Those with higher vitamin D levels tend to have lower rates of obesity, diabetes, and hypertension, but is it cause and effect? Interventional trials finally put vitamin D to the test.
Flashback Friday: Do Vitamin D Supplements Help with Diabetes, Weight Loss, and Blood Pressure?
4.6/5 - (101 votes)
Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.
My last in-depth video series on vitamin D was done more than four years ago—as in 15,950 papers ago. I had a lot of catching up to do.
Review articles like this continue to be published, touting vitamin D as a veritable cure-all. The vitamin D receptor is found in most tissues in the body, including the brain. Upwards of 2,000 genes may be regulated by vitamin D. Within 24 hours of vitamin D exposure, you can change the expression of hundreds of genes.
The term vitamin is actually a misnomer. Vitamins, by definition, cannot be synthesized within our body. But we can make all the D we need with sufficient sun exposure. D is not a vitamin, but a hormone, produced by our skin in response to sunlight exposure. And it’s not just a hormone of calcium regulation and bone health, but a hormone of fertility and immunity and brain function. But is it a panacea, or a false prophet?
Remember when vitamin E was the vitamin du jour, touted as curative for many clinical disorders. “Vitamin E: the radical protector,” with supplement sales in general forming a billion-dollar business to capitalize on the public’s fears. After all, those with low levels of vitamin E in their blood had 50% higher cancer risk. Hey, and what about vitamin A or beta carotene? After all, people who eat lots of greens and sweet potatoes and other beta carotene-rich foods have lower risk of cancer; so, we should give people beta carotene pills. But when they were put to the test, beta carotene pills increased cancer rates. Beta carotene, vitamin A, and vitamin E supplements may increase mortality, in effect potentially paying to shorten our lifespan. So, you can understand the skepticism in the medical community regarding claims about vitamin D, which is now enjoying its moment in the sun.
Having a half-billion dollar vitamin D supplement industry doesn’t help matters, not to mention the highly lucrative vitamin D-testing industry that loves to talk about the studies suggesting having higher vitamin D levels may reduce the risk of heart disease, and cancer, and diabetes, autoimmune diseases, and infections.
But most of this research stems from observational studies—meaning studies that correlate higher D levels in the blood with lower disease risk. It doesn’t mean vitamin D is the cause. It’s like the early beta carotene data. Higher levels in the blood may have just been a marker of healthy eating, just like vitamin D levels may just be a marker of healthy behaviors. Who has high D levels? Those that run around outside. And those that run around outside, run around outside. Higher vitamin D levels may just be a sign of higher physical activity, for example.
So, when you see studies like this, showing significantly lower diabetes rates among those with higher vitamin D levels, it doesn’t mean giving people vitamin D will necessarily help. You have to put it to the test. And when you do, vitamin D supplements fall flat on their face. No benefit for preventing or treating type 2 diabetes.
So, when supplement companies wave around studies like this, suggesting vitamin D deficiency plays a role in obesity, because most population studies show lower vitamin D levels in the blood of those who are obese, is that because they’re exercising less, or, simply because it’s a fat-soluble vitamin, and so is just lodged in all the fat? One might expect obese sunbathers would make more vitamin D since they have more skin surface area. But the same exposure leads to less than half the D, because it gets socked away in the fat. That’s why obese persons may require two to three times the dose of vitamin D—though they may get it back when they lose weight, and release it back into the circulation. So, that would explain the population data. And indeed, when you put vitamin D to the test, try vitamin D as a treatment for obesity, it doesn’t work at all.
Similar story with artery health. Those with low vitamin D levels have worse coronary blood flow, more atherosclerosis, and worse artery function. But if you actually put it to the test in randomized controlled trials, the results are disappointing. Also ineffective in bringing down blood pressures.
This all just adds to the growing body of science casting doubt on the ability of vitamin D supplementation to improve anything beyond just falls, fractures, the common cold, and all-cause mortality.
