What Vitamins Shouldn’t Be Taken Together?

Understanding Vitamin Interactions

We require several minerals and 13 essential vitamins for optimal functioning, some of which are fat-soluble and others water-soluble. Fat-soluble vitamins like Vitamins A, D, E, and K are stored in the body’s fatty tissue, so they are absorbed most easily when you consume them with dietary fat.

In contrast, water-soluble nutrients like Vitamin C and B vitamins are not stored by the body and are released as urine after utilization. While you can take water and fat soluble vitamins together, it is not ideal, as they are absorbed differently and this could impact efficiency.

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Additionally, certain vitamin and mineral pairings interfere with each other's absorption in the body or compete for uptake, impacting their efficiency. Which vitamins should not be taken together? Read on to learn the answer in detail.

Which Vitamins Should Not Be Taken Together?

When you are planning your supplement intake, consider what vitamins should not be taken together to avoid interactions or poor absorption. These are the key parings to stay away from:

• Copper and Zinc: High levels of zinc can decrease the amount of copper absorbed by the body and cause a deficiency in this key nutrient, according to research. For this reason, prolonged zinc supplementation is often not advised. If you take a zinc supplement, you should follow up with copper, but wait at least 2 hours or the benefits may be lost.
• Calcium, Zinc, and Magnesium: You can take these minerals together at moderate levels in a multivitamin, but high doses can be very problematic as they compete with each other for bodily absorption. Calcium especially impacts the uptake of magnesium and zinc, decreasing their efficiency. Experts recommend that you avoid taking these minerals together but rather stagger your usage.
• Vitamin C and Iron: Vitamin C increases levels of non-heme iron, and for this reason, some experts say you should take them together to optimize absorption. However, evidence indicates that taking iron and Vitamin C at the same time can lead to side effects like digestive upset and diarrhea. Taking more than prescribed high amounts of Vitamin C with iron can lead to iron overload or other medical issues like kidney stones.
• Calcium and Iron: Calcium and iron are two essential minerals for the body, but they can interfere with each other's absorption when taken together. Calcium can bind to iron in the digestive system, preventing it from being absorbed properly. This can lead to iron deficiency, which can cause fatigue, weakness, and other health problems.
• Vitamin C and Vitamin B12: These are vitamins you shouldn't take together because Vitamin C can break down B12 during digestion, for low levels of absorption. Evidence indicates that if you take both vitamins at the same time, it may decrease the amount of B12 and limit the benefits. Make sure to take them at least 2 hours apart and monitor B12 levels carefully if taking high amounts of Vitamin C.
• Vitamin E and Vitamin K: In some individuals, taking high levels of Vitamin E can cause an increase in bleeding, and Vitamin K supplementation can help with clotting. While you should take them both, do not take them together, as Vitamin E can lower the efficiency of Vitamin K and block its effects.
• Calcium Carbonate (TUMs) and Vitamin B12: Antacids like calcium carbonate (found in Tums) can interfere with the absorption of vitamin B12, potentially leading to a deficiency over time. This is because antacids can reduce the acidity of the stomach, which is necessary for the proper breakdown and absorption of vitamin B12.

Dr. LeGrand's YouTube video explains which supplements should not be taken together due to absorption conflicts, reduced effectiveness, or potential side effects. He discusses common mistakes people make when combining vitamins and minerals, such as taking calcium with iron or zinc, which can hinder absorption.

Can You Take All Your Vitamins at the Same Time?

Generally speaking, you should not take all of your vitamins at the same time, as there are interactions that can decrease the effects of key nutrients. While you can take water and fat-soluble vitamins safely together, it is not ideal, as they have different absorption mechanisms, and some combinations should be spaced out over time.

Which vitamins should not be taken together? As we mentioned, fat-soluble vitamins should be taken with food to maximize their absorption, while you can consume water-soluble vitamins with or without a meal. In addition, most mineral supplements like calcium, zinc, copper, and magnesium should be taken separately as they often compete for absorption in the body.

If you have taken mega doses of vitamins—whether early on or over several months and experience seizures, mood changes such as irritability or confusion, increased headaches or fatigue, or gastrointestinal symptoms like diarrhea, vomiting, or stomach cramps, you should seek medical attention," stresses Dr. Beth Czerwony, RD, LD.

What Vitamins Should You Consider Taking Together and Why?

While many nutrients do not mix well, some vitamin pairings complement each other, and you should consider taking them together.

B Vitamins - The B vitamins work synergically in the body to convert food into energy, produce and support brain cells, and maintain other bodily tissues.

They are essential for optimal development, and some research indicates that a high B intake in older individuals may help slow aging. You can safely take them together without negative interactions, either individually or in a B complex vitamin, and should consider doing so as they complement each other well.

Vitamin D and Vitamin K - These two vitamins work well together to support the health of the bones and cardiovascular system and should be paired ideally. Vitamin D boosts calcium absorption, and Vitamin K is responsible for the transport of calcium in the blood.

Taking Vitamin D without it can cause the calcium to be utilized less efficiently in the body. For optimal heart and bone health, make sure you are taking these two key nutrients at the same time.

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Magnesium and Vitamin D - Taking these two nutrients together boosts their function in the body, and magnesium is required for optimal Vitamin D absorption and use in the body.

Research in the American Journal of Clinical Nutrition by Qi Dai, et al indicates that insufficient levels of magnesium may disrupt Vitamin D synthesis and metabolism.

Vitamin C and Zinc - You can take Vitamin C and zinc together, and in fact, it’s highly recommended. Some research suggests that zinc may boost Vitamin C absorption.

In addition, both are potent immune-system-boosting supplements and combining them may be an excellent way to combat illness and keep you healthy.

A review of 2 studies published in the Journal of International Medical Research by S Maggini, et al concluded that short-term high-dose Vitamin C and zinc supplementation helped reduce the symptoms of the common cold.

Best Ways to Take Different Vitamins

Vitamins that should not be paired should be taken at least 2 hours apart to ensure that there is no interaction. However, there are other issues to consider, like which time of day is best for taking specific vitamins.

In the morning, a B complex is ideal, as it helps boost energy levels for the day. Some experts recommend taking Vitamin C after your morning meal. Take magnesium in the evening before you go to bed, and it may promote relaxation and enhance sleep quality.

It’s important to note that there are medications like blood thinners and antibiotics that may interact with certain vitamins, so before you supplement, check with your physician to ensure that the nutrients you are taking and the manner you are taking them are medically suitable.

What About Multivitamins?

Multivitamins combine several essential nutrients in one supplement, which is easier than taking separate vitamins daily. Although targeted treatment with key nutrients is probably more effective, less likely to cause interactions, and higher in individual dosages, taking a daily multivitamin may help resolve some nutrient deficiencies.

Multivitamins are also much less expensive than purchasing several individual products. When it comes to timing, you should take your multivitamin with water and your biggest meal of the day for optimal absorption of fat-soluble vitamins.