Longevity Articles

Your Hair Color Could Determine Bone Density

Your Hair Color Could Determine Bone Density
  • Researchers led by experts from Osaka University have discovered an overlap in the primary functions of Rab proteins involved in daily functioning.

  • Rab32 and 38, popularly attached to hair pigmentation have also been found to play core roles in the bone remodeling process.

  • This understanding can enhance the way Rab proteins are explored to manage bone-related conditions.

  • Researchers detailed their findings on this process across two papers.

This article was posted by ScienceDaily

Bone thickness can make all the difference in preventing age-related injuries from routine events like an unexpected trip or losing balance on the stairs.

To properly maintain bone health and integrity, the body orchestrates a delicate series of processes that ensure old bone material is regularly replaced with fresher, stronger bone. 

But while this process is an established bodily function, recent research published in the Journal of Biological Chemistry, plus Cell Structure and Function, has uncovered that some components responsible for this operation are popularly connected to another unsuspecting bodily feature: hair color. 

We’ll examine the connection between bone density and hair color, plus different lifestyle changes that can help improve bone strength for improved physical function later into life.

What is Bone Remodeling?

Bones are metabolically active organs that go through predictable changes throughout a lifetime.

To continuously perform the core functions of providing structural support, protecting vital organs, plus reinforcing movement—the body carries out the natural process of bone remodeling, where old and mature bone tissue is replaced with newer material.

Bone remodeling is the body’s turnover process—the removal of old or damaged bone tissue, replacing the worn-out material with more secure bone structures to promote skeletal strength. 

This specialized process is carried out via osteoclasts, which essentially dissolve old and damaged bone cells, replacing them with healthier structures built by bone-making cells such as osteoblasts.

Understanding the Mechanics of Bone Remodelling 

Bone remodeling via osteoclasts is a complicated process requiring many moving parts, including support from vesicles and proteins. 

Through a highly regulated system, osteoclasts attach to the bone surface at resorption lacunae sites, where they begin the gradual process of bone dissolution.

At these sites, osteoclast cells create a marked area or sealing zone to isolate old or damaged bones, kicking off the resorption process. These osteoclasts release acids and degrading enzymes like H+ acids, TRAP, and CatK to dissolve the weak bones in this area.

Also contributing to this process are specialized compounds called Rab proteins, which guide vesicles to transport relevant enzymes to the isolated sites to dissolve and break down weakened bone. 

However, while Rabs perform a crucial role during bone remodeling, there’s some confusion about the individual functions performed by the over 50 Rab proteins involved in the bone turnover process.

Explaining the approach to identify these functions, Kazuya Noda, lead author of the first paper shares:  "To better understand the molecular mechanisms of osteoclast function, we first screened Rab proteins especially induced during osteoclast formation in mouse [models]." 

While researching the mechanisms behind osteoclast function in rats, researchers at Osaka University identified raised levels of two main proteins—Rab38 and Rab32, which localize to lysosome-related organelles (LROs)—cell structures that indirectly connect to bone health through processes like melanin production. 

Functions of Rab38 and Rab32 Proteins for Bone Health

Rab38 and Rab32 may not be the most popular proteins linked to bone health, but these compounds are critical players in regulating skeletal structures, especially during bone remodeling.

Rab proteins help to regulate vesicle movement across bone cells. This is important because, without these proteins, vesicles will struggle to carry out their primary duty of transporting molecules within cells to support the remodeling process.

Beyond support for transporting nutrients, these proteins also guide vesicle movement within the skeletal cell, ensuring that they make it safely to the site that requires cell replacement, but it doesn’t stop there.

After leading these vesicles to the relevant points, Rab proteins also play a role in ensuring they dock at the target site, and can properly interact with the membranes and organelles involved in bone turnover. Vesicles can release their molecules and factors to promote the cell formation and resorption process via assistance from Rab proteins.

In addition to bone health, Rab proteins contribute to overall health and body functioning.

Rab38 and Rab32 are involved in the transport process of melanosomes—specialized organelles for the production and distribution of melanin—the pigment responsible for skin and eye shades, and is also directly involved in determining hair color.

Research on the Link Between Bone Density and Hair Color

Researchers made an interesting finding when they raised a mouse with Rab38 and Rab32 deleted from its whole body. Constructed by Kanako Tokuda, the lead author of the second paper—this mouse was dubbed a “double knock-out”, and its features grew to reflect an organism devoid of the necessary components needed for adequate coloring.

For one, these mice had beige-like coloring and red eyes, a clear contrast to the control wild mouse, whose black hair and eyes indicated the presence of melanosomes and melanin needed to produce the expected coloring.

But in an interesting twist, researchers found that these mice showed increased bone density, with their spine becoming more bent with age, especially the male mice.

