Vitamin D Dosage Recommendations

Vitamin D is a type of fat-soluble nutrient and part of the list of 24 micronutrients that are currently considered to be essential for human health and survival. Experts have frequently established the fact that sunlight or UVB ray exposure is the best natural source of the vitamin D nutrient, but it is also possible to find small doses of this substance in food products such as eggs, fish, and meat. In some cases, companies have even begun to add supplemental doses of vitamin D into dairy products.

The more vitamin D in your system, the more chances you have of experiencing a wide range of physical and mental benefits, including better cognition, bone health, immune-system health, and overall wellbeing. By supplementing your vitamin D supply with the right dosage, some research suggests that you may even be able to reduce your chances of suffering from various conditions and diseases, including heart disease, cancer, diabetes, and multiple sclerosis.

How Vitamin D Is Unique

The body produces vitamin D naturally from the cholesterol within our skin, provided that there’s an adequate amount of UV light available from sun exposure. It’s important to remember that you can only get the right amount of UV light in your system when the index for UV light is higher than 3. Usually, this only happens year-round in countries located close to the equator.

While most people aren’t necessarily considered to be “deficient” in the dosage of vitamin D they get each day, they don’t have an optimal level in their system either. Because of this, and as a result of the fact that vitamin D comes with many great health benefits, supplementation is highly encouraged if optimal levels aren’t present within the body. Regardless of where you live, who you are, or what your personal circumstances may be, Vitamin D is one of the most useful nutritional tools people have at their disposal for the sake of improving overall health.

As a vitamin, it is completely unique, because it is can be converted into a hormone capable of controlling calcium, phosphorus, and bone metabolism, as well as neuromuscular function. What’s more, vitamin D is the only vitamin that the body can naturally manufacture itself through direct sunlight (UVB rays). However, with today’s focus on indoor living, and the extensive focus being placed on staying out of the sun because of concerns regarding skin cancer, we have emerged into a society of millions all deficient in life-sustaining, immune-modulating and bone-building vitamin D.

As research makes it increasingly clear that Vitamin D can play a wider role in benefitting overall health, it’s becoming equally clear that most people across the world are deficient in this important nutrient. In fact, even individuals who regularly venture out into the sun using suntan lotion may be deficient in Vitamin D. What’s more, as we age, we are less equipped to produce the right amount of vitamin D for our body to thrive. So, how much vitamin D do you need to maintain a healthy lifestyle? The amount will depend on your circumstances and a number of important factors.

The Current Dosage for Vitamin D

The Food and Nutrition Board has developed intake reference values for vitamin D to help people understand exactly how much of this crucial vitamin they should be getting each day. The RDA that has been created for vitamin D is intended to maintain healthy bone function and normal calcium metabolism in people without any other health problems. Because of this, it’s important to recognize that people who are already diagnosed with vitamin D deficiency, or suffering from health problems or conditions that may impact their production of vitamin D, may require a higher dosage than other individuals. Crucially, although the primary source for most people’s vitamin D exposure is sunlight, the vitamin D RDAs that have been provided up to this point are based on individuals who do not get very much sun exposure.

Age  Recommended IU (International Units)
0-12 months  400 IU (10 mcg)
1-13 years  600 IU (15 mcg)
14-18 years  600 IU (15 mcg)
19-50 years  600 IU (15 mcg)
51-70 years  600 IU (15 mcg)
+70 years  800 IU (20 mcg)

Vitamin D is typically included as a supplement in most multivitamins, usually in strengths between 50-100 IU per dose. These supplemental forms of vitamin D can be found in liquids, tablets, capsules, and soft gels. Crucially, however, there has been some debate around the idea of what should be considered the “right” dosage for daily vitamin D. In fact, a number of researchers have begun to suggest that the maximum amount of vitamin D that should be recommended for people throughout the world should be far higher, as larger amounts of vitamin D may improve health. According to some experts, the recommended daily allowance of 600 IU for people between the ages of 1-70 years should be closer to 1000 IU, however until more research has been completed, some medical experts warn against over-doing it when taking vitamin D supplements. Although it is impossible to overdose on Vitamin D from sun exposure alone, it is possible to take too much of a supplement. Also, remember that excessive sun exposure can lead to other problems like skin cancer and sunburn.

Problems Associated with Too Much Vitamin D

Although the majority of people around the world today are able to take vitamin D supplements without suffering any problems, it is possible to take too much. Over-indulging in supplements leads to a condition known as vitamin D toxicity. Take note, however, that vitamin D toxicity generally only happens when you take more than 40,000 IU of vitamin D every day for a period of a couple of months or longer, or take a gigantic one-time dose.

The reason why it is possible to take too much vitamin D is that it is fat-soluble, which means that the body will struggle to get rid of the excess if you accidentally take too much. In other words, when you take significant portions of vitamin D, your liver can produce too much of a chemical known as 25(OH)D. When your 25(OH)D levels are too high, this can cause high levels of calcium to develop in your blood, and high blood calcium leads to a condition known as hypercalcemia, the symptoms of which include:

• Being or feeling sick
• Loss of appetite or poor appetite
• Feeling of extreme thirst
• Frequently passing urine
• Diarrhea or constipation
• Muscle weakness or pain
• Confusion and tiredness
• Bone or abdominal pain

In very rare circumstances, some people find that they are at risk of hypercalcemia even if their vitamin D levels are low, or they haven’t taken much vitamin D. This often occurs as a result of rare diseases known as sarcoidosis or hyperparathyroidism.

You can get a blood test to measure your 25(OH)D levels, and this will let you know whether you are suffering from higher than usual vitamin D levels. Typically, if your levels of 25(OH)D are above 150 ng/ml then this is considered to be potentially toxic, and harmful to your health. You should know that your 25OH(D) levels are toxic through a blood test used to measure calcium. Remember that the current recommended daily allowances for vitamin D that have been set by the Food and Nutrition Board are quite conservative, so you shouldn’t worry too much about toxicity if you take more than their recommended daily allowance.

Problems Associated with Too Little Vitamin D

Although some people may worry about getting too much vitamin D in their system, chances are that you’re far more likely to suffer from a vitamin D deficiency, than an overdose. Problematically, a vitamin D deficiency can lead to a number of health problems that can lower your standard of life and wellbeing. For example, vitamin D deficiency is often quite common in older adults, and is frequently implicated in neurological and psychiatric disorders, such as Alzheimer’s, depression, and impairment of cognitive function.

Another common side effect of vitamin D deficiency is back pain, as low amounts of vitamin D are often linked to musculoskeletal disorders in a number of new studies. One of the newest studies available explored the idea that low vitamin D levels play a significant role in the development of lower back pain, and revealed that patients with low back pain typically had far lower vitamin D levels than the control patients.

Finally, one of the most significant problems associated with vitamin D deficiency is that it fails to deliver improved bone health typically associated with reasonable and regular doses. It’s well documented that vitamin D has a large part to play in fighting off osteopenia, osteoporosis, and osteomalacia. It can also be responsible for reducing your risk of muscle weakness, which can increase the risk of fractures and falls.

Resources and References:

Vitamin D Overdose Effects – Describes the symptoms of overdosing on vitamin D. (
Vitamin D Dosage – Typical doses of vitamin D in most people, including doses for illnesses. (
Recommended Amounts for Vitamin D – a guideline suggesting recommended amounts of vitamin D for certain people. (
Vitamin D and Calcium Requirements – a general resource for the right amounts of vitamin D and calcium in typical diets. (WebMD)