Vitamin D – Is this our miracle solution?
When you look up Vitamin D on the internet and all the wonderful things it can do for you, you could be forgiven for thinking that Vitamin D is the new wonder drug. There is even a book called “The Vitamin D Solution.”
Vitamin D has been said to cure cancer, multiple sclerosis (MS), diabetes, dementia, heart disease and improve bone health.
So, is all this true? And if it is…. How much do you need to take, how do we get it and is it possible to have too much?
Vitamin D is an essential nutrient for our body. Its main purpose is to help us absorb and regulate calcium and phosphate which are the main ingredients in bone. Having adequate amounts of calcium, phosphate and Vitamin D ensure strong bones which do not easily break.
Vitamin D also plays several other important roles in the human body, including:
Assisting muscle function allowing your body to maintain strength and reducing the risk of falls as we age.
Assisting nerve cell transmission which maintains brain function and
Assisting immune function which allows us to fight off viruses and bacteria such as the flu and pneumonia.
How do we get Vitamin D and how much should we have?
Vitamin D is contained in small amounts in fatty fish like salmon, tuna, egg yolks, beef liver and cheese, but is poorly absorbed from food. Many foods have Vitamin D added into them, such as milk, yoghurt and margarine.
Our primary source of Vitamin D is exposure of our skin to ultraviolet (UV) light. When this occurs, the human body will make Vitamin D in the skin.
The recommended daily intake is:
Birth to 12 months 10 mcg/day (400 international units or IU)
1 – 70-year-olds 15mcg/day (600 IU)
Adults over the age of 71 years 20 mcg/day (800 IU)
Pregnant and breastfeeding women 15mcg/day (600 IU)
There are also some groups in the community who should take Vitamin D supplements. These include:
Breastfed babies as breastmilk alone does not contain enough Vitamin D. These babies should have 10mcg or 400 IU per day.
Elderly people as the skin produces less Vitamin D as you age.
People with darker skin as their skin produces less Vitamin D.
People who do not go out in the sun or who only go out in the sun with sunscreen on.
People who are unable to absorb appropriate amounts of Vitamin D. e.g. those who have undergone gastric surgery.
People who follow a vegan diet.
People who are unable to absorb fat properly, e.g. those with inflammatory bowel disease, cystic fibrosis or coeliac disease.
What is fact and what is fiction about the benefits of Vitamin D?
1. Bone health or osteoporosis
Having adequate levels of Vitamin D significantly reduces the risk of osteoporosis (thin bones). One of the most common effects of osteoporosis is hip fractures which is one of the leading causes of morbidity, mortality and nursing home placement for elderly Australians. If you do have low levels of Vitamin D, supplementation will reduce the risk of osteoporosis, fractures and also falls.
2. Mobility
When Vitamin D is deficient, muscles can become weak, and balance can become impaired. If you are Vitamin D deficient, supplementation should improve your mobility.
3. Cancer
Whilst there has been a lot of talk on social media about Vitamin D being able to prevent cancer there is very little evidence, if any, to support this.
4. Heart disease
Adequate Vitamin D levels are important to maintain healthy blood pressure and cholesterol and these in turn reduce the risk of heart disease. This can be achieved via supplementation if Vitamin D levels are low.
5. Depression
Your brain needs adequate levels of Vitamin D to maintain cognitive function and there have been studies which have shown a link between Vitamin D deficiency and depression. However, clinical studies have not been able to show an improvement in depression with Vitamin D supplementation alone.
6. Multiple sclerosis (MS)
There is a well-recognized association between Vitamin D deficiency, living further away from the equator and rates of MS development. It is thought that low Vitamin D might be a risk factor for developing MS. However, so far there have been no studies which have shown a reduction in the incidence of MS with Vitamin D supplementation.
7. Type 2 diabetes
Vitamin D helps to regulate blood sugar levels. However, there have been no clinical trials which have shown that Vitamin D supplementation prevents prediabetes from developing into diabetes or improving diabetic control.
8. Brain function
Several studies have found that Vitamin D assists with nerve conduction and Vitamin D levels may be low in patients with Alzheimer’s, cognitive impairment, dementia and Parkinson’s disease. It is likely that maintaining adequate Vitamin D levels could protect against cognitive impairment. However, there have been no studies which have shown that Vitamin D supplementation can prevent or treat these illnesses.
9. Nerve pain
A deficiency in Vitamin D may be linked to nerve pain with some studies showing an association between low Vitamin D levels and the severity of diabetic peripheral neuropathy which is destruction of nerves in the hands and feet associated with chronic diabetes. It is possible but not proven that supplementation with Vitamin D could help alleviate nerve pain in these patients.
Vitamin D supplementation is also used in chronic daily migraine sufferers to stabilize nerve pain.
10. Immune function
Vitamin D is known to have anti-inflammatory properties, and Vitamin D deficiency has been associated with a reduced risk to fight off common infections. There are now some studies underway looking into how Vitamin D levels might impact COVID-19 outcomes.
11. Weight loss
Unfortunately, there have been no studies which have shown an association between Vitamin D supplements and weight loss.
Can too much Vitamin D be harmful?
Vitamin D supplements can interact with other over the counter and prescribed medications so always tell your doctor if you are taking Vitamin D supplements.
Acute effects of taking excessive Vitamin D supplements include:
Nausea
Vomiting
Muscle weakness
Confusion
Pain
Loss of appetite
Dehydration
Excessive urination
Thirst
Chronic effects of taking excessive Vitamin D supplements include:
Kidney stones
Kidney failure
Irregular heartbeat
You can only have high Vitamin D levels by taking Vitamin D supplements, not from sun exposure.
So, what is the take home message?
Having adequate levels of Vitamin D is important for many aspects of good health and may need to be achieved with Vitamin D supplementation. However, more is not MORE as there is no additional benefit to over supplementation.
REFERENCES
1. The National Institute of Health. Vitamin D. https://ods.od.nih.gov/factsheets/VitaminD-Consumer/ [20/11/2024].
2. Prevention: Here’s how to get enough vitamin D according to the experts. https://www.prevention.com/health/a35183225/vitamin-d-benefits/?utm_source=google&utm_medium=cpc&utm_campaign=mgu_ga_pre_md_pmx_hybd_mix_us_20739785489&gad_source=1&gbraid=0AAAAADA2LlJzyA00VeI9uAX4eIzG92Eoa&gclid=Cj0KCQiAi_G5BhDXARIsAN5SX7o_X8r3TDfbq1Nt3dC8ruF2ErcS-lN8h63tQPc32sqszD7mBYEqlfMaAhcrEALw_wcB [20/11/2024].
3. Health Direct: Vitamin D and your health: https://www.healthdirect.gov.au/amp/article/vitamin-d-and-your-health [20/11/2024].
4. Healthy Bones Australia: Vitamin D and bone health factsheet: Chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://healthybonesaustralia.org.au/wp-content/uploads/2022/10/hba-fact-sheet-vitamin-d.pdf [20/11/2024].