Dear Reader,
I am especially excited to bring you this month's CAM News issue. Along general information about the vitamin I will be discussing, I am going to share with you the results of a study done in Omaha, Nebraska. Cedric Garland, a prominent researcher of the vitamin I will be reporting on calls the study "… a breakthrough of great medical and public health importance." This month we are continuing our series on vitamins. Mainly the fat soluble vitamins. I have already covered vitamin A here. The July issue of CAM News will cover another fat soluble vitamin. Read on…
Technorati Tags: cancer, cholecalciferol, dermatologist, dermatology, ergocalciferol, fat soluble vitamins, hypercalcemia, negative feedback loop, osteomalacia, osteoporosis, rickets, vitamin, vitamin d prevents cancer, vitamin D3
Vitamin D ( Williams' Essentials of Nutrition & Diet Therapy, 2007)
Vitamin D is a prohormone and when in it's active form functions as a hormone. When vitamin D was first discovered it was actually classified as a vitamin. The classification stuck. Vitamin D is a sterol and the precursor fatty molecule is found in human skin. Vitamin D is soluble in fat. It is heat stable and does not oxidize very easily.
There are five forms of vitamin D, but only two of them are utilized by the body.(1)
Vitamin D2, ergocalciferol, and
Vitamin D3, cholecalciferol.
Vitamin D2 does not concern us here, but for your information, it is derived from irradiating ergosterol which is fund in ergot, a fungus growing on cereal grains. On to vitamin D3, cholecalciferol. Vitamin D3 however is of major concern to us humans. It is formed by ultraviolet light on the fatty molecule mentioned above. This fatty molecule is called 7-dehydrocholesterol, and again, it resides in our skin. Vitamin D3 can also be found in some dietary sources. More of the dietary sources later.
Absorption, Transport, Storage(2)
Vitamin D is absorbed by the body in the small intestine in concert with fat. Sufferers from gastric diseases such as celiac disease, cystic fibrosis, Crohn's have difficulty absorbing enough vitamin D.
The Active Hormone Synthesis works something like this. (It gets a bit technical, but bear with me.)
1. Light from the sun arouses 7-dehydrocholesterol in the skin which is converted to vitamin D3, cholecalciferol. Or we can consume food containing cholecalciferol.
2. The next step is the liver, where cholecalciferol is hydroxilated to 25-hydroxy vitamin D3 (25-hydroxycholecalciferol) via an enzyme called 25-hydroxylase.
3. The last step of the hormone synthesis takes place in the kidney in which the product from the previous step, 25-hydroxycholecalciferol, serves
as a building block for 1-alpha-hydroxylase, resulting in the formation of 1,25-dihydroxycholecalciferol, the biologically active form.
A little side not here: So much for my hypothesis I had developed for myself when I was 13, sitting through, what seemed endless hours of chemistry classes. The hypothesis: I never, ever was going to need chemistry again in my life. As any scientist will tell you: a hypothesis is just that, and in light of new evidence we can then create a scientific theory based on a sound hypothesis. Well needless to say, my hypothesis was less than sound and got shot down, even before it had a chance to take off. Chemistry is everywhere. Now I find myself signing up for one chemistry class after another one. Enough with the anecdotal stories. Back to vitamin D.
We have reached our final destination. Our internal chemical factory created something the body actually can work with.
Functions of the Vitamin D Hormone(3)
Vitamin D was thought to be mainly responsible for calcium and phosphorous absorption. With continued research we keep on finding more and more useful functions of vitamin D. Calcium levels are maintained in the body via negative feedback loop. A term, I had pleasure discussing extensively in biology class. Vitamin D works on the intestine to absorp calcium and phosphorous and it assists in the deposit of these in the bone. It is the parathyroid hormone and calcitonin which are responsible to trigger the negative feedback loop and thus maintain proper calcium levels in the blood. Without proper vitamin D3 this process is already inhibited before it has a chance to get started.
Further functions of vitamin D are found to include cell growth, muscle strength, immune function, and insulin levels. A word about cell growth and a study showing promise to possibly prevent several deadly cancers.
The speed of cell division in organic tissues such as the colon, breast, and lung is monitored and kept in check by vitamin D. It is exactly this trait of vitamin D, to proliferate abnormal cells, before they could become malignant, which is of interest to cancer researchers. And wouldn't you know it, there seems to be a study out there reaching the exact same conclusion, by accident mind you, but nontheless.
This study carried out by Creighton University in Omaha,(4)was conducted on 1,179 commonly healthy women with an average age of 67. Three subgroups were formed. 446 received calcium and vitamin D₃ supplements, 445 received just the calcium, and 288 were given a placebo. The daily dose was 1,000 IU of vitamin D3. Current DRI's recommend 5 to 15 mcg per day or 200 to 600IU depending on age and gender. As I mentioned before, the main focus of the study was the effect of calcium on bone health. The outcome on cancer risk was intended to be secondary. Boy, were the researchers in for a surprise! To quote Cedric Garland, again: "No other method to prevent cancer has been identified that has such a powerful impact."(5)
The Outcome?(6)
13 women, or 3 percent developed cancer over four years with calcium and vitamin D3 supplementation.
