What are the benefits of Vitamin D?
Vitamin D deficiency
It has been stated within a review that around 1 in 6 adults and almost 20% of children in the UK have vitamin D levels lower than government recommendations. Older people, the housebound and people from Black and South Asian communities are more likely to have lower levels of this vital vitamin.
Sources of Vitamin D
In the UK, people obtain the majority of vitamin D from sunlight on their skin during the spring and summer, as dietary sources of vitamin D are limited. You can pbtain Vitamin D from:
- Sunlight: The primary source of Vitamin D is exposure to sunlight. When ultraviolet B (UVB) rays from the sun hit the skin, they trigger the conversion of a cholesterol derivative (7-dehydrocholesterol) into Vitamin D3 (cholecalciferol).
- Dietary Sources: Vitamin D can also be obtained through foods such as fatty fish (e.g., salmon, mackerel), egg yolks, and fortified foods (e.g., milk, cereals). Vitamin D2 (ergocalciferol) comes from plant-based sources and supplements.
How does Vitamin D work within the body
Vitamin D undergoes two hydroxylation steps to become active:
- Liver Conversion: Once produced in the skin or ingested, Vitamin D is transported to the liver, where it is converted into 25-hydroxyvitamin D [25(OH)D], also known as calcidiol. This is the main form measured in blood tests to assess Vitamin D levels.
- Kidney Conversion: Calcidiol is then transported to the kidneys, where it is further hydroxylated to form 1,25-dihydroxyvitamin D [1,25(OH)2D], also known as calcitriol, the biologically active form of Vitamin D.
Functions in the Body
- Calcium and Phosphorus Regulation: The primary role of active Vitamin D (calcitriol) is to regulate the absorption of calcium and phosphorus from the intestines. It ensures that adequate levels of these minerals are available in the bloodstream to support healthy bone formation and remodelling.
- Bone Health: By promoting calcium and phosphorus absorption, Vitamin D is essential for maintaining strong bones and preventing disorders such as rickets in children and osteomalacia or osteoporosis in adults.
- Immune System Support: Vitamin D plays a role in modulating the immune system. It enhances the pathogen-fighting effects of macrophages and other white blood cells while reducing inflammation. This helps the body respond more effectively to infections.
Other Roles
- Cell Growth and Function: Vitamin D helps regulate cell growth and differentiation, which may be linked to cancer prevention.
- Mood and Mental Health: Some studies suggest a connection between Vitamin D levels and mood regulation, with deficiencies linked to conditions like seasonal affective disorder (SAD) and depression.
Deficiency and Health Implications
Who is at risk of Vitamin D Deficiency
Inadequate UVB light exposure: Pigmented skin (non-white ethnicity). Lack of sunlight exposure or atmospheric pollution. Skin concealing garments or routine use of sun protection factor 15 or above. Housebound or indoor living (e.g. care homes). Seasonal.
Metabolic factors: Age 65 years old and over (reduced synthesis in the skin). Co-prescribed drugs with potential to affect vit D levels e.g. antacids, anticonvulsants (carbamazepine, oxcarbazepine, phenobarbital, phenytoin, primidone and valproate), calcium channel blockers, cholestyramine, digoxin, glucocorticoids, highly active antiretroviral treatment (HAART),
isoniazid, orlistat, rifampicin, sucralfate, thiazide diuretics. • Severe liver disease/failure. Chronic/end stage renal disease. Pregnancy or breast feeding. Obesity with BMI>30kg/m2 (vitamin D trapped in adipose tissue).
Inadequate dietary intake or absorption: Vegetarian (or other fish-free diet). Malabsorption (e.g. coeliac disease, Crohn’s disease etc.). Short bowel. Cholestatic liver disease, jaundice. Following bariatric surgery.
- Deficiency Risks: Low levels of Vitamin D can lead to weakened bones, increased risk of fractures, and diseases such as rickets in children or osteomalacia in adults. It can also impair immune function and may be associated with chronic conditions such as cardiovascular disease and autoimmune disorders.
- Symptoms of Deficiency: These may include bone pain, muscle weakness, fatigue, and frequent infections.
Vitamin D3 + K2
Vitamin K2 is a form of vitamin K that plays crucial roles in bone health, cardiovascular health, and other physiological processes. Here’s a breakdown of its primary functions:
1. Bone Health and Mineralization
- Calcium Regulation: Vitamin K2 is essential for directing calcium to the right places in the body, particularly bones and teeth. It activates a protein called osteocalcin, which binds calcium and integrates it into the bone matrix. This process helps strengthen bones and improve bone density.
- Preventing Osteoporosis: By supporting the proper distribution of calcium in the bones, Vitamin K2 reduces the risk of osteoporosis and fractures, especially in older adults or those with calcium deficiencies.
2. Cardiovascular Health
- Calcium Mobilization: Just as Vitamin K2 directs calcium to the bones, it also prevents calcium from depositing in the arteries and soft tissues, which can lead to calcification and hardening of the arteries (atherosclerosis).
- Activation of Matrix Gla Protein (MGP): MGP is a protein that inhibits calcium deposition in arterial walls. Vitamin K2 activates MGP, helping to reduce the risk of cardiovascular diseases by keeping arteries flexible and free of calcium buildup.
3. Dental Health
- Supporting Tooth Mineralization: Similar to its role in bone health, Vitamin K2 assists in the proper utilization of calcium in the teeth. This helps strengthen teeth and may contribute to fewer dental issues and cavities over time.
- Synergy with Vitamins D and A: Vitamin K2 works synergistically with vitamins D and A to regulate calcium and ensure it goes to bones and teeth rather than soft tissues. This combination also plays a role in overall dental health.
4. Cellular and Hormonal Health
- Mitochondrial Function: Some research suggests that Vitamin K2 may support mitochondrial function, which can improve cellular energy production and reduce oxidative stress.
- Hormone Production: There is emerging evidence that Vitamin K2 may play a role in hormone synthesis, particularly in supporting the production of sex hormones like testosterone.
5. Potential Anti-Inflammatory and Anti-Aging Effects
- Inflammation Control: Some studies suggest that Vitamin K2 has anti-inflammatory properties, which may contribute to its benefits for bone and cardiovascular health.
- Reduced Risk of Age-Related Conditions: By supporting heart, bone, and cellular health, Vitamin K2 may also play a role in reducing age-related health issues.
Recommended Dosage
The recommended dose of vitamin D is 10 micrograms (400 International Units (IU)) per day. Taking more than this dose is not necessary, but if you are unable to find a vitamin D supplement providing 10 micrograms (400 IU), products providing up to 25 micrograms (1000 IU) are suitable for everyone. Do not take more than 100 micrograms (4,000 IU) of vitamin D a day as it could be harmful. This applies to adults, including pregnant and breastfeeding women and the elderly, and children aged 11 to 17 years.
