Calcium, vitamin D, and fractures (oh my!)

Monique Tello, MD, MPH

Contributing Editor

When I saw the headlines about this recently published study on bone health saying “Vitamin D and calcium supplements may not lower fracture risk.” I thought: Wait, that’s news? I think I remember seeing that headline a few years ago.

Indeed, in 2015, this very blog reported on similar studies of calcium supplements, noting that calcium supplements have risks and side effects, and are not likely indicated for most healthy community-dwelling adults over 50. These folks are not in a high-risk category for vitamin deficiencies, osteoporosis, and fractures, and we usually advise them to get their calcium from food. Dietary sources of calcium are everywhere, including milk and yogurt, but also include green leafy veggies like collard greens, legumes like black-eyed peas, tofu, almonds, orange juice… the list goes on (and you can check it out here).

What’s new with this most recent study?

This research found that taking vitamin D supplements did not protect against fractures in people over 50. The authors examined 33 research studies including over 50,000 people for their analysis. However, and it’s a big however, study investigators note several times that their research included only healthy people out in the community, and that their findings do not apply to elderly people living in nursing homes who may have a poorer diet, less sun exposure and mobility, and who are at particularly high risk for fractures. Indeed, the original recommendations for calcium supplementation were based on a study of elderly, nursing-home bound women with vitamin deficiencies and low bone density, for whom calcium and vitamin D supplements did significantly reduce fracture risk.

What is the takeaway?

Well, simply, not much has changed. My advice to my healthy patients is still to get calcium from foods, and the best diet for this is a Mediterranean-style diet rich in colorful plants, plenty of legumes, and fish. This plus high-protein, low-fat, and low-sugar dairy (yogurt is ideal) can supply plenty of calcium. As far as vitamin D, well, vitamin D supplementation continues to be a topic of lively and livid debate among everyone, including competing guideline-authoring endocrine experts (see my Harvard Health Blog post on this). I hesitate to wander into that minefield again. But here goes…

The scoop on vitamin D deficiency

There is a large group of people who are likely to be deficient in vitamin D. It includes people with eating disorders; people who have had gastric bypass surgeries; those with malabsorption syndromes like celiac sprue; pregnant and lactating women; people who have dark skin; and those who wear total skin covering (and thus absorb less sunlight). In addition, people with or at risk for low bone density (perimenopausal and postmenopausal women, people diagnosed with other skeletal disorders, or who take certain medications), should discuss whether they need supplements and to have blood levels of vitamin D monitored.

Many New England-dwelling (and Northern hemisphere) residents are at risk for a dip in vitamin D levels during the long, dark winter months. In my own practice I do consider that a risk factor, and I advise a vitamin D supplement of 1,000 IUs daily. For people who would rather avoid a supplement but may need a boost of vitamin D, it is also found in some common foods, including sardines, salmon, tuna, cheese, egg yolks, and vitamin-fortified milk. I will add that, for those who fall into the “healthy community-dwelling adult” category, a supplement of anywhere from 400 to 2,000 IUs of vitamin D daily is not likely to cause harm. Yes, vitamin D toxicity is a thing, usually seen at levels above 80 ng/ml, which causes excessive calcium to be released into the bloodstream. This is rare, but I have seen it in patients who took high-dose vitamin D supplementation of 50,000 IUs weekly over a long period of time.

Other important and effective ways to protect your bones

There are other methods that may be more effective at maintaining bone health and reducing fracture risk. One that we can likely all agree on is regular physical activity. Weight-bearing exercise like walking, jogging, tennis, and aerobics definitely strengthens bones. Core exercises like yoga and Pilates can improve balance. All of this can help reduce falls and fracture risk.

And so, in the end, I am recommending what I always end up recommending: a Mediterranean-style diet rich in colorful plants, plenty of legumes, fish, plus low-sugar, low-fat dairy and plenty of varied physical activity throughout your entire life… and maybe calcium and/or vitamin D supplementation for certain people, following a discussion with their doctors.

