Wpływa na tarczycę - 2000iu dziennie
Vitamin D is an important vitamin that not only regulates calcium, but also has many other beneficial
actions. Not many endocrinologists realize this, but several articles published over 20 years ago showed that
patients with hypothyroidism have low levels of vitamin D.
This may lead to some of the bone problems related to hypothyroidism. It was thought that one of two mechanisms
may explain the low levels of vitamin D in patients with hypothyroidism, 1) the low levels of vitamin D may be due
to poor absorption of vitamin D from the intestine or 2) the body may not activate vitamin D properly. Other
articles have demonstrated that patients with Graves disease also have low levels of Vitamin D.
Importantly, both vitamin D and thyroid hormone bind to similar receptors called steroid hormone receptors. A
different gene in the Vitamin D receptor was shown to predispose people to autoimmune thyroid disease including
Graves� disease and Hashimoto�s thyroiditis. For these reasons, it is important for patients with thyroid problems
to understand how the vitamin D system works.
Vitamin D itself is inactive and needs to get converted to the liver to 25-hydroxy vitamin D (25-OH vitamin D) and
then in the kidney to 1, 25-hydroxy vitamin D. It is only the 1, 25- OH vitamin D which is biologically active.
This form of vitamin D acts to allow for absorption of calcium from the intestinal tract. Therefore, patients with
low vitamin D levels will have low calcium and in severe cases get rickets (in children) or osteomalacia (in
adults) which is when the bone bows out and is poorly formed. In mild cases of vitamin D deficiency, osteoporosis
occurs, but low calcium is rare.
The conversion from the 25-OH vitamin D to the 1, 25-OH vitamin D that occurs in the kidney is catalyzed by
parathyroid hormone, also called PTH. Therefore, patients with very low vitamin D levels will have relatively high
PTH levels often with low calcium levels.
This is similar to patients with primary hypothyroidism having elevated TSH levels while having normal thyroid
hormone levels. Additionally, the 25-OH vitamin D form which is the storage form and is much more abundant that
the 1, 25-OH vitamin D form which, although is active, is less abundant. Therefore, in states of vitamin D
deficiency, low levels of 25-OH vitamin D are found, but the 1, 25-OH vitamin D levels are either normal or
actually slightly high. They are slightly high because the excess PTH that is stimulated by the low 25-OH vitamin
D levels stimulates the conversion up to 25-OH vitamin D to the 1, 25-OH vitamin D. Thus, patients that are
vitamin D deficient usually have a low 25-OH vitamin D level, a high PTH level, a low normal calcium, and a normal
or an elevated 1, 25- OH vitamin D level. However some patients may actually have a high normal calcium as the
elevated PTH and 1, 25-OH vitamin D may cause increased calcium absorption from the GI track and reabsorption from
the kidney. If 25-OH vitamin D levels were not measured, these patients might have been incorrectly diagnosed with
mild hyperparathyroidism as they have a high normal calcium and a high PTH.
obniża ryzyko chorób serca
By Greg Arnold, DC, CSCS, February 18, 2010, abstracted from �Levels of vitamin D and cardiometabolic
disorders: Systematic review and meta-analysis� in the 2010 issue of Maturitas
The term "cardiometabolic disorders" has recently been coined to encompass three different diseases:
cardiovascular disease (costing $475.3 billion per year to treat) (1), type 2 diabetes (costing $174 billion) (2),
and metabolic syndrome, which affects 1 in 4 Americans, increases medical costs per patient by 20% (3), and is
"the costliest condition you've never heard of" (4)).
With a total cost to our healthcare system of nearly three-quarters of a trillion dollars per year, it is
paramount to find ways to decrease risk factors for cardiometabolic disorders. Now a new study (5) has found that
keeping vitamin D bloods at healthy levels can significantly improve heart health.
In the study, researchers conducted a review of published medical literature concerning vitamin D blood levels and
the risk of cardiometabolic diseases. They identified 28 studies consisting of 99,745 patients. They found that
vitamin D plays a significant role in heart health. The highest blood levels of vitamin D (more than 29.2
nanograms/millilter) were shown to reduce cardiometabolic risk factors by 43%, compared to the lowest vitamin D
blood levels (less than 17.8 ng/mL). When they separated the risk reductions by each condition, it translated to a
33% reduced risk of cardiovascular disease, 55% reduced risk of type 2 diabetes, and 51% reduced risk of metabolic
When attempting to explain the health-promoting effects of vitamin D, the researchers pointed to how "low levels
of vitamin D may result in higher vascular calcification", how vitamin D can help maintain healthy levels of
inflammation by controlling levels of proteins called
cytokines, and how vitamin D can help maintain healthy blood pressure levels (6).
The researchers concluded that "High levels of vitamin D among middle-age and elderly populations are associated
with a substantial decrease in cardiovascular disease, type 2 diabetes and metabolic syndrome". They then
recommended that "If the relationship proves to be causal, interventions targeting vitamin D deficiency in adult
populations could potentially slow the current epidemics of cardiometabolic disorders."
When it comes to vitamin D supplementation to produce optimal vitamin D blood levels, previous research has
suggested it would between 2,000 and 4,000 IU/day since 2,000 IU/day produces vitamin D blood levels of 20 ng/mL
and 4,000 IU/day produces levels of 40 ng/mL) (7).
