Which vitamin deficiency causes rickets?

December 19, 2025 •

3 min read

Globally, nutritional rickets continues to be a public health concern, particularly in certain regions. The most common cause of this debilitating condition, which results in the softening and weakening of bones in children, is a deficiency in vitamin D. Adequate levels of vitamin D are critical for the body's proper absorption of calcium and phosphorus.

Quick Summary

The most prevalent cause of rickets is a severe lack of vitamin D, which impairs the body's ability to absorb calcium and phosphorus needed for healthy bone development. Factors like insufficient sunlight, inadequate diet, and specific health conditions increase risk, but the condition is preventable and treatable.

Key Points

Vitamin D Deficiency: This is the most common nutritional cause of rickets, as it impairs calcium and phosphorus absorption.
Sunlight and Diet: The body produces vitamin D from sunlight, while fatty fish, eggs, and fortified foods like milk and cereal are key dietary sources.
Risk Groups: Infants, especially those exclusively breastfed, individuals with darker skin, and children with limited sun exposure are at higher risk.
Common Symptoms: Rickets is characterized by skeletal deformities such as bowed legs, bone pain, growth delays, and muscle weakness.
Prevention and Treatment: The condition is preventable through proper diet, supplements, and controlled sun exposure. Treatment focuses on addressing the deficiency.

The Primary Culprit: Vitamin D Deficiency

Vitamin D is a fat-soluble vitamin crucial for controlling the levels of calcium and phosphorus in the body. These two minerals are the fundamental components of bone. Without enough vitamin D, the body cannot absorb enough of these minerals from food, which results in defective bone mineralization—the hallmark of rickets. The body produces vitamin D primarily through skin exposure to sunlight's ultraviolet-B (UVB) rays. While some foods naturally contain vitamin D, few are rich sources, which is why many products like milk and cereal are fortified. This fortification has significantly reduced rickets in developed nations since the 20th century.

Sources of Vitamin D

For healthy bone development, it's essential to ensure an adequate supply of vitamin D. The primary sources include:

Sunlight: Exposure to sunlight prompts the skin to produce vitamin D. The amount of exposure needed varies based on location, time of year, and skin pigmentation. However, balancing sun exposure with skin cancer prevention is important.
Diet: A limited number of foods naturally contain significant amounts of vitamin D. These include:
- Fatty fish like salmon, mackerel, and tuna
- Cod liver oil
- Egg yolks
Fortified Foods: To combat widespread deficiency, many countries fortify common foods with vitamin D. Examples include milk, infant formula, breakfast cereals, and some orange juice and yogurt products.
Supplements: Vitamin D supplements (D2 or D3) can be a reliable way to ensure adequate intake, especially for infants and those with limited sun exposure.

Factors Increasing Risk for Vitamin D Deficiency and Rickets

Several factors can increase a child’s risk of developing rickets, largely by limiting their ability to produce or absorb vitamin D:

Limited Sun Exposure: Living in northern latitudes, spending too much time indoors, or consistent use of sunscreen can reduce natural vitamin D synthesis.
Darker Skin Pigmentation: Melanin reduces the skin's ability to produce vitamin D from sunlight, requiring longer exposure times for those with darker skin.
Exclusive Breastfeeding: Breast milk contains very little vitamin D. Infants who are exclusively breastfed without supplementation are at high risk.
Certain Diets: Vegan or lactose-intolerant diets that lack fortified foods can lead to deficiency.
Medical Conditions: Problems with absorption (e.g., celiac disease, cystic fibrosis) or metabolism (e.g., kidney disease, liver disease) can lead to rickets.
Maternal Deficiency: A mother with a vitamin D deficiency during pregnancy can affect her infant’s vitamin D stores at birth.

Comparison of Nutritional vs. Inherited Rickets


Aspect	Nutritional Rickets	Inherited Rickets
Cause	Inadequate vitamin D, calcium, or phosphorus from diet or sun exposure.	Genetic mutations affecting vitamin D metabolism or the body's ability to absorb phosphate.
Mechanism	The body cannot absorb enough calcium and phosphorus, leading to impaired bone mineralization.	Defects in genes cause an inability to properly utilize vitamin D or regulate phosphate, hindering mineralization.
Treatment	Dietary changes, vitamin D and calcium supplementation, and increased sun exposure.	Specialized, long-term medical management, which can include high-dose vitamin D analogs, phosphate supplements, and calcium.

Symptoms of Rickets

The physical manifestations of rickets are due to the softening of the growth plates in a child's bones. Symptoms can include:

Skeletal Deformities: Bowed legs or knock-knees, thickened ankles and wrists, and a projected breastbone (rachitic rosary).
Pain and Tenderness: Children may experience pain in their spine, pelvis, or legs, leading to reluctance to walk or a waddling gait.
Growth Problems: Delayed growth and overall poor development can occur if the skeleton doesn't grow properly.
Dental Issues: Weak enamel, delayed tooth formation, and a higher risk of cavities are common.
Muscle Weakness: Hypotonia, or poor muscle tone, can contribute to delayed motor skills.
Severe Complications: In severe cases, low blood calcium levels can cause seizures and respiratory problems.

Conclusion: Prevention and Early Intervention

Rickets is a serious condition, but it is largely preventable through proper nutrition and safe sun exposure. For infants, especially those who are exclusively breastfed, vitamin D supplementation is a recommended preventive measure. Early diagnosis and treatment are crucial for correcting the condition and preventing long-term skeletal issues. If rickets is suspected, a healthcare provider can conduct blood tests and X-rays to confirm the diagnosis and determine the appropriate course of treatment. In most cases, nutritional rickets is curable with supplements and dietary changes, ensuring a child can develop strong and healthy bones. For comprehensive information on the signs, diagnosis, and treatment of rickets, you can consult authoritative medical resources like the Mayo Clinic's guide on the topic(https://www.mayoclinic.org/diseases-conditions/rickets/symptoms-causes/syc-20351943).

Frequently Asked Questions

The most common cause of rickets is a deficiency of vitamin D. This impairs the body's ability to absorb calcium and phosphorus, which are necessary for proper bone mineralization.

Yes, while vitamin D deficiency is the main cause, a prolonged and severe lack of calcium in the diet can also lead to rickets, though this is less common.

Yes, because the body produces most of its vitamin D through sun exposure, a lack of sunlight can lead to vitamin D deficiency and cause rickets.

In infants, early signs can be subtle and include poor muscle tone, delayed motor skills, and sometimes seizures due to low blood calcium.

Yes, children with darker skin are at higher risk because their skin's melanin reduces its ability to produce vitamin D from sunlight.

Treatment for nutritional rickets typically involves supplements of vitamin D and calcium, as well as increased sun exposure. Severe deformities may require bracing or surgery.

Rickets is the bone-softening condition seen in children, while osteomalacia is the adult equivalent. Both are most commonly caused by vitamin D deficiency.