Vitamin Information Center

VITAMIN D: “The Sun Vitamin”

Nicholas H.E. Mezitis MD and Despina Komninou MD, PhD, CNS

Did you know that vitamin D, as a hormone, has an important role in metabolic harmony?

Recent studies have shown that vitamin D in its active form is vital for bone health, since it ensures dietary calcium absorption, and helps prevent heart disease, cancer (breast, prostate, lung and colon ), as well as many other illnesses such as diabetes mellitus, rheumatoid arthritis, psoriasis, multiple sclerosis and tuberculosis.

Vitamin D regulates the calcium and phosphorus levels in the blood by promoting their absorption from food in the intestinal tract and by limiting the excretion of calcium by the kidneys. It influences the cells involved in remodeling bone (osteoclasts and osteoblasts) and it inhibits the secretion of parathyroid hormone, which signals calcium release from bone matrix. Importantly, it has a role to stimulate the immune system, promoting phagocytosis and anti-tumor activity among other functions.

The body produces vitamin D when bare skin is exposed to the sun, hence the term �sun vitamin�. Exposure to sunlight for at least 15 minutes two to three times a week produces adequate quantities of this vitamin for the body�s needs. It is estimated that the body can produce more than 20000 IU (international units) of vitamin D with just 20 minutes of sun exposure.. Once adequate amounts of vitamin D have been formed the body, excess amounts formed are rapidly degraded to protect from overload, in the event of prolonged exposure to the sun. However, conditions such as cloudy skies, northern climates, and atmospheric pollution, limit solar ultraviolet radiation exposure and restrict our ability to replete vitamin D stores.

Vitamin D can also be obtained from dietary sources. It is lipid-soluble and is therefore stored in fat. That is why we find it in fatty fish (like salmon and tuna), eggs, cod-liver oil and fortified milk. In our daily diet, 3 servings of milk (about 250 ml) provide us with approximately 900 mg of calcium and 300 IU of vitamin D.

The recommended daily intake (RDI) of vitamin D is 200 IU for infants, youths and adults up to the age of 50 years. The requirement increases to 400 IU for adults ages 51 to 70 and to 600 IU for people older than 70 years. The RDI and the normal reference values for vitamin D in the blood, are based on levels reported to the prevent rickets and osteomalacia, the two main diseases attributed to lack of this vitamin. Rickets is a childhood disease characterized by poor growth and bone weakness, while osteomalacia is the clinical expression of vitamin D deficiency in adults and is characterized by demineralized bones, fractures, bone pain and generalized weakness. Osteoporosis represents abnormal weakening of bone structure with demineralization of the skeleton, and may also be associated with low levels of vitamin D.

Recent studies confirm that optimal vitamin D status is achieved when the 25- OH vitamin D level in the blood is more than 30 ng/ml. Levels between 10-30 ng / ml represent vitamin D insufficiency (hypovitaminosis D) which can either be moderate (21-30 ng/ml) or severe (10-20 ng/ml). Vitamin D levels below 10 ng/ml are considered vitamin D deficiency and have serious consequences. We now know that long before the full clinical presentation of painful osteomalacia, hypovitaminosis D may cause non-specific symptoms such as persistent musculoskeletal pain regardless of age, gender and ethnic origin.

It is worth noting, that a significant proportion of the population has insufficient levels of vitamin D, mainly due to lack of sun exposure, especially during the winter months, which is not compensated by the usual diet. Indeed, today many of us work in buildings with sealed and tinted glass windows and drive everywhere with very few opportunities to walk in the sunlight. During our limited sun exposure opportunities we frequently use a sun screen lotion further obstructing the beneficial effects of sunlight. In areas above 40˚ latitude (e.g. New York, Northern California), sunshine adequate for vitamin D synthesis in the skin is restricted to the months from May through September. Therefore, a large proportion of the population in the United States is at increased risk for vitamin D deficiency

The prevention of hypovitaminosis D has important public health implications. Millions of health care dollars are spent in dealing with the illnesses and complications associated with this problem and additional funds are lost due to curtailed productivity on a societal level. Since sun exposure has its limitations, the diet is our primary source for this vitamin to ensure an intake of at least 1000 IU daily.

The proper diet must be rich in fatty fish such as salmon, mackerel and sardines, mushrooms (Shitake, sun dried, provide 1600 international units per 100 grams), free-range eggs and fortified milk products. Supplementation of vitamin D and calcium is advisable, especially for children and the elderly. Finally, regular, weight-bearing exercise ensures that calcium absorbed through the activity of vitamin D is used to mineralize the skeleton. Similar to a musical composition, health is ensured through harmony in diet and exercise.

More on the maintenance of metabolic harmony will be discussed in our next article *.

