Vitamin D: What It Is, What It's Used For and How to Get It

Vitamin D is a fundamental nutrient for the proper functioning of the human body. Unlike other vitamins, vitamin D functions more like a hormone that is activated in the body when we are exposed to sunlight. It is essential for absorbing calcium and phosphorus, strengthening bones and teeth, and maintaining a healthy immune system.

"Vitamin D is not just a vitamin, it is a fundamental pillar of your bone health and immune system." - Optimal Nutrition Principle

What is Vitamin D?

Vitamin D is a fat-soluble nutrient that plays a crucial role in calcium and phosphorus absorption by the body. Without adequate levels of vitamin D, our body cannot efficiently use these minerals, which can lead to serious health problems.

There are two main forms of vitamin D:

• Vitamin D2 (ergocalciferol): From plant sources
• Vitamin D3 (cholecalciferol): From animal sources and the most effective form for the human body

How Does Vitamin D Work in the Body?

What makes vitamin D unique is its activation process. When you're exposed to direct sunlight, ultraviolet B (UVB) radiation interacts with the skin, triggering vitamin D3 synthesis. Subsequently, this provitamin travels to the liver and kidneys, where it transforms into its active form: calcitriol.

Once active, vitamin D:

• Facilitates intestinal absorption of calcium and phosphorus
• Regulates blood calcium levels
• Participates in bone mineralization
• Supports the immune system
• Influences muscle function

What Vitamin D Is Used For: Essential Functions

1. Bone and Dental Health

The best-known function of vitamin D is its role in bone health. It allows the body to absorb the calcium necessary to:

• Form and maintain strong bones
• Prevent osteoporosis in adults
• Avoid rickets in children
• Strengthen dental structure

Without sufficient vitamin D, bones become fragile, thin and brittle, increasing the risk of fractures.

2. Immune System

Vitamin D is a key modulator of the immune system. It helps defense cells identify and combat pathogens more effectively.

Recent studies have shown that adequate vitamin D levels can:

• Reduce the risk of respiratory infections
• Decrease the severity of autoimmune diseases
• Support healthy inflammatory response

3. Muscle Function

Vitamin D is fundamental for optimal muscle function. Low levels are associated with:

• Greater risk of falls in older people
• Muscle weakness
• Coordination difficulties
• Slower recovery after training

For athletes and people who train regularly at our gym, maintaining optimal vitamin D levels is crucial for performance and recovery.

4. Mental and Cognitive Health

There is increasing evidence on the relationship between vitamin D and mental health:

• Can help reduce the risk of depression
• Improves cognitive function
• Protects against age-related brain deterioration

"The sun doesn't just brighten your day, it also brightens your mind." - Nutritional Wisdom

Vitamin D Sources: How to Get It

Sun Exposure: Your Best Ally

Sunlight is the most efficient source of vitamin D. That's why it's known as the "sunshine vitamin".

How much sun do you need?

• 10-15 minutes per day of direct exposure
• 3-4 days per week is usually sufficient
• Expose arms, legs or back without sunscreen (initially)
• During hours of lower intensity (before 11:00 AM or after 4:00 PM)

Important: The ability to synthesize vitamin D varies according to:

• Skin color (darker skins need more time)
• Age (decreases with years)
• Geographic latitude
• Season of the year

Foods Rich in Vitamin D

Although the sun is the main source, you can also obtain vitamin D through diet:

#### Fatty Fish (Main Source)

• Salmon (wild): 600-1000 IU per 100g serving
• Tuna: 200-300 IU per serving
• Mackerel: 400-600 IU per serving
• Sardines: 200-300 IU per serving

#### Cod Liver Oil

One tablespoon provides approximately 1,360 IU of vitamin D, although in lower concentration than fresh fish.

#### Dairy and Derivatives

• Fortified milk
• Enriched yogurt
• Cheeses (to a lesser extent)

These products are important in a balanced diet to gain muscle mass or lose fat.

#### Eggs

The egg yolk contains approximately 40 IU of vitamin D per unit. Additionally, it provides high-quality protein and other essential nutrients.

#### Mushrooms

Mushrooms are the only significant plant source of vitamin D:

• Mushrooms exposed to UV light: up to 400 IU per 100g
• Common mushrooms: 10-20 IU per 100g

Mushrooms contain vitamin D2, while animal-source foods contain D3.

Vitamin D Deficiency: Risks and Symptoms

Vitamin D deficiency is more common than you think, especially in countries with fewer hours of sun or in people who spend a lot of time indoors.