Wait—what?! Vitamin D supplements can make you live longer? That’s kind of important. I’ll explore that next.
Please consider volunteering to help out on the site.
- J P Ekwaru, J D Zwicker, M F Holick, E Giovannucci, P J Veugelers. The importance of body weight for the dose response relationship of oral vitamin D supplementation and serum 25-hydroxyvitamin D in healthy volunteers. PLoS One. 2014 Nov 5;9(11):e111265.
- N G Forouhi, Z Ye, A P Rickard, K T Khaw, R Luben, C Langenberg, N J Wareham. Circulating 25-hydroxyvitamin D concentration and the risk of type 2 diabetes: results from the European Prospective Investigation into Cancer (EPIC)-Norfolk cohort and updated meta-analysis of prospective studies. Diabetologia. 2012 Aug;55(8):2173-82.
- F Oz, A Y Cizgici, H Oflaz, A Elitok, E B Karaayvaz, F Mercanoglu, Z Bugra, B Omer, K Adalet, A Oncul. Impact of vitamin D insufficiency on the epicardial coronary flow velocity and endothelial function. Coron Artery Dis. 2013 Aug;24(5):392-7.
- K Pathak, M J Soares, E K Calton, Y Zhao, J Hallett. Vitamin D supplementation and body weight status: a systematic review and meta-analysis of randomized controlled trials. Obes Rev. 2014 Jun;15(6):528-37.
- P Pludowski, M F Holick, S Pilz, C L Wagner, B W Hollis, W B Grant, Y Shoenfeld, E Lerchbaum, D J Llewellyn, K Kienreich, M Soni. Vitamin D effects on musculoskeletal health, immunity, autoimmunity, cardiovascular disease, cancer, fertility, pregnancy, dementia and mortality-a review of recent evidence. Autoimmun Rev. 2013 Aug;12(10):976-89.
- J C Seida, J Mitri, I N Colmers, S R Majumdar, M B Davidson, A L Edwards, D A Hanley, A G Pittas, L Tjosvold, J A Johnson. Clinical review: Effect of vitamin D3 supplementation on improving glucose homeostasis and preventing diabetes: a systematic review and meta-analysis. J Clin Endocrinol Metab. 2014 Oct;99(10):3551-60.
- A Alyami, M J Soares, J L Sherriff, J C Mamo. Vitamin D & endothelial function. Indian J Med Res. 2014 Oct;140(4):483-90.
- L A Beveridge, A D Struthers, F Khan, R Jorde, R Scragg, H M Macdonald, J A Alvarez, R S Boxer, A Dalbeni, A D Gepner, N M Isbel, T Larsen, J Nagpal, W G Petchey, H Stricker, F Strobel, V S Tangpricha, L Toxqui, M P Vaquero, L Wamberg, A Zittermann, M D Witham; D-PRESSURE Collaboration. Effect of Vitamin D Supplementation on Blood Pressure: A Systematic Review and Meta-analysis Incorporating Individual Patient Data. JAMA Intern Med. 2015 May;175(5):745-54.
- M J Glade. Vitamin D: health panacea or false prophet? Nutrition. 2013 Jan;29(1):37-41.
- W E Stumpf. Vitamin D and the scientific calcium dogma: understanding the ‘Panacea’ of the sun. Eur J Clin Nutr. 2012 Oct;66(10):1080-1.
- A Hossein-nezhad, M F Holick. Optimize dietary intake of vitamin D: an epigenetic perspective. Curr Opin Clin Nutr Metab Care. 2012 Nov;15(6):567-79.
- K Kupferschmidt. Uncertain verdict as vitamin D goes on trial. Science. 2012 Sep 21;337(6101):1476-8.
- C L Taylor, P R Thomas, J F Aloia, P S Millard, C J Rosen. Questions About Vitamin D for Primary Care Practice: Input From an NIH Conference. Am J Med. 2015 Nov;128(11):1167-70.
