Query: Are Multivitamins Good For You?

Relevant passages:
MULTIVITAMIN USE AND RISK OF CANCER AND CARDIOVASCULAR DISEASE IN THE WOMEN’S HEALTH INITIATIVE COHORTS <=SEP=> Context Millions of postmenopausal women use multivitamins, often believing that supplements prevent chronic diseases such as cancer and cardiovascular disease. Objective To examine associations between multivitamin use and risk of cancer, cardiovascular disease and mortality in postmenopausal women. Design, Setting and Participants 161,808 participants from the Women’s Health Initiative Clinical Trials (n=68,132 in three overlapping trials of hormone therapy, dietary modification and calcium-vitamin D) or Observational Study (n=93,676). Detailed data were collected on multivitamin use at baseline and follow-up time points. Study enrollment occurred between 1993–1998; women were followed for a median of 8.0 years in the clinical trials and 7.9 years in the observational study. Disease endpoints were collected through 2005. Outcome Measures Cancers of the breast (invasive), colon/rectum, endometrium, kidney, bladder, stomach, ovary and lung; cardiovascular disease (myocardial infarction, stroke, venous thrombosis); and total mortality. Results 41.5% of participants used multivitamins. After a median of 8.0 years of follow-up in the CT and 7.9 years in the OS, 9,619 cases of breast, colorectal, endometrium, kidney, bladder, stomach lung or ovary cancer; 8,751 CVD events and 9,865 deaths were reported. Multivariate-adjusted analyses revealed no association of multivitamins with risk of cancer (breast HR=0.98, 95%CI 0.91–1.05; colorectal HR = 0.99, 95% CI 0.88–1.11; endometrial HR = 1.05, 95%CI= 0.90–1.21; lung HR = 1.0, 95% CI=0.88–1.13; ovary HR = 1.07, 95%CI =0.88–1.29); CVD (MI HR= 0.96, 95%CI= 0.89–1.03; stroke HR = 0.99, 95%CI =0.91–1.07; VT HR = 1.05, 95%CI =0.85–1.29); or mortality (HR = 1.02, 95% CI=0.97–1.07). Conclusion After a median follow-up of 8.0 and 7.9 years in the CT and OS, respectively, the WHI cohorts provide convincing evidence that multivitamin use has little or no influence on the risk of common cancers, cardiovascular disease or total mortality in postmenopausal women. Clinical Trial Registration clinicaltrials.gov identifier: NCT00000611

Vomiting from multivitamins: a potential drug interaction. <=SEP=> A commercial weight loss program with a client base composed of >95% women experienced sporadic complaints of nausea and vomiting after changing its multivitamin supplier. This retrospective and observational study was designed to determine if related adverse event reports were significant, and to investigate potential mechanism for their occurrence in this group of subjects, many of whom were concurrently receiving oral contraceptives or hormone replacement therapy. Incidence of nausea, vomiting, rash, and total complaints in the 3 months following the change of the multivitamin formulation was compared with the same complaints in the 3 months before the change. In the 3 months following the multivitamin change, there were 166 complaints of nausea and vomiting, 9 complaints of rash and 194 total complaints from a group of 88,468 patients. In the 3 months before the change in the multivitamin, there had been 2 complaints of nausea and vomiting, no complaints of rash, and 11 total complaints from 88,252 patients. The difference detected by a chi-squared test was significant for all events studied; nausea and vomiting (P < 0.0001), rash (P < 0.02), and total complaints (P < 0.0001). The altered multivitamins contained added citrus bioflavanoids not included in the original formula. Citrus bioflavanoids decrease the clearance of exogenous estrogens by inhibiting cytochrome P450 enzyme systems. Elevated estrogen levels could account for the increased incidence of nausea and vomiting. This experience demonstrates that adding dietary herbal supplements to multivitamins may be associated with adverse interactions with prescription drugs.