Symptoms of Vitamin D Deficiency

• Chronic fatigue and constant feeling of tiredness
• Bone and muscle pain
• Muscle weakness
• Low mood or depression
• Frequent infections
• Slow wound healing
• Loss of bone density

Diseases Related to Deficiency

#### In Adults:

• Osteoporosis: Fragile and porous bones
• Osteomalacia: Bone softening
• Greater risk of fractures
• Progressive muscle weakness

#### In Children:

• Rickets: Bone deformities and growth delays
• Motor development problems
• Soft and curved bones

Risk Factors

Some people have greater risk of deficiency:

• People with little sun exposure
• Older adults (skin synthesizes less vitamin D)
• People with dark skin
• People with obesity (vitamin D gets trapped in fatty tissue)
• Patients with digestive diseases (Crohn's, celiac)
• People living at high latitudes

"Vitamin D is not optional, it's fundamental. Your body demands it every day." - Preventive Health Principle

Excess Vitamin D: Is It Possible?

Although rare, vitamin D toxicity can occur, usually from excessive supplementation, not from sun exposure or diet.

Symptoms of Excess Vitamin D

• Hypercalcemia: Excess calcium in blood
• Nausea and vomiting
• Muscle weakness
• Abdominal pain
• Dehydration
• Mental confusion

Risks of Excess Calcium

• Progressive kidney damage
• Kidney stones
• Calcium deposition in soft tissues:
• Heart
• Lungs
• Blood vessels
• Tendons
• Gastrointestinal problems
• Involuntary weight loss

Safe dose: Most experts agree that up to 4,000 IU daily is safe for healthy adults. However, always consult a healthcare professional before taking supplements.

Vitamin D and Training: Optimal Performance

For those who train regularly, vitamin D is especially important:

Performance Benefits

• Better muscle function and strength
• Faster post-training recovery
• Reduction of muscle inflammation
• Lower risk of injuries
• Strengthened immune system (fewer interruptions due to illness)

If you're following a personalized training program, make sure your vitamin D levels are optimal.

Recommendations for Athletes

• Regular blood tests (minimum 1-2 times per year)
• Conscious sun exposure (especially in winter)
• Diet rich in fatty fish
• Supplementation if necessary (under supervision)

How to Optimize Your Vitamin D Levels

Action Plan:

• Regular Sun Exposure
• 10-15 minutes daily, 3-4 times per week
• Without initial sunscreen (then apply for prolonged protection)
• On arms, legs or back

• Strategic Nutrition
• Include oily fish 2-3 times per week
• Consume whole eggs (with yolk)
• Add mushrooms to your meals
• Choose fortified dairy products

• Smart Supplementation
• Only if deficiency is confirmed
• Prefer vitamin D3 over D2
• Typical dose: 1,000-2,000 IU daily (under supervision)
• Take with a meal containing fat (better absorption)

• Monitoring
• Blood test: optimal level between 30-50 ng/ml
• Adjust according to results and season

Frequently Asked Questions about Vitamin D

Can I get vitamin D through window glass?

No. The UVB rays needed to synthesize vitamin D don't pass through glass. You need direct sun exposure.

Does sunscreen block vitamin D production?

Yes, sunscreen significantly reduces vitamin D synthesis. That's why brief unprotected exposure followed by sunscreen application for prolonged exposures is recommended.

How much vitamin D do I need per day?

• Adults: 600-800 IU daily
• Over 70 years: 800-1,000 IU
• Athletes and active people: 1,000-2,000 IU may be beneficial

Are supplements necessary?

Not for everyone. If you have regular sun exposure and balanced diet, probably not. However, in winter, older people or those with little sun exposure may benefit.

Conclusion: Vitamin D, Your Invisible Ally

Vitamin D is much more than a simple vitamin: it's a fundamental hormonal regulator for your bone, muscle, immune and mental health.

Remember:

• ✅ Regular sun exposure is your best source
• ✅ Diet rich in fatty fish complements your diet
• ✅ Monitor your levels if you have risk factors
• ✅ Supplement only if necessary and under supervision

"The sun is free, bone health is priceless. Take advantage of both." - Natural Health Philosophy

If you need personalized advice on nutrition and supplementation to optimize your performance, our private consultation services can help you design a plan adapted to your needs.

Your body needs vitamin D to function optimally. Give it what it needs: sun, good food and nutritional awareness.