Why Certain Nutrients Shouldn't Be Taken Together

When it comes to supplements, more isn’t always better. While taking the right vitamins and minerals can significantly boost your health, combining certain nutrients may reduce their effectiveness or even cause adverse effects.

Understanding which supplements to avoid pairing is crucial for optimising your nutrient absorption and overall well-being.

Here are some key nutrient combinations you should avoid taking together, along with the reasons why:

1. Calcium and Iron

Calcium and iron are both essential minerals, but when taken together, calcium can block the absorption of iron. This happens because calcium competes with iron for absorption in the intestines. Studies show that taking as little as 300 mg of calcium with an iron supplement can reduce iron absorption by 50-60%

Tip: To maximise benefits, take calcium and iron at different times of the day, ideally, iron should be taken on an empty stomach or with vitamin C to boost its absorption.

2. Vitamin C and Vitamin B12

Vitamin C is a powerful antioxidant that plays a role in immune function and skin health, while vitamin B12 is essential for energy production and nerve function. However, high doses of vitamin C can degrade vitamin B12 in the stomach, potentially lowering its effectiveness .

Tip: If you're supplementing with both vitamins, take vitamin C at a different time from vitamin B12 to avoid interaction.

3. Vitamin K and Vitamin E

Vitamin K and vitamin E are both fat-soluble vitamins, but they can work against each other when taken in high doses. Vitamin E, when taken in excess, can interfere with vitamin K’s role in blood clotting, potentially leading to increased bleeding . For individuals on blood thinners, this interaction can be particularly concerning.

Tip: It's important to monitor your intake of these vitamins, especially if you’re on anticoagulant medications. Stick to recommended doses and consult a healthcare provider if you're considering supplementation.

4. Zinc and Copper

Zinc and copper are trace minerals that play vital roles in immune function and the formation of red blood cells. However, these two minerals compete for absorption in the body. Taking high doses of zinc can deplete your copper levels, potentially leading to a copper deficiency.

Tip: Many multi-vitamin formulations balance the ratios of zinc and copper to prevent deficiencies, but if you’re taking them separately, consider spacing them out throughout the day.

5. Calcium and Magnesium

Calcium and magnesium are often found together in supplements, especially those aimed at bone health. However, these minerals can compete for absorption when taken in large doses together. Calcium may inhibit magnesium’s absorption, and vice versa .

Tip: If you need both calcium and magnesium supplements, consider taking them at different times, or use a well-balanced formula that includes the appropriate ratio.

6. Fat-Soluble and Water-Soluble Vitamins

Fat-soluble vitamins (A, D, E, and K) and water-soluble vitamins (B vitamins and vitamin C) have different absorption pathways. Fat-soluble vitamins require dietary fat for absorption, while water-soluble vitamins dissolve in water and are absorbed directly into the bloodstream. Taking them together may reduce the efficiency of one or both .

Tip: Take fat-soluble vitamins with meals that contain healthy fats, and save your water-soluble vitamins for a different time of day.

Final Thoughts

Combining certain vitamins and minerals can reduce absorption or lead to imbalances in the body, negating the intended benefits. If you are taking multiple supplements, it’s a good idea to consult with a healthcare provider or nutritionist to create a personalised plan that optimises nutrient absorption.

By strategically timing your supplement intake and avoiding combinations that clash, you can ensure you’re getting the most out of your nutrient regimen.

References:

1. Calcium and Iron Interaction: Journal of Nutrition
2. Vitamin C and B12 Degradation: National Institutes of Health (NIH)
3. Vitamin K and Vitamin E Interaction: American Heart Association
4. Zinc and Copper Absorption: Office of Dietary Supplements, NIH
5. Calcium and Magnesium Balance: Linus Pauling Institute