.
The higher the number of vitamins taken at once, the higher the risk of interactions between the supplements, which can affect their absorption and effectiveness. For example, the effect of taking five different vitamins at once will depend on the specific vitamins and doses being taken. Hence, to ensure the safe and effective use of multiple vitamins, consult with a healthcare provider to develop an individualized supplement plan based on personal needs and goals.
If you take too many vitamins at once, it may lead to adverse effects, such as the following:
- Blurred vision
- Abdominal cramps
- Increased bleeding
- Organ damage, like in kidney/liver (in severe cases)
Water-soluble vs. fat-soluble vitamins
Vitamins are categorized as water-soluble or fat-soluble, which impacts their absorption, storage, and excretion in the body. Water-soluble vitamins and fat-soluble vitamins are absorbed and metabolized differently in the body.
- Water-soluble vitamins. Should be taken together and with a meal to enhance absorption.
- Fat-soluble vitamins. Should be taken with a source of dietary fat, such as a meal containing healthy fats like avocado or nuts, to improve absorption.
In general, it's best to take water-soluble vitamins and fat-soluble vitamins separately to maximize absorption and reduce the risk of toxicity.
Here's a table outlining the differences between water-soluble and fat-soluble vitamins:
|Dissolves in water
|Dissolves in fat
|Storage in the body
|Not stored, excreted in urine
|Stored in fatty tissues and liver
|Risk of toxicity
|Generally low risk
|Risk of toxicity with excessive intake
|Absorption in the body
|Absorbed directly into bloodstream
|Absorbed along with dietary fat through the lymphatic system
|Need to be consumed regularly
|Can be stored for longer periods of time in the body
What to consider when taking vitamins
Since it's essential to be mindful of counterproductive interactions among supplements, healthcare professionals recommend a consultation to avoid unwanted side effects. Meanwhile, below are some general dos and don'ts for taking vitamins.
Can you take zinc and magnesium together?
Yes, you can take zinc and magnesium together. They have been shown to have a synergistic effect on immune function, wound healing, and overall health. However, taking too much zinc can interfere with magnesium absorption, so it's important to maintain proper dosage levels.
Can you take vitamin D on an empty stomach?
Yes, you can take vitamin D on an empty stomach. Vitamin D is a fat-soluble vitamin, so it's absorbed into the body along with dietary fat. However, taking vitamin D with a meal that contains fat may help enhance its absorption.
Can you take vitamin B12 and vitamin D together?
Yes, it's generally safe to take vitamin B12 and vitamin D together. These vitamins may work synergistically to support various aspects of health.
- International Journal for Vitamin and Nutrition Research. Calcium and iron absorption--mechanisms and public health relevance.
- American Journal of Physiology. Effect of calcium on magnesium absorption.
- Biomolecules. The Combined Administration of Vitamin C and Copper Induces a Systemic Oxidative Stress and Kidney Injury.
- International Journal for Vitamin and Nutrition Research. High-dose Vitamin C: A Risk for Persons with High Iron Stores?
- National Institute of Diabetes and Digestive and Kidney Diseases. LiverTox: Clinical and Research Information on Drug-Induced Liver Injury.
- StatPearls. Vitamin E Toxicity.
- Novartis Foundation Symposia. Calcium and vitamin D.