Calcium and Vitamin D

Calcium and vitamin D are essential to building strong, dense bones both when you’re young and as you age. The information included here will help you learn all about calcium and vitamin D – the two most important nutrients for bone health.

It is equally important to continue getting enough calcium and vitamin D to prevent further bone loss if you are prescribed a medication to prevent bone loss or fractures.

What is Calcium and What Does it Do?

A calcium-rich diet (including dairy, nuts, leafy greens and fish) helps to build and protect your bones.

Calcium is a mineral that is necessary for life. In addition to building bones and keeping them healthy, calcium enables our blood to clot, our muscles to contract, and our heart to beat. About 99% of the calcium in our bodies is in our bones and teeth.

Every day, we lose calcium through our skin, nails, hair, sweat, urine and feces. Our bodies cannot produce its own calcium. That’s why it’s important to get enough calcium from the food we eat. When we don’t get the calcium our body needs, it is taken from our bones. This imbalance causes bones get weak and easier to break.

Too many Americans fall short of getting the amount of calcium they need every day and that can lead to bone loss, low bone density and even broken bones.

How Much Calcium Do You Need?

The amount of calcium you need every day depends on your age and sex.

How Much Calcium Do You Eat?

Use the International Osteoporosis Foundation’s Calcium Calculator to find out.

Sources of Calcium

Calcium-Rich Food Sources

Food is the best source of calcium. Dairy products, such as milk, yogurt, and cheese are high in calcium. Certain green vegetables and other foods contain calcium in smaller amounts. Some juices, breakfast foods, soymilk, cereals, snacks, breads and bottled water have added calcium in fortified foods. If you consume soymilk, other nut based milks ( i.e.: almond or oat milk) or another liquid that is fortified with calcium, be sure to shake the container well as calcium can settle to the bottom.

A simple way to add calcium to many foods is to add a single tablespoon of nonfat powdered milk, which contains about 50 mg of calcium. It is easy to add a few tablespoons to almost any recipe.

Reading Food Labels – How Much Calcium Am I Getting?

To determine how much calcium is in a particular food, check the nutrition facts panel for the daily value (DV). Food labels list calcium as a percentage of the DV. This amount is based on 1,000 mg of calcium per day. For example:

• 30% DV of calcium equals 300 mg of calcium.
• 20% DV of calcium equals 200 mg of calcium.
• 15% DV of calcium equals 150 mg of calcium.

Calcium Supplements

The amount of calcium you need from a supplement depends on how much you get from food. Try to get the daily amount recommended from food and only supplement as needed to achieve the recommend daily allowance. In general, you shouldn’t take excess supplements that you don’t need. If you get enough calcium from foods, you may not need to take a supplement. There is no added benefit to taking more calcium than you need. Doing so may even carry some risks such as constipation, kidney stones and perhaps excess heart calcification.

Calcium supplements are available without a prescription in a wide range of preparations (including chewable tablets, gummy preparations, powders and liquid) and in varying amounts and sizes. The best supplement is the one that meets your needs for tolerability, convenience, cost, and availability. When choosing a supplement, keep the following in mind:

• Choose brand-name supplements with proven reliability. Look for labels that state “purified” or have the USP (United States Pharmacopeia) symbol. The “USP Verified Mark” on the supplement label means that the USP has tested and found the calcium supplement to meet its standards for purity and quality.
• Read the product label carefully to determine the amount of elemental calcium, which is the actual amount of calcium in the supplement, as well as how many doses or pills you have to take. When reading the label, pay close attention to the “amount per serving” and “serving size.”
• Calcium is absorbed best when taken in amounts of 500 – 600 mg or less. This is the case for both foods and supplements. Try to get your calcium-rich foods and/or supplements in small amounts throughout the day, preferably with a meal. While it’s not recommended, taking your calcium all at once is better than not taking it at all.
• Take (most) calcium supplements with food. Eating food produces stomach acid that helps your body absorb most calcium supplements. The one exception to the rule is calcium citrate, which can absorb well when taken with or without food.
• When starting a new calcium supplement, start with a smaller amount to better tolerate it. When switching supplements, try starting with 200-300 mg every day for a week, and drink an extra 6-8 ounces of water with it. Then gradually add more calcium each week.
• Side effects from calcium supplements, such as gas or constipation may occur or worsen. If increasing fluids in your diet and obtaining enough fiber does not solve the problem, try another type or brand of calcium. It may require trial and error to find the right supplement for you, but fortunately there are many choices.
• Talk with your healthcare provider or pharmacist about possible interactions between prescription or over-the-counter medications and calcium supplements.

