What Vitamins Should Not Be Taken Together?

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Many people pop their morning vitamins without considering whether taking them all at the same time is truly the best approach. Scientists have long known that some substances counteract each other — it’s why women who use hormonal contraception must take additional measures to prevent pregnancy when on antibiotics. Do some vitamins and minerals cancel out each others’ efficacy? What vitamins should not be taken together, if any?

While some vitamins and minerals work together — the body cannot process calcium without adequate levels of vitamin D. for example — others can negate the beneficial effects of certain other supplements. Here’s what to know about supplements to avoid mixing to achieve optimal health.

What Vitamins Should Not Be Taken Together?

What vitamins should not be taken together, and what happens when they are? Don’t toss away that bottle of One-A-Day yet. Taking most commercial multivitamins containing combinations of different nutrients work for the majority of individuals. Problems with mixing substances occur in those who use more than the recommended daily allowance of certain supplements to remedy a health condition.

Look at the labels of many multi-supplements at the local grocery. Many of them contain both vitamin A and vitamin B3, or niacin. For those not suffering from heart disease or elevated stroke risk, this type of supplementation works fine.

However, physicians often prescribe niacin supplements for those with high cholesterol to lower their risk of a heart attack. In such cases, taking vitamin A at the same time as niacin may negate the cardiac benefits. It’s best to take such supplements at opposite ends of the day.

Many people today turn to supplemental vitamin B-12 when they find their energy levels lagging, as the nutrient helps the body break down food into fuel more efficiently. However, taking vitamin C at the same time can negate these enlivening effects. Unless working a third-shift schedule, most people sleep at night, so try taking additional B-12 supplements at lunch instead of with that morning cup of orange juice. As a bonus, this may help stave off the 3 p.m. doldrums.

Magnesium and calcium make the list of what vitamins should not be taken together, too. While both minerals play key roles in protecting bone strength, when taken together, they cancel each other out as the body competes over which to absorb. As menstruating women often find themselves battling food cravings, try taking these supplements at least two hours apart for maximum effectiveness instead of caving in to the call of chocolate.

Calcium also impacts the absorption of iron. As a result of menstruation, many more women than men experience anemia, or iron deficiency. Space iron and calcium supplements at least two hours apart from each other to reap the greatest benefits. Calcium also interferes with the absorption of phosphorous. Research indicates women who supplement with magnesium and phosphorus together decrease their stroke risk, so getting in the habit of taking these independent of calcium makes sense even when it’s not period week.

Other Considerations with Certain Supplements

Just as certain vitamins should not be taken together, neither should some other common supplements. Many women, for example, turn to evening primrose oil for reproductive health benefits, but doing so while on an aspirin regimen can result in greater risks of gastrointestinal bleeding.

The four fat-soluble vitamins A, D, E and K absorb best when enjoyed with a meal high in fats. Take care with these supplements, as the body can retain them for long periods, which can cause toxicity if too much is taken. Take these vitamins with a nice dinner of a fatty fish like salmon for maximum impact.

Melatonin has enjoyed a healthy reputation for regulating sleep cycles of those suffering from insomnia. However, taking this supplement in conjunction with sleep medicines or certain anxiety medications can lead to excessive sleepiness. Those taking prescription meds for certain heart conditions should check with their doctor before taking melatonin, as it can interfere with many common blood thinners.

Some swear by zinc to ward off colds and the flu, but taking this supplement while on antibiotics can minimize the drugs’ effectiveness. If bacterial infections like strep are diagnosed, hold off on zinc supplementation until all medication has been taken according to the doctor’s instructions. Zinc can also interfere with some birth control pills, so women not ready to start a family should have a chat with their gynecologist before supplementing with this mineral.

Taking Vitamins to Help, Not Hurt, Health

People often take vitamin and mineral supplements to increase their overall energy levels and decrease their chances of developing certain disorders. Some physicians suggest complementing medical therapy with over-the-counter remedies. However, because too much of one substance may mean not getting enough of another, women can take better control of their health by discussing everything they regularly take with their doctor to decrease the chances of adverse effects.

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