For decades vitamin D was thought of only in terms of bone health. This nutrient decreases parathyroid hormone (PTH) levels which reduces calcium loss from bone. This is important for maintaining bone density.
However ongoing research reveals vitamin D plays a much broader role.
When converted by the body to its active form this nutrient actually has hormone-like functions. The active form of vitamin D is referred to as D3 and it is now recognised as a hormone, not a vitamin.
D3 is important for many aspects of health including supporting optimal thyroid hormone activity. D3 deficiencies occur more frequently than previously believed.
Reduced sun exposure along with ageing significantly decreases the skin’s capacity to activate D3. A specific blood test of D3, not vitamin D is a good place to assess D3 levels.
The body naturally makes vitamin D when the skin is directly exposed to ultraviolet B (UVB) rays from the sun. That’s why this nutrient is often dubbed the ‘sunshine’ vitamin.
Absorption of vitamin D occurs rapidly and you don’t need to tan or to burn in order to get adequate amounts. In addition, individuals with paler skin are able to produce vitamin D more easily than those with darker skin.
D3 deficiencies occur more frequently than previously believed and a significant number of individuals are at risk due to reduced sun exposure and the widespread use of sunscreens.
More than just bone health
Emerging research reveals vitamin D plays a much broader role to support health. The active form of vitamin D is referred to as D3 and it is now officially termed a hormone rather than a vitamin.
D3 is important for many aspects of health. Most notably this nutrient controls the way in which cells grow and divide. For this reason research continues into the anti-cancer effects of D3.
Some of the functions of the body that D3 supports include:
- Immune system to help fight infection
- Muscle function by reducing inflammation within the muscles
- Cardiovascular function for a healthy heart and circulation
- Respiratory system for healthy lungs and airways
- Brain development to ward off neurological decline
- Anti-cancer effects
Low D3 now common even in countries with abundant sunshine
The most natural way to get vitamin D3 is by exposing your bare skin to sunlight. However there are some limiting factors which can affect the amount of vitamin D your body can produce. This includes:
- The amount of skin you expose. The less skin you expose, the less vitamin D you can produce.
- Your age. As you get older, your skin has a harder time producing vitamin D.
- Wearing sunscreens. Sunscreens block a lot of vitamin D production.
- The altitude you live at. The sun is more intense at the top of a mountain than at the beach. This means you make more vitamin D when you live at a higher altitude.
- Cloudy weather. Less sunlight reaches your skin on a cloudy day and your skin therefore makes less vitamin D.
- Air pollution. Particles in polluted air reflect sunlight back into space. This means that if you live somewhere where there is lots of air pollution your skin produces less vitamin D.
- Working or living behind glass. Glass windows blocks UVB rays so you can’t make vitamin D even when there is sunlight outside.
- You avoid direct sun exposure. If you have had skin cancer or if you’re worried about exposing your skin to the sun you are more likely to have low D3 levels.
D3 and thyroid health
A recent study published in Endocrine Practice reveals low D3 may contribute to the severity of Hashimoto’s thyroiditis. This thyroid disorder is extremely common, especially in women. It is associated with high levels of autoimmune antibodies that directly target the thyroid gland.
Researchers found patients diagnosed with Hashimoto’s thyroiditis had significantly low levels of active D3 in their blood and the scale of the vitamin D deficiency correlated with the severity of the thyroid disorder.
Endocrine Practice is the official journal of the American College of Endocrinology (ACE) and the American Association of Clinical Endocrinologists (AACE).
Additional research is required to determine if low thyroid function causes a vitamin D3 deficiency, or low vitamin D3 status may contribute to a thyroid disorder.
Getting the right amount of vitamin D3
The 25-hydroxycholecalciferol blood test, abbreviated to 25 OHD is the most accurate way to measure how much vitamin D is present in the body.
It’s now accepted vitamin D can do so much more than simply prevent bone disease.
However the ground breaking research into the effects of vitamin D has significantly changed the viewpoints on the accepted reference ranges. It brings into question the current reference ranges that start at around 50 nmol/L.
The Vitamin D Council is a leading US research organisation committed to educating the public on the importance of vitamin D. They currently suggests that 50 ng/ml of 25 OHD is the ideal level to aim for. The equivalent metric measurement is 125 nmol/L.
Whereas the Endocrine Society recommends taking a vitamin D supplement of around 2,000 IU daily to reach and stay above a level of 30ng/ml or 75 nmol/l.
Until the experts agree on an acceptable target if you have been told your levels are low after a blood test it’s a good idea to take a vitamin D3 supplement to restore healthy levels. This is a simple, cost effective step to ensure adequate intake.
Balanced intake using a specific vitamin D3 supplement is the best strategy to consider as this form is more effective at raising levels 25 OHD in the blood than a D2 supplement.
Watch this video – How to make enough vitamin D for your thyroid
Louise O’ Connor, the author of The Natural Thyroid Diet –The 4-Week Plan to Living Well, Living Vibrantly, who is a specialist in Thyroid Health. She is a highly regarded Australian Naturopath and founder of Wellnesswork.
The Natural Thyroid Diet goes beyond diet advice and offers practical and effective ways to achieve healthy thyroid levels within just a short period of time. For more details, Click on The-Natural-Thyroid-Diet.com