17 women, or 4 percent developed cancer over four years with calcium supplementation alone.
20 women, or 7 percent developed cancer over four years with placebo pill supplementation.
Translation?
A whopping 60 percent, again, a whopping 60 percent lower risk of cancer for the group taking both supplements, calcium and vitamin D3. It gets better yet, when researchers excluded first year cancers, ones most likely present before the study began, the combo supplementation group had a 77 percent lower risk of cancer. Again a 77 percent lower risk of cancer.
Dr. Michael Holick of Boston University Medical Center mentioned that this study showed that enough vitamin D3 "markedly reduced the risk of developing the most serious deadly cancers." This is due the fact, that the women in the study who actually were developing cancer, developed a broad range of cancers such as cancers of the breast, colon, lung, and blood. His suggestion is to up the dosage to 1,000IU of vitamin D3. Dr. Holick is the guy who sat on the panel that issued the 1997 guidelines for vitamin D. And of course there is the disclaimer. All of the persons interviewed mentioned to discuss any changes of dietary vitamin D intake with your physician.
And here is why:(7)
Vitamin D is fat soluble and as such it is stored in the body. To be more precise, it is stored in the adipose tissue of the body. Daily doses of 1,000mcg or 40,000IU could cause severe intoxication, which is called hypervitaminosis D. Symptoms are weakness, bone pain, and hypercalcemia. The upper intake level or UL for vitamin D is set a 50mcg.
Food Sources
Now to the food sources of vitamin D. Unfortunately, vitamin D3 does mostly occur naturally in fish liver oils, and a small amount can be found in egg yolk. That is it, the rest has to come from fortified foods, or yes, you guessed right, sunlight. But here is the caveat with that. Pretty much every dermatologist will tell you to stay out of the sun, or slab SPF cream en masse on your exposed skin. If you use SPF 15, vitamin D production is reduced by, get this, 99 percent.(8) This is according to a study by Dr. Michael Holick, of Boston University Medical Center. He was mentioned above.
Vitamin D fortified foods include ready to eat cereals, orange juice, milk, and soy milk.(9)
Vitamin D Deficiency(10)
Without vitamin D the body can not make normal bones, in children this is known as rickets. In adults a similar condition develops called, osteomalacia. This happens when deposited bone minerals start moving out of the bone tissue, resulting in weak, brittle bones. An then there is of course osteoprosis, a disease of bone in which the bone mineral density (BMD) is reduced.
Thank you for reading. In next month's issue of CAM News I will cover yet another fat soluble vitamin. Until then:
Beste Gesundheit,
Werner
References:
1. Schlenker E., Long S. "Williams' Essentials of Nutrition and Diet Therapy." (2007) Mosby-Elsevier. St Louis, Missouri p.114
2. Schlenker E., Long S. "Williams' Essentials of Nutrition and Diet Therapy." (2007) Mosby-Elsevier. St Louis, Missouri p.114-115
3. Schlenker E., Long S. "Williams' Essentials of Nutrition and Diet Therapy." (2007) Mosby-Elsevier. St Louis, Missouri p.116-117
4. Ross T., Donn J. "Study: Vitamin D Reduces Cancer Risk." June 8, 2007. Published on Salon.com.
5. Ross T., Donn J. "Study: Vitamin D Reduces Cancer Risk." June 8, 2007. Published on Salon.com.
6. Ross T., Donn J. "Study: Vitamin D Reduces Cancer Risk." June 8, 2007. Published on Salon.com.
7. Schlenker E., Long S. "Williams' Essentials of Nutrition and Diet Therapy." (2007) Mosby-Elsevier. St Louis, Missouri p.118-119
8.Holick M. "Vitamin D: Importance in the Prevention of Cancers, Type I Diabetes, Heart Disease, and Osteoporosis." (2004). Am J Clin. Nutr. 79:362
9. Schlenker E., Long S. "Williams' Essentials of Nutrition and Diet Therapy." (2007) Mosby-Elsevier. St Louis, Missouri p. 119
10. Schlenker E., Long S. "Williams' Essentials of Nutrition and Diet Therapy." (2007) Mosby-Elsevier. St Louis, Missouri p. 118
A Short History of Medicine:
2000 B.C. – "Here, eat this root."
1000 B.C. – "That root is heathen, say this prayer."
1850 A.D. – "That prayer is superstition, drink this potion."
1940 A.D. – "That potion is snake oil, swallow this pill."
1985 A.D. – "That pill is ineffective, take this antibiotic."
2000 A.D. – "That antibiotic is artificial. Here, eat this root."
~Author Unknown
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