If you take vitamin D supplements to treat any deficiencies, it’s essential to know which other supplements may interfere with vitamin D’s absorption, effectiveness, and how it’s metabolized.
Why it may interfere: You need magnesium to activate vitamin D, but excess levels of magnesium can disrupt the balance of calcium in your body.
What to do instead: “If you’re taking magnesium, vitamin D, and calcium supplements, try spacing out the magnesium and calcium doses by a few hours to avoid absorption competition,” Theresa Gentile, RDN, CDN, and spokesperson for the Academy of Nutrition and Dietetics, told Health.
Gentile also recommends considering a food-first approach with magnesium. Natural food sources of magnesium include leafy greens, nuts, seeds, whole grains, and beans.
Why it may interfere: Some studies show that taking calcium and vitamin D supplements together may be good for bone health. However, while calcium and vitamin D are safe to take together, very high doses of calcium may compete with the metabolism of vitamin D and other nutrients.
What to do instead: If you need to take higher doses of calcium, spacing out when you take your vitamin D and calcium supplements throughout the day can help counteract any potential effects on vitamin D metabolism.
Why it may interfere: Research shows that an imbalance between supplementary vitamin D and vitamin K may lead to excess deposits of calcium into vascular tissue instead of bone. Over time, this could cause conditions such as atherosclerosis (the gradual thickening or hardening of the arteries), which could lead to a heart attack or stroke.
What to do instead: Studies show that taking the right concentrations of vitamin K2 and vitamin D is beneficial, especially when it comes to cardiovascular and bone health. Speak to a healthcare provider before adding these to your daily routine, since the optimal dosage for each will depend on your health goals and needs.
Why it may interfere: Excessive amounts of supplementary vitamin A may counteract the benefits of supplementary vitamin D on bone health. “Since both vitamin A and vitamin D are fat-soluble vitamins, they share absorption pathways and compete for the same receptors affecting calcium metabolism,” said Gentile.
What to do instead: “Balance is more important than avoidance,” said Gentile. “Both vitamin A and D are absorbed better with a fat-containing meal.” Gentile also recommends consuming vitamin A naturally from foods such as carrots, sweet potatoes, spinach, and kale, as these sources provide beta-carotene, which converts to vitamin A only as needed.
“If your multivitamin contains vitamin A, look for a supplement with vitamin A mostly in the form of beta-carotene (not retinyl palmitate or retinyl acetate),” added Gentile.
Vitamin D is safe to take with many other supplements; however, there are some important considerations with specific supplements, such as magnesium, calcium, vitamin K, and vitamin A.
Before adding a new supplement or making any changes to your existing supplement routine, speak to a healthcare provider–such as a registered dietitian or doctor–to determine what’s best for you. By using the proper dosages and timing of these supplements, you can prevent potential interferences and ensure optimal absorption, effectiveness, and nutrient metabolism.
