How Much Vitamin D Should You Take for Optimal Health?

Vitamin D is a fat-soluble vitamin that plays a role in many essential body functions.

There are two forms of vitamin D in the diet and supplements:

• Vitamin D2 (ergocalciferol): found in some mushrooms.
• Vitamin D3 (cholecalciferol): found in oily fish, fish liver oil, and egg yolks.

Significant amounts of vitamin D can also be made in your skin when exposed to UV rays from sunlight. Your body fat stores any excess vitamin D for later use.

Almost every cell in your body has a receptor for vitamin D. It’s essential for many processes, including bone health, immune system function, and reducing inflammation. It also helps the body absorb calcium.

Learn more about vitamin D2 vs D3

Summary

Vitamin D is plays a role in many of your body’s functions. There are two forms in the diet, D2 and D3. Your body can also produce it when you expose your skin to sunlight.

The National Institutes of Health (NIH) recommend the following daily levels of vitamin D:

However, the precise amount of vitamin D you will need from your diet or from supplements depends on many factors.

These include, but are not limited to:

• age
• skin tone, which reflects the amount of melanin in the skin
• the latitude where you live
• season
• sun exposure
• your clothing choices
• whether or not you have obesity

Summary

Vitamin D recommended intake is 400–800 IU/day or 10–20 micrograms, depending on your age.

Doctors assess blood levels of vitamin D by measuring 25(OH)D in the blood. This is the storage form of vitamin D in the body.

However, there is no single definition of optimal blood levels. One reason for this is that scientists do not yet understand precisely how vitamin D acts in the body.

The NIH specifies the following levels:

Summary

Vitamin D levels are typically sufficient when above 50 nmol/l.

Vitamin D deficiency is one of the most common nutrient deficiencies in the world. In the United States, around 35% of people have low vitamin D levels. In comparison, one study found it affected over 90% of infants and older adults in India, Turkey, and Iran.

In the US, rickets — a bone condition that results from low vitamin D levels — is most likely to affect Black American children and infants who have been breastfed.

If you have access to strong sun all year, occasional sun exposure may fulfil your vitamin D requirements.

However, your vitamin D levels may be low if you:

• live far north or south of the equator
• rarely go outdoors
• have obesity
• have higher levels of skin melanin, as with darker skin tones
• wear clothes that cover your whole body

In the US, 50–60% of nursing home residents have low vitamin D levels.

In these cases, you may need to rely on your diet (or supplements) for vitamin D and on vitamin D that’s stored in body fat.

A vitamin D deficiency may lead to:

There may also be links between vitamin D deficiency and:

Summary

Vitamin D deficiency is prevalent worldwide but occurs at higher rates in specific populations. A deficiency in vitamin D is linked to various health problems.

You can get vitamin D from:

Vitamin D intake from the diet is generally quite low since very few foods contain significant amounts.

Foods that contain vitamin D include:

Summary

The main sources of vitamin D are sunshine, fatty fish, egg yolks, fish liver oils, fortified foods, and supplements.

Sun exposure is the most effective way to get enough vitamin D, but it also increases the risk of skin cancer.

The amount of vitamin D your skin produces will depend on factors such as:

• your skin color, as skin with high levels of melanin produces less vitamin D
• the distance from where you live to the equator
• how long you spend each day in the sun
• how much of your body you expose to the sun

Some experts suggest exposing the face, arms, hands, and legs to the sun for around 5–30 minutes between 10 a.m. and 4 p.m., either daily or at least twice a week.

Outside these limits, be sure to use a sunscreen of at least SPF30 to lower the risk of skin damage and skin cancer.

Meanwhile, one team of researchers proposed that, to maintain adequate blood levels of vitamin D, people with brown or dark brown skin in the United Kingdom will likely need to spend around 25 minutes a day in the sun during the summer months to synthesize the vitamin D levels they need.

Summary

Sunshine can help you meet the vitamin D requirements, but it’s important to limit sun exposure to avoid the risk of skin cancer. Some people may need supplements.

While incidences of vitamin D toxicity are rare, getting too much can be harmful.

It could lead to:

• nausea
• vomiting
• muscle weakness
• confusion
• loss of appetite
• dehydration
• kidney stones

Extremely high levels can cause:

This typically only affects people who have accidentally or intentionally taken high doses of vitamin D supplements for a long time.

According to the National Institutes of Health, the safe upper limit for anyone aged 9 years or over is 100 mcg (4,000 IU) per day.

Speak with your healthcare provider before using vitamin D supplements.

How much vitamin D do we need?

Males and females need the same amount of vitamin D, around 15 mcg (600 IU) daily. However, it can be hard to know how much your body is taking in or creating, as both food and sunlight contribute.

What’s better: Vitamin D2 or D3?

Vitamin D3 appears to be more effective than vitamin D2 at helping the body reach its necessary vitamin D levels. For this reason, if you’re taking supplements, vitamin D3 may be your best choice.

What dose of vitamin D3 supplements do I need?

If you’re taking supplements, how much you need to take will depend on your individual requirements. A doctor can advise you on this.

How much vitamin D is too much?

If you are taking supplements, you should not take more than 100 mcg (4,000 IU) per day. Levels of vitamin D in the blood are too high when they are over 125 nmol / L.

How do I take vitamin D correctly?

First, you will need to discuss your specific needs with a doctor. They will advise on whether or not you need supplements and how much to take. If you are using supplements, always follow the instructions on the package.

Vitamin D is essential for your bones and many other aspects of health. Deficiency may have health consequences, such as weak or soft bones, depression, cardiovascular disease, and a higher risk of various other health issues.

If you’re thinking about adding more vitamin D to your diet, start by speaking with your healthcare provider. Not everyone needs vitamin D supplements, and taking too much can have adverse effects.