Bone Health and the Vitamin D – K Connection

According to the Osteoporosis Foundation, one in two women and one in four men will break a bone in their lifetime due to osteoporosis. For women, the incidence is greater than that of a heart attack, stroke, and breast cancer combined.¹

But before you reach for that glass of calcium-rich milk, let’s delve a little deeper into the world of bones—what they are, how they change over time, and which nutrients may help provide support.

What Are Bones?

You rely on bones and joints to support your body and help you navigate the world. But what are your bones actually made of? Bones are made up of a framework of a protein called collagen, along with a mineral called calcium phosphate that makes the framework hard and strong. They are built to withstand great stress from activities like walking, running, and jumping. What you might not know, however, is that your body removes old bone and replaces it with new bone. This means that your bones are constantly changing.

When you are young, bone is replaced much more quickly than it is lost. This is the time when you are building stronger, denser bones. Around age 30, you reach your peak bone mass. After reaching this peak mass, your body replaces about as much bone as it loses for a while. But around age 40, this process slows down and less bone is replaced. Over time, this causes the bones to become thinner and weaker, increasing the risk of osteoporosis. If bone thinning makes your bone density drop below normal, you have what is called osteopenia. And if bone thinning becomes more severe, you’ll be diagnosed with osteoporosis.

Unfortunately, being female puts you at a greater risk of developing osteoporosis and broken bones. One reason is that women tend to have smaller, thinner bones than men. Another reason is that  estrogen, a hormone that protects bones, drop significantly after a women reaches menopause. And this can lead to bone loss.

Ethnicity also plays a role in your risk. Here are some quick stats on how osteoporosis affects different races:²

Caucasian women. Twenty percent of Caucasian women age 50 and older are estimated to have osteoporosis; what’s more, between the ages of 20 and 80, Caucasian women lose 1/3 of their bone-mineral density in their hip.

Asian American women. About 20 percent of Asian-American women age 50 or older are estimated to have osteoporosis. About 90 percent of Asian Americans adults are lactose intolerant, which can make it difficult to get enough calcium.

African American women. Five percent of African American women older than 50 are estimated to have osteoporosis;one reason for this is that about 70 percent of African Americans are lactose intolerant. This can make it difficult to get enough calcium.

Latina women. Ten percent of Latina women have osteoporosis, and half of all Latina women older than 50 have low bone mass. This means their bones are getting weaker but they don’t yet have osteoporosis.

Other Factors that Affect Bone Health

There are a number of factors that can affect bone health beyond gender and race. For example:

• The amount of calcium in your diet. A diet low in calcium contributes to diminished bone density, early bone loss, and an increased risk of fractures.
• A sedentary lifestyle. People who are physically inactive have a higher risk of osteoporosis than folks who are more active.
• Tobacco and alcohol use. Some research suggests that tobacco use contributes to weak bones.³ Also, regularly having more than one alcoholic beverage per day for women and more than two for men may increase the risk of osteoporosis.
• You are at risk if you are extremely thin (with a BMI index of 19 or less) or have a small body frame because you may have less bone mass to draw from as you age.

How to Build Stronger Bones

Several simple steps can help prevent or slow down bone loss. One thing you can do is to include plenty of calcium in your diet. For women ages 19 to 50 and men ages 51 to 70, the recommended dietary allowance (RDA) is 1,000 milligrams of calcium per day. The recommendation increases to 1,200 mg a day for women age 51 and older and for men age 71 and older. Good sources include dairy products, almonds, broccoli, kale, canned salmon with bones, sardines, and tofu. Try to include physical activity in your daily routine too. Weight-bearing exercises like jogging, walking, dancing, and climbing stairs can help you to build strong bones.

In addition to boosting your calcium intake, adding a few other key nutrients can also help. For instance, vitamin D is an essential nutrient for optimal bone health. This is because calcium and vitamin D work together to protect your bones—calcium helps build and maintain healthy bones while vitamin D helps your bones effectively absorb the calcium. So even if you’re getting enough calcium, it could be going to waste if you’re deficient in vitamin D.

Vitamin K is another bone-building nutrient that you mainly get comes from the foods in your diet. This vitamin comes in two forms—vitamin K1, which comes from plants, and vitamin K2, which is found in dairy, eggs, fermented foods, meat, and poultry. Studies show that vitamin K increases bone mineral density in people with osteoporosis and reduces fracture rates.⁴  

The D-K Connection

Now that you’re up to speed on both of these critical nutrients, let’s talk about the synergistic relationship between them. Turns out, vitamins D and K work together to make sure calcium is correctly distributed in your body.

One of the main functions of vitamin D is to maintain adequate levels of calcium in the blood. There are two ways that vitamin D can achieve this. First, it improves the absorption of calcium from the foods you eat.⁵ Second, vitamin D maintains healthy calcium blood levels even when you don’t consume enough of the mineral by drawing on the body’s main calcium supply—your bones.⁶ If this happens often enough or over a long period of time, it can lead to osteoporosis.

While vitamin D ensures you have healthy levels in your blood and promotes the absorption of calcium in bones, it doesn’t fully control where the calcium in your body ends up. That is where vitamin K comes into play. Vitamin K regulates calcium by activating something called osteocalcin, which is a protein that promotes the accumulation of calcium in your bones and teeth.⁷  Vitamin K also activates what’s called the matrix GLA protein, which is a protein that prevents calcium from accumulating in soft tissues like your arteries or kidneys.⁸

Suffice to say, these two vitamins work as a team and provide more bone benefits in the presence of the other than alone. That’s why it’s so important include foods rich in calcium and vitamin K in your daily diet and getting 10 to 15 minutes of unexposed sun exposure every day. You can also ensure healthy levels by taking supplements.

Bottom line? You’re never too old or too young to take care of your bones! Adopting good lifestyle habits and getting healthy amounts of these key nutrients can help protect your bones throughout life and decrease your chances of getting osteoporosis.

1. Osteoporosis fast facts. National Osteoporosis Foundation. n.d. https://cdn.nof.org/wp-content/uploads/2015/12/Osteoporosis-Fast-Facts.pdf
2. Osteoporosis: what women need to know. National Osteoporosis Foundation. n.d. https://www.nof.org/preventing-fractures/general-facts/what-women-need-to-know/#:~:text=Estrogen%2C%20a%20hormone%20in%20women,increases%20as%20women%20reach%20menopause.
3. Sampson W. Alcohol and other factors affecting osteoporosis risk in women. National Institute on Alcohol Abuse and Alcoholism. 2003; https://pubs.niaaa.nih.gov/publications/arh26-4/292-298.htm
4. Weber P. Vitamin K and bone health. Nutrition. 2001; 17(10):880-7.
5. Eisman J, Bouillon R. Vitamin D: direct effects of vitamin D metabolites on bone: lessons from genetically modified mice. Bonekey Reports. 2014; 5;3:499.
6. Hauschka P. Osteocalcin: the vitamin K-dependent Ca2+-binding protein of bone matrix. Haemostasis. 1986; 16(3-4):258-72.
7. Theuwissen E, Smit E, Vermeer C. The role of vitamin K in soft-tissue calcification. Advances in Nutrition. 2012; 1:3(2):166-73.

This article is for informational purposes only. This article is not, nor is it intended to be, a substitute for professional medical advice, diagnosis, or treatment and should never be relied upon for specific medical advice.