What Happens to Your Body When You Take Calcium and Vitamin D Together

Taking calcium and vitamin D together is generally safe and helps support bone health under a doctor’s supervision. Excessive consumption can lead to serious health problems, such as heart and kidney problems.

Vitamin D and calcium support bone health, and vitamin D helps improve the absorption of calcium in the body. In theory, taking these supplements together may increase their bone health benefits.

Some studies have shown that moderate consumption of calcium and vitamin D supplements is safe, especially for older adults. Researchers noted that using the two supplements together may not provide significant benefits.

Additionally, a 2019 study found that taking calcium and vitamin D supplements together could increase your risk of stroke. However, more research is needed to confirm this risk.

About 98% of your body’s calcium intake is found in your bones. Having enough calcium is important for:

• Blood clotting
• Contraction and dilation of blood vessels
• Bone health
• Hormonal secretion
• Muscle function
• Nervous communication

How much you need

Adults need the following daily amounts of calcium:

• Men aged 19 to 70: 1,000 milligrams (mg)
• Men aged 71 and over: 1200 mg
• Women aged 19 to 50: 1000mg
• Women aged 51 and over: 1200 mg
• Pregnant people: 1000mg
• People who are breastfeeding: 1000mg

Vitamin D also protects your bones and supports your muscles. We also need help to:

• Calcium absorption
• How the immune system works
• Nervous communication

One of the most popular ways to get vitamin D is to get outside. Your body produces and stores vitamin D when sunlight hits your skin.

How much you need

Adults need the following daily amounts of vitamin D:

• Adults aged 19 to 70: 15 micrograms (mcg)
• Adults aged 71 and over: 20mcg
• Pregnant people: 15mcg
• People who are breastfeeding: 15mcg

It’s good to have adequate amounts of calcium and vitamin D to help your body function. Both supplements may have drug interactions. It is also possible to consume too many of these nutrients by taking supplements.

Potential drug interactions

Both supplements may interact with certain medications. Calcium supplements may interact with:

• Dolutegravir, which is an HIV medicine
• Levothyroxine, or a thyroid hormone
• Lithium, which treats bipolar disorder
• Quinolone antibiotics

Vitamin D supplements may interact with:

• Cholesterol-lowering statins
• Orlistat, or a weight loss drug
• Steroids
• Thiazide diuretics, which treat hypertension (high blood pressure)

Risks

You may have high calcium levels, but this is usually the result of illness rather than supplements. The risks of high calcium intake are:

• Arrhythmia or abnormal heart rhythm
• Heart disease-related deaths
• Nephrolithiasis (kidney stones)

Very high levels of vitamin D in the body usually come from taking too many supplements. Risks may include:

• Arrhythmia
• Death
• Renal failure

Side effects

Calcium and vitamin D supplements are not without potential side effects. You may collectively experience these side effects:

• Appetite and weight loss
• Confusion
• Constipation
• Dehydration or excessive thirst and urination
• Low phosphate levels
• Muscle weakness or poor muscle tone
• Nausea or vomiting
• Pain
• Poor kidney function
• Fatigue

The U.S. Food and Drug Administration (FDA) minimally regulates dietary supplements, which may or may not be right for you. Talk to a healthcare professional or pharmacist before you start taking supplements.

Dosage

The safest amount of calcium from your diet and supplements is 2,500 milligrams per day. Your body can better absorb calcium at 500 milligrams or less per day. You can spread the calcium supplement throughout the day.

The upper limit of vitamin D is 100 micrograms per day from your diet and supplements. Make sure supplementation alone does not reach this limit unless you have been diagnosed with vitamin D deficiency.

Consult a healthcare professional to determine if you need to take both calcium and vitamin D. Vitamin D may be available in some calcium supplements.

Timing

When you should take calcium supplements depends on the type. Take calcium carbonate supplements when you eat a meal. You can take calcium citrate supplements with or without food.

Vitamin D is fat-soluble and can therefore be broken down into fat. Take it when you eat high-fat meals to better absorb vitamin D in its supplement form.

Do not stop taking calcium and vitamin D supplements together if a healthcare professional has told you to do so. You may consider changing your diet where possible if you are concerned about your calcium and vitamin D intake and are not taking supplements.

Calcium

Many dairy products contain calcium, including cheese, milk and yogurt. Other foods you might eat include:

Vitamin D

Vitamin D is naturally available in limited food sources. Try some of these nutrient-rich options:

• Braised beef liver
• Egg yolks
• Oily fish like mackerel, salmon, trout and tuna
• Fish liver oils
• Mushrooms
• Products fortified with vitamin D, such as cereals, milk and plant-based milk