- P Autier, M Boniol, C Pizot, P Mullie. Vitamin D status and ill health: a systematic review. Lancet Diabetes Endocrinol. 2014 Jan;2(1):76-89.
- J Wortsman, L Y Matsuoka, T C Chen, Z Lu, M F Holick. Decreased bioavailability of vitamin D in obesity. Am J Clin Nutr. 2000 Sep;72(3):690-3.
- C L Rock, J A Emond, S W Flatt, D D Heath, N Karanja, B Pakiz, N E Sherwood, C A Thomson. Weight loss is associated with increased serum 25-hydroxyvitamin D in overweight or obese women. Obesity (Silver Spring). 2012 Nov;20(11):2296-301.
- W E Stumpf. Vitamin D sites and mechanisms of action: a histochemical perspective. Reflections on the utility of autoradiography and cytopharmacology for drug targeting. Histochem Cell Biol. 1995 Dec;104(6):417-27.
- M Vukić, A Neme, S Seuter, N Saksa, V D de Mello, T Nurmi, M Uusitupa, T P Tuomainen, J K Virtanen, C Carlberg. Relevance of vitamin D receptor target genes for monitoring the vitamin D responsiveness of primary human cells. PLoS One. 2015 Apr 13;10(4):e0124339.
- A Hossein-nezhad, A Spira, M F Holick. Influence of vitamin D status and vitamin D3 supplementation on genome wide expression of white blood cells: a randomized double-blind clinical trial. PLoS One. 2013;8(3):e58725.
- P Knekt, A Aromaa, J Maatela, R K Aaran, T Nikkari, M Hakama, T Hakulinen, R Peto, L Teppo. Vitamin E and cancer prevention. Am J Clin Nutr. 1991 Jan;53(1 Suppl):283S-286S.
- R Wolf, D Wolf, V Ruocco. Vitamin E: the radical protector. J Eur Acad Dermatol Venereol. 1998 Mar;10(2):103-17.
- L M De Luca, S A Ross. Beta-carotene increases lung cancer incidence in cigarette smokers. Nutr Rev. 1996 Jun;54(6):178-80.
- R Muggli. beta-Carotene and disease prevention. J Nutr Sci Vitaminol (Tokyo). 1992;Spec No:560-3.
- M K Horwitt. The promotion of vitamin E. J Nutr. 1986 Jul;116(7):1371-7.
- G Bjelakovic, D Nikolova, L L Gluud, R G Simonetti, C Gluud. Mortality in randomized trials of antioxidant supplements for primary and secondary prevention: systematic review and meta-analysis. JAMA. 2007 Feb 28;297(8):842-57.
- T Kummet, T E Moon, F L Meyskens Jr. Vitamin A: evidence for its preventive role in human cancer. Nutr Cancer. 1983;5(2):96-106.
- Y J Foss. Vitamin D deficiency is the cause of common obesity. Med Hypotheses. 2009 Mar;72(3):314-21.
Image thanks to mojzagrebinfo via Pixabay.
Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.
My last in-depth video series on vitamin D was done more than four years ago—as in 15,950 papers ago. I had a lot of catching up to do.
Review articles like this continue to be published, touting vitamin D as a veritable cure-all. The vitamin D receptor is found in most tissues in the body, including the brain. Upwards of 2,000 genes may be regulated by vitamin D. Within 24 hours of vitamin D exposure, you can change the expression of hundreds of genes.
The term vitamin is actually a misnomer. Vitamins, by definition, cannot be synthesized within our body. But we can make all the D we need with sufficient sun exposure. D is not a vitamin, but a hormone, produced by our skin in response to sunlight exposure. And it’s not just a hormone of calcium regulation and bone health, but a hormone of fertility and immunity and brain function. But is it a panacea, or a false prophet?
