Recently, this New York Times (NYT) article suggested that taking vitamin D is a waste of time and money. Gina Kolata, a medical journalist for the NYT, highlighted two new studies concluding that vitamin D does not prevent cardiovascular disease (CVD) or cancer.
Here is a summary of the two studies mentioned in the NYT:
Study #1: High Dose Vitamin D effects on CVD
- 5110 participants were randomized to receive vitamin D3 (n = 2558) or placebo (n = 2552) in Auckland, New Zealand, from April 5, 2011, through November 6, 2012, with follow-up until July 2015.
- Oral vitamin D3 in an initial dose of 200 000 IU, followed a month later by monthly doses of 100 000 IU, or placebo for a median of 3.3 years (range, 2.5-4.2 years).
- Main outcomes measured; 1) number of participants with CVD and death. 2) number of myocardial infarction (heart attack), angina, heart failure, hypertension ( high blood pressure), arrhythmias, arteriosclerosis (hardening of arteries_, stroke, and venous thrombosis (blood clots).
- Baseline 25-hydroxyvitamin D (the standard blood marker measured by doctors) levels <20 ng/mL.
- Study conclusion: Monthly high-dose vitamin D supplementation does not prevent CVD. This result does not support the use of monthly vitamin D supplementation for this purpose.
Study #2: Effects on Vitamin D and Cancer Incidence in Older Women
- 2303 randomized white women, average age 65.2 years from Nebraska
- Average serum 25-hydroxyvitamin D level, 32.8 ng/ml at the beginning of the study
- At year 1, serum 25-hydroxyvitamin D levels were 43.9 ng/mL in the vitamin D3 + calcium group and 31.6 ng/mL in the placebo group.
- Cancer was diagnosed in 109 participants, 45 (3.89%) in the vitamin D3 + calcium group and 64 (5.58%) in the placebo group (P = .06)
- Conclusion: Supplementation with vitamin D3 and calcium compared with placebo did not result in a significantly lower risk of all-type cancer at four years in healthy postmenopausal older women.
How Vitamin D Works
First of all, vitamin D is not a “vitamin,” it’s a hormone.
Vitamins are vital (thus the prefix, vita) nutrients that come from food or other external methods like dietary supplements not made by your body.
For example, your body does not make vitamin C, but a dog’s do, so, in dogs, vitamin C is not really a vitamin. Are you with me?
Hormones are chemicals made from steroids or amino acids produced by the body that attaches to receptors (like a lock and key) and causes a physiological response. For example, when testosterone attaches to receptors on specific cells, it causes facial hair growth and a deeper voice in teenage boys after reaching puberty.
Vitamin D is a steroid (not the anabolic type) hormone with vitamin D receptors (VDR) in virtually every cell in the human body with calcemic effect and a non-calcemic effect.
You see, vitamin D has two jobs; It increases absorption of calcium in the body primarily to maintain bone health and has its action on the body independent of calcium metabolism, i.e. boost immunity, anti-inflammatory, maybe anti-cancer, etc.
Vitamin D insufficiency was defined in most studies as below < 30 ng/mL, and deficiency ranges from < 20 ng/mL to 10 ng/mL.
(The standard unit (SI) for vitamin D is nmol/L. To convert mg/ml to nmol/L, multiply the ng/ml value by 2.5)
My Take on Vitamin D
The association of Vitamin D with prevention of heart disease, cancer and a multitude of other diseases began about forty years ago when researchers observed people who live in sunnier areas succumb less to cancer and other diseases. The health benefits were linked to vitamin D since one of the best methods to get vitamin D in the body is through sun exposure.
Interest in vitamin D grew exponentially since then.
If you search for vitamin D on PubMed, the primary scientific database in the world, there are over seven thousand papers written on it.
After reviewing about a dozen most recent scientific papers on Vitamin D, I will highlight two that were most impactful in my opinion.
In a 9-year follow-up study looking at over 13,000 adults 20 years or older from the Third National Health and Nutrition Examination Survey (NHANES III), there was an increased rate of death in those with low Vitamin D levels (25[OH]D levels <17.8 ng/mL).
After of about 35ng/ml of serum D, mortality slightly climbed again. Women, overall, fared worse with death and blood Vitamin D levels with higher levels than 50 associated with worse mortality. Men do die more with D levels greater than 50 but not as much as women.
The sweet spot, that is, where most participants died the least, was around 40 to 45ng/ml. (Melamed et al. 2008)
The same group was studied for 15-years, increase mortality became apparent in those with D levels steep below 40 nmol/L (16ng/ml) and higher than >120 nmol/L (48 ng/ml). Decrease death rates were noticed in those with D levels between 32 and 40ng/ml.
Another extensive 54-month study, observed over 400,000 and tested for blood vitamin D and noticed that levels between 20-36 ng/mL range were associated with the lowest risk for mortality and morbidity. Levels between 20 ng/ml and higher than 36ng/ml were associated with an increase in all-cause mortality. (Dror et al., 2013)
Before two years ago, I had my patient’s vitamin D blood levels at about 80 ng/ml. This is what my colleagues were doing and what I learned at medical conferences. Since then, I went deep into the research literature and changed my tune. I have patient’s vitamin D levels hover around 40ng/ml.
