Vitamin D a key player in overall health of several body organs, says UC Riverside biochemist

October 9, 2008

Essential for life in higher animals, vitamin D, once linked to only bone diseases such as rickets and osteoporosis, is now recognized as a major player in contributing to overall human health, emphasizes UC Riverside's Anthony Norman, an international expert on vitamin D.

In a paper published in the August issue of the American Journal of Clinical Nutrition, Norman identifies vitamin D's potential for contributions to good health in the adaptive and innate immune systems, the secretion and regulation of insulin by the pancreas, the heart and blood pressure regulation, muscle strength and brain activity. In addition, access to adequate amounts of vitamin D is believed to be beneficial towards reducing the risk of cancer.

Norman also lists 36 organ tissues in the body whose cells respond biologically to vitamin D. The list includes bone marrow, breast, colon, intestine, kidney, lung, prostate, retina, skin, stomach and the uterus.

According to Norman, deficiency of vitamin D can impact all 36 organs. Already, vitamin D deficiency is associated with muscle strength decrease, high risk for falls, and increased risk for colorectal, prostate and breast and other major cancers.

"It is becoming increasingly clear to researchers in the field that vitamin D is strongly linked to several diseases," said Norman, a distinguished professor emeritus of biochemistry and of biomedical sciences who has worked on vitamin D for more than 45 years. "Its biological sphere of influence is much broader than we originally thought. The nutritional guidelines for vitamin D intake must be carefully reevaluated to determine the adequate intake, balancing sunlight exposure with dietary intake, to achieve good health by involving all 36 target organs."

Vitamin D is synthesized in the body in a series of steps. First, sunlight's ultraviolet rays act on a precursor compound in skin. When skin is exposed to sunlight, a sterol present in dermal tissue is converted to vitamin D, which, in turn, is metabolized in the liver and kidneys to form a hormone. It was Norman's laboratory that discovered, in 1967, that vitamin D is converted into a steroid hormone by the body.

The recommended daily intake of vitamin D is 200 international units (IU) for people up to 50 years old. The recommended daily intake of vitamin D is 400 IU for people 51 to 70 years old and 600 IU for people over 70 years old. Norman's recommendation for all adults is to have an average daily intake of at least 2000 IU.

"To optimize good health you must have enough vitamin D," he said. "Vitamin D deficiency is also especially of concern in third world countries that have poor nutritional practices and religious customs that require the body to be covered from head to toe. Ideally, to achieve the widest frequency of good health by population, we need to have 90 percent of the people with adequate amounts of vitamin D."

About half of the elderly in North America and two-thirds of the rest of the world are not getting enough vitamin D to maintain healthy bone density, lower their risks for fracture and improve tooth attachment.

"There needs to be a sea change by various governmental agencies in terms of the advice they present to citizens about how much vitamin D should be taken," Norman said. "The tendencies of people to live in cities where tall buildings block adequate sunlight from reaching the ground, to spend most of their time indoors, to use synthetic sunscreens that block ultraviolet rays, and to live in geographical regions of the world that do not receive adequate sunlight all contribute to the inability of the skin to biosynthesize sufficient amounts of vitamin D."

Found in minute amounts in food, vitamins are organic substances that higher forms of animals need to grow and sustain normal health. Vitamins, however, are not synthesized in sufficient amounts to meet bodily needs. Therefore, the body must acquire them through diet or in the form of supplements.

Because it is found in very few foods naturally, milk and other foods (often orange juice) are fortified with vitamin D.

While deficiency of vitamin D impacts health negatively, ingestion of extremely high doses of vitamin D can cause hypercalcemia, a condition in which the blood's calcium level is above normal. The highest daily 'safe' dose of vitamin D is 10,000 IU.

"More than ever we need to increase the amount of research on vitamin D, with more funding from government agencies and pharmaceutical companies, to meet the challenge of preserving or improving the health of everyone on the planet," Norman said.

Source: University of California - Riverside

Explore further: Fatty diet may boost risk of relapse in kids with multiple sclerosis

Related Stories

Fatty diet may boost risk of relapse in kids with multiple sclerosis

October 9, 2017
A fatty diet may boost the risk of a relapse in kids with multiple sclerosis (MS) by as much as 56 per cent, with saturated fat associated with a tripling in risk, suggests research published online in the Journal of Neurology ...

Hormone therapy may benefit migraine sufferers without increased risk of heart disease

October 11, 2017
Migraine headaches are common among women, but due to various health risks can be challenging to treat in the elderly. While hormone therapy is effective in relieving many menopause symptoms, its safe use in women with migraines ...

Scientists have found another reason for children to eat their green leafy vegetables

October 2, 2017
A study of 766 otherwise healthy adolescents showed that those who consumed the least vitamin K1- found in spinach, cabbage, iceberg lettuce and olive oil - were at 3.3 times greater risk for an unhealthy enlargement of the ...

Do ketogenic diets help you lose weight?

September 20, 2017
Is a ketogenic diet effective for weight loss? The answer depends on whether it achieves a reduction in total kilojoule intake or not.

Six common questions about eating carbs during pregnancy answered

September 27, 2017
During pregnancy women get bombarded with food and nutrition information. Eat this, don't eat that! It gets very confusing. Recent debates about the role of carbohydrates have cranked the confusion up a notch. In pregnancy, ...

What's healthier—fresh, dried or frozen fruit?

September 20, 2017
"Eat more fruit and vegetables" is one of the most common recommendations we hear when we're encouraged to eat healthily. But when it comes to eating more fruit, we get mixed messages about how healthy fruit really is.

Recommended for you

Study shows stress could be just as unhealthy as junk food

October 16, 2017
We all know that a poor diet is unhealthy, but a new BYU study finds that stress may just as harmful to our bodies as a really bad diet.

Childhood poverty, poor support may drive up pregnant woman's biological age

October 16, 2017
Pregnant women who had low socioeconomic status during childhood and who have poor family social support appear to prematurely age on a cellular level, potentially raising the risk for complications, a new study has found.

Blood vessel 'master gene' discovery could lead to treatments for liver disease

October 16, 2017
Scientists have identified a key gene in blood vessels which could provide a new way to assess and potentially treat liver disease.

Chronic inflammation plays critical role in sustained delivery of new muscular dystrophy therapy

October 16, 2017
Macrophages, a type of white blood cell involved in inflammation, readily take up a newly approved medication for Duchenne muscular dystrophy (DMD) and promote its sustained delivery to regenerating muscle fibers long after ...

New study demonstrates importance of studying sleep and eating in tandem

October 13, 2017
A new study from scientists on the Florida campus of The Scripps Research Institute (TSRI) offers important insights into possible links between sleep and hunger—and the benefits of studying the two in tandem. A related ...

'Ridiculously healthy' elderly have the same gut microbiome as healthy 30 year-olds

October 11, 2017
In one of the largest microbiota studies conducted in humans, researchers at Western University, Lawson Health Research Institute and Tianyi Health Science Institute in Zhenjiang, Jiangsu, China have shown a potential link ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.