January 24, 2013

• Vitamin D and breast cancer

  Health

  

  A new study published in the journal Cancer Causes and Control revealed that women with high levels of Vitamin D in their blood decrease their chances of developing breast cancer by up to three times.

  The study led by researchers from the University of California, San Diego School of Medicine and collaborated with researchers from San Diego State University and Heartland Assays of Ames, Iowa, examined blood levels of 1,200 healthy women, 600 of whom later developed breast cancer while the other 600 remained healthy.

  Comparing the Vitamin D levels of these women, the researchers found out that the 600 women who developed breast cancer had lower levels of Vitamin D in their blood.

  "Based on these data, further investigation of the role of vitamin D in reducing incidence of premenopausal breast cancer, particularly during the late phases of its development, is warranted," said principal investigator Dr. Cedric Garland, professor in the Department of Family and Preventive Medicine at UC San Diego.

  “While the mechanisms by which vitamin D could prevent breast cancer are not fully understood, this study suggests that the association with low vitamin D in the blood is strongest late in the development of the cancer," he said.

  The researchers, comparing several studies, estimates that 4000 IU per day of vitamin D from food and supplement sources, which would bring blood levels of vitamin D to 50 ng/ml, could lower the risk of premenopausal breast cancer by 50 percent. Garland believes that the action of vitamin D is critical most especially during the last three months before tumor diagnosis is made.

  Garland said that this is the time when the tumor actively recruits blood vessels required for its growth.

  Despite these findings, he urges patients to first ask their health care provider to measure their vitamin D blood levels, particularly serum 25-hydroxyvitamin D or 25(OH)D, before increasing their vitamin D intake. 25(OH)D is the form of vitamin D after it passes through the liver. It is also the metabolite used in measuring vitamin D levels in blood plasma.

  “Reliance should not be placed on different forms of vitamin D, such as vitamin D2, and megadoses should be avoided except those ordered by a doctor for short-term use,” he cautions.

  Note that many commercially produced foods like milk, tofu, and cereals are already fortified with vitamin D, still that doesn't mean that they are good sources of the nutrient, as such, it is always better to choose natural. Here are some natural sources of vitamin D:

  1. Cod liver oil is the richest source of vitamin D at 21,803 IU or 5,451 percent of the daily recommended values for adults, but then who would want to drink 1 cup of cod liver oil in a day? One teaspoon or 4 grams of the oil is able to provide 450 IU or 113 percent of the daily recommended value. Many supplements are available in the market, mostly in capsule form, and most of these have been stripped of their "fishy" smell, making it even more acceptable to the palate. Aside from vitamin D, cod liver oil is a good source of vitamin A at 90 percent of the daily recommended value, and Omega 3 fatty acid. It also has strong anti-inflammatory properties making it an ideal supplement for people suffering from arthritis.

  2. Fish. The fish with the richest source of vitamin D is raw Atlantic herring at 2,996 IU or 749 percent of the daily recommended values for a 184 grams fillet. This is followed by raw wild catfish at 795 IU or 199 percent of the daily recommended values for a 159 grams fillet. What would be widely available to us would be canned Pacific sardines in tomato sauce. Each 38 gram sardines would contain at most 182 IU or 46 percent of the recommended daily values. Tuna would have the lowest at 66 IU or 17 percent of the recommended daily values.

  3. Mollusks, particularly wild raw oysters, are another rich source of vitamin D. A 100-gram serving would have around 320 IU or 80 percent daily values of vitamin D. Oysters are also a rich source of protein, vitamin B12, iron, zinc, copper, manganese, and selenium. And contrary to popular notion, they actually have a very strong anti-inflammatory factor according to Nutrition Data. Researchers suggest that this is because of its high Omega-3 fatty acid content, purported to have anti-inflammatory properties, at 672 mg per 100 grams. Oysters, however, has very high cholesterol content, the reason why it is also advisable to eat in moderation.

  4. Mushroom. A cup of drained canned mushroom at 156 grams contains 32.8 IU or 8 percent daily values for vitamin D. So, if you're having pizza or some pasta, load it up with some mushrooms and increase your vitamin D intake. Aside from vitamin D, mushrooms are a good source of vitamin B6, folate (vitamin B9), iron, magnesium, potassium, zinc, manganese, fiber, thiamin (vitamin B1), niacin (vitamin B3), pantothenic acid (vitamin B5), phosphorus, copper, and selenium. And, unlike other sources of vitamin D mentioned earlier, mushrooms has very low saturated fat and cholesterol, making it a great nutritional source for those trying to control their cholesterol levels.

  5. Sunshine. Our body naturally produces vitamin D, particularly cholecalciferol or vitamin D3. Vitamin D2 is ergocalciferol and is synthesized by plants. Vitamin D3 is produced in our skin when it is exposed to the sun's ultraviolet rays, particularly UVB. A thirty-minute whole body exposure to UVB could produce around 10,000 to 20,000 IU of vitamin D. So, the next time you try to hide from the sun, think again. The best times to be exposed to the sun (in the tropics) would be around 7 to 10 in the morning, after that, the UV rays you'll be getting from the sun would be more harmful than beneficial.

  Here is a 2010 ABC report on a similar study:

  Source: Newswise | Photo from Times of India/Getty Images. Video from YouTube. All food nutrition figures quoted in this article were from Nutrition Data.
  

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