## Intake vitamin supplementation is measured in [[../../Concepts/IU(International Units)]] Is generally produced when the human skin is exposed to the sun, through ultraviolet-b light. Can also be intaken through some foods, generally fish: | Food Name | Vitamin D (IU) | Serving<br> | | ----------------------------------------------------------------- | -------------- | ----------- | | [salmon](https://www.nutritionix.com/food/salmon/100-g) | 526 | 100 g | | [halibut](https://www.nutritionix.com/food/halibut/100-g) | 231 | 100 g | | [sardine](https://www.nutritionix.com/food/sardine/100-g) | 193 | 100 g | | [tilapia](https://www.nutritionix.com/food/tilapia/100-g) | 150 | 100 g | | [flounder](https://www.nutritionix.com/food/flounder/100-g) | 139 | 100 g | | [tuna](https://www.nutritionix.com/food/tuna/100-g) | 82 | 100 g | | [canned tuna](https://www.nutritionix.com/food/canned-tuna/100-g) | 80 | 100 g | | [anchovy](https://www.nutritionix.com/food/anchovy/100-g) | 69 | 100 g | | [cod](https://www.nutritionix.com/food/cod/100-g) | 46 | 100 g | | [haddock](https://www.nutritionix.com/food/haddock/100-g) | 23 | 100 g | | [catfish](https://www.nutritionix.com/food/catfish/100-g) | 10 | 100 g | | [shrimp](https://www.nutritionix.com/food/shrimp/100-g) | 4 | 100 g | human skin that is exposed to the sun through glass is not producing vitamin-d, as ultraviolet light is blocked by common glas. ## Deficiency / Lower-than-optimal Usually when someone says they have a vitamin-d deficiency they mean that they have a lowe-than-optimal level. Deficiency is only used when symptoms/health problems solely stem from the lack of a specific nutrient. To counteract a lower-than-optimal vitamin-d level you can take vitamin-d supplements. ## Supplements ### Forms - In form of animal oils - Tablets ### Effectiveness #### Pro >This large study suggests that in the real world, the efficacy of vitamin D supplements in reducing mortality may be at least as good as observed in RCTs. - pubmed source >Vitamin D affects the health of bones and also plays a role in our muscles, immunity, and prevention of some diseases. - longevity.stanford >Without vitamin D your bones can become soft, thin and brittle. Insufficient vitamin D is also connected to osteoporosis. If you don't get enough vitamin D through sunlight or dietary sources, you might need vitamin D supplements. - mayoclinic.org #### Contra > - In conclusion, supplementation of vitamin D-replete individuals does not generate overall health benefits; however, correction of severe vitamin D deficiency remains essential. - nature.com >Dr. Manson was a principal investigator of the recently published Vitamin D and Omega-3 Trial (VITAL), a large study (more than 25,000 participants nationwide). The study found that those taking a vitamin D supplement did not lower rates of heart attack, stroke, or cancer. However, among people who later developed cancer, those who took vitamin D supplements for at least two years had a 25% lower chance of dying from their cancer compared with those who received a placebo. - health.harvard >U.S. and Canadian governments to request that the Institute of Medicine (IOM, now called the Health and Medicine Division) review the evidence on vitamin D and calcium and update the DRIs. The long-awaited report, Dietary Reference Intakes for Calcium and Vitamin D, was published in 2011. The IOM concluded that evidence for benefits other than improved bone health came from studies that could not be considered reliable and provided often-conflicting results. - health.harvard ### dosage >**Watch your numbers.** If you're taking a vitamin D supplement, you probably don't [need](https://www.health.harvard.edu/staying-healthy/how-much-vitamin-d-do-you-need) more than 600 to 800 IU per day, which is adequate for most people. Some people may need a higher dose, however, including those with a bone health disorder and those with a condition that interferes with the absorption of vitamin D or calcium, says Dr. Manson. Unless your doctor recommends it, avoid taking more than 4,000 IU per day, which is considered the safe upper limit. -health.harvard > - When choosing a vitamin D supplement, D3 is recommended over D2, and should be combined with a fat (such as a handful of almonds or an Omega-3 supplement). You should not take more than 4,000 IU (100 mcg) per day due to the potential for toxicity unless recommended by a medical professional. - longevity.stanford > Dr. Pojednic emphasizes the importance of considering the fat-soluble nature of vitamin D when taking a supplement. “Vitamin D absorption, especially when consumed in concentrated doses, will be significantly enhanced when taken in conjunction with dietary fat, such as a handful of almonds or an omega-3 supplement,” she says. >However, a review of multiple large randomized controlled trials indicated that daily vitamin D supplementation of 2,000 international units (50 micrograms) prevents and treats vitamin D deficiency. The authors posited that long-term supplementation at this dose is deemed safe, with no significant safety concerns reported, even for those with sufficient baseline vitamin D levels. - foundmyfitness ## 🔗Resources ### Supplements Pro - https://pubmed.ncbi.nlm.nih.gov/36208176/#:~:text=Furthermore%2C%20regular%20vitamin%20D%20supplement,significant%20for%20cardiovascular%20disease%20mortality). - https://www.nature.com/articles/s41574-021-00593-z - https://www.mayoclinic.org/drugs-supplements-vitamin-d/art-20363792#:~:text=Research%20suggests%20that%20long%2Dterm,Osteoporosis. - https://www.foundmyfitness.com/topics/vitamin-d ### Supplements Contra - https://www.nature.com/articles/s41574-021-00593-z - https://www.health.harvard.edu/staying-healthy/taking-too-much-vitamin-d-can-cloud-its-benefits-and-create-health-risks ### Supplements Usage - https://www.health.harvard.edu/staying-healthy/how-much-vitamin-d-do-you-need ### Vitamin-D General facts - https://www.dietaryguidelines.gov/resources/2020-2025-dietary-guidelines-online-materials/food-sources-select-nutrients/food-sources-vitamin-d