As we learn more about the importance of nutrition and diet as related to cancer, vitamin D is often the subject of interesting and important research. Several recent studies have shed light on the potential use and benefits of getting enough vitamin D for the prevention of cancers—and in certain circumstances, as part of a treatment program for certain cancers. Its role in promoting bone health is important, especially for people with cancers that are associated with bone loss, such as breast and prostate cancer. The following review, written by my colleague Anne Chiavacci, a senior nutritionist at Brigham and Women's Hospital and Dana-Farber Cancer Institute in Boston, provides very useful information about vitamin D's role in preventing cancer.
What is vitamin D?
Vitamin D is a fat-soluble vitamin, well-known for helping the body absorb calcium and promote bone health. It's now well-established that getting enough vitamin D decreases your risk of getting many cancers, such as colon, prostate, breast, ovarian, pancreatic and digestive tract cancers.
You can get vitamin D from foods and supplements but the best source is from exposure to sunlight, which triggers the production of vitamin D3 (cholecalciferol). D3 is then changed by the liver to the active form of Vitamin D, called 25-hydroxycholecalciferol (25-OH-D). The final step to make the most active form occurs in the kidneys.
A simple blood test called Total 25-OH-D can tell you if you are getting enough vitamin D from all sources. A 25-OH-D blood level between 30 and 70 ng/ml is optimal.
The hallmark of cancer is uncontrolled cell growth. Vitamin D seems to keep abnormal cell growth in check by:
- blocking a phase of the cancer cell growth cycle
- hindering angiogenesis, the growth of blood vessels that feed a tumor
- triggering the death of abnormal cells
- stimulating cell differentiation, the development of characteristics of normal cells.
Preliminary research is beginning to suggest that, in addition to cancer prevention, vitamin D may also improve survival and decrease the risk of a cancer returning. Several studies, for example, suggest a better survival rate for people with colon, prostate, breast, lung and Hodgkin's lymphoma when they are diagnosed and treated in the summer and fall months. That's when vitamin D levels are typically higher.
How Much Vitamin D Do You Need?
The current recommendation for Vitamin D, issued nearly 10 years ago, is 200 to 600 International Units (IU) a day. Research suggests that much higher intakes are needed to maintain sufficient blood levels for optimum health. People who live in the Northern part of the United States, and those with darker skin pigmentation are more prone to vitamin D deficiency.
1. Make foods rich in vitamin D part of your diet. Choose from this list:
o salmon – 3.5 ounces (360 IU)
o mackerel – 3.5 ounces (345 IU)
o sardines – 3.75 ounces (250 IU)
o shrimp – 4 ounces (162 IU)
o milk, any type – 8 fluid ounces (100 IU)
o orange juice, D-fortified – 8 fluid ounces (100 IU)
o yogurt, vitamin D-fortified – 6 to 8 ounces (40-80 IU)
o fortified cereal – ¾ cup (40-50 IU)
2. Take a supplement. A reasonable and safe starting dose is 1,000 IU of vitamin D3 (cholecalciferol) per day, in addition to food sources. Vitamin D2 (ergocalciferol) is a less effective form. It takes about 1,000 IU of vitamin D3 to increase D blood levels by 10 ng/ml. It's safe to take 2,000 IU per day; some researchers would say 4,000 IU per day. Consult with your doctor or dietitian before taking more than 2,000 IU per day.
3. Achieve and maintain a healthy weight. Being overweight is associated with lower blood levels of vitamin D because the fat-soluble vitamin is stored in body fat and less available for the body's needs.
4. Enjoy the sunshine. About 15 minutes of sun exposure daily without sunscreen to 50% of the skin can help boost vitamin D levels without increasing skin cancer risk.
Did you know about the connection between cancer and vitamin D? Do you eat a lot of the foods listed above, or do you make sure to get out in the sun for a short period of time every day? If you have any questions about how you can get enough vitamin D, let me know!
Source: gather.com
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