Showing posts with label Vitamin D. Show all posts
Showing posts with label Vitamin D. Show all posts

Friday, September 7, 2012

Immune Health and Vitamin D

When our immune system malfunctions, the consequences can range from microbial infections to cancer.

Many nutritional supplement ingredients are readily available and can help improve immune system health. Some of the more popular and scientifically substantiated ingredients include:
1.     Echinacea has been shown to stimulate the immune system by increasing the activity of certain immune cells and by promoting the release of cytokines (cellular communication and regulatory molecules) from these immune cells.#
2.     Elderberry contains flavonoid derivatives called anthocyanidins that appear to have immunomodulatory effects. These compounds in elderberry extract have been found to bind to viruses and block their ability to invade host cells.# In this way, elderberry is thought to reduce the severity of viral flu symptoms.
3.     Scientific studies on ingredients such as zinc, Korean ginseng, Vitamin C, beta-glucans and arabinogalactans all enhance and improve the effectiveness of the immune system by increasing the protective activity of certain immune cells. Macrophages, neutrophils, NK (natural killer) cells and T-cells (T-lymphocytes) are responsible for attacking and neutralizing foreign, disease-causing microbes. Without the proper functioning of these immune cells, infectious diseases such as colds and the flu usually occur more frequently, are more severe, and have a longer duration.
4.     Another promising avenue for natural immune support is vitamin D3. Studies now indicate that vitamin D, once only recognized for supporting bone health, may be a key nutritional component in enhancing immune function.

The following overviews of some recent studies tout the immune system benefits of vitamin D:

  • A recent study showed that vitamin D signals the immune system to fight infections. Scientists discovered that T cells—white blood cells that are like soldiers who search out and destroy the targeted invaders—require vitamin D to function. The study author explains, “When a T cell is exposed to a foreign pathogen, it extends a signaling device or ‘antenna’ known as a vitamin D receptor, with which it searches for vitamin D. This means the T cell must have vitamin D or activation of the cell will cease. If the T cells cannot find enough vitamin D in the blood, they won’t even begin to mobilize.” From this study, researchers realize how crucial vitamin D is for activating the immune system. The finding could have significant implications in the fight against global epidemics. Nearly half of the world’s population has sub-optimal levels of vitamin D, a problem that’s getting worse as people spend more time indoors.
  • Researchers theorized that the flu season occurs in winter months because of the lack of direct sunlight, and subsequent lower levels of protective vitamin D produced in the body. Their research indicates that influenza epidemics, and possibly even the common cold, are brought on by seasonal deficiencies in antimicrobial peptides, resulting from winter-time deficiencies in vitamin D.
  • In a study of Japanese schoolchildren, vitamin D supplements taken during the winter and early spring helped prevent seasonal flu. The study found that children receiving 1,200 IU of vitamin D daily were 58 percent less likely to catch influenza A.
  • People with higher blood levels of vitamin D had a 50 percent reduction in the risk of developing acute respiratory tract infections than those with lower blood levels. Additionally, of those with high vitamin D blood levels who did develop infections, there was a marked reduction in the number of days they were ill. Researchers concluded, “Maintenance of a [sufficient] 25-hydroxyvitamin D serum concentration should significantly reduce the incidence of acute viral respiratory tract infections and the burden of illness caused thereby, at least during the fall and winter in temperate zones.”
Source: Boosting Immune System

Monday, May 7, 2012

Sun Exposure and Vitamin D

Sad to say, most cases of vitamin D deficiency are due to the lack of outdoor sun exposure.  Vitamin D can be synthesized in the skin through a photosynthetic reaction triggered by exposure to UVB radiation.

For most white people, a half-hour in the summer sun in a bathing suit can initiate the release of 50,000 IU vitamin D into the circulation within 24 hours of exposure, for tanned individuals the same amount of exposure yields 20,000-30,000 IU and for those with dark skin 8,000-10,000 IU.

At least 1,000 different genes governing virtually every tissue in the body are now thought to be regulated by 1,25-dihydroxyvitamin D, the active form of the vitamin, including several involved in calcium metabolism and neuromuscular and immune system functioning.  According to Michael Holick, medical professor and director of the Bone Health Care Clinic at the Boston University Medical Center, the primary physiologic function of vitamin D is to maintain serum calcium and phosphorous levels within the normal physiologic range to support most metabolic functions, neuromuscular transmission, and bone mineralization.

In a study reported in the Journal of Investigative Dermatology, June 2003, Holick pointed out that most melanomas occur on the least sun-exposed areas of the body and occupational exposure to sunlight actually reduced melanoma risk.

Rolfdieter Krause and his colleagues of the Free University of Berlin Department of Natural Medicine studied to determine the potential link between sun exposure and the protective effect in preventing hypertension by exposing a group of hypertensive adults to a tanning bed that emitted full-spectrum UVR, which is similar to the summer sunlight and another group of hypertensive adults to a tanning bed that only emitted UVA radiation, which is similar to the winter sunlight.  After 3 months, those who used the full-spectrum UVR tanning beds had an average 180% increase in their 25(OH)D levels and an average 6 mm Hg decrease in their systolic and diastolic blood pressures, which brought them into normal ranges.  The group that used the UVA-only tanning beds showed no change in either 25(OH)D or blood pressure.

A research, published in the Archives of Internal Medicine, showed that those with the lowest vitamin D levels have more than double the risk of dying from heart disease and other causes over an eight-year period compared with those with the highest vitamin D levels.

In the International Journal of Epidemiology, a study led by Robyn Lucas, an epidemiologist at Australian National University, concluded that, far more lives are lost to diseases caused by a lack of sunlight than to those caused by too much.

As reported in Arthritis & Rheumatism, January 2004, the greater intake of vitamin D has been linked with lower rheumatoid arthritis risk.

Source:  www.ncbi.nlm.nih.gov/pmc/articles/PMC2290997

For your information:
The United States UV Index Forecast - Everyday the National Weather Service calculates the predicted UV Index for the next day in the U.S.

The United States Naval Observatory - Gives data on when the sun is at 50 degrees or more in any given area, which is the best range to get vitamin D exposure on sunny days.

Shared with: the healthy home economist