Multivitamins in the Prevention of Cancer in Men: The Physicians’ Health Study II Randomized Controlled Trial <=SEP=> Context Multivitamin preparations are the most common dietary supplement, taken by at least one-third of all US adults. Limited observational studies have not provided evidence regarding associations of multivitamin use with total and site-specific cancer incidence or mortality. Objective To determine whether long-term multivitamin supplementation decreases the risk of total and site-specific cancer events among men. Design The Physicians’ Health Study II is a randomized, double-blind, placebo-controlled trial of a common multivitamin that began in 1997 with treatment and follow-up through June 1, 2011. Setting and Participants A total of 14,641 male U.S. physicians initially aged ≥50 years (mean [± SD] age; 64.3 [± 9.2] years), including 1,312 men with a history of cancer at randomization, were enrolled. Intervention Daily multivitamin, as Centrum Silver. Main Outcome Measures A primary outcome was total cancer (excluding non-melanoma skin cancer), with prostate, colorectal, and other site-specific cancers among secondary endpoints included in this report. Results During a median (interquartile range) follow-up of 11.2 (10.7 to 13.3) years, there were 2,669 men with confirmed cancer, including 1,373 cases of prostate cancer and 210 cases of colorectal cancer. Compared with placebo, men taking a daily multivitamin had a statistically significant reduction in the incidence of total cancer (active and placebo multivitamin groups, 17.0 and 18.3 events, respectively, per 1,000 person-years; hazard ratio [HR], 0.92; 95% confidence interval [CI], 0.86–0.998; P=0.044). There was no significant effect of a daily multivitamin on prostate cancer (HR, 0.98; 95% CI, 0.88–1.09; P=0.76), colorectal cancer (HR, 0.89; 95% CI, 0.68–1.17; P=0.39), or other site-specific cancers There was a lower risk of cancer mortality that did not reach statistical significance (HR, 0.88; 95% CI, 0.77–1.01; P=0.07). Daily multivitamin use was associated with a reduction in total cancer among 1,312 men with a baseline history of cancer (HR, 0.73; 95% CI, 0.56–0.96; P=0.022), but this did not differ significantly from that among 13,329 men initially free of cancer (HR, 0.94; 95% CI, 0.87–1.02; P=0.15) (P, interaction = 0.07). Conclusions In this large prevention trial of male physicians, daily multivitamin supplementation modestly but significantly reduced the risk of total cancer.

Who uses multivitamins? A cross-sectional study in the Physicians' Health Study. <=SEP=> PURPOSE: The aim of this study was to examine the prevalence of self-reported multivitamin use in the Physicians' Health Study (PHS) cohort and its association with various lifestyle, clinical, and dietary factors to improve our understanding of who tends to use multivitamins. METHODS: Among 18,040 middle-aged and older men, information on lifestyle and clinical factors was collected from a baseline enrollment questionnaire, and supplement use and dietary factors were assessed through a food-frequency questionnaire. Four categories of multivitamin use were considered: (1) no supplement use, (2) use of multivitamins only, (3) use of multivitamins with other individual vitamin/mineral supplements, and (4) use of other supplements only. We used logistic regression to calculate multivariate odds ratios and 95% confidence intervals of taking multivitamin supplements for various lifestyle, clinical and dietary factors. RESULTS: Overall, 36% of men reported current multivitamin use. Men who were older, current smokers, and currently using aspirin were 143, 43, and 74% more likely to use multivitamins only. Men having a history of hypercholesterolemia were 16% more likely to use multivitamins only. A 14, 24, and 26% greater likelihood of using multivitamins was also observed among men consuming more fruits and vegetables, whole grains, and tea, respectively. Similar associations were observed for the likelihood of using multivitamins with other supplements; however, men with higher physical activity, history of cancer, hypertension, higher consumption of nuts, and lower consumption of red meat and coffee were also more likely to use multivitamins with other supplements (all P < 0.05). CONCLUSION: Self-reported multivitamin use associated with lifestyle, clinical and dietary factors may be an indicator of healthy behaviors. These results provide important information for the interpretation of the recent findings from the PHS II trial and consideration of results from observational studies of multivitamin use and chronic disease.

