Physicians’ Health Study 3-carotene supplementation

However, intervention trials investigating the effects of P-carotene and lycopene supplementation on CVD have not reported convincing results (Table 3.1.3). Among the seven studies reviewed herein, four primary prevention trials, namely the Multicenter Skin Cancer Prevention Study, the Beta Carotene and Retinol Efficacy Trial, the ATBC cancer prevention study, " and the Physicians Health Study have shown no association between a supplementation of P-carotene and risk of death from CVD or fatal and non-fatal MI. 

Cook, N.R., Lee, I.M., Manson, J.E., Buring, J.E., and Hennekens, C.H., Effects of beta-carotene supplementation on cancer incidence by baseline characteristics in the Physicians Health Study (United States), Cancer Causes Control, 11,617, 2000. 

Grodstein, F., Kang, J.H., Glynn, R.J., Cook, N. R. and Gaziano, J. M., 2007. A randomized trial of beta carotene supplementation and cognitive function in men the Physicians Health Study II. Archives of Internal Medicine 167(20), 2184-2190. 

A number of trials have attempted to investigate the effect of yS-carotene supplementation on nonmelanoma skin cancer, the most common forms of which are basal cell and squamous cell carcinomas (these types of cells are both found in the top layer of the skin). However, none have shown any significant effect on skin cancer prevention. For example, the Physicians Health Study found no effect after 12 years of yS-carotene supplementation on the development of a first nomnelanoma skin cancer. The Nambour Skin Cancer Prevention Trial of 1621 men and women followed for nearly 5 years (most of whom had no history of skin cancer at baseline) showed that those supplemented with 30 mg yd-car-otene did not experience any reduction in risk of basal cell or squamous cell carcinoma or the occurrence of solar keratoses (precancerous skin growths that are a strong determinant of squamous cell... 

Frieling, U.M. et al., A randomized, 12-year primary-prevention trial of beta carotene supplementation for nonmelanoma skin cancer in the physician s health study, Arch. Dermatol., 136, 179, 2000. 

ATBC trial found no reduction in the prevalence of cataracts with vitamin E, jS-carotene, or both among male smokers and the Health Physicians Study of more than 22000 men showed no benefit from 12 years of supplementation with, 3-carotene (50 mg on alternate days) on cataract incidence. In fact, current smokers at the beginning of this trial who received the supplement experienced an increased risk of cataract (by approximately 25%) compared to the placebo group. The Vitamin E, Cataract and Age-Related Maculopathy Trial also reported no effect of supplementation with vitamin E for 4 years (500IU/day) on the incidence or progression of cataracts or AMD. 

---