While vitamin K, especially vitamin K2, seems to be straightforwardly protective, the story of vitamins A and D is more complex. When vitamins A and D are both provided abundantly, they maximize the protective effect of vitamin K, but when vitamin D is provided in great excess of vitamin A, it actually promotes abnormal, pathological calcification of soft tissues, including arteries.12,13,14 This finding suggests that vitamin D may be a double-edged sword, with the ability to either prevent or promote heart disease, depending on the dietary context in which it is provided.
Indeed, both severe deficiencies of vitamin D 15 and hefty excesses of the vitamin 16 promote atherosclerosis in animal experiments. Observational studies in humans show that the risk of heart disease declines as vitamin D status increases. This relationship plateaus at about 24 ng/mL, and there is very little data exploring higher levels (see Figure 1). However, a recently published study suggested that having vitamin D status higher than 40 ng/mL is just as dangerous as having vitamin D status lower than 12 ng/ mL (see Figure 2). When viewed together, the evidence in animals and humans suggests that vitamin D protects against heart disease at the right dose, but that too much vitamin D actually contributes to heart disease.
This figure is adapted from Figure 3 as originally published in reference 27. The horizontal axis has been converted from nmol/L to ng/mL so that the units correspond to those used by clinical laboratories in the United States. The figure depicts data pooled from sixteen independent studies measuring serum 25(OH)D and subsequent risk of cardiovascular disease. 25(OH) D is a metabolic product of vitamin D that is often used as a measure of vitamin D status, though there are problems with this. Each circle represents an independent risk estimate for a given category of 25(OH)D from an individual study. The size of the circle represents the statistical power of the study, driven in part by low variation but mostly by large sample size. Circles further to the right represent higher concentrations of 25(OH)D and those higher up represent higher risks of cardiovascular disease. The shaded area represents the confidence interval. The more narrow the shaded area, the higher our confidence in the estimates; the wider the shaded area, the more uncertainty we have.
The risk of cardiovascular disease declines with increasing 25(OH)D up to 24 ng/mL but appears to plateau thereafter. There are only two data points with poor statistical power at concentrations higher than 32 ng/mL and there are no data points at concentrations higher than about 45 ng/mL. The paucity of the data in these regions makes the uncertainty surrounding the risk estimate very high, represented by the increasingly wide shaded area.
Figure 2: The Risk of Cardiovascular Events is Lowest between 20-40 ng/mL among Cardiac Surgery Patients
This figure is adapted from the data in reference 28. The researchers measured serum 25(OH)D in just under 4,500 cardiac surgery patients, in whom the risk of future cardiovascular events was very high. Over the following year, 11.5 percent of the patients suffered a major event. The risk decreased with increasing concentrations of 25(OH)D up to 40 ng/mL, but increased thereafter. Those with 20-40 ng/mL had the lowest risk, but those with concentrations greater than 40 ng/mL had just as high a risk as those with less than 12 ng/mL.
Many readers may be surprised that people with vitamin D status higher than 40 ng/mL have a higher risk of heart disease when so many advocates of vitamin D supplementation recommend levels much higher than this. Part of the reason many people recommend higher levels is because they view the evidence within the framework of the very influential but very problematic “naked ape” hypothesis of optimal vitamin D status (see sidebar).
We should keep in mind, however, that none of these studies takes into account the interactions between vitamins A, D and K. It may be that vitamin D status higher than 40 ng/mL protects against heart disease in the context of a diet that provides liberal amounts of organ meats, animal fats and fermented foods. It may also be that a simple cause-and-effect relationship between vitamin D exposure and serum 25(OH)D, or between serum 25(OH)D and disease risk, greatly oversimplifies the issue (see sidebar). The uncertainty over these questions underlines the need to pay more attention to optimizing the nutrient density and nutrient balance of the diet rather than overemphasizing the usefulness and importance of optimizing blood levels of vitamin D.
- 12. Masterjohn C. From Seafood to Sunshine: A New Understanding of Vitamin D Safety. Wise Traditions. Fall, 2006.
- 13. Masterjohn C. Vitamin D toxicity redefined: vitamin K and the molecular mechanism. Med Hypotheses. 2007;68(5):1026-34.
- 14. Masterjohn C. Thyroid Hormone and Vitamin A Protect Against Vitamin D Toxicity in Cows. Mother Nature Obeyed. Published April 3, 2013. http://www.westonaprice.org/blogs/cmasterjohn/2013/04/03/thyroid-hormone-and-vitamin-a-protect-against-vitamind- toxicity-in-cows/ Accessed November 21, 2013.
