Vitamin D is a powerful nutrient that has far-reaching impacts on everything from immune function to thyroid health to bone strength. In truth, vitamin D is more of a hormone than a vitamin and as a consequence, it plays a huge role in many different biological functions inside your body.
Since it can’t be synthesized inside your body, there are really only two ways to get the benefits of vitamin D: either by exposure to sunlight (which generates vitamin D in your skin), or by taking a supplement.
Since many people don’t get enough sun exposure (especially in wintertime), a supplement is the way to go if you want to reap the following health benefits of vitamin D.
Vitamin D benefits
1. Vitamin D helps your body absorb calcium
For that reason alone, it’s crucial that we get enough of this important vitamin in our diets. After all, calcium (along with phosphate) is the essential building block of bones.
If you don’t get enough calcium in your diet, or if you aren’t absorbing the calcium you do consume, bone production and bone tissue are severely impacted.
2. The best natural source of vitamin D is sunlight
It’s estimated that worldwide, around a billion people don’t get enough vitamin D (1). There are very few food sources of vitamin D, but beef liver, cheese, mushrooms, and egg yolks provide tiny amounts.
Fatty fish like salmon provide even more, but the best way to get your vitamin D is to drink fortified milk, get at least 15 minutes of full sunshine on a large part of your body every day, or take supplements.
In fact, it’s very difficult to get all the vitamin D from food sources. Likewise, if you live in a northern part of the world it can be hard to get your vitamin D from sunshine, too.
Not only that, but certain segments of the population have trouble getting enough of the vitamin from the sun, too: people with dark skin.
Finally, the elderly need more vitamin D than the rest of us. For all these reasons, vitamin D supplements are among the most widely necessary supplements on the planet.
3. High vitamin D levels might protect your body against cancer
Thirty years ago, it was discovered that people living in northern areas had higher rates of colon cancer (2).
That led to the theory that lower vitamin D levels might increase colon cancer risk. Dozens of studies have been performed since then that strongly support the theory, but that doesn’t necessarily mean vitamin D supplements will lower the risk.
4. High levels of vitamin D might also help prevent heart attacks
A 20-year study (3) found that men with vitamin D deficiencies had double the risk of having a heart attack.
While more research is needed, this association may be related to the fact that vitamin D has been linked to your overall levels of inflammation.
5. Vitamin D can help retain muscle strength in older adults
Many older adults get weaker as they age–a condition known as sarcopenia. Vitamin D might be able to augment the effects of protein supplementation in retaining muscle strength and aging healthier.
That’s according to a 2015 study on elderly patients found that adding leucine (as well as whey protein) to the vitamin D supplementation regimen of people at risk for sarcopenia found that this supplementation regimen helped prevent muscle loss (4).
Vitamin D side effects
Vitamin D has been established as safe at doses of at least 4000 IU per day. However, there is some risk of adverse effects if you take extremely high doses for a long time.
What’s ‘excessive’? Even doses of 10,000 IU per day is not known to cause significant side effects in the general population (5). These side effects at very high doses (many tens of thousands of IUs of vitamin D) can be serious, and include dysregulated blood levels of calcium.
Vitamin D can interact with thyroid hormones. People with thyroid conditions seem to be at a higher risk for vitamin D toxicity, because of the relationship between vitamin D and thyroid hormones.
For people who do not have thyroid problems, though, typical doses of vitamin D found in over the counter supplements pose little or no risk.
Vitamin D dosage
Official recommendations are 600-800 IUs per day. Current recommendations from medical governing bodies recommend that adults take 600 IUs of vitamin D per day and the elderly take 800 IUs of vitamin D per day (6).
Some researchers think these recommendations are too low. However, the current recommendations have generated substantial controversy.
One scathing review of the most recent recommendations pointed out that with 600 IUs of vitamin D per day as your only input of vitamin D, your blood levels of the metabolically active form of vitamin D would only be one-third of the minimum biologically healthy level (7).
Second, the recommendations for vitamin D intake as it stands are based solely on evidence for its role in bone health, not its role in preventing chronic diseases or improving physical performance.
Many nutritionists recommend 1000-2000 IUs per day. What’s a typical dosage among adherents to the ‘more vitamin D is necessary’ hypothesis? Usually a few thousand IUs per day, though researchers note that people who are overweight and obese need higher doses (as with most supplements) to get the same effect as a lean person, simply because of their greater body mass.
In terms of dosage safety, up to 4000 IUs of vitamin D is known to be safe, based on experimental research. Higher doses are not known to be dangerous, but have not had their safety firmly established in controlled research settings.
Vitamin D benefits FAQs
Q: Does vitamin D supplementation work?
