Possible Interaction: Beta Carotene and Retinyl Palmitate

“OBJECTIVE The Carotene and Retinol Efficacy Lung Cancer Chemoprevention Trial (CARET) ended prematurely due … unexpected findings that the active treatment group on the combination of 30 mg beta-carotene and 25,… IU retinyl palmitate had a 46% increased lung cancer mortality and … 26% increased cardiovascular mortality compared with placebo.”

“OBJECTIVE The Carotene and Retinol Efficacy Lung Cancer Chemoprevention Trial (CARET) ended prematurely due … unexpected findings that the active treatment group on the combination of 30 mg beta-carotene and 25,… IU retinyl palmitate had a 46% increased lung cancer mortality and … 26% increased cardiovascular mortality compared with placebo.”

“At present, 13cRA, BC plus RP , and RP alone cannot be recommended for chemoprevention, and new, better agents are needed in this setting.”

“The clinical response rate of RP alone (20.0%) was significantly lower than that of BC plus RP (42.9%; P = .03).”

“The CARET study, conducted in 18,000 high-risk smokers in the US, found that a combination of beta-carotene and retinyl palmitate resulted in a 28% increase in the incidence of lung cancer.”

“ BC deposition was decreased both in the testicles and in the follicles, indicating a competition between RP and BC for the storage capacity of organs.”

“We conclude that retinoic acid spares endogenous retinol and that beta-carotene greatly enhances liver retinyl palmitate levels.”

“Although the photolysis of retinol and retinyl palmitate was also inhibited by 190 mumol/L beta-carotene , alpha-tocopherol and ascorbic acid did not exert inhibiting effects.”