Remember when vitamin E was the vitamin du jour, touted as curative for many clinical disorders. “Vitamin E: the radical protector,” with supplement sales in general forming a billion-dollar business to capitalize on the public’s fears. After all, those with low levels of vitamin E in their blood had 50% higher cancer risk. Hey, and what about vitamin A or beta carotene? After all, people who eat lots of greens and sweet potatoes and other beta carotene-rich foods have lower risk of cancer; so, we should give people beta carotene pills. But when they were put to the test, beta carotene pills increased cancer rates. Beta carotene, vitamin A, and vitamin E supplements may increase mortality, in effect potentially paying to shorten our lifespan. So, you can understand the skepticism in the medical community regarding claims about vitamin D, which is now enjoying its moment in the sun.
Having a half-billion dollar vitamin D supplement industry doesn’t help matters, not to mention the highly lucrative vitamin D-testing industry that loves to talk about the studies suggesting having higher vitamin D levels may reduce the risk of heart disease, and cancer, and diabetes, autoimmune diseases, and infections.
But most of this research stems from observational studies—meaning studies that correlate higher D levels in the blood with lower disease risk. It doesn’t mean vitamin D is the cause. It’s like the early beta carotene data. Higher levels in the blood may have just been a marker of healthy eating, just like vitamin D levels may just be a marker of healthy behaviors. Who has high D levels? Those that run around outside. And those that run around outside, run around outside. Higher vitamin D levels may just be a sign of higher physical activity, for example.
So, when you see studies like this, showing significantly lower diabetes rates among those with higher vitamin D levels, it doesn’t mean giving people vitamin D will necessarily help. You have to put it to the test. And when you do, vitamin D supplements fall flat on their face. No benefit for preventing or treating type 2 diabetes.
So, when supplement companies wave around studies like this, suggesting vitamin D deficiency plays a role in obesity, because most population studies show lower vitamin D levels in the blood of those who are obese, is that because they’re exercising less, or, simply because it’s a fat-soluble vitamin, and so is just lodged in all the fat? One might expect obese sunbathers would make more vitamin D since they have more skin surface area. But the same exposure leads to less than half the D, because it gets socked away in the fat. That’s why obese persons may require two to three times the dose of vitamin D—though they may get it back when they lose weight, and release it back into the circulation. So, that would explain the population data. And indeed, when you put vitamin D to the test, try vitamin D as a treatment for obesity, it doesn’t work at all.
Similar story with artery health. Those with low vitamin D levels have worse coronary blood flow, more atherosclerosis, and worse artery function. But if you actually put it to the test in randomized controlled trials, the results are disappointing. Also ineffective in bringing down blood pressures.
This all just adds to the growing body of science casting doubt on the ability of vitamin D supplementation to improve anything beyond just falls, fractures, the common cold, and all-cause mortality.
Wait—what?! Vitamin D supplements can make you live longer? That’s kind of important. I’ll explore that next.
Please consider volunteering to help out on the site.
- J P Ekwaru, J D Zwicker, M F Holick, E Giovannucci, P J Veugelers. The importance of body weight for the dose response relationship of oral vitamin D supplementation and serum 25-hydroxyvitamin D in healthy volunteers. PLoS One. 2014 Nov 5;9(11):e111265.
- N G Forouhi, Z Ye, A P Rickard, K T Khaw, R Luben, C Langenberg, N J Wareham. Circulating 25-hydroxyvitamin D concentration and the risk of type 2 diabetes: results from the European Prospective Investigation into Cancer (EPIC)-Norfolk cohort and updated meta-analysis of prospective studies. Diabetologia. 2012 Aug;55(8):2173-82.
- F Oz, A Y Cizgici, H Oflaz, A Elitok, E B Karaayvaz, F Mercanoglu, Z Bugra, B Omer, K Adalet, A Oncul. Impact of vitamin D insufficiency on the epicardial coronary flow velocity and endothelial function. Coron Artery Dis. 2013 Aug;24(5):392-7.
- K Pathak, M J Soares, E K Calton, Y Zhao, J Hallett. Vitamin D supplementation and body weight status: a systematic review and meta-analysis of randomized controlled trials. Obes Rev. 2014 Jun;15(6):528-37.
