By John Cannell, MD, The Vitamin D Council

Continuing with part 2 of Dr. Cannell's vitamin D test

8. Dr. Scragg showed that higher vitamin D levels are associated with lower risk for heart attack.

A. True
B. False

True. In 1979, the Tromso Heart Study found corrected vitamin D levels showed the same thing.

Int J Epidemiol. 1990 Sep;19(3):559-63.
Br Med J. 1979 Jul 21;2(6183):176.

9. Dr. Scragg is such a good scientist, he then published a study which seemed to disprove his theory.

A. True
B. False

True. He discovered that a single oral dose of 100,000 units of vitamin D had no effect on risk factors (serum cholesterol or blood pressure) five weeks later. This seemed to disprove his theory, but he published the data anyway, always a mark of a good scientist. We now know that 100,000 units are a small dose and that such "stoss" therapy is not physiological.

Such a small single dose will raise vitamin D levels for a month or two, but then they rapidly fall towards baseline and would have little physiological effect five weeks later.

Eur J Clin Nutr. 1995 Sep;49(9):640-6.

10. Zittermann points out that vitamin D reduces vascular smooth muscle proliferation, reduces vascular calcification, decreases parathormone levels, reduces C reactive protein (CRP) and other markers of inflammation, and decreases renin, all of which should prevent or treat heart disease.

A. True
B. False

True. He discusses most of the evidence that exists, tying heart disease to vitamin D deficiency. A vitamin D theory of heart disease explains the excess cardiovascular deaths at high latitude, low altitude and during the winter. Furthermore, it explains the higher incidence of heart disease in African Americans, older, inactive, and obese individuals as these groups have significantly lower vitamin D blood levels.

Br J Nutr. 2005 Oct;94(4):483-92.

11. In 2003, Zittermann discovered that patients with congestive heart failure (CHF) have very low levels of vitamin D.

A. True
B. False

True. Furthermore, he found that a protein (NT-proANP), which is a predictor of CHF severity, was inversely associated with vitamin D levels.

J Am Coll Cardiol. 2003 Jan 1;41(1):105-12.

12. Blood cholesterol measurements are worse at higher latitudes, lower altitudes and in the winter.

A. True
B. False

True. The effects of latitude on cholesterol seen in the first study are quite remarkable. In the Greek study, total serum cholesterol for both men and women were significantly lower at higher altitude in spite of similar diets. The seasonal variations in cholesterol are well known and not explained by seasonal dietary changes.

QJM. 1996 Aug;89(8):579-89.
J Epidemiol Community Health. 2005 Apr;59(4):274-8.
J Clin Epidemiol. 1988;41(7):679-89.
Chronobiol Int. 2001 May;18(3):541-57.

13. Blood pressure is higher at higher latitudes, lower altitudes, in the winter, in African Americans, in the aged, and in the obese.

A. True
B. False

True. High blood pressure is one of the strongest predictors of heart disease. Here, six facts about hypertension can be explained by one theory: vitamin D.

Hypertension. 1997 Aug;30(2 Pt 1):150-6.
Ann Hum Biol. 2000 Jan-Feb;27(1):19-28.
Harv Health Lett. 2005 Sep;30(11):8.

14. Diabetes is more common at higher latitudes, at lower altitudes, in African Americans, in the aged and the obese. Both blood sugar and hemoglobin A1C are higher in the winter.

A. True
B. False

True. Six final facts that can be explained with one theory: vitamin D.

Eur J Epidemiol. 1991 Jan;7(1):55-63.
Nutrition. 2001 Apr;17(4):305-9.
Diabetes Res Clin Pract. 2005 Aug;69(2):169-74. Epub 2005 Jan 12.
Diabetologia. 1982 Apr;22(4):250-3.
Am J Epidemiol. 2005 Mar 15;161(6):565-74.

15. Two studies show vitamin D significantly reduces C reactive protein (CRP), which may be a better predictor of heart disease than LDL cholesterol.

A. True
B. False

True. The Belgian study found a significant effect on CRP even though their high-dose vitamin D group only got 500 units a day.

QJM. 2002 Dec;95(12):787-96.
J Clin Endocrinol Metab. 2003 Oct;88(10):4623-32.

16. The risk for total mortality is significantly lower in subjects with high vitamin D levels.

A. True
B. False

True. However, the study is in Finnish and has not been translated into English (author communication).

Seppanen R, Marniemi J, Alanen E, Impivaara O, Jarvislo J, Ronnemaa T, et al. Ravinnon ja seerumin vitamiinit ja kivennaisaineet vanhusten kuolleisuuden ennustajina. Suom Laakaril 2000;42:4255-60 [Finnish]. Reported in Nutr Metab Cardiovasc Dis. 2005 Jun;15(3):188-97.

17. It is now a proven scientific fact that vitamin D both prevents and treats heart disease.

A. True
B. False

False. Like so may other fields of vitamin D research, we lack the definitive interventional trials that would settle the point. It would be simple for the National Institutes of Health to fund a study giving physiological doses of real vitamin D (5,000 units of cholecalciferol) to heart disease patients for a year and see if CRP, proinsulin, blood pressure, cholesterol, body weight, heart attacks, or death rate decreases.

We will have to wait years for science to find out if vitamin D prevents and/or treats heart disease. While you are waiting, you have a choice. You can wait vitamin D deficient (levels less than 40 ngs/ml) or you can wait vitamin D sufficient (levels around 40-60 ngs/ml). The choice is yours -- another Pascal's Wager -- this time you are betting your heart.

Also, while you wait for more studies, remember that vitamin D should be obtained daily, not monthly or weekly. It should be obtained physiologically, not in an all-then-none manner, as would happen if you took 100,000 units one day a month and nothing the other 29 days. It appears likely that high blood levels followed by low blood levels may do harm.

The reason is that falling blood levels reset the enzymes maintaining intracellular levels of activated vitamin D, resulting in low intracellular levels.

Int J Cancer. 2004 Sep 1;111(3):468; author reply 469.

Vitamin D should be consumed the way the human genome consumed it during its evolution in subequatorial Africa, a steady amount every day. If you live down south, you can go in the sun for a few minutes every day. If you live up north you can sun in the warmer months and use a sunlamp or take real vitamin D (cholecalciferol) in the winter.

Adults in the north could take one 5,000 unit capsule a day in late fall, winter, and early spring, less in the late spring and early fall, and none in the summer months -- depending on your sunning habits. Children over 50 pounds need two of the 1,000 unit capsules every day in the colder months while children under 50 pounds need about 1,000 units in the colder months.

Few people need to take oral vitamin D in the summer unless you are a sunphobe. Get enough vitamin D every day to maintain stable vitamin D blood levels (25-hydroxy-vitamin D) around 50 ngs/ml, year-around.

Last question: Should patients dying from heart disease be allowed to die vitamin D deficient?  According to the current paradigm, the answer is yes. At least, none of the cardiologists I know even bother to check a vitamin D level.

Given the scientific literature, that's a bit paradoxical.