Comments:

  1. John

    Wow, this information is a bit distressing. I believed that the evidence was quite clear on how beneficial taking vitamin d was. I understand that some people do not get the benefits from it from sunlight due to them not being able to absorb, but always thought that taking it in supplement form fixed that problem. I found another article online that talks about it as well: https://www.neptunebeachdreams.com/blog/the-most-underrated-vitamin

  2. Clinica Vicario

    Women tend to be diagnosed with osteoporosis more often than men because once they reach menopause estrogen levels decrease. Estrogen helps maintain bone density in women. Post-menopausal women can lose up to 4% of bone mass annually in the first 10 years following menopause.

  3. Bob

    Monique you virtually answered everyones comments on this post. I have to commend you on your generosity and care for people. A very rare trait indeed.

  4. Richard Barnard

    Dr. Tello,
    Another good exercise and easy for insiders is rebounding on a rebounder (also known as a mini trampoline).

  5. Joyce Low

    I am on Prolia and I have had coronary artery surgery and my doctor has instructed that except for the month before and the month after I have my 6 monthly injection (when I take a calcium supplement), the rest of the time, I should try to get my calcium from food. So each day I eat a piece of cheese (200mg Ca on package) and a glass of High calcium soy miljk (400 mg). I now realise that the Ca in the soy milk is supplemented as calcium carbonate so I am not really getting the calcium in its natural state. On the other hand , maybe the Ca in the soy milk is more available for absorbtion than Ca in a pill.

  6. Ella Krucoff

    What is recommended (D and calcium?) during recovery from a fracture?

    • Monique Tello, MD, MPH
      Monique Tello, MD, MPH

      There is not yet an evidenced-based guideline for dosing after a fracture, but I can bet it would be similar to dosing in osteopenia and osteoporosis. The goals are increasing bone density and strength in both cases. Approximately 1200 mg of calcium per day in divided doses (ideally from dietary sources, as reviewed above) and 800 to 2000 IUs of Vitamin D daily, knowing that higher doses are unlikely to cause harm.

  7. Carole

    I am sorry, but I have been taking Vit. D and Calc. a long time,, and I have also fallen many times – the last 3 yrs, ago, I am 80 yrs. old and have not broken anything. So I will stick with what I am doing.

    • Monique Tello, MD, MPH
      Monique Tello, MD, MPH

      Yes, you seem to fit into the category that would require supplementation of both, as an elderly (over 65) person with frequent falls. I am very glad that you are doing this and that you have not fractured anything!

  8. Juan

    Is it true that in patients who have undergone a partial nephrectomy because of clear cell carcinoma often show in their labs a vitamin D deficiency when in reality there is no vitamin D deficiency but there may be a thyroid problem. The thyroid is on these cases trying to remove excess vitamin D. I. These cases should the doctor check the patient ‘s calcium level to rule out a vitamin D deficiency and focus instead on the thyroid.

  9. Danae Martin

    Bella, Many groups near the equator did well on non-dairy diets, but those in the more northern latitudes often ate dairy and
    meat, and were able to thrive due to evolutionary changes. Sometimes what works for some people and not for others has little to do with politics, but more with human adaptation to available nutrition.

  10. Nancy

    Please look into bio density machines to help build bone mass. There are several located in Osteostrong. me locations , and I personally go to one located in Houston TX at a HBOT.

    It is strategic weight induced force on the muscles and bones, over several weeks that makes you feel better and builds bone mass.

    I am on my 6th week of training and plan to do another bone density test to see how I’ve progressed.

    Not to sound like a commercial for the two above places, but it took a lot of my own time and research to find an alternative treatment to drugs. I already follow a great diet, supplements of D3 and Cal, and exercise regularly .. I still have transitioned into osteoporosis in my hip.

    Rather then using one of the drugs prescribed for bone density, I am trying the bio density treatment… so far so good.

    • Monique Tello, MD, MPH
      Monique Tello, MD, MPH

      Or you could go walking. There is no good published evidence to support the technique you mention. Walking, hiking, aerobics, dancing… These may be more fun, too.