- P Pludowski, M F Holick, S Pilz, C L Wagner, B W Hollis, W B Grant, Y Shoenfeld, E Lerchbaum, D J Llewellyn, K Kienreich, M Soni. Vitamin D effects on musculoskeletal health, immunity, autoimmunity, cardiovascular disease, cancer, fertility, pregnancy, dementia and mortality-a review of recent evidence. Autoimmun Rev. 2013 Aug;12(10):976-89.
- J C Seida, J Mitri, I N Colmers, S R Majumdar, M B Davidson, A L Edwards, D A Hanley, A G Pittas, L Tjosvold, J A Johnson. Clinical review: Effect of vitamin D3 supplementation on improving glucose homeostasis and preventing diabetes: a systematic review and meta-analysis. J Clin Endocrinol Metab. 2014 Oct;99(10):3551-60.
- A Alyami, M J Soares, J L Sherriff, J C Mamo. Vitamin D & endothelial function. Indian J Med Res. 2014 Oct;140(4):483-90.
- L A Beveridge, A D Struthers, F Khan, R Jorde, R Scragg, H M Macdonald, J A Alvarez, R S Boxer, A Dalbeni, A D Gepner, N M Isbel, T Larsen, J Nagpal, W G Petchey, H Stricker, F Strobel, V S Tangpricha, L Toxqui, M P Vaquero, L Wamberg, A Zittermann, M D Witham; D-PRESSURE Collaboration. Effect of Vitamin D Supplementation on Blood Pressure: A Systematic Review and Meta-analysis Incorporating Individual Patient Data. JAMA Intern Med. 2015 May;175(5):745-54.
- M J Glade. Vitamin D: health panacea or false prophet? Nutrition. 2013 Jan;29(1):37-41.
- W E Stumpf. Vitamin D and the scientific calcium dogma: understanding the ‘Panacea’ of the sun. Eur J Clin Nutr. 2012 Oct;66(10):1080-1.
- A Hossein-nezhad, M F Holick. Optimize dietary intake of vitamin D: an epigenetic perspective. Curr Opin Clin Nutr Metab Care. 2012 Nov;15(6):567-79.
- K Kupferschmidt. Uncertain verdict as vitamin D goes on trial. Science. 2012 Sep 21;337(6101):1476-8.
- C L Taylor, P R Thomas, J F Aloia, P S Millard, C J Rosen. Questions About Vitamin D for Primary Care Practice: Input From an NIH Conference. Am J Med. 2015 Nov;128(11):1167-70.
- P Autier, M Boniol, C Pizot, P Mullie. Vitamin D status and ill health: a systematic review. Lancet Diabetes Endocrinol. 2014 Jan;2(1):76-89.
- J Wortsman, L Y Matsuoka, T C Chen, Z Lu, M F Holick. Decreased bioavailability of vitamin D in obesity. Am J Clin Nutr. 2000 Sep;72(3):690-3.
- C L Rock, J A Emond, S W Flatt, D D Heath, N Karanja, B Pakiz, N E Sherwood, C A Thomson. Weight loss is associated with increased serum 25-hydroxyvitamin D in overweight or obese women. Obesity (Silver Spring). 2012 Nov;20(11):2296-301.
- W E Stumpf. Vitamin D sites and mechanisms of action: a histochemical perspective. Reflections on the utility of autoradiography and cytopharmacology for drug targeting. Histochem Cell Biol. 1995 Dec;104(6):417-27.
- M Vukić, A Neme, S Seuter, N Saksa, V D de Mello, T Nurmi, M Uusitupa, T P Tuomainen, J K Virtanen, C Carlberg. Relevance of vitamin D receptor target genes for monitoring the vitamin D responsiveness of primary human cells. PLoS One. 2015 Apr 13;10(4):e0124339.