* This article is part of medical communication produced by the MEZITIS EDUCATION AND RESEARCH INSTITUTE for the print media, television and radio programs(Cosmos FM “����� ��� ���” every Saturday at 12:30 pm on 91.5 FM and the internet, live streaming, at gaepis.org) focusing on topics in general health, metabolism and nutrition.

Experts are increasingly pushing for higher daily recommended intakes of vitamin D, saying that while current amounts may prevent signs of deficiency, they are insufficient to provide a protective benefit against cancer.

Vitamin D is an essential nutrient produced by the body when ultraviolet radiation from sunlight strikes the skin. In northern latitudes, however, when sunlight is dim for significant parts of the year, many people cannot get enough sun to synthesize sufficient levels of the vitamin. This problem is particularly pronounced among those with darker skin. Few foods are rich in vitamin D. Fish oil and fortified food sources, such as milk or non-dairy milk substitutes, provide the most common dietary sources.

The United States and Canadian governments recommend a daily vitamin D intake of 200 IU. But vitamin D and cancer experts warn that this value is far too low.

Recently, the Canadian Cancer Society advised that light-skinned people take a 1,000 IU vitamin D supplement daily during fall and winter months, and that dark-skinned people or those who regularly keep all their skin covered while outdoors take a supplement year-round.

“We’re recommending 1,000 IU daily because the current evidence suggests this amount will help reduce cancer risk with the least potential for harm,” said Heather Logan, director of the society’s Cancer Control Policy.

“I have to commend the Canadian Cancer Society,” vitamin D researcher Joan Lappe said. “They’re right out in the lead there on changing the recommendations.”

Lappe was lead researcher in a recent study that found that women taking 1,100 IU of vitamin D per day showed a 60 percent reduced risk of developing cancer than women taking a placebo. Excluding women who developed cancer during the first year of the four-year study, the risk reduction from vitamin D was 77 percent.

In a paper published in the “American Journal of Clinical Nutrition,” a group of vitamin D experts recently advised that an upper daily limit of 10,000 IU be set for vitamin D exposure, making a break with the current, more cautious, government recommendations.

New research has concluded vitamin K2 consumption can aid recovery from hip fractures as well as have potential osteoporosis benefits.

Published in the European Journal of Epidemiology, Japanese researchers found a positive link between vitamin K2 and hip fractures and osteoporosis, and suggested a review of the, “dietary reference value of vitamin K from the perspective of osteoporosis would be useful.”

The current Japanese reference value is 55mcg for women and 65mcg per day for men. In the US and Canada it is 120mcg per day for men and 90mcg per day for women. In France the limit is 65mcg per day for both men and women.

“Since regions which consumed a lot of vitamin K, especially vitamin K2, showed a low incidence of hip fracture, we considered that vitamin K intake, not absorption, of over 300 mcg/day would be helpful to reduce the incidence of hip fracture,” the researchers concluded.

Family K

The vitamin K family includes the forms phylloquinone (K1) that are typically found in cruciferous vegetables and menaquinone (K2), which are sourced from bacteria. Studies have shown K2 to be the more important nutrient in regard to bone health.

“Menaquinone-7 (K2) showed a very long half-life time compared to vitamin K1,” the researchers wrote. With this in mind they recommended higher doses in regions like Europe and North America, where vitamin K1 consumption is higher.

The study also investigated vitamin D, calcium and magnesium, which have strong clinical bone health backing, and found when these were adjusted for, vitamin K2 continued to reveal a beneficial effect.

Dietary sources

The study assessed population diets in various regions of Japan as well as dietary differences, and found that those regions where certain vitamin K-rich fruits and vegetables were prominent had reduced rates of hip fracture.

“There was also a striking pattern of high intake of vitamin K and low incidence of hip fracture in eastern areas of Japan, with the opposite pattern-a low intake of vegetables rich in vitamin K and a high incidence of hip fracture-in western areas,” they wrote.

“These findings lend support to the idea that vitamin K is an important factor explaining regional differences in the incidence of hip fracture.”

Natto, a food made from fermented soy beans, was singled out as being a particularly abundant vitamin K source.

K for bones

The researchers recognised that the role of Vitamin K role in assisting bone health is relatively new.

“Calcium, the most studied nutrient in the area of bone health, is known for its effectiveness in retarding bone loss in postmenopausal women,” they said. “Magnesium and vitamin D play important roles in calcium and bone metabolism. Vitamin K, originally recognised as a factor required for normal blood coagulation, is beginning to receive more attention for its role in bone metabolism.”

Due to the ecological nature of the study, a “causal linkage between the incidence of hip fracture and intake of vitamin K” could not be confirmed but the researchers said, “further research using more robust epidemiological methods is warranted.”

