It is well-known that older, heavier adults have lower blood levels of vitamin D. A new study from Tufts shows that a lack of sunshine does not seem to be responsible.

The researchers analyzed information on 381 men and women age 65 or older and found no difference in sun exposure among groups based on body fat percentage. The team did find that those with the highest percentage of body fat had 20 percent lower blood levels of vitamin D.

According to Dr. Susan S. Harris, one explanation could be that vitamin D is getting trapped in fat tissue and therefore not available to the blood. It seems that heavier people may need more vitamin D, whether from the sun or supplements.

A recent study published in The Prostate by Dr. Lagunova and colleagues suggests that the season of prostate cancer diagnosis may be linked with survival. The study showed that men diagnosed with prostate cancer in the summer and autumn have better survival.

Vitamin D deficiency has been linked to higher prostate cancer mortality in previous studies. The authors put forth a theory that levels of calcidiol, an intermediate metabolite of Vitamin D, are higher during the summer and autumn and therefore may impact prostate cancer incidence and outcome. The researchers divided Norway into three areas based on sun exposure and documented Vitamin D intake.

The best prognosis for prostate cancer patients were for those diagnosed in the summer and autumn, defined from June to November.

In a recent column by Dr. Leslie Baumann, Baumann addresses the risks of tanning addiction. According to Baumann, tanning addiction is not 'just in your head'.

Baumann cites a study where doctors used substance-abuse screening techniques to examine frequent beachgoers and found that over 50 percent of the beachgoers in the study showed signs of dependence. Researchers theorize that UV exposure stimulates endorphin-like production and therefore, a sense of heightened well-being. From an evolutionary perspective, this trait would be adaptive as it would encourage adequate levels of vitamin D.

Baumann adds that since we can access adequate vitamin D through supplements now, these are the best bets for those at high-risk for skin cancer. If you're going the sun route, it only takes 20 minutes a day to generate the needed vitamin D levels.

Ahh, the feeling of the sun's rays on the skin can be so refreshing. Well, as long as you keep that exposure to a certain level and don't overdo it during the bright afternoon hours. A nice side benefit? Sunlight helps your body naturally produce its own Vitamin D.

But did you know that getting the proper amount of daily vitamin D may help you ward of cancer as well? In a recent spate of research, scientists found that 250,000 cases of colorectal cancer and 350,000 cases of breast cancer could be prevented every year around the world by having those affected with these cancers increase their vitamin D intake. Specifically, vitamin D3.

It's quite a statement to say that 600,000 cancer cases per year could be eliminated by increasing vitamin D intake, but that's the conclusion here. Pardon me while I walk outside and get some sunlight for 10 minutes.

Though spending time in the sun is generally considered a bad thing as far as skin cancer goes, it can help prevent breast cancer. A study shows that women who stay inside more often are at a high risk for breast cancer than those who spend time outside. What's more, breast cancer is less prevalent closer to the equator, where sunlight is more common. The key ingredient is the valuable Vitamin D that exposure to the sun provides, though I would be interested to know if it makes a difference whether people get natural vitamin D from the sunlight or if similar health benefits could be derived simply from staying inside and taking vitamin D supplements. I tend to think that people who get outside are generally healthier overall than those who are housebound.

This isn't the green light to spend your days cooking your skin under the hot sun in the hopes of achieving that golden brown glow, though. While sunlight in important, it's also important to take precautions in the sunlight, like covering up and wearing sunscreen.

Postmenopausal women who take calcium and vitamin D supplements may reduce their risk of cancer, according to a report published in the American Journal of Clinical Nutrition. The study was a randomized controlled trial. This is in contrast to many earlier studies that show that vitamin D is protective against cancer, but were only observational trials.

The researchers found that women who took both calcium (1400-1500 mg/day) and vitamin D (1100 IU vitamin D3/day) had a lower incidence of cancer than those who took the placebo. There were 13 cases among the 446 women who took the supplements versus 20 cases among 288 women who took the placebo during the four year period.