  11. Bella

    Please stop disseminating dairy industry propaganda. Look at countries with low dairy consumption and their low incidences of osteoporosis and compare it to the SAD western diet, full of dairy and animal fats – high rates of osteoporosis. For more accurate and honest health advice, I recommend the Physicians Committee for Responsible Medicine or Dr Greger at nutritionfacts.org

    • Prakash Krishna

      Thanks much appreciated

    • Monique Tello, MD, MPH
      Monique Tello, MD, MPH

      I love Dr. Greger’s work and I recommend “How Not To Die” to my patients all the time. His website is a wonderful resource. Please reread the first paragraph where I point out all the varied sources of dietary calcium, including vegan ones: “Dietary sources of calcium are everywhere, including milk and yogurt, but also include green leafy veggies like collard greens, legumes like black-eyed peas, tofu, almonds, orange juice… the list goes on..”

      • Bella

        Thank you Monique, however with all the research coming out now on the benefits of plant-based diets and the elevated health risks of animal-based diets, it seems unethical to continue endorsing animal products.

  12. Cecile Moochnek

    i am always surprised by the idea of low fat yogurt
    i have always purchased organic whole milk yogurt
    it is now commonly known that good fats are essential
    i have heard that the fat helps to absorb the calcium
    thanks for comments on this
    cecile

  13. Richard Luczak

    I thought it was this same Harvard newsletter a few years ago that found that 8 hours of exposure to sunlight produced about 10,000 u of Vit D in the body — regarding safe levels of vit D intake.

    • Pete

      It is much less than 8 hours, it’s about 30 minutes, although it depends on how much clothes and if you are lay down. It has to be midsummer and midday.

  14. Richard Luczak

    due to a pituitary prolactinoma, I have low testosterone and showed up with osteopenia on a bone scan. my scan returned to normal after two years of 600 mg Ca w/vit D plus 2000 IU of Vit D.

    my problem is that I seem to be photosensitive from the Vit D. I get the sensation of sunburn after just even a brief exposure to outdoor UV light, even on a cloudy day.

  15. Gabby

    Quite an interesting read..
    I am a female originally from sub continent, grew up drinking one cup of organic milk, the in the morning, one cup at night. (hand milking straight from the cow, boiled & consumed immediately.) Only had access to organic foods, wild caught seafood. (advantage of being in the developing country). Played outdoor sports for minimum of 3 hours daily from the age of 7. Move to Sydney, Australia 30 years ago and eating habits remained unchanged but the products purchased from supermarkets & still an outdoor lover, exposed to sun at least 2-3 hours a day. But recently, I was diagnosed with food intolerant, including Milk & been advised to intake vitamin D supplement and has 2.5% deviation on lower lump spin.

    Four years ago, I moved to the coastal-country side, back to my childhood life style. ie, I buy the fruit and vegetables straight from organic farmers, plucked daily. Intake freshly squeezed juice. Eat only wagyu meat or meat from grass fed cow, lamb..etc. I don’t dislike any fruits or vegetable. I rarely consumed any soft drinks, but drink plenty of water, but my weakness is, I have sweet tooth. Continue to expose to sun at least 2 hours daily. Yet I am lacking in vitamin D.

    I am at a loss!! Any suggestion…

    • Monique Tello, MD, MPH
      Monique Tello, MD, MPH

      You may be in the group of people who will benefit from a Vitamin D supplement. Talk with your doctor about this, decide on a dose, and recheck your levels at some interval, would be my suggestion.

  16. Robert Mueller

    It is well to consider the following “While total dairy intake was not significantly associated with PD risk in our cohorts, intake of low-fat dairy foods was associated with PD risk.” (PD is Parkinson’s disease.) copied from
    “Intake of dairy foods and risk of Parkinson disease
    Katherine C. Hughes, ScD, Xiang Gao, MD, PhD, Iris Y. Kim, ScD, Molin Wang, PhD, Marc G. Weisskopf, PhD, ScD, Michael A. Schwarzschild, MD, PhD and Alberto Ascherio, MD, DrPH
    +SHOW AFFILIATIONS| + SHOW FULL DISCLOSURES
    Correspondence to Dr. Hughes: kch460@mail.harvard.edu

    In short, one must think about the relative risks of heart and other problems versus the years of downhill trend of the mental functions in Parkinson’s. How bad is dairy fat? I hope we have a more reliable measure then was used for decades of warning us about the dangers of egg consumption and thus get a handle on a rational decision process.

