Skin Conditions | October 2, 2014 | Author: The Super Pharmacist
Vitamin B3, better known as niacin and also known as nicotinic acid, is a critical molecule for many biological processes. The recommended daily allowance (RDA) of niacin is between 16 and 18 mg a day. When people consume too little niacin, they developed a disease called pellagra, which results in diarrhoea, dementia, dermatitis, and death (i.e. The Four Ds). On the other hand, supplementation of niacin has been shown to be an effective treatment for high cholesterol. There is also evidence that niacin or vitamin B3 may protect against certain forms of skin cancer.
Cancer patients tend to be vitamin B3-deficient. While chemotherapy can block the metabolism of certain vitamins and cellular processes, it is also possible that the cancer process itself causes deficiencies in certain vitamins. Both cancer and chemotherapy may cause cancer patients to eat less, develop painful sores around the mouth and in the digestive tract, and as a result, suffer from nutritional deficiencies.These findings have led to the hypothesis that supplementing with vitamin B3 might prevent the development of cancer.
The immune system detects cells that are foreign to the body and eliminates them.
We usually think of the immune system attacking foreign bacterial cells during an infection; however, cancer cells are sufficiently different from normal human cells that the immune system can sometimes detect and remove them before they develop into a tumor. In fact, the immune system plays a critical role in preventing cancer. This is especially true in melanoma and non-melanoma skin cancers.
Organ transplant recipients who must stay on immunosuppressive drugs to avoid transplant rejection have experienced a 33-fold increase in non-melanoma skin cancer and a 3.3 fold increase in melanoma compared to people with intact immune systems.
Even at intensity levels much lower than those required to cause sunburn, ultraviolet A (UVA) and ultraviolet B (UVB) radiation can damage DNA in skin cells and compromise the skin's immunity.
People who live in countries with relatively low levels of niacin in their diets are more likely to develop certain cancers--gastric, colon, oral, and oesophageal cancer-- but not necessarily skin cancer. One important finding is that niacin content in skin is inversely proportional to malignancy in people with skin cancer. In other words, the more niacin found in a person’s skin, the less likely it is that person will develop malignant skin cancer. The opposite is also true: the less niacin a person has in their skin, the more likely their skin cancer will be malignant. These results are based on observational studies; however, it is important to remember that correlation is not causation.
Animals with niacin deficiency have an increased risk of developing skin cancer. Conversely, laboratory tests indicate that niacin supplementation, in specific dosages, can block the development of skin cancer in mice. Mice were given various levels of niacin supplementation in their diets and then exposed to ultraviolet radiation, which causes skin cancer. Niacin reduced the risk of developing skin cancer substantially by blocking UV radiation's ability to damage DNA and suppress the immune system.
One of the key steps in the process by which UV radiation leads to skin cancer involves changes in the skin's immune system.
Ultraviolet radiation suppresses the immune system, which allows cancerous cells to multiply and thrive.
This effect appears to be greater in men than it is in women. In fact, men appear to be three times more sensitive to the immune-suppressing effects of UV radiation than women are. Interestingly, topical nicotinamide significantly reduced this immunosuppression, again suggesting that vitamin B3
may help prevent skin cancer.
Unfortunately, there is no data from clinical trials that helps shed light on whether niacin supplementation is truly preventative against skin cancer. People who have taken niacin for the treatment of high blood cholesterol have rates of cancer similar to those taking other treatments for high cholesterol. Those taking niacin did have lower levels of all-cause mortality (i.e. death from any cause), but this does not necessarily mean that they had lower cancer risk.
Since there is no clinical trial data to support the use of vitamin B3 in the prevention of cancer, it is impossible to say conclusively whether oral or topical vitamin B3 supplementation is better (or even if either is effective). Oral niacin supplementation appears to increase levels of niacin in the skin to the degree that it protects UV-induced immunosuppression. On the other hand, niacin apparently has to be present in the skin in order to have a preventative effect on the development of cancer. This fact seems to support topical vitamin B3 treatments.
It is important to remember that high doses of oral niacin can cause uncomfortable side effects such as flushing and stomach upset. In addition, oral niacin may also interact with other cholesterol-lowering medications.
With limited clinical trial data it is difficult to say with certainty whether vitamin B3 protects against various skin or other cancers.
Nevertheless, the discovery of the mechanism by which vitamin B3 potentially blocks oxidative DNA damage and protects against UV radiation-induced immunosuppression suggests that niacin may be more effective in treating non-melanoma skin cancers, such as squamous cell carcinoma and basal cell carcinoma, than in treating melanoma.
Skin exposure to UVA and UVB radiation is still the most important risk factor for both non-melanoma and melanoma skin cancers.
Although niacin deficiency is related to skin problems, including dermatitis which accompanies pellagra, and may also be connected to various forms of cancer, it is as yet unclear exactly how and why the relationship exists and whether it is a causal one.
Exposure to UV radiation appears to increase the risk of skin cancer for people with low niacin levels, and chemotherapy may play a role in depleting niacin in cancer patients. Non-melanoma skin cancers such as squamous cell carcinoma and basal cell carcinoma are caused by damage to DNA and disruption of the immune system from UV radiation.
Laboratory and observational clinical studies suggest that vitamin B3 (also called niacin, nicotinamide, and nicotinic acid) may help guard against UV radiation-induced immunosuppression. However, to date no clinical trials have directly examined the role of niacin supplementation in the treatment or prevention of non-melanoma or melanoma skin cancers.
Oral supplementation with vitamin B3 causes significant increases in skin levels of niacin, but oral supplementation with high doses of niacin also can cause unpleasant side effects and drug interactions.
More studies are needed to determine the precise nature of the connection between niacin levels and the development of skin and other cancers.
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