Vitamin D, often referred to as the “sunshine vitamin,” plays a vital role in children’s health and development. From bone growth to immune function and mental wellness, vitamin D is essential throughout all stages of childhood. In the field of functional medicine, which seeks to address root causes of health issues through a holistic and personalized approach, maintaining optimal vitamin D levels is considered fundamental—especially for children.
Functional medicine practitioners, including specialists such as functional cardiologists, focus on preventing disease early in life. This includes looking beyond the “normal range” of vitamin D seen in conventional medicine and instead targeting levels that support long-term vitality, resilience, and organ development in children.
Why Vitamin D Is Crucial for Children
Vitamin D is not just a nutrient; it acts more like a hormone in the body. It supports:
- Calcium absorption and bone mineralization, crucial during growth spurts
- Immune regulation, reducing the risk of infections, asthma, and allergies
- Neurological development, influencing mood and behaviour
- Cardiovascular health, by modulating inflammation and supporting blood pressure regulation
A growing number of functional medicine providers, including functional cardiologists, now view optimal vitamin D levels as a non-negotiable part of pediatric wellness plans.
Conventional vs. Functional Medicine: Different Views on “Optimal”
In traditional medical practice, vitamin D deficiency is defined as having serum 25(OH)D levels below 20 ng/mL, and insufficiency falls between 20–30 ng/mL. However, functional medicine experts advocate for optimal vitamin D levels that are higher—usually between 50–80 ng/mL for children, depending on age, health history, and lifestyle.
“We’re not just trying to avoid rickets or disease. We’re supporting peak immune function, cognitive development, and long-term cardiovascular health,” notes a leading functional paediatrician.
Functional medicine focuses on what is optimal, not merely what is “not deficient.” This proactive philosophy is what sets it apart.
The Functional Approach to Testing Vitamin D in Children
Most children do not have their vitamin D levels routinely tested in conventional care unless there are signs of a bone disorder or malnutrition. Functional medicine takes a different approach.
Testing is typically done using a 25-hydroxyvitamin D (25(OH)D) blood test. Functional practitioners test early—often as part of a routine wellness check—and interpret the results based on optimal levels, not just minimum thresholds.
Testing is particularly recommended if a child:
- Has frequent colds or respiratory infections
- Is often fatigued or has a low mood
- Has autoimmune or inflammatory conditions (like eczema or asthma)
- Has limited sun exposure
- Is on a restricted diet (e.g., vegan)
Sources of Vitamin D: Are Children Getting Enough?
1. Sunlight
The best natural source of vitamin D is sun exposure, but modern lifestyles have changed this. Children spend more time indoors and use sunscreen regularly (rightfully so, for skin protection), which reduces vitamin D synthesis.
2. Food
Few foods naturally contain significant amounts of vitamin D. Fatty fish like salmon and sardines, fortified dairy products, and egg yolks can help, but dietary intake alone is rarely sufficient.
3. Supplementation
Because sunlight and diet often fall short, supplementation is commonly used in functional medicine to achieve optimal levels.
Functional medicine experts recommend individualized supplementation based on test results. For many children, this ranges between 400 IU to 2,000 IU daily, depending on need and lifestyle.
A functional cardiologist may also recommend vitamin D to support heart development and function in children at risk for cardiovascular issues.
Vitamin D and the Developing Heart
Emerging research supports vitamin D’s role in cardiovascular health, even in children. It helps regulate blood pressure, supports endothelial function, and modulates inflammation—factors that influence heart health long before adulthood.
Functional cardiologists now often look at vitamin D status in children with a family history of heart disease, high blood pressure, or metabolic conditions.
“It’s not just a bone vitamin. Vitamin D helps program the heart and vascular system during critical developmental years,” says one functional cardiologist.
This is a vital reason why optimal vitamin D levels in functional medicine are emphasized as early as infancy.
Risks of Low Vitamin D in Childhood
Low vitamin D levels can increase the risk of various health issues in children, including:
- Rickets (soft, weak bones)
- Frequent infections
- Mood disorders like irritability or low motivation
- Delayed growth or development
- Autoimmune conditions, including type 1 diabetes
- Asthma severity and flare-ups
- High blood pressure and heart rhythm issues
A proactive approach—testing, supplementation, and lifestyle changes—can significantly reduce these risks when guided by functional medicine.
Maintaining Optimal Vitamin D Levels Year-Round
1- Smart Sun Exposure
- Aim for 10–20 minutes of midday sun a few times per week (without sunscreen, on the face, arms, or legs).
- Adjust depending on skin tone, latitude, and season.
2- Nutritious Diet
- Include vitamin D-rich foods: oily fish, fortified milk, mushrooms, and eggs.
3- Targeted Supplementation
- Choose high-quality vitamin D3 (cholecalciferol) supplements.
- Work with a healthcare provider to adjust the dose based on lab results.
- Many functional practitioners combine D3 with vitamin K2 to support bone and cardiovascular health.
When to See a Functional Medicine Practitioner
If you suspect your child may have low vitamin D levels or you want a personalized wellness plan that includes proper nutrient testing and long-term health planning, seeing a functional medicine provider or a functional cardiologist (if heart concerns are present) is a wise choice.
Functional medicine provides:
- Deeper diagnostic testing
- Holistic lifestyle and nutrition advice
- Personalized supplement plans
- Root-cause analysis of health issues
Conclusion
Optimal vitamin D levels in functional medicine are viewed as a foundation of pediatric wellness—not just a vitamin to prevent rickets. From supporting the immune system to building strong bones and protecting the heart, vitamin D is a powerhouse nutrient for growing children.
By understanding the difference between “normal” and “optimal” vitamin D levels—and by working with professionals who take a proactive, functional approach—parents can give their children a healthier future. Whether through sunlight, food, or supplementation, supporting ideal vitamin D levels from an early age can create lifelong health benefits.