As Jacki pointed out here, it appears that vitamin D consumption can lead to a lowered risk of breast cancer development, as a new study has found that vitamin D does indeed help lower the risk of cancer (beyond just breast cancer).

What intrigued me about this research is that vitamin D supplements are not being discussed as part of a prevention program. I've always been of the mind that high levels of isolated nutrients may not be good for the human body at all (or be completely ineffective), and the attention to not using vitamin D supplements in the wake of this news confirm this line of thinking.

In general, the working together of several vitamins and minerals at the same time in the body generally gives the best and more preventative results. In the case of vitamin D, a little walk in the sun each day can help your body form its own -- and it's free.

Canadian and international researchers suspect adding a high-dose vitamin D pill to chemotherapy might improve treatment for advanced prostate cancer. So they are recruiting 1,000 men for a two-year clinical trial in order to investigate their suspicions. Currently, there is little to offer patients who no longer respond to to standard treatment.

The trial will test the pill calcitriol -- a biologically active form of vitamin D and naturally occurring hormone -- to see how it works in combination with the chemotherapy drug docetaxel. Precautions will be taken to minimize side effects that can occur with high-dose supplements.

The Canadian Cancer Society estimates that 20,700 men in Canada will be diagnosed with prostate cancer this year. About 4,200 of these men are expected to die from the disease.

Women with advanced breast cancer were found to have lower levels of vitamin D when compared to women with early-stage breast cancer, leading researchers to conclude that vitamin D might play a role in slowing the progression of breast cancer.

Imperial College London researchers are not certain if the lower level of vitamin D found in women with advanced breast cancer is the result of the cancer, or one of the factors promoting the progression of the breast cancer, only that there appears to be a connection.

This adds to the body of knowledge that women living in northern climates, where there is less year-round sun exposure, are more prone to developing breast cancer.

One of the natural ways to get vitamin D is from exposure to sunlight. Also, women can get vitamin D from fortified milk and dairy products, cod liver oil and fatty fish, such as salmon. Previous research has indicated that vitamin D might play a role in the prevention in a number of cancers. For related information into research conclusions regarding vitamin D:

• Fatty fish offers women cancer prevention
• Vitamin D: supplement aids in reducing risk of cancer
• Vitamin D: lack of summer sun increases risk for 16 cancers

In two large studies, vitamin D have been found to have a significant effect in reducing the risk of pancreatic cancer. According to Northwestern University researchers, their study is one of the first known studies to use a large-scale epidemiological survey to examine the relationship between vitamin D supplements and cancer of the pancreas.

Previous research and researchers have gone so far as to state that exposure to solar ultraviolet B (UVB) radiation, which causes the body to manufacture vitamin D, might reduce the risk of 16 types of cancer. "Enhancing vitamin D status appears to be the single most important simple thing people can do to reduce their risk of cancer, apart from avoiding tobacco and moderation in the intake of alcohol."

Because of concern regarding prolonged exposure to the sun and skin cancer risks, and for those living in northern climates, it seems reasonable to conclude that perhaps the sensible alternative is a daily vitamin D supplement. However, if you are a cancer patient undergoing treatment, you should check with your physician before embarking on any supplement program.

Between pale is the new tan and cultural or religious beliefs that require young girls to wear clothing that covers all skin areas and young girls who are restricted from outdoor activities, adolescent girls are paying the price in insufficient levels of vitamin D needed for peak bone mass -- increasing the risk of osteoporosis fracture later in life. By shunning the sun they might be decreasing the risks for skin cancer, but they are increasing the risks for 16 other cancers.

Of the 51 healthy girls tested, Saint Mary's Hospital for Women and Children in Manchester researchers found 73 percent were vitamin D deficient, and 17 percent were severely deficient in vitamin D.

Lack of a sufficient level of vitamin D was in direct correlation to the lack of exposure to sun and not to dietary intake. "This is in keeping with the fact that the main source of vitamin D is that produced by the action of solar ultraviolet B radiation acting on 7-dehydrocholesterol in skin," the team explains. "Only small amounts are obtained from dietary sources."