A: Yes, as long as the dosage is high enough, vitamin D supplementation is a very successful strategy for raising levels of the biologically active form of vitamin D, which is the 25-hydroxy form (technically, 25-hydroxycholecalciferol).
Doctors have noted that it is difficult to effectively raise vitamin D levels with the moderate doses (600-800 IUs per day) recommended for healthy adults, so in cases of clinical vitamin D deficiency, doctors often use substantially higher doses, especially initially, to kick-start an increase in vitamin D levels in the blood.
Q: How is a vitamin D deficiency treated?
A: The treatment plan for a vitamin D deficiency depends on how low your blood levels of vitamin D are. For severely low blood levels, direct medical supervision is usually necessary.
This is diagnosed with a blood test for the 25-hydroxy form of vitamin D, which is the biologically active form. If your levels of 25-hydroxy vitamin D are extremely low, you might be given a massive initial dose to boost your levels of vitamin D rapidly, then sustain these levels with regular high-dose supplementation going forward.
Moderate to mild vitamin D deficiency is usually treated with a daily vitamin D supplement, typically that provides a few thousand IUs per day of vitamin D. If you are deficient in vitamin D, just taking the recommended 600-800 IUs per day for healthy adults is often not enough to actually raise your vitamin D levels.
Q: Why is vitamin D important for athletes?
A: Athletes put huge loads on their body, and bone strength is a huge concern. Vitamin D helps improve bone strength and may help prevent stress fractures, but on top of that, it may benefit performance as well.
A 2018 study showed that impaired vitamin D levels hurts endurance exercise performance, and these impairments are ameliorated when supplementation or sun exposure is used to bring vitamin D back up to a healthy level (8).
Q: Why do you need more vitamin D in the winter?
A: The main pathway that your body typically uses to synthesize vitamin D is through exposure to sunlight.
In the winter, not only is there less light during the day, but you typically have most of your skin covered up because of the cold. As a result, vitamin D levels drop precipitously in the winter, especially in cold climates.
A vitamin D supplement is the best way to keep your vitamin D levels high during the winter if you live in a cold climate.
Related: Our best vitamin D picks
Vitamin D is an essential nutrient that you can only get in high amounts from two places: sunlight exposure or a vitamin D supplement.
Research suggests that vitamin D plays a role in everything from bone strength to immune function to cardiovascular health, so it’s clearly plays a critical role in health.
Add to that the fact that a huge swath of the population is deficient in vitamin D (especially people who live in northern climates), and you’ve got great justification for making sure you have optimal vitamin D levels.
Vitamini D ni virutubisho vyenye nguvu ambavyo vina athari kubwa kwa kila kitu, kuanzia utendaji wa kinga hadi afya ya tezi ya tezi hadi nguvu ya mifupa. Vitamini D ni zaidi ya homoni, na kwa sababu hiyo, ina jukumu kubwa katika kazi nyingi za kibiolojia ndani ya mwili wako. Kwa kuwa haiwezi kutengenezwa ndani ya mwili wako, kuna njia mbili tu za kupata faida za vitamini D: ama kwa kuambukizwa na jua (ambayo inazalisha vitamini D katika ngozi yako), au kwa kuchukua nyongeza. Kwa kuwa watu wengi hawapati jua la kutosha (hasa wakati wa majira ya baridi kali), virutubisho ni njia ya kwenda ikiwa unataka kuvuna faida zifuatazo za afya za vitamini D. Faida za vitamini D 1. Vitamini D husaidia mwili wako kunyonya kalsiamu Kwa sababu hiyo pekee, ni muhimu kwamba tunapata kiasi cha kutosha cha vitamini hii muhimu katika lishe yetu. Kwa kweli, kalsiamu (pamoja na fosfati) ndiyo msingi wa