- 15. Schmidt N, Brandsch C, Kuhne H, Thiele A, Hirche F, Stangle GI. Vitamin D receptor deficiency and low vitamin D diet stimulate aortic calcification and osteogenic key factor expression in mice. PLoS One. 2012;7(4):e35316.
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- 24. Libby P and Theroux P. Pathophysiology of Coronary Artery Disease. Circulation. 2005;111:3481-8.
- 25. Glagov S, Weisenberg E, Zarins CK, Stankunavicius R, Kolettis GJ. Compensatory enlargement of human atherosclerotic coronary arteries. N Engl J Med. 1987;316(22):1371-5.
- 26. Burke AP, Kolodgie FD, Farb A, Weber DK, Malcom GT, Smialek J, Virmani R. Healed plaque ruptures and sudden coronary death: evidence that subclinical rupture has a role in plaque progression. Circulation. 2001;103(7):934-40.
- 27. Wang L, Song Y, Manson JE, Pilz S, Marz W, Michaelsson K, Lundgvist A, Jassal SK, Barett-Connor E, Zhang C, Eaton CB, May HT, Anderson JL, Sesso HD. Circulating 25-hydroxy-vitamin D and risk of cardiovascular disease: a meta-analysis of prospective studies. Circ Cardiovasc Qual Outcomes. 2012;5(6):819-29.
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- Failure to also increase Vitamin K2 ==> excess Calcium deposited in arteries
- Failure to also increase Vitamin A
- Failure to also increase Magnesium ==> strain the heart
- Failure to also reduce Calcium intake: More D ==> More Calcium ==> Calcium into arteries
- Vitamin D possible interaction with drugs used for bad hearts
Greatly increasing or decreasing the effect of the drug(s)
- ACE Inhibitors: ACE inhibitors are a type of medication that dilates (widens) arteries to lower blood pressure and make it easier for the heart to pump blood. They also block some of the harmful responses of the endocrine system that may occur with heart failure.
- Angiotensin II Receptor Blocker (ARBs): ARBs are used to decrease blood pressure in people with heart failure. ARBs decrease certain chemicals that narrow the blood vessels so blood can flow more easily through your body. They also decrease certain chemicals that cause salt and fluid build-up in the body.
- Beta-Blockers: Beta-blockers block the effects of adrenaline (epinephrine) which can improve the heart's ability to perform. They also decrease the production of harmful substances produced by the body in response to heart failure.
- Calcium Channel Blockers: Calcium channel blockers are prescribed to treat angina (chest pain) and high blood pressure. Calcium channel blockers affect the movement of calcium in the cells of the heart and blood vessels. As a result, the drugs relax blood vessels and increase the supply of blood and oxygen to the heart, while reducing its workload.
- Cholesterol -Lowering Drugs: Cholesterol helps your body build new cells, insulate nerves, and produce hormones. But inflammation may lead to cholesterol build-up in the walls of arteries, increasing the risk of heart attack and stroke.
- Digoxin : Digoxin helps an injured or weakened heart to work more efficiently and to send blood through the body. It strengthens the force of the heart muscle's contractions and may improve blood circulation.
- Diuretics: Diuretics, commonly known as "water pills," cause the kidneys to get rid of unneeded water and salt from the tissues and bloodstream into the urine. Getting rid of excess fluid makes it easier for your heart to pump. Diuretics are used to treat high blood pressure and reduce the swelling and water build-up caused by various medical problems, including heart failure. They also helps make breathing easier.
- Inotropic Therapy: Inotropic therapy is used to stimulate an injured or weakened heart to pump harder to send blood through the body. It helps the force of the heart muscle's contractions and relaxes constricted blood vessels so blood can flow more smoothly. Inotropic therapy may also speed up the heart's rhythm.
- Potassium or Magnesium: Potassium and magnesium are minerals that can be lost because of increased urination when taking diuretics. Low levels in the body can be associated with abnormal heart rhythms. Some patients take them as supplements.
- Vasodilators: Vasodilators are used to treat heart failure and control high blood pressure by relaxing the blood vessels so blood can flow more easily through the body. Vasodilators are prescribed for patients who cannot take ACE inhibitors.
- Warfarin : Warfarin is an anticoagulant medication. "Anti" means "against," and "coagulant" means "causing blood clotting." Therefore, warfarin helps prevent clots from forming in the blood.