Aside from encouraging more outdoor activity for these young girls, the researchers stated that it remains to be determined how to meet the needs of older children and adolescents from cultures that avoid sunlight.

When it comes to reducing sun exposure cancer risks, the information all gets a little confusing and seemingly contradictory in nature. We are told repeatedly to stay out of the sun, as this is the single greatest risk to the development of skin cancer. Campaigns are launched all summer long about the benefit of shade, of avoiding the sun, and the media makes headlines out of it in an attempt to raise awareness.

So if we are all doing what we are supposed to in reducing skin cancer risks by avoiding the sun, what do we make of the new study supporting University of California research that solar ultraviolet B (UVB) radiation reduces the risk of 16 types of cancer? UVB rays are what promotes the body's manufacture of the essential vitamin D that acts as a prevention to cancer risk.

According to study authors Cedric Garland and William Grant, "Enhancing vitamin D status appears to be the single most important simple thing people can do to reduce their risk of cancer, apart from avoiding tobacco and moderation in the intake of alcohol."

It might be a matter of practical common sense that moderation is the key. In the summer, researchers estimate it only takes 20 minutes of skin exposure to the sun to achieve the optimum levels of vitamin D derived from UVB rays. For darker skin, it can require over an hour to reach the same benefit. After that amount of time, it has no additional benefit. In addition, vitamin D supplements can supply a person's daily need for vitamin D.

So shade, sunscreen and covering up are still the best bets in skin cancer prevention. However, without sun exposure, the body is at risk for low levels of vitamin D, and the lack of vitamin D is linked to an increase in 16 different cancers.

According to the results of a British study involving more than one million patients, the time of the year when you are diagnosed and treated for cancer affects your chances of surviving cancer -- and it has to do with sunlight.

You have a greater chance of surviving cancer if you are diagnosed with cancer in the summer or autumn, and they believe this has to do with the amount of vitamin D derived from the sunlight you are exposed to during cancer treatment. Vitamin D, which is primarily obtained from sunlight, regulates the rate of healthy cell division. The two cancers that benefit most from exposure to the sun and vitamin D are breast cancer and lung cancer, although all cancers seem to be affected by seasonal differences in sunlight.

This study follows an earlier one that stated taking a large dose of vitamin D every day - 1,000 international units or 25mcg - could cut in half the chance of developing cancers such as breast, ovarian, colon, and prostate. Personally, I try to limit my sun exposure during the summer months, because skin cancer is a real concern, but I do spend time in the sun gardening and enjoying shaded outdoor activities, and I do take a vitamin D supplement. If vitamin D turns out to play as significant role as some research is beginning to suggest, then it is a simple step to take in cancer prevention and cancer survivorship.

After two days of meeting to discuss the safety and effectiveness of multivitamin and minerals supplements, MVMs, a 13-member independent panel of experts in the fields of food science and human nutrition, biostatistics, biochemistry, toxicology, geriatric medicine, family medicine, pediatrics and pediatric endocrinology, cancer prevention, epidemiology, disease prevention and health promotion, and consumer protection made the following observations and recommendations.

Button mushrooms for prostate and breast cancer prevention, posted several months ago, reported on a study that showed white button mushrooms offer both breast cancer and prostate cancer protection, and might be a significant nutritional resource as a cancer prevention food.

Our sibling blog, Slashfood, points to a study that reports exposing mushrooms to ultraviolet light for a short period of time enhances them as a nutritional superfood with 869 percent of the recommended daily allowance of vitamin D. As Joe DiStefano remarks, "That's more of the vitamin than is found in two tablespoons of cod liver oil, and probably much tastier." I would agree -- and there is a whole generation of grandparents who would agree -- since cod liver oil was administered to children on a daily basis back then. Yuck. My grandparents do not have fond taste memories of cod liver oil.

Past research indicates that the lack of an adequate level of vitamin D puts a person at higher cancer risk. These enhanced mushrooms would be a novel way to include another food enriched with vitamin D as part of a cancer prevention diet without relying too much on sun exposure for vitamin D, and the resulting skin cancer risk from the sun.