Greg Arnold is a Chiropractic Physician practicing in Danville, CA. You can contact Dr. Arnold directly by
emailing him at mailto:PitchingDoc@msn.com or visiting his web site at www.PitchingDoc.com
1. �Cardiovascular Disease Cost� posted on http://www.americanheart.org/presen...identifier=4475
2. �Number of People with Diabetes Continues to Increase� from the CDC Website
3. Curtis LH. Costs of the Metabolic Syndrome in Elderly Individuals Findings from the Cardiovascular Health
Study. Diabetes Care October 2007 vol. 30 no. 10 2553-2558
4. �The Costliest Condition You�ve Never Heard Of� posted on http://www.medicalnewstoday.com/articles/24042.php
5. Parker J. Levels of vitamin D and cardiometabolic disorders: Systematic review and meta-analysis. Maturitas
2010; 65(3): 225-236
6. E. Giovannucci, Vitamin D and cardiovascular disease, Curr Atheroscler Rep 2009; 11: 456�461
7. Garland CF. Symposium in Print on the Epidemiology of Vitamin D and Cancer. Annals of Epidemiology. In Press
Corrected Proof , Available online 03 April 2009 DOI: 10.1016/j.annepidem.2009.02.002
chroni przed rakiem
Abstracted February 18, 2010 by Marcia J. Egles, MD from Association between pre-diagnostic circulating vitamin D concentration and risk of colorectal cancer in European populations: a nested case-control study by Mazda Jenab et al in BMJ, 21 January 2010.
KEY WORDS: vitamin D, cancer
A large European case-control study, recently reported in the British Medical Journal (1), links low vitamin D levels with a higher risk of colorectal cancer. The study is part of EPIC, the European Prospective Investigation into Cancer and Nutrition which involved 520,000 participants from ten western European countries (2). Between 1992 and 1998, personal histories and blood samples were collected from men and women of the general population aged 30 to 76 years (average age 58). During a follow-up period averaging 3.8 years, 1248 persons were diagnosed with colorectal cancer. These cases were matched with similar persons in the study who did not have cancer. Their characteristics including their vitamin D levels from the blood samples at the start of the study were compared (1).
The vitamin D levels (serum 25-(OH)D) showed a strong inverse dose-response associated with a higher risk of colorectal cancer (p for trend less than 0.001). That is, lower levels of vitamin D were associated with higher risk of colorectal cancer. (A serum 25-hydroxyvitamin D level of less than 50 nanomoles per liter is generally considered deficient.) When compared to a vitamin D level of 50- 75 nanomoles per liter, those with vitamin D levels lower than 25 nanomoles per liter had an incident rate ratio* of 1.32 ( 95% confidence interval 0.87-2.01). Those with vitamin D levels 25 to 49 nanomoles per liter had an incident rate ratio of 1.28. (95% confidence interval, 1.05 to 1.56). Those with vitamin D levels 75.5 to 99 nanomoles per liter showed an incident rate ratio of 0.88 (95% confidence interval 0.68 to 1.13).
When the results were analyzed by �quintiles�, dividing the populations into fifths, a similar pattern emerged. Those in the highest quintile, the highest fifth of vitamin D levels, had a 40% lower risk of colorectal cancer than those in the lowest quintile (p less than 0.001). The findings in this study did not significantly vary between men compared to women, nor was there any effect based on season or month of the blood collection.
Also noted in the study, those with the lowest vitamin D levels who also reported the highest alcohol consumptions had among the highest cancer risk in the study. The incident rate ratio for this subgroup was 1.46 (95% confidence interval 1.16 to 1.83). In the same study, when vitamin D dietary intakes were considered, no associations were found with colorectal cancer risk. This was not an unexpected result as diet surveys do not account for vitamin D obtained by sunlight exposure.
The results of this EPIC study of vitamin D blood levels may help clarify some previous studies which report no association between vitamin D and colorectal cancer (3). The Women�s Health Initiative Study, a major clinical trial (4), showed no benefits of supplementation (1000mg per day calcium plus 400 I.U. per day of vitamin D). However, both the EPIC study and the Women�s Health Initiative Study reported similar findings with vitamin D blood levels. The Women�s Health Initiative Study also found that those who had a baseline serum 25-hydroxyvitamin D level of less than 30 nanomoles per liter had a 253% increase in the risk of colorectal cancer over a follow-up of 8 years (5).
The researchers from the EPIC case-control study stressed that additional randomized clinical trials are needed to test whether or not increases in 25-hydroxyvitamin D concentrations are effective in reducing colorectal cancer risk (1).
*incident rate ratio- The higher the ratio is over 1, the higher the risk. If the ratio is less than 1, the risk is reduced.
1. Jenab, Mazda et al. Association between pre-diagnostic circulating vitamin D concentration and risk of colorectal cancer in European populations:a nested case-control study BMJ Published 21 January 2010, doi:10.1136/bmj.b5500
2. Riboli E, Hunt KJ, Slimani N, Ferrari P, Norat T, Fahey M, et al. European Prospective Investigation into Cancer and Nutrition (EPIC): study populations and data collection. Public Health Nutr 2002;5:1113-24
3. Feskanich D, et al. Plasma vitamin D metabolites and the risk of colorectal cancer in women. Cancer Epidemiol Biomarkers Pre 2004: 13: 1502-8.
4. Wactawski-Wende J, Kotchen JM, Anderson GL, Assaf AR, Brunner RL, O�Sullivan MJ, et al. Calcium plus vitamin D supplementation and the risk of colorectal cancer. N Engl J Med 2006;354:684-96.I
5. Holick MF. Calcium plus vitamin D and the risk of colorectal cancer. N Engl J Med 2006: 354: 2287-8