What is Vitamin D and What Does it Do?

Vitamin D is a fat soluble vitamin and plays an important role in protecting your bones, both by helping your body absorb calcium and by supporting muscles needed to avoid falls. Children need vitamin D to build strong bones, and adults need it to keep their bones strong and healthy.

How Much Vitamin D Do You Need?

Sources of Vitamin D

There are three ways to get vitamin D:

• Sunlight
• Food
• Supplements

Sunlight

Your skin makes vitamin D in reaction to sunlight and stores it in fat for later use. How much vitamin D your skin can produce depends on time of day, season, latitude, skin pigmentation, age, and other factors.

There are many reasons people do not have enough vitamin D. As we age, our skin loses its ability to generate vitamin D. People who live in cities or in institutional settings like nursing homes spend too little time outdoors. Even people who spend time outdoors often use sunscreen to prevent skin cancer. Sunscreen with an SPF as low as 8 reduces vitamin D production by 95 percent.

Vitamin D in Food

Vitamin D is found in very few foods. Sources include fatty fish like wild-caught mackerel, salmon, and tuna. Vitamin D is added to milk and other dairy products, orange juice, soymilk, and fortified cereals.

Check the food label to see if vitamin D has been added to a particular product. One eight-ounce serving of milk usually has 25% of the daily value (DV) of vitamin D. The DV is based on a total daily intake of 400 IU of vitamin D. So, a serving of milk with 25% of the DV of vitamin D contains 100 IU.

It is often difficult to get all the vitamin D you need from sunlight and food alone. Some people with underlying conditions may need to take vitamin D supplements to support bone health.

Vitamin D Supplements

Healthy adults with no vitamin D deficiency should be able to get adequate amounts of vitamin D from sunlight and by consuming a well-balanced diet. People with osteoporosis and low bone mass should discuss their vitamin D levels with their healthcare provider to ensure they are getting an optimal amount.

Before adding a vitamin D supplement, check to see if any of the other supplements, multivitamins, or medications you take contain vitamin D. Many calcium supplements also contain some vitamin D.

There are two types of vitamin D supplements. They are vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). Both types are good for bone health.

Vitamin D supplements can be taken with or without food and the full amount can be taken at one time. While your body needs vitamin D to absorb calcium, you do not need to take vitamin D at the same time as a calcium supplement. If you need help choosing a vitamin D supplement, ask your healthcare provider to recommend one.

Vitamin D Deficiency: Are You at Risk?

Vitamin D deficiency occurs when you are not getting the recommended level of vitamin D over time. Certain people are at higher risk for vitamin D deficiency, including:

• People who spend little time in the sun or those who regularly cover up when outdoors;
• People living in nursing homes or other institutions or who are homebound;
• People with certain medical conditions such as Celiac disease and inflammatory bowel disease;
• People taking medicines that affect vitamin D levels such as certain anti-seizure medicines;
• People with very dark skin;
• Obese or very overweight people; and
• Older adults with certain risk factors.

Talk to your healthcare provider if you have any of these risk factors. If you have osteoporosis, low bone mass or another medical condition that can lead to bone loss and also have a vitamin D deficiency, your healthcare provider may recommend vitamin D supplement to bring you up to a healthy 25-hydroxy vitamin D level which is generally agreed upon by medical societies to be between 30-60 ng/ml.

A Guide to Calcium-Rich Foods

We all know that milk is a great source of calcium, but you may be surprised by all the different foods you can work into your diet to reach your daily recommended amount of calcium. Use the guide below to get ideas of additional calcium-rich foods to add to your weekly shopping list.

Last Reviewed 5/23/2023