Researchers have found that excess levels of niacin (the form of vitamin B3 found in foods such as chicken and nuts) lead to breakdown products called 2PY and 4PY. Elevated levels of either of these compounds were associated with a higher risk of cardiovascular events, such as heart attacks or strokes. 4PY can cause inflammation and the development of plaques on blood vessels, which leads to cardiovascular complications.
The study did not specifically address several issues that may be relevant to people taking nicotinamide for skin cancer prevention:
- The study did not address the effect of vitamin B3 taken in the form of nicotinamide.
- It’s not clear what dosage of nicotinamide is required to lead to the production of 4PY and 2PY.
- The study looked at blood samples from cardiac patients and may not be relevant to skin cancer patients without a history of cardiovascular disease or risk factors
Skin cancer doctors are not yet sure of the implications for their patients, but because of the potential for cardiovascular risk in at least some of them, it will be important to be cautious.
It might be appropriate to discontinue vitamin B3 supplementation in people at high risk of heart attack and stroke and only to take vitamin B3 if there is a a high risk of serious non-melanoma skin cancers.
Each case is different, and we recommend that people taking or considering taking nicotinamide should discuss the risks and benefits with a skin cancer doctor.