How much vitamin D should I take a day

How much vitamin D should I take a day?

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Vitamin D is super-important for multiple health areas including bone health, immune system function, and heart health. However, you are probably asking yourself, how much vitamin D should I take a day? After all, everyone is different, and we know that some people get more sun than others. Also, did you know that your level of body fat and genetic factors can also play a role? And how much vitamin D is too much? Well, let’s dive in!

We’ll cover:

What is vitamin D, and where can I get it?

Vitamin D is a fat-soluble vitamin that can be formed in the skin by exposure to UV rays. It gets processed by the liver and then activated by the kidney into a key hormone that regulates calcium metabolism. This function is important for both bone and heart health. In addition, it helps the various cells in your immune system do their jobs.

Vitamin D is found in foods such as fish, mushrooms, and fortified foods like milk. You can check the USDA database for the foods with the highest amounts. However, you might notice that these aren’t exactly the most popular foods in the American diet. To be honest, if you aren’t a big milk drinker it’s hard to get enough. No surprise then that about half of Americans have low vitamin D levels!

The next best option is to take a vitamin D supplement. You will see vitamin D3 and D2 supplements on the market. Vitamin D3 is the best form because it’s the one that’s made in your body. However, it’s usually derived from lanolin (from sheep’s wool) so if you are a vegan that can be an issue. However, there are vegan D3s out there. Vitamin D2 is found in fungi and yeast, and can also raise your vitamin D levels, but D3 has been shown to be slightly more potent. Most good multivitamins have about 800-1000 IU (20-25 mcg) of vitamin D, and good prenatal vitamins, some of which we’ve reviewed, also have it. If you want an easy way to convert between IU and mcg, be sure to check out our IU to mcg conversion page.

What are healthy blood vitamin D levels?

With the importance of vitamin D for health, you would think this would be an easy answer. However, there are some differences of opinion among leading health authorities. The US Institute of Medicine has suggested that a level of at least 20 ng/mL (50 nmol/L) is good enough for bone health, based on the dietary reference intakes. However, other organizations, like the Endocrine Society, have suggested that at least 30 ng/mL should be achieved.

Interestingly, it seems like 30 ng/mL may really be necessary for optimal immune system health. A recent study conducted during the height of the 2020 COVID pandemic found that vitamin D levels above 30 ng/mL were associated with a lower risk of hospitalization and death. This is consistent with a recent meta-analysis of several clinical studies that concluded that higher vitamin D levels were associated with a lower risk of COVID infection. I would say that’s reason enough, eh?

So how do I find out my vitamin D levels? You can ask your doctor to include it during your annual physical (many already do). There are also a number of companies out there that offer at-home testing as well, here is one you can get for about 50 bucks. So, when you want to know how much vitamin D should I take a day, it’s always best to get tested so that you know you are taking the right amount.

How much vitamin D should I take a day?

So, how much vitamin D do you need every day? Well again, just like vitamin D levels, it sort of depends on who you ask. The US Institute of Medicine recommends 800 IU (20 mcg) for the average adult. This is estimated to be enough to achieve the 20 ng/mL discussed above. On the other hand, the Endocrine Society recommends 1500-2000 IU (37.5-50 mcg) in order to achieve 30 ng/mL. Based on the benefits of vitamin D for the immune system, above and beyond preventing simple deficiency for bone health, it seems smart to shoot for 1500-2000 IU on a daily basis.

However, there are other factors that can also impact how much vitamin D you need. If you don’t get a lot of sun exposure, you may need even more. Most of us, especially those in the northern latitudes, definitely don’t get a level of sun exposure in the winter months that can keep our vitamin D levels up. In addition, there are a few genetic factors that can lead to disrupted vitamin D metabolism. Finally, carrying a higher amount of body fat can also have a harder time bringing vitamin D levels up, as it can get trapped in the fat tissue. For these reasons, it’s always best to test.

How much vitamin D is too much?

As you’ve seen above, supplementation is probably necessary for most people in order to achieve the desired blood levels (>30 ng/mL). However, how much vitamin D is too much? Well, the US Institute of Medicine recommends no more than 4000 IU per day. However, there is a good margin of safety in this recommendation, and other experts have suggested that up to 10,000 IU vitamin D is not a problem. However, considering that vitamin D is a fat-soluble vitamin that can build up in your system, it’s probably best to avoid taking more than 4000 IU unless you have been testing your vitamin D levels and you know that you are having trouble getting to 30 ng/mL. If you find that your vitamin D levels are above 60 ng/mL (150 mmol/L), then you should back off on the supplements.

In summary

How much vitamin D should I take a day? The answer depends on how much it takes to get YOU to a vitamin D level above 30 ng/mL (75 mmol/L). For most people, this will be 1500-2000 IU (37.5-50 mcg). However, it may be higher if you have a certain genetic profile, higher body fat, or lower sun exposure. On the other hand, you should stay below 4000 IU (100 mcg) per day. That is unless you have been testing and know that you are below 30 ng/mL. If your blood levels are approaching 60 ng/mL you should hold off on the supplements.

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