When to take Calcium | PlanYourVitamins.com

What is calcium good for?

Short answer: Calcium has potential benefits for bone health, muscle function, the nervous system and cardiovascular health.

Did you know that calcium is the most abundant mineral in the human body? I had never stopped to consider this, but it makes perfect sense, as we are essentially skeletons draped with accessories.

Role in bone health

Of course, we are all trained from an early age to associate generous dietary calcium intake with healthy bones, and while it is true that 99% of the body’s calcium is indeed found in our bones and teeth, calcium intake does not directly correlate with bone formation, as there is a whole myriad of dependencies, processes and interactions involved that incorporate the activity of many other nutrients, including magnesium, vitamin C, vitamin D, vitamin K and collagen.

Role in muscle function

Aside from bone health, calcium plays an equally important role in our nervous system, assisting in the communication of signals from the brain to the rest of the body, regulating muscle contraction, and perhaps most importantly, our heartbeat.

It works like this. When a nerve is targetted to stimulate a specific muscle, the body then releases calcium within the muscle which assists the proteins in performing the required contraction. When the contraction has ended and the muscle can be relaxed, the body then removes the calcium from the muscle, resetting it. And all of this can happen in the time it takes to snap your fingers.

In addition to calcium's well known role in bone health, it also plays a key function in muscle contraction.

Other benefits of calcium

Calcium is also known to play a fundamental role in blood clotting, which is a complex process that involves a broad range of chemicals.

Aside from bone, blood and muscle health, emerging studies suggest that calcium, especially when paired with vitamin D, could have significant benefits in other aspects of our health, perhaps even protecting against diseases such as cancer and diabetes, or reducing the risk of developing conditions such as high blood pressure.

Precautions regarding calcium supplementation

All that said, in my opinion you should only take calcium supplements if explicitly advised to do so by your trusted healthcare practitioner, as supplemental doses of calcium can cause an excess of calcium in the blood, which in turn could potentially result in calcium being deposited where it shouldn't be, such as in your artery walls. Many types of supplement are handled by our body just fine when taken in excess, but calcium supplements aren't one of them.

It's actually very easy to achieve sufficient levels of calcium through diet alone, and the human body already does a miraculous job of distributing the calcium obtained through your diet precisely to where it is needed. It's advisable to not disrupt that process, unless you are absolutely certain that you know what you are doing!

When should I take calcium?

Short answer: Calcium is best taken with breakfast, or with the first meal of the day.

The best time to take calcium supplements can depend on the particular type of calcium. For example, calcium citrate can be taken without a meal if required, but calcium carbonate will benefit from the stomach's acid during digestion at mealtime for absorption. By default, or if you are not certain, you can safely take your calcium supplements with a meal.

Also, given its important role in muscle function, as well as its vital interaction with vitamin D for bone health, the best time to take calcium is early in the day, making breakfast time the perfect opportunity.

What should I avoid taking calcium with?

Short answer: Avoid taking calcium supplements at the same time as iron, L-lysine, magnesium, manganese, multivitamin, vitamin D or zinc.

Avoid with magnesium

While it is true that our bodies require several other vitamins and minerals in order for calcium to be properly absorbed and distributed to where it is needed, including magnesium, vitamin D and vitamin K, it is not actually necessary to take them at the same time, and magnesium is actually known to compete for absorption with calcium.

Specifically, studies have found that calcium competes with magnesium for intestinal absorption and transport pathways.

Avoid with vitamin D

Also, while calcium and vitamin D are often recommended to be taken together, and sometimes even paired together within the same supplement, taking supplemental doses of both can lead to an excessive amount of calcium in the blood, a condition known as hypercalcemia.

This can lead to an increased risk of kidney stones, or even cardiovascular issues. One study revealed that there is a significant increase in the risk of suffering a stroke when calcium supplements are taken in combination with vitamin D supplements.

Avoid with zinc, iron or manganese

Another study demonstrated that zinc absorption was reduced by up to 50% when a calcium supplement was also taken at the same time.

Another mineral that has reduced absorption when combined with calcium is manganese. In one set of studies, calcium supplementation was found to decrease manganese bioavailability in healthy adults.

It is also known that calcium can affect the absorption of iron.

Avoid with L-lysine

Conversely, L-lysine can actually increase the amount of calcium that is absorbed by the body, therefore it is recommended to avoid taking any significant amount of calcium while taking lysine supplements in order to avoid an excessive presence of calcium in the blood.

Avoid with multivitamin

While it should be avoided to take calcium together with vitamin D or magnesium, both core ingredients of any multivitamin supplement, it is also advisable to not "stack" supplements that contain calcium, as excessive calcium intake can lead to calcium being deposited in places where it doesn't belong, including your arteries.

What are natural sources of calcium?

If you are interested in achieving your daily calcium intake through your diet, rich sources of calcium include:

Milk
Cheese
Yoghurt
Seeds
Nuts
Whey protein
Legumes
Leafy greens

It's important to remember that some varieties of leafy greens, such as spinach and rhubarb, are extremely high in oxalates. Oxalates are naturally occurring compounds that can be found in many plants that are able to bind to calcium and impair its absorption.

Calcium data sources & further reading

Last updated by Asklepios on 30th January, 2025