From collagen powder and probiotics to prenatal vitamins and St. John\u2019s wort, the sale of vitamin, mineral, and herbal supplements is skyrocketing. In fact, according to data from the most recent National Health and Nutrition Examination Survey, an estimated 57% of Americans older than 20 took at least one dietary supplement in the past 30 days. Multivitamins, vitamin D, and omega-3 fatty acids are the most popular.<\/p>\n
Maybe you take a daily multivitamin<\/a> to enhance your overall health and wellness. Or perhaps you rely on supplements to fill in essential nutrient gaps. Either way, it\u2019s important to be aware of possible interactions. Vitamins are organic compounds that are essential in small amounts to support\u00a0 metabolism and other bodily functions. Taking certain vitamins or minerals together can affect their absorption in the body, sometimes reducing and other times improving bioavailability.<\/p>\n Additionally, some vitamins can interfere with the efficacy of medications and even increase side effects. Although measuring blood levels of several vitamins is widely available, testing for deficiencies is usually unnecessary. Here\u2019s what you need to know about using vitamin supplements wisely.<\/p>\n It is very important to read the label and the suggested dosing instructions for each supplement you are taking, advises Jenna Litt, RD, CDN<\/a>, a registered dietitian at Northwell Health\u2019s Lenox Hill Hospital<\/a> in New York. \u201cFor example, some supplements may need to be taken with food, some may be administered daily, multiple times a day, or even weekly,\u201d she says. \u201cIf you are not sure about dosage, contact your healthcare provider to ensure you are taking proper dosages.\u201d<\/p>\n It\u2019s also important to know which vitamins should not be taken together<\/i>. Here are supplements that don\u2019t go together\u2014or shouldn\u2019t be taken with food.<\/p>\n Why not together: <\/b>These two minerals work together for bone, muscle, and nerve health. Magnesium<\/a> can help promote calcium<\/a> absorption indirectly by activating vitamin D. However, large doses of calcium may interfere with the absorption of magnesium. Research <\/a>also indicates that a calcium-to-magnesium ratio above 2:1 is linked to an increased risk of metabolic, inflammatory, and cardiovascular disorders, so getting the right dose is important.<\/p>\n Recommendations:<\/b> To be sure you\u2019re taking the right amount, consult with your provider for guidance, especially since large doses of calcium and magnesium may need to be avoided or separated.<\/p>\n Why not together:<\/b> Research<\/a> shows that iron deficiency is common among adults in the U.S., with around 14% having absolute iron deficiency. Your healthcare provider may recommend taking iron supplements if you\u2019re not getting enough iron through your diet. But if you also supplement with calcium, your best bet is spacing out the doses. Calcium can temporarily reduce iron absorption<\/a>, meaning iron supplements won\u2019t be as effective.<\/p>\n Recommendations: <\/b>For best results, take iron supplements at least two hours before or after calcium supplements, dairy products, and calcium-rich foods for maximum absorption.<\/p>\n Why not together:<\/b> It\u2019s not a good idea to take your iron supplement<\/a> (or eat iron-rich foods) at the same time as green tea. That\u2019s because one of the main components in green tea, epigallocatechin gallate (EGCG), binds with iron<\/a> and reduces its absorption. A case study<\/a> linked drinking large amounts of green tea with the development of iron deficiency anemia.<\/p>\n Recommendations:<\/b> Green tea has health benefits, though, so feel free to drink it. However, drink it one to two hours before or after taking an iron supplement or eating iron-rich foods.<\/p>\n Why not together: <\/b>It\u2019s not advised to take vitamin C<\/a> and vitamin B-12<\/a> at the same time, says Litt. That\u2019s because high doses of vitamin C can reduce the amount of vitamin B12 that\u2019s absorbed and metabolized by the body, she says. However, this interaction is based on older studies<\/a> in test tubes, and studies in humans suggest there is no impact on vitamin B12 absorption<\/a>. Still, some healthcare providers recommend separating the doses out of caution.<\/p>\n Recommendations:<\/b> Most people can safely take vitamin C and vitamin B12 together, but if you\u2019re taking high-dose vitamin C supplements (1,000 mg or more), you may want to separate them by at least two hours as a precaution.<\/p>\n RELATED:<\/b> Can you take too much B12?<\/b><\/a><\/p>\n Why not together: <\/b>Most people don\u2019t need to take a copper supplement, but individuals<\/a> with celiac disease, Menkes disease (a rare genetic disorder), and those taking high amounts of zinc may. Taking high doses of vitamin C can reduce the absorption of copper. In addition, some research<\/a> in mice suggests that mixing the two supplements can cause oxidative stress and kidney damage.<\/p>\n Recommendations: <\/b>Play it safe by spacing out your copper and vitamin C supplements by two to three hours, especially if you\u2019re taking high-dose vitamin C supplements.<\/p>\n Why not together:<\/b> Vitamin E and vitamin K have opposite effects, with vitamin E acting as a blood thinner at high doses and vitamin K increasing blood clotting. Taking both vitamins could cancel out their effects. However, this interaction is more of a concern when taking high doses of vitamin E and a blood thinner like warfarin.<\/p>\n Recommendations:<\/b> It\u2019s uncommon to have a vitamin E or vitamin K deficiency, but it\u2019s important to consult a healthcare provider before taking these supplements, especially in high doses or while taking a blood thinner like warfarin.<\/p>\n Why not together:<\/b> High doses of calcium or iron can reduce zinc absorption when taken at the same time, especially on an empty stomach. Zinc is essential for immune function and wound healing, so this is worth knowing if you’re supplementing with more than one of these minerals.<\/p>\n Recommendations:<\/b> Take zinc at a different time of day than calcium or iron supplements, or pair it with a meal that doesn’t include a calcium or iron supplement dose.<\/p>\n <\/p>\nWhat vitamins should not be taken together?<\/h2>\n
Magnesium and calcium<\/h3>\n
Iron and calcium<\/h3>\n
Iron and green tea<\/h3>\n
Vitamin C and B12<\/h3>\n
Vitamin C and copper<\/h3>\n
Vitamin E and K<\/h3>\n
Calcium, iron, and zinc<\/h3>\n