Estimates suggest that in the absence of primary prevention the number of hip fractures worldwide will increase to approximately 2.6 million by the year 2025, and 4.5 million by the year 2050.

Osteoporosis weakens bone strength which increases the likelihood of hip fracture, a problem that increases with age.

By Helen ChickeringNBC News Channel

Debate is raging over how much sun you should get. For years, we’ve been warned that sunscreen is a must, but now some health professionals are saying some exposure to the sun’s rays is necessary. An American Academy of Dermatology survey finds that ten percent of Americans in their 40s, 50s, 60s and even 70s hit the tanning bed.

Sunlight, even artificial is a prime source of Vitamin D, a nutrient that helps the body absorb calcium and one a growing body of research suggests may also help prevent diseases from cancer to diabetes. Unfortunately, up to half of the population is not getting enough, according to the Duke Diet Center’s Elisabetta Polilti.

“Vitamin D sources are not very common,” she explained.

Oily fish like salmon and fortified milk are among the few dietary sources of Vitamin D. That leaves supplements and sunshine, unless you wear sunscreen.

“The skin lotion is preventing vitamin D from being absorbed,” Politi said.

While it’s doubtful we’ll ever say ’so long’ to sunscreen, the Vitamin D dilemma does have the scientific and medical communities taking a closer look at the safe sun message.

Boston University’s Dr. Michael Holick calls it “sensible sun exposure.”

“Typically maybe five to ten minutes of arms and legs, two to three times a week, followed by good sun protection is a good recommendation,” he said.

It’s a recommendation that has gotten heat from major skin and cancer organizations who’ve noted the rise in skin cancer. All parties do agree people aren’t getting enough of the sunshine vitamin.

©2008 NBC News Channel. All rights reserved. This material may not be published, rewritten, or redistributed.

A vitamin is a small organic molecule essential for normal metabolism and growth. Since it cannot be synthesized by the body in adequate amounts, it must be obtained in the diet. According to this definition, vitamin D isn’t even a vitamin, since very large amounts can be synthesized in the skin. However, many if not most people don’t make enough vitamin D and need to consume it in food or supplements.

Vitamin D has been in the news a lot partly because of this very problem. It turns out that the skin can synthesize vitamin D only if it is exposed to adequate amounts of sunlight. So, people who don’t get a lot of sun, such as patients in hospitals, or elderly people living in institutions, are often deficient in vitamin D. Even healthy active adults, who live in northern latitudes, such as in New England, are frequently deficient in vitamin D, as are people who live in sunny climates but habitually cover their skin. The UV rays that produce vitamin D in the skin are the very same UV rays that produce sunburn and that are blocked by sunscreen, shade, clothing and dark skin pigmentation, so even people who are active outdoors can be deficient in vitamin D.

Why do we care? Vitamin D is essential for regulating blood calcium levels and for promoting calcium absorption to maintain strong bones. It also regulates certain immune functions and can decrease the proliferation of normal and cancerous cells. This may explain why low vitamin D levels are associated with increased risks of certain kinds of cancer and other diseases, and why vitamin D supplementation has been shown to decrease the risk of some cancers in post-menopausal women.

Fortunately, it is easy to supplement vitamin D levels. The recommended daily intake of vitamin D3 is 400 IU daily, although many experts recommend intake of 800 IU daily for children and adults. There are several good dietary sources: a 3.5 ounce serving of fresh wild salmon has between 600 and 1000 IU of vitamin D3 (farm-raised salmon may only contain 100 to 250 IU in the same size serving); canned tuna contains about 230 IU in a 3.6 ounce serving (which is a little more than half a can). Fortified milk, yogurt, cheese, orange juice and breakfast cereals often contain 100 IU of vitamin D3 per serving. Over-the-counter supplements containing vitamin D3 are also widely available.

Finally, there is the option of careful, sensible sun exposure. It is difficult to calculate “adequate” sun exposure because the amount of sun needed for a person to synthesize enough vitamin D varies with season, latitude, time of day and skin pigmentation. These factors affect the amount of UV that reaches and is absorbed by the skin. Also, older skin has less capacity to synthesize vitamin D. For most people, 5 to 10 minutes of sun exposure on the arms and legs twice a week may be enough to maintain vitamin D levels. With sun exposure, moderation is key; too much UV exposure and sunburns increase the risk of skin cancer. So, it is still important to avoid excessive sun exposure and to use sunscreen daily to minimize this risk.

