How fitting to be writing about this after the longest stretch of overcast, rainy days we’ve had in ages.
For the past few weeks, our eight-year-old has been complaining of what we’ve been calling growing pains. They’ve mostly been happening at night, to the point where the poor guy was asking for a herbal pain cream to keep in his bed. If you’ve had a child waking up with aching legs, you’ll know how upsetting it can be. Nobody likes seeing their child uncomfortable.
So, what are growing pains? Growing pains usually feel like an ache or throbbing in both legs. Children often feel them around the calves, thighs or behind the knees, and they tend to come and go in the evening or overnight. (1, 2)
How did we approach this episode of growing pains? One of the first things I tend to consider is potential nutritional deficiencies. For growing pains, the most commonly considered culprits are deficiencies in the following: iron, magnesium, calcium and vitamin D. Let's take a look at what these presentations may look like, and the approach we took to resolve the issue.
Iron
Low iron can contribute to restless legs and nighttime leg discomfort, so is definitely worth considering if your child complains of night-time leg pain. (3) Signs and symptoms of low iron, particularly if iron deficiency has progressed to anaemia, can include: pale skin (including the gums and eyelids), fatigue, low appetite, shortness of breath, pica (cravings for non-food items), cold hands & feet, and behavioural / developmental issues such as irritability & mood swings, poor sleep, cognitive impairments (such as short attention span, poor memory & focus) and slowed growth. (3–6)
Our son already eats an iron-rich diet, shows little to no other signs of iron deficiency, and we combine his meals with optimal iron absorption in mind. An absence of any abnormal gut symptoms gave me little reason to suspect malabsorption. So, inadequate iron intake wasn’t high on my list. That doesn’t completely rule out low iron stores, but it gave me a reason to look at other possibilities too.
Magnesium
Magnesium helps our muscles and nerves function normally, as well as playing an important role in energy production. Deficiency can cause fatigue, weakness and a reduced appetite, with more pronounced deficiency potentially leading to muscle contractions, cramps or tingling. (7)
We’d already been giving our son a magnesium powder containing several highly bioavailable forms at a therapeutic dose, although admittedly not on a regular basis. Once he made us aware of the growing pain issue, we ensured that he received the magnesium every night before bed. After about a week, he thought it might have helped a little - but the pains were still bothering him and he still kept his pain cream by the bed.
Calcium
Calcium is needed for strong bones & normal muscle & nerve function. (8) When blood calcium becomes too low, it can cause symptoms such as pins & needles around the mouth or fingers & toes, cramps & muscle spasms (sometimes being mistaken for magnesium deficiency), & mental changes such as confusion, memory porblems, irritability & depression. (9, 10) Low vitamin D can contribute to this because it affects how well we absorb calcium. (8, 11)
Our son eats plenty of calcium-rich foods, so I wasn't convinced that this was the chief suspect in his growing pains issue. Much of his dietary calcium comes from sources the body can readily absorb, so inadequate dietary intake seemed even less likely. Onto the next suspect.
Vitamin D
Symptoms of low vitamin D can include fatigue & children tiring more easily during physical activity, aching bones & muscles, (12, 13) and increased susceptibility to infections. More severe deficiency can affect bone development and cause rickets - but many children with low vitamin D have no obvious symptoms. (11, 12)
This was the nutrient that made me stop and think about his usual habits. He’s a quiet, crafty child who is very happy staying inside in order to build his cardboard empire. He does play outdoors, but he’s also told me he prefers the shade because he doesn’t want to get sunburnt. Fair enough!
Then I considered his food preferences. He doesn’t like oily fish. If we cook eggs, he leaves the yolk. He only eats a little butter, and we haven’s been using cod liver oil. Oily fish and fish liver oils are among the richest natural sources of vitamin D, with egg yolks providing smaller amounts. (14) We also had run out of our pastured pork from Paleo Beef Direct and I’d been slack in reordering – the fat from free range pigs that get regular sunlight exposure is also a good way to increase your intake of vitamin D. (17) Simply put, several foods that contribute to a high level of vitamin D3 intake simply aren’t part of his usual diet.
Between his self-limited sun exposure and food preferences, I wondered whether vitamin D could be something we’d overlooked. We hadn’t tested his levels, so it was a possibility rather than a confirmed deficiency.
Some interesting findings.
That led me to look into the research. In a study of 120 children with growing pains, researchers found that 86.6% had vitamin D levels below 50 nmol/L (which is considered to be low). Following treatment, average pain scores fell from 6.8 to 2.9 out of 10 over three months (Vehapoglu et al., 2015), and vitamin D levels increased to a mean of 111nmol/L. (15)
It's important to note here that the children also received calcium, and there was no placebo comparison group either. So we can’t separate the effects of vitamin D from calcium and we also can’t rule out some improvement happening naturally. Even with those limitations, I found the results interesting. (15)
Supplementation
After reading the study, I gave our son vitamin D (following a conservative dosage protocol that was outlined in the study) in his morning hot chocolate. The next morning, he told me he hadn’t had any growing pains that night. I was both surprised & pleased to hear that, considering how long he'd been living with the nightly discomfort. Fast forward to two weeks later with regular vitamin D3 supplementation in his morning cuppa, & our child has not had a single night of pain since that initial dose of D3. It is important to note that I didn’t test his blood levels of vitamin D3, so we don’t have definitive proof that vitamin D deficiency was the root of his issue.
