Dr. Yim Answers Great Questions About Vitamin D
Vitamin D has become one of the most popularly consumed supplements. Its importance is so well known that all health professionals from naturopathic physicians, medical doctors, chiropractics, and physiotherapists are recommending their patients take it. Over the years, my patients have asked some really great questions about this vitamin. I want to share some of those questions and with you.
Q: What is the difference between vitamin D2 and D3?
A: Vitamin D2 come from plant sources such as mushrooms. Vitamin D3 come from animal sources such as cod or halibut oils, salmon, rainbow trout, and smaller amounts in eggs, liver, tuna, and cheese. Vitamin D3 is the form found in us humans when we make it from the sun. D3 seems to do a better and faster job of increasing blood levels.
Q: Besides bone health, what else does vitamin D do to benefit our health?
A: Vitamin D helps with skin growth and repair, muscle building and strength, blood sugar regulation, immune function (decrease risk of infections, certain autoimmune conditions, and lower rates of some cancers like breast, colon, and prostate), cardiovascular health (improves cholesterol and triglyceride levels), moods, and cognitive function.
Q: How much vitamin D should I take?
A: The only really way to know is to get your blood levels tested. The 25 - hydroxyvitamin D is what our doctors request from Life Lab. The reference range is between 75 and 250 nmol/L. Ideally you should be taking enough vitamin D to give you a result of around 160 which is about half way along the range.
Q: Should I stop taking my vitamin D before I get my test?
A: No, the result of the test will tell your blood level of D based on your current dose. One patient had been on 1,000 iu of D for a full year and her result was 62. She was surprised because that was the dose she thought was appropriate for an adult. Another patient was taking 5,000 iu and we wanted to make sure she wasn’t taking too much. Her result was 261. I suggested she might cut her dose down to 4,000 iu/day. This patient said she had osteoporosis and was comfortable to be slightly above the reference range in order to maximize her calcium absorption.
Q: Is there a toxic dose for vitamin D and what are the side effects of too much D.
A: One source I read reported the LD 50 is 37 mg/kg of body weight. LD 50 is the dose that will kill 50% of the people taking that amount. When I did the calculation for my body weight, I would have take more than 800,000 iu. Considering most products are 1,000 iu/serving, that would be 800 servings at one time. You get the idea. It’s pretty safe stuff. Too much vitamin D, where doses take you well above the reference can lead to high calcium in the blood. It is the high calcium that can lead to side effects such as nausea, vomiting, constipation, poor appetite, increase thirst, increase urination, muscle weakness or twitches, fatigue, confusion, bone pain, or high blood pressure. These might show up in doses greater than 10,000 iu/day. Definitely consult a naturopathic physician and do blood testing before and during dosing at high levels.
Q: Do you recommend taking vitamin D in the summer if one is getting lots of sun.
A: One summer years ago, a patient came to see me with the diagnosis of osteoporosis. She told me she would take 1,000 iu from fall to spring but not during the summer. To show me how much sun she would get, she pointed at the lovely tan she had from shoulders to hands and down her legs. I told her based on the fact that she has osteoporosis, we should see what her blood level of vitamin D is in the summer when she is not supplementing. It came back at 52 and she was shocked. I told her it is more difficult to make vitamin D from the sun as we get older and the increased melanin accumulated in her skin from her tanned skin actually acts as sun block, decreasing the amount of ultraviolet rays penetrating the skin in order to make D.
If you are one of those people who stops taking D in the summer, consult your health care provider for a requisition to get tested to see if you are in the range or low.
Q: A CT scan showed I have calcium building up in my aorta. My medical doctor told me to stop taking calcium and vitamin D. The problem is I have osteopenia and I don’t want this getting worse. I haven’t told my doctor, but I have been taking very high doses of D, in the 6,000 iu/day range. What should I do?
A: I suggested she test blood levels of calcium and vitamin D. When both came back high, I suggested she stop supplementing calcium for a while and just focus on calcium rich foods. We also cut down her D to 4,000 iu/day. Most importantly we had her add a high dose of vitamin K2. This vitamin stimulates proteins in bones and teeth that increase uptake of calcium in those two tissues. Studies have shown that high dose K2 also can reverse the inappropriate deposition of calcium in places it doesn’t belong like the artery walls and your kidneys.
Q: I have been informed that my vitamin D level is very low, but even after taking extremely high doses like 6,000 iu/day for 6 months, my level only slightly increased. How can I get my D levels up?
A: Call our clinic to make appointments for vitamin D to be given by intramuscular injection weekly. This bypasses the gut and goes directly into a muscle and then the circulation will distribute it around your body. After a number of injections, we will retest your blood. If the level is not adequate, we will continue the injections. If the level is fine, we maintain with the high dose of oral D with a periodic injection so the levels don’t drop low again.
Q: What factors can affect serum vitamin D levels?
A: The latitude where you live (high latitude less UV hitting your skin), air pollution (think smoke from forest fires), sunscreen, colour of your skin (more melanin, less UV getting through), age (older individuals are less efficient at making D), leaky gut (poor absorption), insufficient bile or lipase (important for D absorption), liver and kidney disease.