It was brought to my attention this past weekend after giving a talk at an excellent Syracuse Health Fair that this website recommends blood levels of vitamin D between 40 to 60mg/ml. Again, I have not seen the evidence for this – maybe it’s out there, deep within the thousands of articles published on this topic, but I have not seen it.
Here’s the other thing.
You should exercise caution taking health advice from the media. Their primary goal is to get more people to read their stuff, not provide the best health advice to the public. Scientific reports are not critically read or interpreted correctly by the media.
The “devil is in the detail,” as they say, and that concept is real when reading medical journals.
Two Problems in the two recent studies covered in the NYT
The Vitamin D Cancer and CVD studies used by the Gina Kolata do not prove that supplementation of this “vitamin” is a waste.
Participants in cancer/vitamin D paper started at a baseline of 33ng/ml suggesting supplementation might not have been necessary. I find it hard to believe that those with normal vitamin D levels in the study were not taking supplements. I almost never see a patient with normal ranges of vitamin D without consuming dietary supplements.
In the CVD / vitamin D study, 50% of participants were current or past smokers. There is not enough vitamin D in the world that can offset the bad effects smoking has on the heart.
The Bottom line on Vitamin D
Your blood levels of vitamin D dictates how much D supplementation you need if any.
You want your blood levels of vitamin D taken by your doctor and want your levels to be between 35ng/ to 40 ng/ml/ (nmol / l), not much higher. There is disagreement here but I am basing my opinion on the best science I have come across.
Staying between 35 to 40 ng/ml may mean taking no vitamin D during the summer if you are outdoors more with sunshine exposure.
Or that may mean taking 2000IU of vitamin D a day.
Or that may mean taking 5000 to 10,000 IU a day depending on your size and your complexion.
Bigger people need more Vitamin D as this hormone is lipid-soluble (dissolve in fat) and so do people with darker skin complexions. Dark skinned people tend to have extremely low vitamin D levels which may indicate why this population is more prone to many life-threatening diseases.
And why would anyone think one vitamin is a panacea anyway?
It is utterly ridiculous to think that one vitamin, one drug or one surgery is the cure for all maladies. Diseases, especially cancer is complex and have many causes. Finding the one thing to cure the one disease is a reductionist approach in medicine that has failed us time and time again.
Should we tell our patients to take vitamin D but eat high refined carbs and not exercise to cure cancer? Ridiculous I tell you.
What if What we Need is more Sun?
Naturopathic medicine was founded on the use of sunbathing (and fasting, and hydrotherapy) as a cornerstone therapeutic.
The best method of obtaining adequate amounts of vitamin D in the body is through sun exposure. Second best method is through supplementation.
Milk (after fortification) and fish contain some vitamin D but not enough to reach good blood levels when eating normal amounts of these foods. Besides, milk consumption is not recommended as many people have milk allergies and dairy intolerances.
But vitamin D production may not be the only benefit of sun exposure. There are many health benefits from sun exposure way beyond a nice tan. Ultra Violet Rays (UVA) from the sun also increases Nitric Oxide (NO) production on the skin. This result is strongly associated with widening of the arteries, lower blood pressure, and better sugar metabolism.
By the way, using sunscreen prevents penetration of sun rays, so it negates the benefits of UVA exposure.
How about skin cancer caused by sun exposure?
The connection is of sun exposure causing skin cancer, even melanoma, the most aggressive kind is debatable. I know. Crazy right?
In fact, it seems that those with the least sun exposure are more at risk of skin cancer.
And sunscreen may not protect against some types of skin cancer.
Lastly, this study showed women with more sun exposure live longer. I suspect the same is for men.
Fair skin people with a history or family history of skin cancer should still be cautious with sunbathing. But 10 to 15 minutes a day of getting some sun rays without sunscreen is beneficial and unlikely to cause problems.
I will end with this…
The fact is that you don’t spend much time outdoors under the sun.
Neither do I.
Yes, we do on weekends and on our way to and from work but that’s it.
The way most of us make a living these days is indoors, under fluorescent lights, sitting down in front of a computer.
In the perfect world, we would eat local, organic food, wild game, grass-fed meats, wild caught fish and move a lot – mostly outdoors in sunny areas of the world.
That’s not me, at least as often as I’d like. And very likely not you.
That’s why I supplement with vitamin D and take several other nutritional supplements in pills, move as often as I can and eat the best foods possible.
In the summer I spend more time outdoors soaking the sun without much sunscreen and supplement with vitamin D less.
Again, get your D levels measured and supplement accordingly.
Melamed ML1, Michos ED, Post W, Astor B. 25-hydroxyvitamin D levels and the risk of mortality in the general population. Arch Intern Med. 2008 Aug 11;168(15):1629-37.
Dror Y1, Giveon SM, Hoshen M, Feldhamer I, Balicer RD, Feldman BS. Vitamin D levels for preventing acute coronary syndrome and mortality: evidence of a nonlinear association. J Clin Endocrinol Metab. 2013 May;98(5):2160-7.
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