Vitamin and Mineral Use and Risk of Prostate Cancer: The Case-Control Surveillance Study <=SEP=> Background Many studies have evaluated the association between vitamin and mineral supplement use and the risk of prostate cancer, with inconclusive results. Methods The authors examined the relation of use of multivitamins as well as several single vitamin and mineral supplements to the risk of prostate cancer risk among 1,706 prostate cancer cases and 2,404 matched controls using data from the hospital-based Case-Control Surveillance Study conducted in the United States. Odds ratios (OR) and 95% confidence intervals (CI) for risk of prostate cancer were estimated using conditional logistic regression model. Results For use of multivitamins that did not contain zinc the multivariable odds ratios of prostate cancer were 0.6 for 1–4 years, 0.8 for 5–9 years, and 1.2 for 10 years of more, respectively (p for trend =0.70). Men who used zinc for 10 years or more, either in a multivitamin or as a supplement, had an approximately 2-fold (OR=1.9, 95% CI: 1.0, 3.6) increased risk of prostate cancer. Vitamin E, beta-carotene, folate, and selenium use were not significantly associated with increased risk of prostate cancer. Conclusion The finding that long-term zinc intake from multivitamins or single supplements was associated with a doubling in risk of prostate cancer adds to the growing evidence for an unfavorable effect of zinc on prostate cancer carcinogenesis.

Intake of Fiber and Nuts during Adolescence and Incidence of Proliferative Benign Breast Disease <=SEP=> Objective We examined the association between adolescent fiber intake and proliferative BBD, a marker of increased breast cancer risk, in the Nurses’ Health Study II. Methods Among 29,480 women who completed a high school diet questionnaire in 1998, 682 proliferative BBD cases were identified and confirmed by centralized pathology review between 1991 and 2001. Multivariate-adjusted Cox proportional hazards regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). Results Women in the highest quintile of adolescent fiber intake had a 25% lower risk of proliferative BBD (multivariate HR (95% CI): 0.75 (0.59, 0.96), p-trend = 0.01) than women in the lowest quintile. High school intake of nuts and apples was also related to significantly reduced BBD risk. Women consuming ≥2 servings of nuts/week had a 36% lower risk (multivariate HR (95% CI): 0.64 (0.48, 0.85), p-trend < 0.01) than women consuming <1 serving/month. Results were essentially the same when the analysis was restricted to prospective cases (n = 142) diagnosed after return of the high school diet questionnaire. Conclusions These findings support the hypothesis that dietary intake of fiber and nuts during adolescence influence subsequent risk of breast disease and may suggest a viable means for breast cancer prevention.

Multivitamin Use and the Risk of Mortality and Cancer Incidence <=SEP=> Although multivitamin/mineral supplements are commonly used in the United States, the efficacy of these supplements in preventing chronic disease or premature death is unclear. To assess the relation of multivitamin use with mortality and cancer, the authors prospectively examined these associations among 182,099 participants enrolled in the Multiethnic Cohort Study between 1993 and 1996 in Hawaii and California. During an average 11 years of follow-up, 28,851 deaths were identified. In Cox proportional hazards models controlling for tobacco use and other potential confounders, no associations were found between multivitamin use and mortality from all causes (for users vs. nonusers: hazard ratio = 1.07, 95% confidence interval: 0.96, 1.19 for men; hazard ratio = 0.96, 95% confidence interval: 0.85, 1.09 for women), cardiovascular diseases, or cancer. The findings did not vary across subgroups by ethnicity, age, body mass index, preexisting illness, single vitamin/mineral supplement use, hormone replacement therapy use, and smoking status. There also was no evidence indicating that multivitamin use was associated with risk of cancer, overall or at major sites, such as lung, colorectum, prostate, and breast. In conclusion, there was no clear decrease or increase in mortality from all causes, cardiovascular disease, or cancer and in morbidity from overall or major cancers among multivitamin supplement users.