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August 23, 2021


Lindsay Delk, RDN
Calcium, Vitamin D, And Vitamin K For Bone Health

Fact Checked By Lindsay Delk, RDN
 August 23, 2021

Bone Health

When it comes to your diet, three main nutrients are vitally important for your bone health—calcium, vitamin D, and vitamin K.

Let’s dig into each one separately then see how they work together as a team for building healthy bones.

Why Are Healthy Bones Important?

Your bones play many roles in your body.

In addition to providing structure for your body, they protect your organs, store calcium and phosphorus, and support your muscles, tendons, and ligaments to help your body move.

Maintaining healthy bones is important for your entire lifetime.

Your bone mass increases until around age 30 as you gain new bone faster than you break down old bone.

Most people reach their peak bone mass around 30 years old.

Then, you slowly break down bone faster than you make new bone.

The key is slowing down this process as much as possible by giving your bones what they need to be healthy.



  • Why It’s Important For Healthy Bones

Many parts of your body, such as your heart, muscles, and nerves, need calcium to work properly. But when you hear the word calcium, you probably think about bones.

About 99% of the calcium in your body is in your bones (1).

Your body can’t make calcium, so you must get enough calcium from your diet. If you don’t eat enough calcium, it will be taken from your bones, which will lead to weaker bones that are easier to break.

Not enough calcium in your diet can significantly contribute to osteoporosis, and studies show that low calcium intake throughout your life can lead to more broken bones (2).

  • How Much Calcium Do You Need?

The Recommended Dietary Allowance (RDA) for calcium is 1,000 mg per day for all adults up to age 50 and men up to age 70 (3).

Women over the age of 50 and men over the age of 70 need 1,200 mg per day.

Surveys show that most people are not getting enough calcium to grow and maintain healthy bones (4).

  • Ways To Get Calcium

Good sources of calcium are milk, yogurt, cheese, green leafy vegetables (collard greens, turnip greens, broccoli, and kale), tofu, and calcium-fortified juices.

Even if you eat a healthy diet, you may have difficulty getting enough calcium.

Ask your doctor about a calcium supplement if you may not be getting your recommended amount.

Your body can only absorb 500 to 600 mg or less of calcium at a time, and calcium supplements are absorbed better if they are taken with food (5).

Vitamin D

  • Why It’s Important For Healthy Bones

Vitamin D helps your body absorb calcium. Without enough vitamin D, your bones can become thin and brittle.

If you eat enough calcium, vitamin D helps to get the calcium into your bones to make them stronger (6).

  • How Much Vitamin D Do You Need?

The RDA for vitamin D is 600 IU (15 mcg) per day for ages 1 to 70 years and 800 IU (20 mcg) per day for over 70 years (7).

Many healthcare professionals don’t think the RDA is enough.

The Endocrine Society recommends 1500–2000 IU (37.5–50 mcg) per day for all adults. Your doctor can recommend an appropriate dosage (8).

  • Ways To Get Vitamin D

Your body makes vitamin D when your skin is exposed to UV rays from the sun.

But you may have limited sun exposure, especially in some climates and seasons, or you may use sunscreen, which blocks vitamin D production.

A few foods have a good amount of vitamin D, such as cod liver oil, fatty fish, beef liver, cheese, egg yolks, mushrooms, and vitamin D-fortified milk, breakfast cereals, and orange juice.

But many people will not be able to get enough vitamin D from their diet alone.

If you’re not sure if you are getting enough vitamin D from your diet or sun exposure, talk to your doctor about a supplement.

Vitamin D has two main forms: D2 and D3. Vitamin D3 raises vitamin D levels in the blood higher and keeps them there longer than vitamin D2 (9).

Vitamin K

  • Why It’s Important For Healthy Bones

Vitamin K has roles in blood clotting and healthy bones.

Vitamin K works with vitamin D to get calcium into the right place—your bones and not your blood vessels and soft tissues.

Vitamin K is required by certain proteins to make bone tissue (10).

Osteocalcin is a protein that uses calcium to build your bones. Osteocalcin can’t work without vitamin K (11).

Some studies show that people who eat more vitamin K have stronger bones and are less likely to break a hip (12).

  • How Much Vitamin K Do You Need?

There is no RDA for vitamin K, but the adequate intake (AI) for adults is 120 mcg per day for men and 90 mcg per day for women (13).

  • Ways To Get Vitamin K

Bacteria in your gut make some vitamin K.

Vitamin K is also found in many foods, such as green leafy vegetables (spinach, kale, lettuce, and broccoli), blueberries, meat, cheese, eggs, soybeans, and vegetable oils.

However, up to 31% of adults have insufficient levels of vitamin K, so a vitamin K supplement may be necessary (14).

The vitamin K family includes vitamin K1 and vitamin K2.

Vitamin K1 is more important for blood clotting, and vitamin K2 is more important for bone health and preventing the calcification of arteries (15, 16).

MK-7 is the most effective type of vitamin K2 because of its higher bioavailability and longer half-life (17).

Higher bioavailability means that more of the vitamin is absorbed and used by your body. A longer half-life means that the vitamin stays in your body longer.

The Healthy Bones Team

Many vitamins and other nutrients depend on each other to work properly.

Calcium, vitamin D, and vitamin K are like that.

Calcium can’t get into your body well without vitamin D. And it can’t get into your bones without vitamin K.

Calcium can only make your bones stronger with the help of vitamins D and K.

One study on postmenopausal women showed that adding vitamin K to a vitamin D and calcium supplement increased bone density compared to the vitamin D and calcium supplement alone (17).

If there is not a balance between vitamin D levels and vitamin K levels, extra calcium will be deposited in your blood vessels and soft tissue instead of your bone (18).

This makes your bones weak and your blood vessels hard.

Over time, this could lead to osteoporosis and cardiovascular disease.

So, talk with your doctor to make sure you are striking a balance with your healthy bones team of calcium, vitamin D, and vitamin K.