How much vitamin D should I take?

How do I know if I have a vitamin D deficiency? | How much vitamin D should I take? | Am I taking too much vitamin D? | What kind of vitamin D supplement should I take? | When to see a doctor

Vitamin D is a fat-soluble vitamin that the skin produces when exposed to ultraviolet light. Some foods and supplements also contain vitamin D. Vitamin D is essential for absorbing calcium and building healthy, strong bones. It’s also necessary for managing blood sugar levels, combating heart disease, regulating hormones and improving moods, and helping with concentration and memory.

How do I know if I have a vitamin D deficiency? 

Being deficient in vitamin D means that the body doesn’t have enough of the vitamin and may not be functioning correctly because of it. About 40% of people in the United States may have a low level of vitamin D. People with darker skin tones and pregnant women may be especially prone to vitamin D deficiency. 

Vitamin D deficiency can be caused by many things, including but not limited to: 

• Not enough sun exposure
• Diets that lack vitamin D
• Certain medical conditions
• Certain medications
• Darker skin
• Wearing too much sunscreen

Being deficient in vitamin D can increase your risk of developing other health conditions, so it’s essential to be aware of some of the warning signs. Here are some of the most common symptoms that could come from having low vitamin D:     

• Anxiety
• Chronic fatigue
• Depression
• Trouble sleeping
• Inflammation and swelling
• Weak or broken bones
• Weakness

If your doctor thinks you may be deficient in vitamin D, he or she may order a blood test to confirm it. Blood tests measure the circulating form of vitamin D in the body called 25-hydroxy vitamin D, or 25(OH)D. If your blood levels are low, your doctor may recommend vitamin D supplementation.     

How much vitamin D should I take?

An average person without a deficiency should be taking a daily dose of at least 600 international units (IU) of vitamin D, according to Yale Medicine. However, the amount of vitamin D that a person should take depends on their age, individual symptoms, medical history, and response to taking the vitamin.

People over the age of 70 and menopausal women may require more than 600 IU. As people age, their skin produces less vitamin D, which means they will likely need supplementation.

Pregnant women and people with certain health conditions that interfere with vitamin D absorption—like celiac disease or cystic fibrosis—will need a higher daily intake that’s more than 600 IU. You can take vitamin D at any time of day, but it may be more beneficial—especially for those with hindered vitamin D absorption—to take it with some dietary fat that comes from foods like nuts or seeds since it’s fat-soluble.  

Many doctors and health professionals recommend taking smaller doses of vitamin D over time to bring levels back up. For adults, this might mean a higher vitamin D intake of 1,500-2,000 IUs. Higher doses closer to 10,000 IU may be necessary for certain people who have osteoporosis or other similar conditions. However, taking higher doses of vitamin D (i.e., 40,000 IU) could cause vitamin D toxicity and further health problems. It’s important to talk to your doctor about the right dose of vitamin D for you. 

Am I taking too much vitamin D?

Even though taking vitamin D has many health benefits, it’s possible to take too much. Vitamin D toxicity is possible and can cause a buildup of calcium in the blood (hypercalcemia). Vitamin D toxicity, or hypervitaminosis D, is rare but can result in bone pain, nausea, vomiting, or kidney problems. 

Here is a list of the more common side effects that someone might experience from taking too much vitamin D:  

• Fatigue
• Excessive urination
• Loss of appetite
• Weight loss
• Nausea 
• Weakness 

Some medications may interact with vitamin D. Steroid medications may interfere with how the body metabolizes vitamin D. The cholesterol-lowering drug cholestyramine and weight-loss drug orlistat can both lower the body’s ability to absorb vitamin D. Some drugs can also increase vitamin D levels.

What kind of vitamin D supplement should I take?

Multiple types of vitamin D are available as dietary supplements, which can make it confusing to choose the right option. There are two different types of vitamin D. Vitamin D2 (ergocalciferol) mainly comes from plant-based foods like UV grown mushrooms, or fortified foods and supplements. Vitamin D3 (cholecalciferol) comes from animals and supplements. You’ll get vitamin D3 from fish oil, butter, liver, and egg yolks.  

Vitamin D is available in supplemental form as a liquid, tablet, or capsule. Some doctors will even give vitamin D injections. Vitamin D2 typically requires a prescription to get, and Vitamin D3 is commonly available for purchase over-the-counter. There is some debate about whether or not vitamin D2 is stronger than D3; seeking medical advice is the best way to make sure you get the right form and dosage that you need.   

According to Tod Cooperman, M.D. and founder of ConsumerLab, “The best form of vitamin D to take as a supplement is D3, although D2 is acceptable. D3 is less likely to result in errors on blood tests and may raise levels better when high doses are used. In terms of formulations, liquids and pills are generally both fine (although we have found some products that don’t provide the amounts listed on labels). My preference is liquid drops, as you can easily adjust the dose. Plus, you can put it right on food or in a beverage, which should remind you that vitamin D, which is fat-soluble, should be taken with foods that contain fats to improve absorption.” 

Other ways to get enough vitamin D

There are other ways to get vitamin D beyond just taking a supplement. Sunshine is a great source of vitamin D, and so are many foods.

Spending about 10 to 20 minutes every day in the sun will give you between 1,000-10,000 IUs of vitamin D. The amount of time you should spend and IUs you’ll get will vary depending on the season, where you live in the world, and how dark your skin is. No matter where you are, the short time in the sun that you spend daily should be unexposed so that your body can adequately absorb the light.    

Try incorporating vitamin D-rich foods into your diet too. Here are some options: 

• Fatty fish (like salmon, halibut, sardines, tuna, and whitefish) are high in vitamin D.
• Some mushrooms, like portobello and maitake, have proper levels of vitamin D, especially if they’re grown using UV light. 
• The United States fortifies milk with vitamin D, but raw milk is known to have naturally occurring vitamin D as well, and may even have a higher concentration of nutrients.      

When to see a doctor

Having a vitamin D deficiency could be caused by or cause serious health conditions. Vitamin D helps the body absorb calcium, magnesium, and phosphorus, which are essential for maintaining healthy bones. Vitamin D deficiency can lead to inadequate calcium absorption that can cause osteoporosis, osteopenia, or rickets in children.

Rickets can be serious for children’s bone health because it causes soft bones and skeletal deformities. Osteomalacia is the same condition but for adults, which sometimes leads to falls and broken bones that are hard to heal. With osteoporosis, bones become thinner and are more likely to break or cause posture issues.

Sometimes, being deficient in vitamin D isn’t just caused by not getting enough sunshine. Certain health conditions affect how the body absorbs or processes vitamin D. Kidney and liver diseases can lower the amount of an enzyme that the body needs to use vitamin D. Celiac disease, Crohn’s disease, and cystic fibrosis all cause the intestines to absorb less vitamin D. Even being overweight can lead to a vitamin D deficiency because fat cells store vitamin D, keeping it from being easily used.

Bone pain and muscle weakness may be a sign that it’s time to see a doctor. Vitamin D deficiency can also cause other symptoms like depression, fatigue, asthma, and it may even be linked to erectile dysfunction. Seeking professional medical advice by consulting a doctor is the best way to determine whether or not you need supplementation. If you’re advised by a healthcare provider to take vitamin D, it’s possible to save money on prescription vitamin D2 or D3 with an Rx savings card through SingleCare.