The Vitamin Linked to Healthy Bones and Muscles

When people think about nutrients for strong bones, calcium is usually the first one that comes to mind. But calcium is not the only nutrient involved in maintaining a healthy skeleton. Vitamin D also plays an important role in bone health and normal muscle function.

Sometimes called the “sunshine vitamin,” vitamin D is produced by the body when bare skin is exposed to sunlight. It can also be obtained from certain foods and dietary supplements.

As people get older, maintaining adequate vitamin D status becomes especially relevant because bone and muscle health are important parts of staying active and independent.

But what exactly does vitamin D do? How do you get enough of it, and when might supplementation be appropriate?

Let’s take a closer look.

Why Is Vitamin D Important?

Vitamin D is a fat-soluble vitamin that helps the body perform several important functions.

One of its best-known roles is helping the body absorb calcium. Calcium is essential for maintaining bones and teeth, but the body needs appropriate vitamin D status to efficiently absorb calcium from the digestive tract.

Vitamin D is also involved in normal muscle function and plays a role in the immune system.

This means vitamin D is not simply a “bone vitamin.” It is involved in several processes throughout the body.

However, more is not necessarily better. Taking excessive amounts of vitamin D supplements can be harmful, which is why supplementation should be approached thoughtfully.

Vitamin D and Bone Health

Your bones are living tissue. They are constantly undergoing a process in which old bone is broken down and new bone is formed.

Calcium and vitamin D are important components of this process.

Vitamin D helps maintain appropriate calcium and phosphate levels in the body, which are needed for normal bone mineralization.

When vitamin D levels are inadequate for a prolonged period, bone health can be affected.

In children, severe deficiency can lead to rickets, a condition that affects normal bone development.

In adults, severe deficiency can contribute to osteomalacia, in which bones become softer than normal.

Maintaining adequate vitamin D is therefore one part of a broader approach to protecting bone health throughout life.

What Does Vitamin D Have to Do With Muscles?

Vitamin D is also associated with normal muscle function.

Muscles need to work properly for everyday activities such as walking, climbing stairs, getting up from a chair, carrying groceries, and maintaining balance.

Research has investigated relationships between vitamin D status, muscle strength, physical performance, and the risk of falling, particularly among older adults.

The relationship is complex, however. Muscle health depends on many factors, including physical activity, protein intake, age, overall health, medications, and other nutrients.

Vitamin D should therefore not be viewed as a standalone solution for maintaining strength.

Regular physical activity — particularly appropriate strength and balance exercises — remains an important part of maintaining physical function as we age.

Where Does Vitamin D Come From?

There are three main ways people can obtain vitamin D:

• Sunlight

• Food

• Dietary supplements

Sunlight

Your skin can produce vitamin D when exposed to ultraviolet B radiation from sunlight.

However, the amount produced varies considerably from person to person.

Factors include:

• Time of year

• Time of day

• Geographic location

• Skin pigmentation

• Age

• Clothing

• Amount of skin exposed

• Use of sunscreen

• Weather and environmental conditions

As a result, there is no universal number of minutes in the sun that guarantees an adequate vitamin D level.

Sun exposure also needs to be balanced against the well-established risks associated with excessive ultraviolet exposure.

You should not deliberately expose your skin to excessive sunlight or use tanning beds simply to obtain vitamin D.

Food Sources

Only a relatively small number of foods naturally contain substantial amounts of vitamin D.

Examples include fatty fish such as salmon, trout, sardines, and mackerel.

Egg yolks and certain other foods can also provide vitamin D in smaller amounts.

Many countries also have foods fortified with vitamin D, such as certain types of milk, plant-based beverages, breakfast cereals, or other products.

Checking nutrition labels can help you determine whether a food is fortified.

Do Older Adults Need More Vitamin D?

Vitamin D requirements can vary with age and individual circumstances.

Older adults may be at increased risk of inadequate vitamin D status for several reasons. The skin becomes less efficient at producing vitamin D with age, and people may spend less time outdoors.

Dietary intake can also vary.

However, the appropriate amount depends on individual factors and the recommendations applicable in your country.

If you are concerned about vitamin D, particularly if you have risk factors for deficiency, talk with a healthcare professional. They can determine whether testing or supplementation is appropriate.

Signs of Vitamin D Deficiency

Vitamin D deficiency does not always cause obvious symptoms.

Some people may have no noticeable symptoms even when their vitamin D status is low.

When deficiency becomes significant, symptoms can include bone pain or muscle weakness.

Because these symptoms can have many possible causes, they should not automatically be attributed to vitamin D deficiency.

