Vitamin D is much more than just "the sunshine vitamin" - it's an essential nutrient that functions almost like a hormone in our body, affecting more than a thousand different genes and playing a crucial role in our overall health. Despite its importance, approximately one billion people worldwide have suboptimal levels, including 70% of the American population.
What exactly is vitamin D?
Vitamin D is a fat-soluble vitamin, which means that:
- It needs fats from our diet to be properly absorbed
- It's stored in our adipose tissue and liver
- It works similarly to other fat-soluble vitamins (A, E, and K)
However, vitamin D is unique because it acts more like a hormone than a traditional vitamin, influencing numerous bodily processes.
Fundamental health benefits
1. Bone health
The best-known function of vitamin D is its essential role in bone health:
- Increases calcium absorption, fundamental for strong bones
- Deficiency can cause bone deformities such as rickets in children
- Prevents osteoporosis and osteomalacia (bone softening) in adults
Practical tip: A simple test to detect possible deficiency is to press firmly with your thumb on your shin - if it hurts, you might have insufficient levels of vitamin D.
2. Powerful immune system
Vitamin D is fundamental for strengthening our immune system:
- Modulates the production of immune cells and cytokines
- Regulates T cells and B cells, critical components of our immune system
- Significantly reduces the risk of infections
During the COVID-19 pandemic, it was observed that:
- People with vitamin D levels above 50 ng/ml had zero risk of mortality
- Low levels increased the risk of hospitalization, ICU admission, or death by 70%
- An Israeli study showed a 1400% increase in severe COVID in patients with deficiency
3. Protection against chronic diseases
Vitamin D also plays a crucial role in preventing numerous diseases:
- Regulates cell growth and promotes the elimination of damaged cells
- Reduces inflammation, a common factor in many chronic diseases
- Decreases the risk of various types of cancer (breast, prostate, ovarian, lung)
A 2018 study found that women with levels above 60 ng/ml had 82% less risk of breast cancer compared to those with levels below 20 ng/ml.
Who is at higher risk of deficiency?
Certain groups have an elevated risk of vitamin D deficiency:
- People with dark skin (higher melanin reduces production)
- Residents of northern latitudes (less sun exposure)
- Older adults (skin produces less vitamin D with age)
- People with obesity (body fat retains vitamin D)
- Individuals with digestive or gallbladder problems
- Those taking certain medications (steroids, acid blockers, anticonvulsants)
How to get enough vitamin D?
Safe sun exposure
The natural way to get vitamin D is through sun exposure:
- Seek moderate exposure between 10 a.m. and 3 p.m.
- Recommended time varies according to skin tone: 10-15 minutes for light skin, 25-40 minutes for darker skin
- Expose arms, back, and legs (you can protect your face with sunscreen)
- The goal is not to burn while gradually building pigmentation
Important: Use non-toxic mineral sunscreens. Check the Skin Deep database from Environmental Working Group for safe options.
Adequate supplementation
For most people, supplementation is necessary:
- The typical dose ranges from 2,000-5,000 IU daily
- Some people may need up to 10,000 IU depending on their current levels
- Take the supplement with foods containing fat to improve absorption
- Check your levels every 3-6 months to adjust the dose as needed
Know your levels: measuring is key
The fundamental principle for vitamin D is "measure, don't guess":
- Request the 25-hydroxy vitamin D test (the correct measure)
- The optimal level is between 45-75 ng/ml
- Levels above 100-150 ng/ml are still safe
- Standard reference ranges (20-30 ng/ml) are insufficient for optimal health
Regular testing is essential to personalize your dose and ensure you're maintaining optimal levels to protect your long-term health.
Vitamin D is truly a fundamental nutrient that we should all prioritize. Maintaining optimal levels could be one of the simplest and most effective strategies to protect our health and prevent chronic diseases in the long term.