NattoPharma, Norway, and P.L. Thomas today note the publication of a new study demonstrating vitamin K’s role in promoting healthy bones in children. Published online at the British Journal of Nutrition link, the researchers followed 307 healthy children, with an average age of 11.2 years, over a two year period and measured skeletal bone mineral content. They found improved status of the K vitamins over the two year period resulted in better mineral content and improved bone mass of the whole body.

According to the lead author, Marieke Summeren, Ph.D., “As children grow the increase in bone mass may fail to keep up with the increase in height, or length of the bone, and as a consequence, this imbalance may result in fracture.” She continued, “But the main threat of a long-term shortage of K vitamins is that peak bone mass may be compromised, and as we age and begin to lose bone density, the risk of fracture in later life is increased.”

Study author Leon J. Schurgers,Ph.D.commented, “Numerous population studies and interventional trials have established the consumption of K vitamins to bone strength, structure and the reduction of the risk of fracture. This is due to the need to activate the vitamin K-dependent protein osteocalcin, which is essential for the body to utilize calcium in a healthy bone tissue. Unfortunately, most people, including children, are likely deficient in the K vitamins related to the need for bone health.”

This is among the first studies linking K vitamins to bone health in children. Vitamin K status was evaluated by measured by the amount of active osteocalcin to inactive osteocalcin. Without adequate vitamin K, the osteocalcin remains inactive, and thus not effective. Previous research has evaluated vitamin K status in children and found that they have inadequate K vitamins consumption to fully activate osteocalcin.

“There are two types of vitamin K from dietary sources. Vitamin K1 is found in leafy green vegetables, and Vitamin K2, also called menaquinones, are predominately found in fermented cheeses, curd, and the fermented soy called natto,” stated Schurgers. “Vitamin K1 is mostly used by the liver where it is involved in the synthesis of certain blood clotting factors. Vitamin K2 is also equally active outside the liver, in tissues including bone. Thus it is important to have good sources of both types of vitamin K!”

The recommended intakes of vitamin K today are based solely on coagulation. However, K vitamins are also necessary for the activation of osteocalcin, a protein necessary to transport calcium from the blood to form healthy bone matrix. Also, K vitamins are needed to activate matrix GLA protein (MGP), the most potent inhibitor of vascular calcification known. In essence, K vitamins are necessary to keep calcium in your bones and out of your arteries.

About Vitamin K2
The role of newly recognized vitamin K2 has for the past decade been linked to two of the most important health issues, osteoporosis and cardiovascular disease. This link specifically centers on calcium utilization- implying that there is concurrent arterial calcification and osteoporosis when metabolism of calcium is inadequate. K vitamins are essential to activate proteins involved in calcium metabolism.

Numerous population studies and interventional trials have established the consumption of vitamins K and K2 to bone strength, structure and the reduction of the risk of fracture. More recently, and specifically to vitamin K2, a significant role in cardiovascular health has been established.

A study published in the Journal of Nutrition called the “Rotterdam Study” in 2004, followed over 4,800 people for a ten year period. The study found increased intake of specifically vitamin K2 from dietary sources significantly reduced the incidence of arterial calcification and the risk of CHD mortality by 50% as compared to low dietary vitamin K2 intake. In this study, vitamin K1 had no effect at all.

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PLT offers a natural vitamin K2 under the trade name MenaQ7 in alliance NattoPharma, Norway, the owner of the brand MenaQ7.

About MenaQ7™
MenaQ7 provides Natural Vitamin K2 as an extract of natto, a fermented soy food from Japan. Natto is particularly rich in the highly bio-available form of vitamin K2 called menaquinone-7 (MK-7). MenaQ7 provides the only commercially available Natural Vitamin K2 with guaranteed actives and stability, clinical substantiation and international patents awarded and pending.

For more information on the health benefits of MenaQ7, please visit www.menaq7.com

About NattoPharma
NattoPharma, Norway, is a publically-traded company and the exclusive international supplier of MenaQ7 natural Vitamin K2. NattoPharma has entered into a multi-year research and development program to substantiate and discover the health benefits of natural vitamin K2 for applications in the exciting marketplace for functional food and health food supplements. www.nattopharma.com

About PL Thomas
PL Thomas, a New Jersey-based ingredient supplier, offers fifty years of innovation in securing reliable, high quality raw materials for the food/functional food and nutrition industries. PLT is a one-stop resource for application solutions, current industry information and technical service, and specializes in water-soluble gums and clinically-supported botanical extracts. www.plthomas.com

For more information, please contact Eric Anderson at eric@plthomas.com - 973-984-0900 x215.

MONDAY FEB 4, 2008 (Foodconsumer.org) — Combo treatments with vitamin D and calcium may not reduce the risk of diabetes in postmenopausal women, suggests a study published Jan 30 online in the journal Diabetes Care. Continue Reading…