    • Monique Tello, MD, MPH
      Monique Tello, MD, MPH

      While it is true that various studies point to potential risks associated with some dairy products, especially ones involving added hormones, it is also true that we can’t draw conclusions from one study alone. This study of dairy and PD is thought-provoking, but more will be needed.

  17. Jayne Wright

    As someone who found out they were ill with hyperparathyroidism as a result of a Vit D deficiency can I alert readers to this horrible disease of the parathyroid glands where they turn into adenomas and over produce Parathyroid Hormone. This takes calcium from the bones and puts it at too higher levels into the blood, depositing calcium unhelpfully around the body! http://www.parathyroid.com explains more! It would be good for Harvard to do an article on this largely undiagnosed, misunderstood, damaging disease that slowly deprives you of the joy of life! If you’ve ever had a major Vit D deficiency and haven’t felt better for supplements….if you have had stones (kidney, gall or calcifications) Or if you are really achey with no energy and brain fog, maybe anxious or depressed, possibly told you have fibromyalgia then PLEASE ASK FOR A CALCIUM, vitamin D AND PARATHYOID HORMONE BLOOD TEST. If both are high and your vitamin D (mostly deficient) then chances are you need an operation to removed a tumour! Good luck!

  18. Judy Maloni

    I’m unclear in this about when it describes content related to vitamin. . DO our mean any kind of Vitamin D?. I’ve been told Vitamin D 3 is good for bones

    • Pete

      Vitamin d2 is made by fungi. Vitamin d3 is made by mammals. Humans can use of both vitamin d3 and vitamin d2, however, they only make vitamin d3 and vitamin d2 comes from food. It appears to be a useful adaptation to get through the winter, and other apes cannot do it.

      It would seem logical therefore to stick to using vitamin d3 and there is some evidence that it is more effective. Vitamin d3 is also very cheap, mainly because it is used in vast amounts in farming. It is used to improve the health of animals in the winter.

  19. Jeremiah Driscoll

    Please clarify if the 50,000 IUs you are referring to for toxicity was prescribed D2. Or OTC D3? I routinely ask patients if their provider discussed options of OTC daily vs weekly megadoses.

    • Maurice H

      So many doctors on this site. Glad to see your not one of them. I take 5,000 Units a day to supplement milk-when I have it. My doctor told me this problem is mostly with women, and if you exercise and are a man your chances are greatly reduced. Still, I would take a supplement of 2000-5000 daily adding up to less than 50,000 a week. It is better safe than sorry!… Good luck…Maurice H

    • Monique Tello, MD, MPH
      Monique Tello, MD, MPH

      It was prescribed ergocalciferol (D2). We usually use the weekly megadose to replete patients who are deficient for their needs, and then maintain levels with OTC cholecalciferol (D3). Per MGH clinical guidelines.

    • Pete

      Both vitamin d2 and vitamin d3 are toxic at a high enough dose, and the toxicity profile is not that different. The 50,000iu refers not to a single dose but a daily dose taken for about 6 months. Even then it is only toxic to a few because in most people consumption rises with supply. There are people with certain lymphomas and sarcoidosis you will become ill at much lower doses, these are symptoms of diseases hidden by a lack of vitamin d rather than toxicity. Most toxicity data in humans comes from industrial accidents (eg adding too much to milk) not from people taking supplements.

  20. Mary

    I am proof that the calcium pills work: I take Citracal MAX with D. My story is a bit too long, so here is the short version:
    1) I refused to take a prescription drug for osteoporosis of spine and other places on my body (the year 2011), because of the known side effects of regular prescribed medications.

    2) Three doctors showed concern (my spine) over the above, so I promised them this:
    I would take “4” CITRACAL Max at 4 different times of the day for 2 years, and I would eat yogurt and add as much skim milk to my diet as I can (Usually only in my Cheerios or the Quaker Old Fashioned Oatmeal that I eat a least 5 times a week. I was faithful taking the pills approximately 4 hours apart from each other (and at least 4 hours away from my Synthroid–medication). I even made myself bone soup a few times.

