Too Much Vitamin D Can Be Bad for You

Context:

Optimal levels of vitamin D have been a topic of heavy debate, and the correlation between 25-hydroxyvitamin D [25(OH)D] levels and mortality still remains to be established.

Objective:

The aim of the study was to determine the association between all-cause mortality and serum levels of 25(OH)D, calcium, and PTH.

Design and Setting:

We conducted a retrospective, observational cohort study, the CopD Study, in a single laboratory center in Copenhagen, Denmark.

Participants:

Serum 25(OH)D was analyzed from 247,574 subjects from the Copenhagen general practice sector. In addition, serum levels of calcium, albumin-adjusted calcium, PTH, and creatinine were measured in 111,536; 20,512; 34,996; and 189,496 of the subjects, respectively.

Main Outcome Measures:

Multivariate Cox regression analysis was used to compute hazard ratios for all-cause mortality.

Results:

During follow-up (median, 3.07 yr), 15,198 (6.1%) subjects died. A reverse J-shaped association between serum level of 25(OH)D and mortality was observed. A serum 25(OH)D level of 50–60 nmol/liter was associated with the lowest mortality risk. Compared to 50 nmol/liter, the hazard ratios (95% confidence intervals) of all-cause mortality at very low (10 nmol/liter) and high (140 nmol/liter) serum levels of 25(OH)D were 2.13 (2.02–2.24) and 1.42 (1.31–1.53), respectively. Similarly, both high and low levels of albumin-adjusted serum calcium and serum PTH were associated with an increased mortality, and secondary hyperparathyroidism was associated with higher mortality (P < 0.0001).

Conclusion:

In this study from the general practice sector, a reverse J-shaped relation between the serum level of 25(OH)D and all-cause mortality was observed, indicating not only a lower limit but also an upper limit. The lowest mortality risk was at 50–60 nmol/liter. The study did not allow inference of causality, and further studies are needed to elucidate a possible causal relationship between 25(OH)D levels, especially higher levels, and mortality.

Note: 50-60 nmol/L equals 20-24 ng/ml. To convert nmol/L to ng/ml, divide by 2.5. To convert ng/ml to nmol/L, multiply by 2.5.  

The full article is available here:

http://press.endocrine.org/doi/full/10.1210/jc.2012-1176

Is Vitamin K2 the New Vitamin D?

This article is dated November 18, 2014, and appeared on Medscape. It is the opinion of one doctor, who admits from the start that he knows nothing about nutrition as it relates to chronic illness. As pointed out by one commenter, he goes on to prove his ignorance by stating that green, leafy vegetables are a good source of vitamin K2. Wrong! They are a good source of vitamin K1. Because the doctor's article is controversial, there are many comments revealing various viewpoints. Be sure to drag and drop the link below and read the comments. There is also a video of the doctor giving his talk.


"Hello and welcome. I am Dr George Lundberg, and this is At Large at Medscape.

I do not know anything about nutrition as it relates to chronic illness, including obesity. I used to think that was because, probably like you, I was taught so little about nutrition in medical school. I have spent a medical lifetime reading articles about nutrition, before and after publication. But I am still woefully ignorant of "nutritional truth."

Take vitamin D. The minimum daily requirement prevents rickets. But then, just a few years ago, it became popular to check vitamin D blood levels. And many people were found to have "low" vitamin D levels. Then many diseases were found to be associated with "vitamin D deficiency," except it turns out that many labs were not doing the tests in equivalent ways.

After a whole lot of fuss and study, the Agency for Healthcare Research and Quality (AHRQ) issued a report this year that finds no consistent correlation between vitamin D and health outcomes such as cardiovascular disease, all-cause mortality, several types of cancer, or bone health.^[1] Amazing.

Which Brings Us to Vitamin K

What do you know about vitamin K? It has something to do with blood coagulation, right? Yes, but that is vitamin K₁. I am asking about vitamin K₂. I bet you have not thought much about that vitamin.
Here are nine things every physician should know about vitamin K₂:

1. It exists.
2. It is essential for life and health.
3. There is currently no reliable blood test to measure it.
4. Your body makes a certain amount via menaquinone-4 (M-4) in your gut from vitamin K₁.
5. That may not be enough.
6. Your body probably needs more vitamin K₂ for disease prevention than it manufactures, so nutritional sources are important.
7. Foods rich in vitamin K₂ (often in the form of M-4 or M-7) include: natto (fermented soybeans); green, leafy vegetables; organ meats such as goose liver; grass-fed beef; dairy; eggs; and fish.
8. Or you can take nutritional supplements to achieve healthy levels of vitamin K₂.
9. Deficiencies of vitamin K₂ are now being reported in serious journals to be associated with—get this—all-cause mortality, cardiovascular disease, osteoporosis, diabetes, many forms of cancer, dementia, and chronic inflammation.

Sound familiar?
Is vitamin K₂ the ubiquitous disease-associated vitamin D-like deficiency, sans blood testing, all over again? A fad disease about to pop up, flourish, and disappear? Or is this a real, late-to-the-table, fundamental new understanding of possible causes of many common diseases, disability, and death? And if vitamin K₂ is taken correctly, will it result in prevention and treatment of same? Look it up; check it out.

I do not know how this is going to work out, but I have a hunch that vitamin K₂ will turn out to be a really big deal rather than only "the new vitamin D," with much fuss and little substance.

Most of this research is being done in Japan and Europe, especially The Netherlands, well away from the US Department of Agriculture and lobbyists for the American food industry and its captured government and academic partners.

I owe my current interest in this topic to a product of the Internet as the world's greatest library—a well-educated, nonscientist who got really interested in this topic and will not let up. Thank you, Micki Jacobs of Cincinnati.

That's my opinion. I am Dr George Lundberg, at large at Medscape."

 http://www.medscape.com/viewarticle/834763?nlid=70845_1521&src=wnl_edit_medp_wir&uac=127701PY&spon=17