mifupa. Ikiwa hupati kalsiamu ya kutosha katika mlo wako, au ikiwa huwezi kunyonya kalsiamu unayokula, uzalishaji wa mifupa na tishu ya mifupa huathiriwa sana. 2. Uwezekano wa kupata Chanzo bora cha asili cha vitamini D ni mwanga wa jua. Inakadiriwa kwamba ulimwenguni kote, karibu watu bilioni moja hawapati vitamini D ya kutosha. Kuna vyanzo vichache sana vya vyakula vyenye vitamini D, lakini ini la ng'ombe, jibini, uyoga, na manjano ya mayai hutoa kiasi kidogo sana. Samaki wenye mafuta kama samaki wa samaki hutoa hata zaidi, lakini njia bora ya kupata vitamini D ni kunywa maziwa yenye nguvu, kupata angalau dakika 15 ya jua kamili kwenye sehemu kubwa ya mwili wako kila siku, au kuchukua virutubisho. Kwa kweli, ni vigumu sana kupata vitamini D yote kutoka vyanzo vya chakula. Kwa upande mwingine, ikiwa unaishi kaskazini mwa nchi, unaweza kupata vitamini D kutoka kwa jua. Kwa sababu hii, watu wengi wana matatizo ya kupata vitamini vya kutosha kutoka kwa jua, hasa watu wenye ngozi nyeusi. Kwa kweli, wazee wanahitaji vitamini D zaidi kuliko watu wengine. Kwa sababu hizi zote, virutubisho vya vitamini D ni miongoni mwa virutubisho vinavyohitajika zaidi duniani. 3. Uwe na mtazamo wa kweli Viwango vya juu vya vitamini D vinaweza kulinda mwili wako dhidi ya saratani Miaka thelathini iliyopita, iligunduliwa kwamba watu wanaoishi katika maeneo ya kaskazini walikuwa na viwango vya juu vya saratani ya utumbo mzito. Utafiti huo ulionyesha kwamba viwango vya chini vya vitamini D vinaweza kuongeza hatari ya kansa ya utumbo. Majaribio kadhaa yamefanywa tangu wakati huo ambayo yanaunga mkono sana nadharia hiyo, lakini hiyo haimaanishi kuwa virutubisho vya vitamini D vitapunguza hatari. 4. Uwe na uhakika Vitamini D inaweza kusaidia kuzuia mshtuko wa moyo Utafiti wa miaka 20 uligundua kuwa wanaume wenye upungufu wa vitamini D walikuwa na hatari maradufu ya kushikwa na mshtuko wa moyo. Ingawa utafiti zaidi unahitajika, uhusiano huu unaweza kuhusiana na ukweli kwamba vitamini D imeunganishwa na viwango vyako vya jumla vya uvimbe. 5. Uwe na mtazamo mzuri. Vitamini D inaweza kusaidia kuhifadhi nguvu ya misuli katika watu wazima wazee Watu wazima wengi wazee kupata dhaifu kama wao umri - hali inayojulikana kama sarcopenia. Vitamini D inaweza kuongeza athari za kuongeza protini katika kudumisha nguvu ya misuli na kuzeeka kwa afya. Utafiti uliofanywa mnamo 2015 na wagonjwa wazee uligundua kuwa kuongeza leucine (na pia protini ya whey) kwa dawa ya vitamini D ya watu walio hatarini kwa sarcopenia iligundua kuwa dawa hii ya ziada ilisaidia kuzuia upotezaji wa misuli. Vitamini D ina athari za athari za vitamini D imethibitishwa kuwa salama kwa vipimo vya angalau 4000 IU kwa siku. Hata hivyo, kuna hatari ya athari mbaya ikiwa utachukua kipimo cha juu sana kwa muda mrefu. Ni nini "zaidi ya kiasi"? Hata kipimo cha 10,000 IU kwa siku hakijulikani kusababisha athari kubwa za upande katika idadi ya watu kwa ujumla. Matokeo haya ya upande katika vipimo vya juu sana (makumi ya maelfu ya IUs ya vitamini D) yanaweza kuwa mbaya, na ni pamoja na viwango vya damu vya kalsiamu. Vitamini D inaweza kuingiliana na homoni za tezi-kibofu. Watu wenye ugonjwa wa tezi-kibofu wana hatari kubwa ya kuwa na sumu ya vitamini D, kwa sababu ya uhusiano kati ya vitamini D na homoni za tezi-kibofu. Kwa wale ambao hawana matatizo ya tezi-kibofu, hata hivyo, kiasi cha kawaida cha vitamini D kinachopatikana katika virutubisho vya dawa za kulevya ni hatari kidogo au hakuna. Vipimo vya vitamini D: Mapendekezo rasmi ni 600-800 IU kwa siku. Kwa mujibu wa mapendekezo ya sasa ya taasisi za matibabu, watu wazima wanapaswa kuchukua IU 600 za vitamini D kwa siku na wazee kuchukua IU 800 za vitamini D kwa siku. Watafiti fulani hufikiri kwamba mapendekezo hayo ni ya chini sana. Hata hivyo, mapendekezo ya sasa yamezua ubishi mkubwa. Kwa mfano, utafiti wa hivi karibuni unaonyesha kwamba ikiwa mtu angepokea