    3) I also promised the doctors that IF I still have Osteoporosis at the end of 2 years (when my “next” Dexa test was due) that I would indeed go to a prescription drug.

    4) At the end of 2 years (the year was 2013) I went from Osteoporosis to Osteopenia. Yay! My general practitioner was happily shocked (and so was I).

    5) Soon after (it’s in my notes somewhere as to when), I felt OVERLY CONFIDENT (mistake) and made a dreadful error: I started to lower my dose to only 3 CITRACAL MAX TABLETS a day. In 2016, my latest Dexa test indicated Osteoporosis of spine again (probably because I reduced my pills to 3 tablets).

    6) In conclusion, I MUST take 4 tablets to keep the Osteoporosis at bay. I experimented with myself, and I will see what my next test indicates — I should be taking my next test this year, in 2018. Hopefully, my Osteoporosis is gone–for me, the scary mystery continues . . . .

    7) Doctors MUST always be included with regard to a patient’s decisions. I tell the doctors what I am going to do with regard to my personal health, and they assist me with patience, assistance, agreement, and disagreement, and sometimes, scolding.

  21. KATHLEEN L CAMPBELL

    Why are there no topics on muscle cramps? I am taking magnesium and it has helped but am concerned about possible side affects.

  22. Roger Charlesworth

    I am surprised to find that you totally bypass the essential role of magnesium in calcium uptake, and that without magnesium in the correct ratio of Ca:Mg 100:40 you are at risk of calcium being deposited in the SOFT tissues and NOT the bones. Vitamin K is also essential in calcium uptake but supplementation is not usually necessary as long as the diet is replete with dark green leafy vegetables.

    • upperhandspiano@gmail.com

      Also I have read from many sources that magnesium supplementation is mostly not bio-available unless used topically as a spray.

    • Monique Tello, MD, MPH
      Monique Tello, MD, MPH

      Thanks for sharing. There is not enough published evidence for this to be considered for clinical guidelines. Definitely an area for more research. This is for safety and efficacy reasons.

  23. Chris Lazarus

    Vit D is needed FAR beyond New England!! Of course Harvard is in New England – but everyone in the northern and central US who is indoors during the cold months — actually we are ALL indoors more, glued to our screens of various sizes — need Vit D for several reasons not related to fracture risk – especially to fend off depression, which is a major problem here in the Pacific NW, where we have many overcast and rainy days for a good part of the year. My internist warned me that I should be on 2000IU daily of Vit D. Vit D is also beneficial to the immune system. Sure – don’t take 50,000 IU a week — but 2000 a day seems a good precaution to keep your immune system strong and fend off depression, which is RAMPANT here (and generally in the US).

    • Monique Tello, MD, MPH
      Monique Tello, MD, MPH

      Yes, if one is indoors all winter, they may benefit from a Vitamin D supplement.

      • Pete

        If you are outdoors all winter you still need a vitamin d supplement, assuming by winter we mean the sun is low in the sky and you are wearing clothes. You make vitamin d by exposing the skin to specify wavelengths of UVB to start a complex chemical reaction. If the UVB is not present or the skin covered no vitamin d is produced. Covered includes glass, cloud and also chemical smog.

  24. Fred

    In my previous comment it should state for every 100 mg of magnesium per day will increase bone density by 1% per year. There was no way to edit my comment. Thanks

  25. Fred

    Magnesium is the missing element from this article. This is what helps Vitamin D and calcium do its job. If you are low in Mag- D will not work properly. Every 100 mg of magnesium can increase bone density by 1% per year. You can get mag from pumpkin seeds and various nuts and seeds. Epson salt baths or foot baths if you have a hard time getting in and out of tub. Magnesium gel applied topically . Have your mag serum level checked first then RBC mag test to see if your cells have adequate levels. Throw in some potassium and you should have strong and healthy bones for life. Vitamin D3 should be taken with some healthy fat.

