Could vitamin B-3 help to prevent melanoma?

In a new review, researchers claim that nicotinamide may have the potential to prevent melanoma - the deadliest form of skin cancer - and they say that it should be tested for this purpose in clinical trials.

Nicotinamide, also referred to as niacinamide, is a form of vitamin B-3, or niacin. It is present in a variety of foods, including milk, eggs, fish, green vegetables, and lean meats. It is also available as a dietary supplement.

Nicotinamide is already recognized as an effective cholesterol-lowering medication, and it is also used for the prevention and treatment of pellagra, which is a disease caused by niacin deficiency.

The new review - conducted by Prof. Gary Halliday, of the University of Sydney in Australia, and colleagues - suggests that nicotinamide could also help to prevent melanoma, particularly in people who are at high risk of the disease.

Prof. Halliday and his team recently reported their findings in the journal Photodermatology, Photoimmunology & Photomedicine.

Melanoma is a form of skin cancer that begins in melanocytes. These are skin cells that produce a pigment called melanin, which works to protect the deeper skin layers against the harmful effects of ultraviolet (UV) radiation.

According to the American Cancer Society, there will be 87,110 new cases of melanoma diagnosed in the United States this year, and around 9,730 people will die from the disease.

Exposure to UV radiation is considered a key risk factor for melanoma; it damages the DNA in skin cells. This DNA damage can cause the skin cells to grow out of control, which may lead to cancer.

Nicotinamide boosts skin DNA repair

While sunscreen is widely recommended for skin cancer prevention, Prof. Halliday and team say that the benefits of sunscreen for melanoma prevention are "inconclusive."

"These conflicting results may stem from insufficient application [...] and reapplication of sunscreen and increased motivation to sunbathe, as long as sunscreen is applied," write the authors.

However, the researchers say that there are a number of other agents that have shown promise for melanoma prevention - one of which is nicotinamide.

For their research, Prof. Halliday and colleagues reviewed numerous studies that have previously investigated the effects of nicotinamide against melanoma cancer cells. The results suggest that the vitamin may be an effective candidate for prevention, especially for patients at high risk of melanoma.

The team cites a wealth of research that reveals how nicotinamide can protect the skin against the harmful effects of UV radiation. For example, studies in human cell lines have shown that nicotinamide can boost DNA repair in response to UV exposure.

Research has also indicated that the vitamin might reduce immunosuppression and inflammation, both of which are known to contribute to cancer development.

"Nicotinamide replenishes cells' energy stores, which are depleted by UV exposure. This extra energy enables cells to repair any DNA damage more efficiently, and also helps to reduce the immune suppressive effects of sunlight on the skin," study co-author Prof. Diona Damian, also of the University of Sydney, told Medical News Today.

With this in mind, the team hypothesizes that nicotinamide could reduce the risk of melanoma.

Clinical trials warranted

In their review, Prof. Halliday and colleagues discuss the results of The Oral Nicotinamide To Reduce Actinic Cancer study, which was a phase III clinical trial of nicotinamide for the prevention of non-melanoma skin cancers (NMSCs).

The trial involved 386 participants, each of whom had been diagnosed with at least two non-melanoma skin cancers within the past 5 years.

Participants were randomized to one of two groups: one group took 500 milligrams of nicotinamide daily for 12 months, while the other group received a placebo.

Over the 12-month period, the development of new non-melanoma skin cancers was found to be 23 percent lower for subjects who took nicotinamide, compared with those who took a placebo.

While this trial was unable to investigate the effects of nicotinamide against melanoma - due to few cases of the disease among participants - Prof. Halliday and team say that the results suggest that it is worth conducting clinical trials to assess how the vitamin may fare against this deadly skin cancer.

"To assess melanoma incidence, the cohort would need to recruit individuals at high melanoma risk, such as those with a previous melanoma, [or] those with a genetic susceptibility to develop melanomas," the authors note.

"The study was also conducted over a 12-month period," they add, "and it is likely that a longer trial period, and a much larger study cohort, is necessary to adequately assess the incidence of melanomas, which are much less frequent than NMSCs."

In conclusion to their review, Prof. Halliday and team say:

"Based on current clinical evidence of the use of NAM [nicotinamide] in NMSC and early in vitro studies conducted with melanocytes and melanoma cells, randomized placebo-controlled trials are now warranted to determine the efficacy and safety of NAM for melanoma prevention in high-risk patients."

In the meantime, the researchers stress that nicotinamide should not be viewed as an alternative to current sun-protective behaviors.

"Nicotinamide should only be used as an adjunctive measure, in combination with sensible sun behavior, sunscreen, and sun-protective clothing, and only in people at particularly high risk of skin cancer," Prof. Damian told MNT.