Tuesday, August 6, 2013
Vitamin D and Transverse Myelitis
We all need adequate Vitamin D. It is a steroid hormone crucial for calcium and phosphate absorption, and therefore very important in helping us avoid osteoporosis as we age. In addition, it has become clear that low levels of vitamin D may be connected to Alzheimer's disease, Parkinson's disease, multiple sclerosis, epilepsy, and schizophrenia. Of crucial importance to those of us with Transverse Myelitis, higher intake of vitamin D is associated with a lower risk for Multiple Sclerosis across the world. At this point, there is no direct evidence for a similar effect in TM, but there are similarities between the two diseases.
There are two forms of Vitamin D, both metabolised by the liver. D2 (ergocalciferol) comes from our food, being found in fish and milk. D3 (cholecalciferol) is formed in our skin after exposure to sunlight or ultra violet radiation. You can have your blood levels measured by your local doctor. A blood concentration of less than 30ng/mL is considered low, and may have short-term consequences like poor sleep or recurrent headaches. In the summer, our levels may rise to 80ng/ml. People with darker skin pigmentation may have more difficulty creating D3 from exposure to sun. Those living at higher altitudes or in generally colder climates with less year round sun, may not get enough. If you are obese, the cells in your skin that make the D3 may not get enough sun. And, generally as we age our skin absorption is less efficient. Low levels (known as Hypovitaminosis D) are associated with increased pro-inflammatory cytokines and decreased anti-inflammatory cytokines - that is in general you may not deal with infections and body repair very well.
Vitamin D metabolites are normally found in the brain, for instance in the substantia nigra (responsible for motor function), so they must have the ability to cross the blood brain barrier. They are also found in the hypothalamus, which links the nervous system to the endocrine system, but is also important for control of emotions, new learning and a whole lot more. Vitamin D receptors are in fact widespread in the brain, and we must assume it is important for brain and nervous function in humans, indirectly being responsible for the growth and survival of neurons.
A goal of supplementation is to keep blood levels between 30 and 80ng/ml. A general recommendation is take an extra 600-800 IU per day, but that may be somewhat cautious. Overall we may need 5,000 IU per day just to maintain our levels, though some sources set the toxic level at about 4,000 IU per day. There is no evidence yet what may be the right level for people with TM, and it is possible we need to have an intake at the higher end of this recommendation. There may be some dangers in taking too much Vitamin D, so you must be reasonable about how you go about your supplementation. Taking 50,000 international units (IU) a day of vitamin D for several months has been shown to cause Vitamin D toxicity with a build-up of calcium in your blood (hypercalcemia) which, in turn, can cause symptoms such as poor appetite, nausea and vomiting, weakness. Kidney problems can also occur over time.
It is probably a good idea to see your doctor and get blood levels and then monitor those every few months until you have established a regime. A dietitian can help you to organise your diet to make sure you are getting the best for TM.
Just for the record
One tablespoon cod liver oil contains about 1,300 IU of vitamin D, which is more than twice the recommended dietary allowance of 600 IUs per day. It doesn't exceed the maximum level intake of 4,000 IU for people over 9 years old, but it exceeds the daily maximum for infants (1,000 IU). Again be cautious...
Fatty fish is a good source of vitamin D (eg salmon, trout, mackerel, tuna, and eel) as well as Omega 3 fatty acids. A 3-ounce salmon fillet has about 450IU of Vitamin D. Canned tuna has about 40 IUs per ounce and canned sardines have about 20 IUs per sardine.
Certain mushrooms, particularly those grown in UV light rather than in the dark (eg Shitake) can give you 400IU of vitamin D for a 3-ounce serving (about 1 cup of diced mushrooms).
There is vitamin D in egg - about 40 IU in one yolk. But one egg contains about 200 milligrams of cholesterol, and most authorities recommend no more than 300 milligrams a day to avoid heart problems.
A cup of milk has 100 IU, so you would need a lot of milk to keep up daily requirements. There are fortified milks that may contain higher levels. You can also get vitamin D from fortified orange juice. One 8-ounce glass of fortified juice usually has around 100 IUs of vitamin D, though that will vary by brand.
When we sit in the midday sun, with chest, face, and arms exposed for 15 minutes or so, we can make at least 5,000 IU of vitamin D. But obviously we have to balance this to avoid sunburn. Brighter sun, or extended exposure, and we may damage the skin. So take care, but perhaps make a ritual of sitting out in the sun for 15 minutes or so, ceasing if you begin to burn.
If you can’t get sun, but believe you may be at risk of vitamin D deficiency you could try a UV lamp. However, again be careful. There are some skin-cancer risks (like with too much sun) and you need protective eyewear.