    • Monique Tello, MD, MPH
      Monique Tello, MD, MPH

      Thanks for sharing. There is not enough published evidence for this to be considered for clinical guidelines. Definitely an area for more research. This is for safety and efficacy reasons. Though that kind of low dose of Mg is unlikely to do any harm at all.

  26. Jean P Muller

    How about for a 67 year old who eats vegan, Whole Foods only diet? And dairy protein allergy.

    • Fred

      D2 is appropriate for vegans but does not work as well as D3. Doctors prescribe 50,000 once a week. I spoke to some people one with M.S. and her level was 4-5 and she switched to D3 and now her levels are up. You can get adequate D from tanning beds in winter but be very careful as not to get skin cancer. Maybe 5 or 10 minutes 2-3 times a week, but not the 30 minute session. Talk to your doctor to see if this is a good idea. In summer try about 10 minutes at noon without sunblock then sunblock. Also have your B-12 level checked since you do not eat meat. Sublingual under your tongue works best. Vegans can have very low B-12 levels. Remember always check with your doctor before starting or stopping anything. Hope this helps. Take Care

  27. Jeffrey Lilly

    For those on immunosuppressants, exposure to sunlight without sunscreen produces a greater occurrence of skin cancer.

    There is also a problem with some antioxidants that produce reactions to immunosuppressant drugs. In my case, it became life threatening.

    The use of some antibiotics without probiotics can also cause also cause serious health problems. Long term use of probiotics is also not recommended.

  28. Beth Cooper Tabakin, Ph.D.

    What studies have been done about the parathyroid glands & influence in bone health? Isn’t the parathyroid hormone PTH a crucial factor & indicator of how calcium is used in the body? After having 2 PTH adenomas removed, my blood calcium levels are normal and my bones are not aching. Please comment.

    • Monique Tello, MD, MPH
      Monique Tello, MD, MPH

      If you have had parathyroidectomies, you should meet with an endocrinologist to sort out where you are and what you may need. This is a specific clinical situation.

  29. Rich

    Really should get updated info about low-fat anything being good for anyone.

    • Bella

      Totally agree. The plant world has given us everything. We don’t need processed junk.

      • Monique Tello, MD, MPH
        Monique Tello, MD, MPH

        There is a mountain of evidence supporting a plant-based diet as the best diet. For those that aren’t ready or able to go vegan, being as plant-based as possible is the next best step.

    • Monique Tello, MD, MPH
      Monique Tello, MD, MPH

      For those that eat dairy, there is conflicting evidence regarding the risks and benefits of low vs regular fat products. I personally prefer whole milk and yogurt etc. but the evidence-based jury is still largely out on this.

  30. David Pieter van Velden

    The Western diet is acidogenic due to the large amount of animal protein. In order to maintain homeostasis, the kidneys excrete calcium to maintain the pH of 7.45.
    The alkaline, Mediterranean -type diet rich in plant products, limits the excretion of calcium.
    Osteoporosis can be prevented with an alkaline diet, weight bearing exercise, and sun exposure. Vit D supplementation is only necessary when a deficiency can be demonstrated

    • Monique Tello, MD, MPH
      Monique Tello, MD, MPH

      The field of nephrology is devoted to acid/base balance in the body. It requires a three year fellowship, after three years of postgraduate training… and I’m not a nephrologist. I think some of what you’re saying is sound, that there is plenty of published evidence suggesting that a diet high in animal products is not so good for us, while a plant-based diet is much, much better.

    • Pete

      The body looses calcium because it lacks vitamin d, not because your diet is acid or alkaline. The lack of vitamin d causes the parathyroid to produce more hormone that releases calcium from the bones in an attempt to maintain blood calcium levels. This mechanism should be a short term survival method, but lack of vitamin d in modern people means it is permanently turned on. Low blood calcium levels will kill long before bone weakening.

