Nutrition and Bone Stress Injuries in Running-Based Sports: What the Research Really Suggests

Bone stress injuries (stress reactions, stress fractures) the whole frustrating spectrum are incredibly common in running-based sports. Athletics, soccer, AFL, basketball, netball, hockey, triathlon… if a sport involves repeated impact, sprinting, jumping, or sharp changes of direction, bones are under constant load.

Training load absolutely matters. But nutrition is one of the most controllable risk factors, and perhaps one of the most underestimated. Bones aren’t just hard structures that “wear out.” They’re living tissue. They respond, adapt, remodel. But only if they’re given enough energy and the right building blocks.

What follows isn’t hype or supplement marketing. It’s a practical summary of what research consistently points toward, especially for runners and field sport athletes managing high workloads.

The biggest nutrition risk factor: low energy availability

If there’s one theme that keeps showing up in the research, it’s this: under-fuelling is a major driver of bone stress injuries.

Low energy availability happens when your intake doesn’t match the cost of your training and daily life. The body doesn’t just shrug and carry on, it starts prioritising survival over performance. Hormones shift. Bone formation slows. Repair gets compromised.

This sits at the centre of RED-S (Relative Energy Deficiency in Sport), and in females, the Female Athlete Triad. Both are strongly associated with impaired bone health and higher stress fracture risk.

And here’s the part that surprises people: you do not need to have an eating disorder. You do not need to look underweight. You can be “eating clean” and still be chronically under-fuelled.

Common clues during a heavy training block:

• Niggles that don’t quite settle

• Repeated calf or shin pain

• Poor sleep, irritability, low mood

• Menstrual changes or missed periods (females)

• Reduced libido or loss of morning erections (males)

• Heavy legs and performance plateaus

• Feeling cold frequently

• Night-time hunger

Research in male endurance runners shows something similar: even with all the impact loading from running, which we often assume strengthens bone, low energy intake relative to training load can still impair bone outcomes.

Impact alone isn’t protective if the system is under-fuelled.

Keywords: low energy availability, RED-S, female athlete triad, stress fracture risk, bone stress injury runners.

Calcium and vitamin D: the fundamentals (food first)

Calcium is central to bone structure. Vitamin D helps regulate calcium absorption and bone metabolism. That part is well established.

One large randomized controlled trial in female military recruits showed that calcium plus vitamin D supplementation reduced stress fracture incidence during intense training. That’s meaningful. But it doesn’t mean everyone needs to immediately buy supplements.

The practical interpretation is simpler:

If you’re not hitting calcium targets through food, fix that.
If your vitamin D is low, which is common in winter or in indoor athletes. Correcting it matters.

Calcium-rich foods:

• Milk, yoghurt, cheese

• Fortified soy milk and plant yoghurts

• Canned salmon or sardines with bones

• Calcium-set tofu

• Some leafy greens and almonds (smaller contributions)

Vitamin D sources:

• Sensible sun exposure (varies by season and skin type)

• Salmon, eggs, fortified products

• Blood testing if you have repeated Bone Stress Injuries, winter fatigue, or limited sun exposure

Supplement only if indicated, ideally guided by a clinician.

Keywords: calcium for runners, vitamin D stress fractures, bone health nutrition.

Carbohydrates protect more than performance

Carbohydrates are often framed purely as a performance fuel. But during heavy training blocks, they also appear to influence bone turnover.

Studies in elite endurance athletes show that low carbohydrate availability, particularly alongside low overall energy availability, can reduce markers of bone formation and increase markers of bone breakdown, even over short time frames.

That’s not theoretical. It’s measurable.

Practical takeaways:

• Don’t restrict carbs when mileage or intensity increases

• Fuel before and after key sessions

• Avoid body composition cuts mid-season

• If changing body composition is a goal, do it off-season with guidance

Trying to train hard, recover, and protect bone health while chronically restricting carbohydrates is, frankly, a difficult equation to win.

Keywords: carbohydrates for runners, fueling for bone health, under-fuelling injury risk.

Protein and total intake: repair needs raw materials

Protein supports muscle repair, connective tissue, and overall recovery. During rehabilitation from a bone stress injury, this becomes even more relevant — you’re rebuilding tissue while often training less and potentially losing conditioning.

Common sports nutrition principles apply:

• Spread protein across the day

• Include quality protein at breakfast

• Prioritise post-training intake

• Maintain adequate total daily intake, especially during rehab

But again, protein cannot compensate for an overall calorie deficit. Total energy intake still underpins everything.

Reviews in endurance athletes continue to highlight that low energy availability remains one of the central drivers of bone stress injuries. Adequate dietary intake isn’t a bonus strategy: it’s foundational prevention.

Keywords: protein for injury recovery, nutrition for stress fracture healing.

Collagen and vitamin C: interesting, but not foundational

There’s growing interest in collagen or gelatin combined with vitamin C taken before loading sessions. Some studies show increases in markers associated with collagen synthesis.

Most of that research relates more directly to tendons and ligaments than bone itself. Still, in running-based sports, muscle, tendon, and bone capacity are interconnected. It’s not unreasonable to see it as a potential adjunct.

But it’s not a magic fix.

If the basics aren’t in place (enough total energy, adequate calcium and vitamin D, sensible carbohydrate availability, progressive loading) then collagen supplementation is probably just polishing the edges of a bigger issue.

Keywords: collagen supplementation athletes, gelatin vitamin C protocol.

A practical bone stress injury prevention checklist

Use this during pre-season or whenever training load climbs:

• Avoid chronic calorie deficits during hard blocks

• Place carbohydrates around demanding sessions

• Ensure daily calcium intake through food

• Check vitamin D if there’s a history of stress fractures or limited sun exposure

• Distribute protein across the day

• Monitor RED-S / Triad signs

• Take menstrual changes, persistent fatigue, or libido changes seriously

These signals aren’t minor inconveniences. They’re often early warning signs.

When to get help

If you have a diagnosed stress fracture, repeated bone stress pain, a history of shin, foot, or hip stress injuries, or signs of under-fuelling, a combined approach usually works best.

Load management matters. So does strength training. But matching nutrition to the actual demands of the program is often the missing piece.

In practice, and this is something I see repeatedly, athletes will tweak footwear, adjust cadence, change surfaces… yet continue under-fuelling slightly. Not dramatically. Just enough. And over time, that small gap accumulates.

Bones adapt when they’re stressed appropriately and supported adequately.

Remove either piece, and the system eventually pushes back.