- A Hossein-nezhad, A Spira, M F Holick. Influence of vitamin D status and vitamin D3 supplementation on genome wide expression of white blood cells: a randomized double-blind clinical trial. PLoS One. 2013;8(3):e58725.
- P Knekt, A Aromaa, J Maatela, R K Aaran, T Nikkari, M Hakama, T Hakulinen, R Peto, L Teppo. Vitamin E and cancer prevention. Am J Clin Nutr. 1991 Jan;53(1 Suppl):283S-286S.
- R Wolf, D Wolf, V Ruocco. Vitamin E: the radical protector. J Eur Acad Dermatol Venereol. 1998 Mar;10(2):103-17.
- L M De Luca, S A Ross. Beta-carotene increases lung cancer incidence in cigarette smokers. Nutr Rev. 1996 Jun;54(6):178-80.
- R Muggli. beta-Carotene and disease prevention. J Nutr Sci Vitaminol (Tokyo). 1992;Spec No:560-3.
- M K Horwitt. The promotion of vitamin E. J Nutr. 1986 Jul;116(7):1371-7.
- G Bjelakovic, D Nikolova, L L Gluud, R G Simonetti, C Gluud. Mortality in randomized trials of antioxidant supplements for primary and secondary prevention: systematic review and meta-analysis. JAMA. 2007 Feb 28;297(8):842-57.
- T Kummet, T E Moon, F L Meyskens Jr. Vitamin A: evidence for its preventive role in human cancer. Nutr Cancer. 1983;5(2):96-106.
- Y J Foss. Vitamin D deficiency is the cause of common obesity. Med Hypotheses. 2009 Mar;72(3):314-21.
Image thanks to mojzagrebinfo via Pixabay.
Republishing "Flashback Friday: Do Vitamin D Supplements Help with Diabetes, Weight Loss, and Blood Pressure?"
Terms
You may republish this material online or in print under our Creative Commons licence. You must attribute the article to NutritionFacts.org with a link back to our website in your republication.
If any changes are made to the original text or video, you must indicate, reasonably, what has changed about the article or video.
You may not use our material for commercial purposes.
You may not apply legal terms or technological measures that restrict others from doing anything permitted here.
If you have any questions, please Contact Us
Title
Flashback Friday: Do Vitamin D Supplements Help with Diabetes, Weight Loss, and Blood Pressure?
LicenseCreative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)
Content URLDoctor's Note
This video is the first of a six-part series on the latest in vitamin D, which includes:
- Will You Live Longer If You Take Vitamin D Supplements?
- How Much Vitamin D Should You Take?
- The Optimal Dose of Vitamin D Based on Natural Levels
- The Best Way to Get Vitamin D: Sun, Supplements, or Salons?
- The Risks and Benefits of Sensible Sun Exposure
And check out these other videos on vitamin D’s potential benefits:
- The Best Supplement for Fibromyalgia
- Vitamin D for Inflammatory Bowel Disease
- Vitamin D for Asthma
- Vegetarians and Stroke Risk Factors—Vitamin D?
For additional videos on supplements, see:
- Dietary Supplement Snake Oil
- Some Dietary Supplements May Be More Than a Waste of Money
- Risk Associated with Iron Supplements
- Treating Asthma with Plants vs. Supplements?
- Broccoli: Sprouts vs. Supplements
- Antioxidants and Depression
- Are Calcium Supplements Safe?
- Are Calcium Supplements Effective?
- Industry Response to Plants Not Pills
- Resveratrol Impairs Exercise Benefits
- Lycopene Supplements vs. Prostate Cancer
- Dangers of Dietary Supplement Deregulation
- Do Vitamin C Supplements Prevent Colds But Cause Kidney Stones?
- Black Raspberry Supplements Put to the Test
- Dietary Supplements for Autism
If you haven't yet, you can subscribe to our free newsletter. With your subscription, you'll also get notifications for just-released blogs and videos. Check out our information page about our translated resources.
Previous Video
Next Video