vitamini D kwa kiwango cha IU 600 kwa siku, kiwango cha vitamini D katika damu ingekuwa theluthi moja tu ya kiwango cha chini cha afya ya kibiolojia. Kwa upande mwingine, mapendekezo ya ulaji wa vitamini D kama ilivyo sasa yanategemea tu ushahidi wa jukumu lake katika afya ya mifupa, sio jukumu lake katika kuzuia magonjwa ya muda mrefu au kuboresha utendaji wa mwili. Wataalamu wengi wa lishe wanapendekeza kutumia IU 1000 kwa siku. Ni nini kipimo cha kawaida miongoni mwa wafuasi wa "vitamini zaidi D ni muhimu" nadharia? Kwa kawaida, ni maelfu ya IU kwa siku, ingawa watafiti wanabainisha kuwa watu wenye uzito wa ziada na wanene wanahitaji kipimo cha juu (kama ilivyo na virutubisho vingi) kupata athari sawa na mtu mwembamba, kwa sababu tu ya uzito wao mkubwa. Kwa mujibu wa utafiti wa majaribio, kiasi cha vitamini D cha IU 4000 kinaweza kutumiwa kwa muda mrefu. Vipimo vya juu havijulikani kuwa hatari, lakini usalama wao haujathibitishwa kwa uthabiti katika mazingira ya utafiti uliodhibitiwa. Faida za Vitamini D: Je, Vitamini D Inaweza Kuongezwa? Kwa sababu ya matumizi ya dawa ya vitamini D, dawa ya vitamini D ya 25 ya 25 hydroxychloroquine (HCl2) inaweza kutumika kwa ufanisi katika kuongeza viwango vya vitamini D katika mwili. Kwa sababu ya matatizo ya vitamini D, madaktari hutumia vipimo vya juu zaidi, hasa kwa watu wazima wenye afya, ili kuongeza viwango vya vitamini D katika damu. Q: Ugonjwa wa upungufu wa vitamini D unashughulikiwaje? Utaratibu wa matibabu ya upungufu wa vitamini D hutegemea kiwango cha chini cha vitamini D katika damu. Kwa viwango vya chini sana vya damu, kwa kawaida uangalizi wa moja kwa moja wa daktari ni muhimu. Kwa mfano, uchunguzi wa damu unaonyesha kwamba vitamini D ina aina ya 25-hydroxy, ambayo ni aina ya vitamini D yenye nguvu. Ikiwa viwango vya vitamini D vya 25-hydroxyvitamin D ni vya chini sana, unaweza kupewa kipimo kikubwa cha kwanza ili kuongeza viwango vya vitamini D haraka, kisha kudumisha viwango hivi kwa kuongeza virutubisho vya kawaida vya vitamini D. Ukosefu wa vitamini D wa wastani hadi wa upole kwa kawaida hupatikana kwa kuongeza vitamini D kila siku, ambayo hutoa maelfu ya IU kwa siku ya vitamini D. Ikiwa una upungufu wa vitamini D, kuchukua tu 600-800 IU kwa siku kwa watu wazima wenye afya mara nyingi haitoshi kuongeza viwango vya vitamini D. Kwa nini vitamini D ni muhimu kwa wanariadha? "Mchezaji wa michezo ""huchukua mzigo mkubwa"" kwenye mwili wake, na nguvu ya mifupa ni wasiwasi mkubwa." Vitamini D husaidia kuboresha nguvu ya mifupa na inaweza kusaidia kuzuia kuvunjika kwa mkazo, lakini juu ya hayo, inaweza kusaidia utendaji pia. Utafiti wa mwaka 2018 ulionyesha kuwa viwango vya chini vya vitamini D huathiri utendaji wa mazoezi ya uvumilivu, na udhaifu huu hupunguzwa wakati virutubisho au mwangaza wa jua hutumiwa kuleta vitamini D nyuma hadi kiwango cha afya. Kwa nini unahitaji vitamini D wakati wa baridi kali? Njia kuu ambayo mwili wako hutumia kutengeneza vitamini D ni kupitia mwangaza wa jua. Wakati wa baridi kali, sio tu kwamba kuna mwanga mdogo wakati wa mchana, lakini kwa kawaida ngozi yako imefunikwa kwa sababu ya baridi. Kwa sababu hiyo, kiwango cha vitamini D hupungua sana wakati wa majira ya baridi kali, hasa katika maeneo yenye hali ya hewa baridi. Vitamini D ni njia bora ya kuweka viwango vya vitamini D juu wakati wa majira ya baridi kali. Vitamini D ni virutubisho muhimu ambavyo unaweza kupata kwa kiasi kikubwa kutoka kwa sehemu mbili tu: mwangaza wa jua au virutubisho vya vitamini D. Utafiti unaonyesha kwamba vitamini D ina jukumu katika kila kitu kutoka nguvu ya mifupa kwa kazi ya kinga kwa afya ya moyo na mishipa, hivyo ni wazi ina jukumu muhimu katika afya. Kwa kuongezea ukweli kwamba idadi kubwa ya watu wana upungufu wa vitamini D (haswa watu wanaoishi katika hali ya hewa ya kaskazini), una haki kubwa ya kuhakikisha kuwa una viwango bora vya vitamini D.