Vitamin D

Introduction to Vitamin D Supplements

Vitamin D is an essential nutrient that plays a crucial role in overall health and wellbeing. This vitamin helps the body absorb calcium which is vital for strong bones. It also supports immune, cardiovascular and cognitive functions. Vitamin D deficiency is common in Australia, making supplementation an important consideration for many individuals. This article provides an overview of vitamin D - its functions, deficiency, and the benefits of supplementation. We also offer guidance on recommended intakes and choosing an appropriate vitamin D supplement.

What is Vitamin D?

Vitamin D is a unique vitamin that functions as a hormone in the body. There are two main forms - vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). Vitamin D3 is produced in the skin when exposed to sunlight. It can also be obtained through certain foods and supplements. Once ingested or synthesized, it undergoes transformations in the liver and kidneys to create the active form of vitamin D.

Importance of Vitamin D

Vitamin D has several critical roles in the body:

• It aids calcium absorption and bone metabolism - vitamin D helps maintain proper calcium and phosphate levels to support bone health.
• It supports immunity - vitamin D activates cells that fight infection and inflammation.
• It regulates cell growth - it can help inhibit the uncontrolled multiplication of cells seen in cancer.
• It influences cardiovascular function - vitamin D is linked to better heart health.
• It affects brain development and cognition - optimal vitamin D levels may protect cognitive abilities.

Sources of Vitamin D

The major natural source of vitamin D is sunlight. Ultraviolet B (UVB) rays interact with cholesterol in the skin to generate vitamin D3. However, factors like skin pigmentation, sunscreen use, and latitude impact vitamin D production.

Understanding Vitamin D Deficiency

With limited food sources, avoiding sun exposure, and other risk factors, vitamin D deficiency is widespread. Low levels are linked to poor bone health and potential problems like osteoporosis.

Causes and Symptoms of Vitamin D Deficiency

Causes of deficient vitamin D status include:

• Inadequate sun exposure - living in high latitudes, cold climates, mostly indoors
• Having darker skin tones - greater melanin reduces vitamin D production
• Being elderly - less efficient vitamin D synthesis
• Obesity - vitamin D is trapped in body fat
• Gastrointestinal disorders - diseases like Crohn's, celiac disease impair absorption
• Some medications - steroids, weight loss drugs decrease levels

Mild deficiency may have no obvious symptoms. More pronounced deficiency can result in:

• Bone and back pain
• Increased bone fractures
• Muscle weakness
• Mood changes - depression, anxiety
• Fatigue and tiredness
• Impaired wound healing
• Hair loss
• Poor growth and development in children

Consequences of Vitamin D Deficiency

Without adequate vitamin D, calcium absorption is impaired, resulting in secondary hyperparathyroidism. This causes more bone resorption, mineralization defects, and progressive bone loss over time. Results include soft, thin bones leading to:

• Rickets in children - bent legs, spinal deformities
• Osteomalacia in adults - weak, fragile bones
• Osteoporosis - increased fractures, disability, chronic pain

Vitamin D deficiency is also associated with increased susceptibility to viruses, autoimmune disorders, cardiovascular disease, diabetes, neurocognitive disease, and cancer. Optimizing vitamin D levels can help minimize these risks.

Benefits of Vitamin D Supplementation

Supplementing with vitamin D offers many benefits beyond just maintaining bone health.

Role of Vitamin D in Bone Health

Adequate vitamin D is essential for proper calcium absorption and utilization. This allows optimal bone mineralization and strength. Vitamin D supplements have been shown to:

• Reduce bone loss in elderly individuals
• Improve bone density and reduce fracture risk
• Help correct vitamin D deficiency to prevent osteomalacia
• Heal rickets and correct deformities in children
• Minimize falls by improving muscle function and strength

Other Potential Health Benefits of Vitamin D

Research indicates vitamin D may provide additional benefits:

• Enhanced immunity - reduced respiratory infections; faster recovery
• Lower cancer risk - decreased progression for some cancers
• Improved cardiovascular health - lower blood pressure; reduced risk of heart attack
• Better blood sugar control - linked to reduced diabetes prevalence
• Healthy cognition and mental health - may delay cognitive decline
• Reduced inflammation - helps manage chronic inflammatory conditions
• Faster wound healing and tissue regeneration

However, more research is needed to confirm many of these benefits conclusively.