If you have unexplained muscle weakness, persistent bone pain, frequent falls, or other concerning symptoms, it is better to seek medical advice rather than simply starting high-dose supplements.

A healthcare professional can help determine the underlying cause.

Can You Get Vitamin D From Your Diet Alone?

It depends on the individual and the foods available in their diet.

Some people obtain adequate vitamin D through a combination of foods, fortified products, and sunlight.

Others may have difficulty getting enough, particularly if they have limited sun exposure or certain dietary restrictions.

People who eat little or no animal products may need to pay particular attention to fortified foods and appropriate sources of vitamin D.

A balanced diet can provide many important nutrients, but vitamin D is one nutrient for which dietary sources can be relatively limited.

What About Vitamin D Supplements?

Vitamin D supplements are widely available, but that does not mean everyone needs to take one.

For people who have inadequate vitamin D intake or are at increased risk of deficiency, a healthcare professional may recommend supplementation.

The amount matters.

Taking very high doses without medical supervision can cause vitamin D levels to become excessively high. This can lead to elevated calcium levels in the blood and potentially cause serious health problems.

More is not automatically better.

If you already take a multivitamin or another supplement, check the label before adding additional vitamin D. You may unknowingly be combining multiple sources.

Vitamin D and Calcium Work Together

It is useful to think of vitamin D and calcium as partners rather than competing nutrients.

Calcium provides an essential mineral component of bone, while vitamin D helps the body absorb calcium and maintain appropriate mineral levels.

But healthy bones require more than these two nutrients.

Protein, magnesium, vitamin K, phosphorus, and other nutrients also contribute to normal nutrition and bone maintenance.

Lifestyle matters too.

Weight-bearing physical activity and resistance training can provide important mechanical stimulation to bones and muscles.

Avoiding tobacco and keeping alcohol intake within recommended limits are also relevant to overall bone health.

Simple Habits That Support Bone and Muscle Health

Maintaining healthy bones and muscles is not about finding one “magic” vitamin.

Instead, consider a combination of everyday habits.

Stay Physically Active

Walking, climbing stairs, resistance exercises, and other appropriate activities can help support physical function.

Balance exercises can also be useful, particularly as people get older.

If you have health conditions or have been inactive for a long time, ask a healthcare professional what type of exercise is appropriate for you.

Eat a Balanced Diet

Include a variety of foods that provide protein, calcium, vitamins, minerals, and other nutrients.

Dairy products, fortified alternatives, leafy greens, beans, fish, eggs, nuts, seeds, fruits, and vegetables can all contribute to a varied diet.

Spend Time Outdoors Safely

Being outdoors can support an active lifestyle and provide opportunities for sunlight exposure, but protecting your skin from excessive ultraviolet radiation remains important.

Pay Attention to Fall Prevention

Strong muscles and good balance can help support mobility.

Keeping walkways clear, using appropriate lighting, wearing suitable footwear, and addressing vision problems can also reduce environmental risks associated with falls.

Who May Need to Pay Particular Attention to Vitamin D?

Certain groups may have a higher risk of inadequate vitamin D.

This can include people who spend little time outdoors, individuals with limited dietary sources, older adults, and people with certain medical conditions that affect vitamin D absorption or metabolism.

People with darker skin may also produce vitamin D less efficiently from the same amount of sunlight than people with lighter skin.

However, risk varies from person to person.

If you fall into a group that may be at increased risk, this does not automatically mean you are deficient. It simply means that discussing your vitamin D intake with a healthcare professional may be worthwhile.

Should Everyone Get a Vitamin D Blood Test?

Not necessarily.

Routine testing is not appropriate for everyone, and recommendations can differ depending on individual circumstances and healthcare guidelines.

A healthcare professional may recommend testing when there is a particular reason to suspect deficiency or when monitoring is clinically appropriate.

If you are considering testing, ask why it is recommended and how the result would affect your treatment or supplementation plan.

The Bottom Line

Vitamin D is an important nutrient associated with healthy bones and normal muscle function. It helps the body absorb calcium and plays several other roles in normal health.

You can obtain vitamin D through sunlight, certain foods, fortified products, and supplements when appropriate.

However, vitamin D is only one piece of the puzzle.

A balanced diet, regular physical activity, resistance and balance exercises, adequate protein and calcium intake, and sensible lifestyle habits all contribute to maintaining healthy bones and muscles.

If you are concerned that you may not be getting enough vitamin D — especially if you are older, spend little time outdoors, have limited dietary sources, or have a condition that affects nutrient absorption — talk with a healthcare professional before taking high-dose supplements.

The goal is not to consume as much vitamin D as possible. It is to maintain an appropriate level as part of an overall healthy lifestyle.