What is vitamin D?

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Vitamin D is a fat-soluble hormone essential for growing and maintaining strong, healthy bones and supporting a strong immune system that helps protect against cancer.

Vitamin D precursors are formed in the skin in the presence of sunlight. The kidneys convert these substances into the active form of vitamin D, which the bloodstream carries throughout the body. Immune system cells produce vitamin D as an aspect of the body’s defenses against disease.
Marjorie Nolan Cohn
Nutrition & Dietetics

Vitamin D is a fat-soluble vitamin that is naturally present in very few foods, added to others, and available as a dietary supplement. It is also produced endogenously when ultraviolet rays from sunlight strike the skin and trigger vitamin D synthesis. Vitamin D obtained from sun exposure, food, and supplements is biologically inert and must undergo two hydroxylations in the body for activation. The first occurs in the liver and converts vitamin D to 25-hydroxyvitamin D [25(OH)D], also known as calcidiol. The second occurs primarily in the kidney and forms the physiologically active 1,25-dihydroxyvitamin D [1,25(OH)2D], also known as calcitriol.

Vitamin D is called the “sunshine vitamin” because it is made in your body with the help of ultraviolet (UV) rays from sunlight. Many healthy people can synthesize all the vitamin D they need as long as they get adequate sun exposure. People who don’t get enough sun exposure must meet their Vitamin D needs through their diets.

Milk and fortified yogurt are both good sources of vitamin D. Other sources include:
 
Dr. Michael Roizen, MD
Internal Medicine
Proofreader genes protect the body by rooting out cells that have become abnormal or malignant. Vitamin D appears to work to decrease immune aging and cancer risk by strengthening the functioning of your proofreader gene. Whether or not this works the ways the theories propose, the ability of vitamin D to decrease the risk of cancer is consistent in both epidemiologic and test-tube studies. The first theory is that the D3 form of the vitamin -- the active form the body can use -- kills cell mutations. Somehow, vitamin D is directly toxic to possibly cancerous cells. The second theory, supported by more data, is that adequate levels of vitamin D are necessary for proofreader genes to spot cancerous cells and cause them to die.

The proofreader gene recognizes mutated deoxyribonucleic acid (DNA) and cells. Vitamin D3 is an essential component used in this attempt by the body to rid itself of the cells. Vitamin D3 helps make protein for the functioning of the P53 gene, which is one of the body's main proofreader genes and cancer watchdogs. This gene helps prevent cancer by regulating protein production of specific oncogenes -- genes that, when mutated, can cause cancers. Indeed, vitamin D not only helps in the proper functioning of the gene, but also appears to actually help safeguard the P53 gene itself from genetic damage. Although studies still need to be done to confirm the link between vitamin D and cancer prevention, it is very possible that vitamin D does double duty by helping prevent aging of both the musculoskeletal and immune systems. When I think of vitamin D, I think of "defense." Vitamin D helps your body defend itself.

Vitamin D may also help protect the body from the onset and aging effects of arthritis, although this data is still somewhat speculative. Osteoarthritis is a disease that afflicts more than 10 percent of people who are sixty-five or older. It is painful, disabling, and aging. Recent studies have shown that taking calcium, vitamin C, and particularly vitamin D can retard the progression of arthritis and perhaps even prevent it's progression.
Jill A. Grimes, MD
Family Medicine

Vitamin D is linked to bone health, and deficiency puts you at greater risk of fractures. Vitamin D deficiency may also cause fatigue, low energy, decreased immunity, depression, muscle weakness, cramps, or altered sensation.

Recent studies show that having good levels of Vitamin D correlates with lower levels of colon, breast, and prostate cancer.

Vitamin D plays an important role in bone health, and also plays a role in the strength of our immune system and helps regulate cell growth. In fact, if you don't get enough vitamin D, you may have greater loss of bone mass, which can lead to osteoporosis and you may be at greater risk for softening of the bones.
Dr. Daniel Hsu, DAOM
Alternative & Complementary Medicine
You need vitamin D to help maintain strong bones and teeth. Vitamin D also helps regulate the activity and growth of your cells and can help prevent excessive inflammation in the body.
Dr. Robin Miller, MD
Internal Medicine
When it comes to the health benefits of vitamins, researchers are continuing to discover new reasons to make sure you get enough vitamin D. In this video, I will talk about a new study which linked low levels of vitamin D to a sign of potential damage that can occur throughout your body.
Romy Nelson
Nutrition & Dietetics
Vitamin D is a natural, inexpensive protection against heart disease, diabetes, osteoporosis and many forms of cancer? Not simply a vitamin, but a hormone as well, vitamin D is emerging as one of the most important indicators of physical and mental health.

Your body synthesizes vitamin D from cholesterol when the skin is exposed to sunlight. You also may obtain vitamin D through food or supplements.

Food sources include fatty fish (such as tuna, herring, catfish, and salmon), as well as eggs and cod liver oil. Vitamin D3 is added to most milk and cereals.

Emerging research has demonstrated low-levels of vitamin D are implicated in a person’s risk for the “big four” (heart disease, type 2 diabetes, several types of cancer and osteoporosis), as well as several other conditions, including, but not limited to: stroke, autoimmune diseases (such as MS, rheumatoid arthritis, type 1 diabetes, Chron’s disease), depression, flu, colds, asthma, chronic fatigue, allergies, chronic pain, osteoarthritis, obesity, high blood pressure, muscle weakness and wasting, and some birth defects.

Researchers estimate that 30-60% of Americas are deficient. To find out if you are among them, ask your doctor to run a serum OH D test next time you have blood work performed.

There is a wide-range of theories to explain the epidemic of low D levels. Implicated is an increase in sunscreen use, more indoor living, or the increase in pollution. It is important to note that due to darker skin color, African Americans living at higher latitudes are at greater risk of vitamin D deficiency; everyone living at higher latitudes is at increased risk in the winter.

Another theory is that certain medications lower vitamin D levels. For instance, one of the most common side-effects of taking statin drugs (a class of cholesterol-lowering drugs) is muscular pain caused by vitamin D deficiency. Other medications that cause a deficiency of vitamin D in the body are blood thinners, anti-seizure drugs, corticosteroids, and some categories of acid-reflux drugs. People on calcium channel blockers or thiazide diuretics must check with their physician; for them, it can be dangerous to supplement with vitamin D.

Depending on your skin tone, experts advise to get some sun exposure on the body (arms or legs) without sunscreen most days of the week. No one is suggesting excessive sun exposure. Moderate sun exposure is the key to safely increasing your D levels.

Vitamins are compounds that our bodies need to stay healthy and Vitamin D is a nutrient in food and a dhemical produced by our bodies when skin is exposed to sunlight. Vitamin D aids in the absorption of calcium which is needed for strong bones and teeth. Children who don't get enough vitamin D may develop weak bones and teeth, which is a condition called rickets. In adults, a deficiency in vitamin D may cause osteomalacia. This is where calcium is lost from the bones and makes them weak. Other conditions, like liver disease, kidney disease, intestinal diseases, pancreas disease, alcoholism, overactive parathyroid glands, or stomach removal, may cause you to need more vitamin D in your system.

Although vitamin D is usually categorized as a fat-soluble vitamin, it actually functions as a hormone in the body. Vitamin D helps to activate calcium and phosphorus (another key mineral for keeping bones strong) into the bloodstream.  
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Diet for a Pain-Free Life: A Revolutionary Plan to Lose Weight, Stop Pain, Sleep Better and Feel Great in 21 Days, ADA...sound nutritional advice...do-able, delicious..a godsend to pain sufferers.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.