Recommended Vitamin D Intake in Australia

The recommended dietary intake (RDI) for vitamin D in Australia is:

Age Group	RDI
Infants 0-12 months	5 μg/day
Children 1-18 years	5 μg/day
Adults 19-50 years	5 μg/day
Adults 51-70 years	10 μg/day
Adults >70 years	15 μg/day

Higher doses may be needed in some individuals to correct deficiency. However, vitamin D intake from all sources should not routinely exceed 80 μg/day.

Reference: Nutrient Reference Values for Australia and New Zealand

Safe Upper Levels of Vitamin D Intake in Australia

The safe upper limit for vitamin D intake in Australia is:

Age Group	Upper Limit
Infants 0-12 months	25 μg/day
Children 1-18 years	80 μg/day
Adults 19+ years	80 μg/day

Consuming too much vitamin D over time can lead to a toxic buildup of calcium in the blood and tissues. Symptoms of vitamin D toxicity include nausea, vomiting, poor appetite, constipation, weakness, and confusion. Excessive doses may also cause kidney stones and abnormal heart rhythms.

Factors Affecting Vitamin D Requirements

Some individuals need more vitamin D based on:

• Age - older adults synthesize less vitamin D and require higher intakes.
• Body weight - overweight and obese individuals need larger doses.
• Skin pigmentation - darker skin results in lower vitamin D production.
• Sunlight exposure - less sun requires higher vitamin D intake.
• Malabsorption disorders - conditions like celiac, Crohn's hinder vitamin D absorption.
• Medications - steroids, seizure drugs accelerate vitamin D breakdown.
• Pregnancy and breastfeeding - higher amounts needed for mom and baby.

Doctors can check vitamin D levels with a simple blood test to determine if supplementation is warranted.

How to Choose a Vitamin D Supplement

There are two main forms of supplemental vitamin D - D2 and D3. Vitamin D3 (cholecalciferol) is considered more potent and effective. When selecting a vitamin D supplement, keep the following factors in mind:

Types of Vitamin D Supplements

• Vitamin D3 - derived from animal sources; more bioavailable.
• Vitamin D2 - derived from plants; not as effective long-term.
• Calcitriol - active hormone form; prescribed for deficiencies.
• Multivitamins - contain smaller amounts of vitamin D.
• Fortified foods - provide varying vitamin D amounts.

Vitamin D3 has greater potency and longer lasting effects in the body. Look for supplements providing D3 not D2.

Considerations When Selecting a Supplement

• Dosage - depends on your needs and blood levels; average is 600-800 IU.
• Form - tablets, capsules, softgels, liquid drops all work.
• Quality - select reputable brands; look for independent testing.
• Additives - avoid unnecessary fillers, preservatives, artificial ingredients.
• Cost - find good value; prices range from 5-40 cents per 1,000 IU.
• Convenience - once daily dosing improves compliance.
• Safety - never exceed 80 μg per day from all sources.

Talk to your doctor before taking high doses for extended periods. Get vitamin D levels tested regularly if supplementing long-term.

FAQ

How much vitamin D should I take each day?

The recommended dietary allowance is 5-15 μg per day for adults in Australia. Some individuals need more based on age, body weight, sunlight exposure, and other factors. Upper intake should not exceed 80 μg per day without medical supervision.

When is the best time to take vitamin D?

Vitamin D supplements are best absorbed with a meal that contains fat or oil. Taking your daily dose during your largest meal will enhance absorption.

Can I get too much vitamin D?

Yes, excessive vitamin D intake over 80 μg per day can lead to a dangerous buildup of calcium in Australia. Symptoms of toxicity include nausea, vomiting, poor appetite, constipation, confusion, and abnormal heart rhythm. Do not exceed 80 μg per day without medical monitoring.

How long does it take to correct a vitamin D deficiency?

It can take 2-3 months for vitamin D levels to normalize after starting on the recommended daily dose. Your doctor may prescribe short-term high-dose vitamin D to rapidly boost levels if deficient. Get blood work done after 3 months to confirm your status.

Can I get enough vitamin D from the sun?

Some vitamin D comes from sunlight, but time outdoors and other factors limit how much you make through your skin. Diet and supplementation are needed for adequate intake, especially in the winter. Speak to your doctor about your specific requirements.

Are there any side effects of taking vitamin D?

Vitamin D is well tolerated at appropriate doses below 80 μg per day. Side effects like nausea, vomiting, weakness, and confusion only occur with extremely high intake. Stay below 80 μg per day unless prescribed higher temporary doses by your doctor.