Vitamin D is one of 24 micronutrients essential for human

Vitamin D is one of 24 micronutrients essential for human survival. The most common natural source for vitamin D is the sun, although it is also found in fish and eggs. Supplementation is only necessary if you don't get enough from your diet, or if you live in a part of the world that lacks the required amount of sun exposure to get enough naturally. Unfortunately, this includes most of us. While most men aren't fully deficient in vitamin D, plenty don't have optimal levels of the vitamin, and could benefit from supplementation.

What it does:

If you're living with sub-optimal levels of vitamin D, supplementation will likely deliver a broad spectrum of benefits. Increased cognition, better immune health, better bone strength, reduced risk of cancer and heart disease are just some of what to expect. 

How to take it:

For most people not living in extremely northern or southern areas relative to the equator, doses of 1,000 to 2,000 IU should be ideal. Doses of up to 5,000 IU are commonly sold in stores, but be careful not to take too much, as 10,000 IU is considered 

Having enough vitamin D is important for a number of reasons, including maintaining healthy bones and teeth; it may also protect against a range of conditions such as cancer, type 1 diabetes, and .

If you shun the sun, suffer from milk allergies , or adhere to a strict vegan diet , you may be at risk for vitamin D deficiency. Known as the sunshine vitamin, Vitamin D is produced by the body in response to skin being exposed to sunlight. It is also occurs naturally in a few foods -- including some fish, fish liver oils, and egg yolks -- and in fortified dairy and grain products.

Vitamin D is essential for strong bones, because it helps the body use calcium  from the diet. Traditionally, Vitamin   has been associated with rickets, a disease in which the bone tissue doesn't properly mineralize, leading to soft bones and skeletal deformities. But increasingly, research is revealing the importance of vitamin D in protecting against a host of health problems.

Symptoms and Health Risks of Vitamin D Deficiency

Symptoms of bone pain and muscle weakness  can mean you have a vitamin D deficiency. However, for many people, the symptoms are subtle. Yet, even without symptoms, too little vitamin D can pose health risks. Low blood levels of the vitamin have been associated with the following:

• Increased risk of death from cardiovascular disease
• Cognitive impairment in older adults
• Severe asthma in children
• Cancer 

Research suggests that vitamin D could play a role in the prevention and treatment of a number of different conditions, including type1 and type 2 diabetes , hypertension , glucose intolerance, and multiple  sclerosis.