Ultimately, researchers concluded that the absence of Rab38 and Rab32 in observed mice led to a defect in bone resorption in these subjects. 

Explaining how this knowledge can be applied to improve health and well-being, senior author of the study on bone density and hair color, Takeshi Noda shared: "...understanding the underlying mechanism of bone resorption facilitated by Rab32 and Rab38 will provide us useful information regarding potential treatment target for these diseases". 

Lifestyle Changes to Improve Bone Health

The good news about human bones is, that these living minerals are constantly renewed and can grow stronger with correct physical activity, diet, and other lifestyle measures in place.

Being mindful of bone health is especially important because humans tend to lose bone mass beginning around the mid-30s, with women prone to losing mass faster after menopause. It’s necessary to prioritize bone health for structural support, organ protection, valuable mineral storage, blood production, and more.

Stay active

Just as the muscles grow stronger from regular physical exercise, bones can benefit from staying active to avoid weakness, fractures, and age-related bone conditions.

You can build up bone strength by starting with simple activities like walking and stair climbing. Likewise, weight-bearing and resistance exercises can help to avoid bone-related problems later.

Eat right

Eating for healthy bones means upping calcium and vitamin D intake to strengthen the body’s bone structure. As the most abundant mineral in the body, almost all calcium is stored in the bones and teeth to provide structure and hardness, requiring a constant supply for sustained health. Cheese, leafy greens, whey protein, sardines, beans, and lentils can boost calcium supply. 

As an essential sidekick, vitamin D helps to absorb the calcium derived from food into bone tissue and can protect older adults from bone weakness

A diet rich in cod liver oil, salmon, swordfish, tuna fish, sardines, and beef liver can improve vitamin D intake. You can also support your nutrient supply through calcium and vitamin D supplements, but be mindful to choose bioavailable forms in appropriate doses. Calcium from food sources is typically better absorbed than calcium from supplements, though supplemental vitamin D can be a beneficial addition for many people, given our general lack of exposure to sunlight. 

Stay informed about bone-weakening medicines

Medicines and supplements are steady companions to navigate the changes that come with the aging process. However, it’s important to be mindful of the effects of these drugs on overall well-being, as certain medications like steroids, neurotransmitter modifiers, and stomach acid modifiers may hasten bone loss.

It’s necessary to discuss with a health provider on ways to protect bones while managing other health issues that could complicate your bone strength plan.

Limit alcohol and smoking use

Excessive smoking and alcohol use can be reasons behind reduced bone mass in older adults. To extend bone health, it’s important to limit alcohol use in later life, with similar restrictions for smoking to improve bone strength.


Healthy bones are a strong guarantee for independence as we grow in age.

Maintaining bone health through proper nutrition, regular exercise, and healthy lifestyle choices is ideal for guarding against fractures and bone conditions that become more pervasive with age.

Prioritizing bone health is not only vital for structural well-being, but can also benefit overall health.


  1. Osaka University. "Bone density is kept up by the same process with hair color." ScienceDaily. ScienceDaily, 26 October 2023. 
  2. Hadjidakis DJ, Androulakis II. Bone remodeling. Ann N Y Acad Sci. 2006;1092:385-396. doi:10.1196/annals.1365.035
  3. Rowe P, Koller A, Sharma S. Physiology, Bone Remodeling. [Updated 2023 Mar 17]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-.
  4. Raggatt LJ, Partridge NC. Cellular and molecular mechanisms of bone remodeling. J Biol Chem. 2010;285(33):25103-25108. doi:10.1074/jbc.R109.041087
  5. Hutagalung AH, Novick PJ. Role of Rab GTPases in membrane traffic and cell physiology. Physiol Rev. 2011;91(1):119-149. doi:10.1152/physrev.00059.2009
  6. Tokuda K, Lu SL, Zidi Z, et al. Rab32 and Rab38 maintain bone homeostasis by regulating intracellular traffic in osteoclasts [published online ahead of print, 2023 Oct 4]. Cell Struct Funct. 2023;10.1247/csf.23061. doi:10.1247/csf.23061
  7. Benedetti Osaka University. "Bone density is kept up by the same process with hair color." ScienceDaily. ScienceDaily, 26 October 2023. 
  8. National institute of Musculoskeletal and Skin Diseases. Bone health: what it means to you. 
  9. Benedetti Osaka University. "Bone density is kept up by the same process with hair color." ScienceDaily. ScienceDaily, 26 October 2023. 
  10. Laird E, Ward M, McSorley E, Strain JJ, Wallace J. Vitamin D and bone health: potential mechanisms. Nutrients. 2010;2(7):693-724. doi:10.3390/nu2070693
  11. Panday K, Gona A, Humphrey MB. Medication-induced osteoporosis: screening and treatment strategies. Ther Adv Musculoskelet Dis. 2014;6(5):185-202. doi:10.1177/1759720X14546350

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