How Much Vitamin D Should You Take and How Does It Help

Have you wondered about your immune health lately? 

It’s important, (especially in the midst of a global health crisis) to make sure you’re doing everything you can to try and keep yourself healthy and fit to fight infection.

Vitamin D is most notably used by the body to help absorb calcium for bone health, however, recent research has opened our eyes to many more metabolic functions that benefit from or even totally depend on adequate vitamin D levels.  We know it’s great for immune health, but how does it help and how much of it should you take? 

Read on for everything you need to know about why Vitamin D works and how to use it to get the best out of your body. 

Basics of Vitamin D

Vitamin D is a fat-soluble vitamin crucial for calcium absorption leading to strong bones and a myriad of other metabolic functions. 

Unlike most other vitamins, vitamin D is not found naturally in many foods beyond fatty fish such as sardines, tuna, mackerel, and salmon. It’s fortified (added) in foods like cereals, orange juice, and milk. Your best source for the elusive vitamin, however, is the sun. UV rays from the sun react with elements in skin cells to synthesize vitamin D. 

People with a healthy balanced diet and regular sun exposure may be able to maintain appropriate levels of vitamin D since it can be stored in fat cells for months or even years. With the practice of fortifying foods, certain bone diseases such as rickets saw a dramatic decrease in prevalence in the United States. However, over 40% of adults in the U.S. are still vitamin D deficient.

Deficiencies are commonly seen in individuals with more restrictive diets, like vegetarians and vegans, or in people with limited exposure to sunlight perhaps due what part of the world they live, their occupation, or their dress choices. 

In such individuals, vitamin D supplementation is often necessary.  


foods that can be used as a source for vitamin D in humans.

How Vitamin D Works

Unlike most vitamins, while Vitamin D isn’t naturally found in the body, it’s still technically synthesized by the body from certain precursors into a usable, active form. These precursors include D2 and D3, but D3 has been shown to be more effective in raising levels of the vitamin and should be the preferred option when supplementing. 

Using sunlight (our most abundant source) as an example, the mechanism for production of active vitamin D goes as follows: 

Energy from the sun’s UVB rays converts a specific form of cholesterol found in human skin into D3, on of the precursors to the form of Vitamin D our bodies can actually utilize. D3 then moves through to the liver and kidneys where it picks up extra hydrogen and oxygen molecules to become 1,25(OH)2D, or “active vitamin D” for us laymen. 

New research tells us that once vitamin D is synthesized, its applications in the body are numerous and include maintenance of proper immune function (found to decrease the risk of infection), lower the risk of cancer and type 1 diabetes, and even manage depression. 

Signs of Vitamin D Deficiency

The recommended daily intake (RDI) of vitamin D are: 

  • 400 IU (10 mcg) for infants aged 0-12 months
  • 600 IU (15 mcg) for adults and kids aged 1-70
  • 800 IU (20 mcg) for older adults and pregnant or breastfeeding women

These are very small amounts, and yet large portions of the population are deficient. Older adults are especially susceptible to this deficiency as conversion to the active compound in the body becomes more difficult with age. 

In addition, heart attack victims are very likely to be deficient. One study found 96% of heart attack sufferers were low in vitamin D

The most common symptom of a vitamin D deficiency is developing rickets, a bone disease that causes weak and deformed bones. 

Osteoporosis, reduced mineral density, and increased risk of falls and fractures in older adults are common symptoms as well.

For most people, signs are very subtle and can take years to present. 


obtain vitamin d from the sun


Vitamin D is a fat-soluble vitamin that is crucial for bone health and many other systems. It can be found in certain fatty fish and fortified foods, or obtained from sunlight or dietary supplements. 

It is a pretty common deficiency, so consider supplementing if you have a restrictive diet or don’t get enough sunlight. 

Vitamin D can vastly improve health and quality of life.

Leave a comment

All comments are moderated before being published