Vitamin D is one of my ‘Desert Island’ supplements, assuming it was an island with no sunshine. Vitamin D is a fat soluble vitamin, but vitamin D is really a hormone that is involved in over 2000 reactions in your body, meaning it is fundamental to health and wellness.
What does vitamin D do?
- Plays a role in calcium absorption and bone health
- Backbone for steroid hormones such as testosterone and progesterone
- Keeps immune system healthy
- Manages appetite by raising leptin levels
- Muscle function
- Cardiovascular function, healthy lungs and asthma
- Brain development and mental health
Vitamin D deficiency is a problem is many countries including the US and UK. Often the public have no idea they are deficient in vitamin D or why it even matters. Due to fears about sun exposure and skin cancer, people wear sunblock and sunglasses, making the vitamin D deficiency problem worse. One common symptom of low vitamin D is pain. Many people go to their doctor for aches and pains or ‘bone ache’. If they are an older patient they get told its ‘wear and tear’ or ‘arthritis’ or just ‘old age’. Younger people with ‘aches and pains’ can end up with a diagnosis of fibromyalgia or chronic fatigue syndrome. Both these misdiagnoses and can simply be a vitamin D deficiency.
A lack of vitamin D has also been linked to conditions such as cancer, asthma, type-II diabetes , high blood pressure, obesity, depression, Alzheimer’s and autoimmune diseases like multiple sclerosis, Crohn’s and type-I diabetes.
Vitamin D and Weight
Low levels of vitamin D interferes with the function of a hormone called leptin. Leptin tells the brain that you are full and should stop eating. When leptin is low you feel hungry all the time and not satisfied even after eating a full meal. Being overweight compounds low vitamin D because extra body fat absorbs and ‘holds onto vitamin D’, making it unavailable for use by the rest of the body.
Is there just one kind of vitamin D?
When exposed to sunshine, your skin makes vitamin D3-sulphate which is a water soluble version of vitamin D3, and this version can travel all round the body, but still need to be activated. Oral vitamin D3 supplements are not unsulfated, so are less effective. When you go out in the sun your skin also synthesizes high amounts of cholesterol sulphate, which is very important for heart and cardiovascular health and yet another form of good cholesterol which is different to HDL. Cholesterol is something that requires a whole blog post of its own.
When you take a vitamin D supplement or eat foods containing vitamin D, your liver changes it to a substance called Vitamin D 25-OH, .To see if you have a Vitamin D deficiency a Vitamin D 25-OH test is required, not Vitamin D2 levels. Vitamin D2 is a different and weaker form of vitamin D, so a vitamin D3 supplement is superior. In order to do its job in the body the Vitamin D 25-OH has to be converted into activated vitamin D, and a variety of organs and tissue can do this via a series of chemical reaction. Your body can’t turn vitamin D3 into vitamin D3-sulphate or vitamin D2 into vitamin D3.
To summarise so far
- There are many forms of vitamin D and several chemical reaction eventually make ‘activated vitamin D.
- Vitamin D3-sulphate, from the sun is the best of all.
- Activated vitamin D manages calcium in the blood, bones and gut and help lots of different types of cells all in the body communicate properly.
How to get Vitamin D
Foods such as dairy and eggs contain vitamin D3. The most natural way to get vitamin D is by exposing your bare skin to sunlight (ultraviolet B rays). You only need to expose your skin for around half the time it takes for your skin to begin to burn. The length of time you need to spend in the sun varies as it will depend on your skin type, amount of skin exposed, age and where you live. Your body can produce 10,000 to 25,000 IUs of its own vitamin D after full body sun exposure. Older people’s skin finds it harder to make vitamin D, the darker your skin the longer you need to stay in the sun, while the closer you are to the equator the less time you need to stay in the sun. Wearing sun screen,being behind glass, out on a cloudy day or in a polluted city will reduce the amount of vitamin D your skin makes.
Dr. John Cannell is founder of the Vitamin D Council suggests doses of vitamin D3 at 1000iu per 25lb body weight for children and 6000iu for adults, with a maximum dose of 10,000ui, although some sources suggest more. Vitamin D can be harmful, usually if you take 40,000 IU a day for several months.
Excess Vitamin D and calcium without enough magnesium and Vitamin K2 to balance and partition the calcium (send the calcium to the right place) can causes calcium deposits in the soft tissue, arteries and other places in the body.
Thank you for reading
Vitamin D, Third Edition by Feldman D, Pike JW, Adams JS. Elsevier Academic Press, 2011.
Tao , Yuan Q, Mao L, Chen FL, Ji F, Cui ZH.Vitamin D deficiency causes insulin resistance by provoking oxidative stress in hepatocytes.Oncotarget. 2017 Jun 28
Fatima SS, Farooq S, Tauni MA, Irfan O, Alam F. J Effect of raised body fat on vitamin D, leptin and bone mass.
Pak Med Assoc. 2015 Dec;65(12):1315-9.
Li S, Niu G, Wu Y, Du G, Huang C, Yin X, Liu Z, Song C, Leng HVitamin D prevents articular cartilage erosion by regulating collagen II turnover through TGF-β1 in ovariectomized rats.Osteoarthritis Cartilage. 2016 .
Ali NS1, Nanji K1.CureusA Review on the Role of Vitamin D in Asthma.. Mol Cell Endocrinol. 2017 Jun 7.
Vitamin D deficiency in adolescents in a tier 4 psychiatric unit.Stewart NF, Lewis SN Psych Bull. 2017 Jun;41(3)
Dr. John Cannell Vitamin D council https://www.vitamindcouncil.org