Now, why did this seem to work for our child? As previously discussed, vitamin D3 assists in calcium absoprtion - so that may be factor here. (14) There’s also a connection between vitamin D and magnesium. Magnesium supports the enzymes involved in activating and processing vitamin D - with research finding that magnesium supplementation influences vitamin D metabolism (Dai et al., 2018). (16) These nutrients all work together. That doesn’t explain my son’s response, but it does help to explain the broader picture.
This experience has reminded me to consider vitamin D when looking into recurring aches, especially in a child who spends much of their time indoors. We'll continue with the vitamin D3, while also focusing on increasing his daily sunlight exposure and gradually incorporating more vitamin D rich foods into his diet.
If your child has recurring leg pain, it’s worth discussing it with your healthcare practitioner. They can assess the symptoms and consider whether vitamin D testing would be useful. (1, 12) It's important to note that some symptoms need checking with a GP - these include pain that persists into the morning or consistently affects one leg. Limping, swelling or fever also need assessment. Waking before dawn with an ache is different from pain that continues once a child is up and moving. (1)
I’ll be keeping an eye on how things go over the next few weeks, but so far, our experience suggests growing pains may be a message that your child could do with some more sunshine.
References
NHS (2026) ‘Growing pains’. Available at: Growing pains (Accessed: 23 October 2026).
Rady Children’s Health (n.d.) ‘Growing pains’. Available at: Growing pains (Accessed: 23 October 2026).
National Institute of Neurological Disorders and Stroke (2026) ‘Restless legs syndrome’. Available at: Restless legs syndrome (Accessed: 23 October 2026).
The Royal Children’s Hospital Melbourne (n.d.) ‘Clinical practice guidelines: Iron deficiency’. Available at: Iron deficiency (Accessed: 23 October 2026).
The Royal Children’s Hospital Melbourne (n.d.) ‘Iron’ [patient information leaflet]. Available at: Iron information leaflet (Accessed: 23 October 2026).
National Heart, Lung, and Blood Institute (2022) ‘Iron-deficiency anemia’. Available at: Iron-deficiency anemia (Accessed: 23 October 2026).
National Institutes of Health, Office of Dietary Supplements (2026) ‘Magnesium: Fact sheet for health professionals’. Available at: Magnesium fact sheet (Accessed: 23 October 2026).
National Institutes of Health, Office of Dietary Supplements (n.d.) ‘Calcium: Fact sheet for health professionals’. Available at: Calcium fact sheet (Accessed: 23 October 2026).
Merck Manual, Consumer Version (n.d.) ‘Hypocalcemia (low level of calcium in the blood)’. Available at: Hypocalcemia (Accessed: 23 October 2026).
Cleveland Clinic (2022) ‘Hypocalcemia’. Available at: Hypocalcemia (Accessed: 23 October 2026).
The Royal Children’s Hospital Melbourne (n.d.) ‘Kids Health Info: Vitamin D’. Available at: Vitamin D (Accessed: 23 October 2026).
The Royal Children’s Hospital Melbourne (2020) ‘Clinical practice guidelines: Vitamin D deficiency’. Available at: Vitamin D deficiency (Accessed: 23 October 2026).
The Royal Children’s Hospital Melbourne (2026) ‘Low vitamin D: A guide for families’. Available at: Low vitamin D: A guide for families (Accessed: 23 October 2026).
National Institutes of Health, Office of Dietary Supplements (2025) ‘Vitamin D: Fact sheet for health professionals’. Available at: Vitamin D fact sheet (Accessed: 23 October 2026).
Vehapoglu, A. et al. (2015) ‘Are growing pains related to vitamin D deficiency? Efficacy of vitamin D therapy for resolution of symptoms’, Medical Principles and Practice, 24(4), pp. 332–338. doi: 10.1159/000431035.
Dai, Q. et al. (2018) ‘Magnesium status and supplementation influence vitamin D status and metabolism: results from a randomized trial’, The American Journal of Clinical Nutrition, 108(6), pp. 1249–1258. doi: 10.1093/ajcn/nqy274.
Jakobsen, J. and Christensen, T. (2021) ‘Natural vitamin D in food: To what degree does 25-hydroxyvitamin D contribute to the vitamin D activity in food?’, JBMR Plus, 5(1), e10453. doi: 10.1002/jbm4.10453.