  31. Miriam

    Please stop calling orange juice a good food source of calcium. This is wrong on many fronts. Instead, call it “calcium fortified” and maybe even point out that it is in the form of calcium carbonate which may be problematic in those with low stomach acid and/or constipation. And as someone else commented, K2 is needed to move calcium from blood to tissues. My other major issue with orange juice is the concentration of sugars in just one glass, enough to spike both glucose and insulin. You recommend (rightfully) that people consume low-sugar dairy (better yet: NO added sugar dairy) then suggest they drink OJ for the calcium??

    • Matt

      The author of the article did not suggest drinking orange juice as method of obtaining calcium from the diet. They did, however, point out that this beloved beverage–drank by millions of Americans every single day–does indeed contain calcium. If you go back and actually read the article, you will see that the author was pointing out that sufficient calcium is easily obtained through an average person’s diet. They go on to say, “My advice to my healthy patients is still to get calcium from foods, and the best diet for this is a Mediterranean-style diet rich in colorful plants, plenty of legumes, and fish.” Do you see orange juice in that recommendation?

    • upperhandspiano@gmail.com

      Yes! Eat an orange, not the juice- so important

    • Monique Tello, MD, MPH
      Monique Tello, MD, MPH

      What Matt said.

  32. Sébastien E. Fortin

    sport +D3

  33. Tom Spradley

    Have you ever heard of vitamin K2? D helps the gut absorb calcium whether from food or supplement. But K2 is necessary to direct calcium to bones and avoid ending up in arterial plaques. Ask most doctors about K2 and they only know about K1, usually just called k, that is necessary for clotting.

    • Monique Tello, MD, MPH
      Monique Tello, MD, MPH

      There’s alot out there that hasn’t been rigorously studied yet. We clinicians need to keep an open mind, but we are duty-bound to recommend only things for which there is solidly studied evidence.

  34. Pete

    The take away from this is you should take significant amounts of vitamin d before you have bone problems, not after. You cannot fix chronic malnutrition with a big meal later on in your life.

    The risks of heart problems reported in your 2015 blog have been shown not to exist by a larger better controlled experiment
    https://www.ncbi.nlm.nih.gov/pubmed/29314248

  35. Marc

    Calcium and vitamin D supplements are not the answer. Those countries of the world who consume the greatest quantity of calcium also have by far the highest risk of osteoporosis and hip fracture. Be careful what you teach. Calcium supplementation of 1,000 mg per day has been shown to double the risk of heart attack. Lack of calcium is not the reason for osteoporosis! The real reason for osteoporosis is lack of sunlight. A Spanish study demonstrated that women who were sun seekers had only about one-eleventh the risk of hip fracture as those who stayed indoors. Sun exposure produces vitamin D in the skin, which is absolutely essential for the absorption of calcium. However, vitamin D supplementation is not nearly as effective as sunlight. That could be because sun exposure can produce up to 20,000 IU of vitamin D in 20 minutes of whole-body exposure at midday. Sun lamps and sun beds also produce large quantities of vitamin D. Here are more important facts about the vital necessity of sun exposure for human health:
    •Men who work outdoors have half the risk of melanoma as those who work indoors.
    •Women who avoid the sun have 10-times the risk of breast cancer as those who embrace the sun.
    •Women who sunbathe regularly have half the risk of death during a 20-year period compared to those who stay indoors.
    •Sun exposure increases nitric oxide production, which leads to a decrease in heart disease risk.
    •Sun exposure dramatically improves mood through the production of serotonin and endorphin.
    • Sun exposure increases the production of BDNF, which is vital to human health.
    For more information: http://sunlightinstitute.org/

    • upperhandspiano@gmail.com

      Very confusing to me as there is so much melanoma! My friend was a sun-lover and died of melanoma. My dermatologist warns against sun exposure!

    • Mary

      This is a damn if you and damn if you don’t kind of situation. We all know that the sun is important for getting enough vitamin D, but we are also told that sun causes skin cancer so we douse ourselves with suntan lotion. I have a friend who walks long distances everyday and yet she is Vitamin D deficient. So sun or no sun, that’s the million dollar question.

    • Monique Tello, MD, MPH
      Monique Tello, MD, MPH

      The disappearing ozone layer is a complicating factor here. Skin cancer is a thing. The right answer is probably in between. Some sun, some diet, some supplement for those that need it.