Taking calcium and vitamin D together is generally safe and helps support bone health when supervised by a doctor. Excess intake can cause serious health issues like heart and kidney issues.
Both vitamin D and calcium support bone health, and vitamin D helps improve calcium absorption in the body. In theory, taking these supplements together may compound their benefits for bone health.
Some studies have found that using calcium and vitamin D supplements is safe in moderation, particularly for older adults. Researchers noted the use of both supplements together may not have a significant benefit.
Also, a 2019 study found that taking calcium and vitamin D supplements together might increase your risk of stroke. However, more research is needed to confirm this risk.
About 98% of your body’s calcium supply can be found in your bones. Having enough calcium is important for:
- Blood clotting
- Blood vessel contraction and dilation
- Bone health
- Hormonal secretion
- Muscle function
- Nerve communication
How Much You Need
Adults need the following daily amounts of calcium:
- Men aged 19-70 years old: 1,000 milligrams (mg)
- Men aged 71 years and older: 1,200 mg
- Women aged 19-50 years old: 1,000 mg
- Women aged 51 years and older: 1,200 mg
- Pregnant people: 1,000 mg
- Breastfeeding people: 1,000 mg
Vitamin D also protects your bones and supports your muscles. It’s also necessary to help with:
- Calcium absorption
- Immune system functioning
- Nerve communication
One of the most popular ways to get vitamin D is going outside. Your body makes and stores vitamin D when sunlight reaches your skin.
How Much You Need
Adults need the following daily amounts of vitamin D:
- Adults aged 19-70 years old: 15 micrograms (mcg)
- Adults aged 71 years and older: 20 mcg
- Pregnant people: 15 mcg
- Breastfeeding people: 15 mcg
It’s good to have adequate amounts of calcium and vitamin D to help your body function. Both supplements can have drug interactions. It’s also possible to have too much of these nutrients from taking supplements.
Potential Drug Interactions
Both supplements can interact with certain medications. Calcium supplements might have interactions with:
- Dolutegravir, which is an HIV medicine
- Levothyroxine, or a thyroid hormone
- Lithium, which treats bipolar disorder
- Quinolone antibiotics
Vitamin D supplements can have interactions with:
- Cholesterol-lowering statins
- Orlistat, or a weight loss drug
- Steroids
- Thiazide diuretics, which treat hypertension (high blood pressure)
Risks
You may have high levels of calcium, but it’s usually the result of a condition rather than supplements. The risks of high calcium intake are:
- Arrhythmia, or an abnormal heart rhythm
- Heart disease-related death
- Nephrolithiasis (kidney stones)
Very high levels of vitamin D in the body usually come from taking too many supplements. Risks may include:
- Arrhythmia
- Death
- Kidney failure
Side Effects
Calcium and vitamin D supplements do not come without potential side effects. You may collectively experience these side effects:
- Appetite and weight loss
- Confusion
- Constipation
- Dehydration or excessive thirst and urination
- Low levels of phosphate
- Muscle weakness or poor muscle tone
- Nausea or vomiting
- Pain
- Poor kidney function
- Tiredness
The U.S. Food and Drug Administration (FDA) minimally regulates dietary supplements, which may or may not be suitable for you. Speak with a healthcare provider or pharmacist before you start any supplements.
Dosage
The safest amount of calcium from your diet and supplements is 2,500 milligrams daily. Your body can best absorb calcium at 500 milligrams or less daily. You may spread calcium supplementation throughout the day.
The upper limit for vitamin D is 100 micrograms daily from your diet and supplements. Ensure supplementation alone does not reach this limit unless you have been diagnosed with vitamin D deficiency.
Consult a healthcare provider to determine if you need to take both calcium and vitamin D together. Vitamin D may be available in some calcium supplements.
Timing
When you need to take calcium supplements depends on the type. Take calcium carbonate supplements when you are eating a meal. You can take calcium citrate supplements with or without food.
Vitamin D is fat-soluble, so it can break down in fat. Take it when eating meals with fat content to best absorb vitamin D in its supplement form.
Do not stop taking calcium and vitamin D supplements together if a healthcare provider has instructed it. You may consider making dietary changes where possible if you are worried about your calcium and vitamin D intake and do not take supplements.
Calcium
Many dairy products have calcium, including cheese, milk, and yogurt. Other foods you could 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
- Fatty fish like mackerel, salmon, trout, and tuna
- Fish liver oils
- Mushrooms
- Vitamin D-fortified products, such as cereals, milk, and plant-based milk
