Vitamin C and its role in optimal bone health

The most potent food source of vitamin C was once banned from parts of the United States. Farmers couldn’t grow it, and stores couldn’t import it until 2006.

If you’re confused, it might be because you think oranges, which have been a staple of American breakfasts for decades, have the highest concentration of vitamin C––but they don’t.

That title goes to the black currant. Luckily for fans of the tart, gem-toned berries, farmers with some serious spine fought the ban and won (that’s a bone joke), bringing this source of the bone-building vitamin back into the U.S. 

Vitamin C, also known as ascorbic acid and ascorbate, is an essential vitamin. We require it, but our bodies cannot produce it for us, so we need dietary sources or supplemental vitamin C intake to meet our daily needs.

This water-soluble vitamin is also involved in critical processes in your body like collagen synthesis, the creation of collagen fibers, which assist with tissue repair and wound healing. Vitamin C also supports immune health as one of the three big antioxidant vitamins (along with vitamin E and beta carotene), fighting off free radicals that cause cellular damage and oxidative stress. 

Bone health is complicated. We don’t just form bone mass and then, hopefully, maintain it in the same quality. We go through a complicated process of bone formation, modeling or consolidation, and remodeling––the latter of which happens when we’re adults.

Remodeling refers to the process that happens when a bone is broken down and formed again, not always at the same quality. These internal supports also go through mineralization, a process in which mineral crystals are deposited in a structure.

The strength of our bones is determined by two factors: bone mineral density, how many of those mineral crystals there are in an area of bone, and bone matrix quality, which is basically everything about the bone’s structure and composition that doesn’t involve minerals.

So it’s safe to say that bone mineralization is a little important. And this process isn’t possible without collagen, which forms the foundation. Vitamin C is essential for collagen synthesis, the process in which collagen fibers are formed, and also for mineralization to take place on top of these fibers (DePhillipo, 2018).

The accumulation of mineral crystals along these frames is essential for bone strength. One study found that vitamin C may help increase bone density, especially in the spine (New, 1997). 

While another found that fruit and vegetable nutrients, like vitamin C, may help establish bone health in premenopausal women and ward off bone loss. This, in turn, may reduce fracture risk in the femoral neck even after going through menopause (Macdonald, 2004).

But you don’t just need these foods and the nutrients that come along with them––you need the right amounts. Not hitting your fruit and vegetable needs (five servings a day) is associated with a higher risk of hip fracture, one study with a 14.2-year follow-up determined (Byberg, 2015). 

One study even suggests that vitamin C may have a protective effect, decreasing the risk of osteoporosis in people with lower levels of physical activity. But vitamin C also plays an important role as a support in other mechanisms involved in bone health. This vitamin helps boost the absorption of calcium, a mineral essential to building strong bones (Kim, 2016). 

Vitamin C is also a cofactor for vitamin D, another essential vitamin for healthy bones, to be broken down into calcitriol, which then regulates calcium and calcification of our bones. Emerging research also found that vitamin C may help with bone regeneration by blocking osteoclasts and promoting the formation of osteoblasts, cells in charge of bone growth (Choi, 2019).

Although this has been suggested by other researchers in previous clinical trials, studies are now confirming that suspicion and uncovering the pathways that make it happen––though they’re still only done on animals.

Vitamin C deficiency isn’t common in America but should be taken seriously since this nutrient is a powerhouse of potential health benefits (as you probably know, vitamin C deficiency causes the disease scurvy).

About 7% of adults in the United States suffered from a lack of this essential nutrient between 2003 and 2004. There are several groups of people that are at increased risk of developing this deficiency, like those who suffer from alcoholism or anorexia.

That also includes people who are low income, smoke, are on dialysis, or have a severe mental illness. Even so, it’s possible for everyone to get enough vitamin C intake to reap the health benefits (Schleicher, 2009).It should be noted, though, that everyone is different. There’s no doubt that vitamin C is essential and healthy, but not everyone will experience the same beneficial effects in the same way.

And you might have heard about some purported benefits, like protecting against eye diseases such as age-related macular degeneration, but there isn’t enough research to back up those claims. You can read all about the health benefits here, but particularly noteworthy effects of vitamin C include:

• Reduce the risk of chronic diseases

• Protect against certain cancers

• Combat heart disease

• Lower blood pressure

• Protect cognitive function

• Improve immunity

Not an orange fan? Don’t worry. There are plenty of ways to get enough dietary vitamin C without turning to citrus. For the record, oranges are a good choice as they boost both vitamin C and calcium intake.

You can, of course, turn to the food sources of vitamin C, which we’re all familiar with (oranges and grapefruits) but you can also add more kiwi and berries to your diet. Even cantaloupe and papaya are excellent ways to boost your dietary intake.

And this essential vitamin isn’t just in fruits, either. Load up your plate with cruciferous veggies like Brussels sprouts, kale, and cauliflower to boost your intake. But dietary supplements are also an option for everyone who struggles to get their intake of vitamin C up to the recommended dietary allowance (RDA).

Supplemental vitamin C intake can be a necessity for people with certain health conditions that cause malabsorption. People with gastrointestinal issues such as Crohn’s disease, celiac, or irritable bowel syndrome (IBS) may require vitamin C supplementation since their bodies cannot properly absorb the nutrient.

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Current version

December 05, 2021

Written by

Linnea Zielinski

Fact checked by

Mike Bohl, MD, MPH, ALM

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About the medical reviewer

Mike Bohl, MD, MPH, ALM

Dr. Mike is a licensed physician and a former Director, Medical Content & Education at Ro.