So before you check out this info – let me just say the physicians are losing money – stop taking vitamins so they can give you more medication that kills hundreds of thousands of people each year.
Vitamins don’t kill people – they might not be that effective – but Dr. OZ swears by them and he is one of the best Doctors of our time. A genius. Check out his advice for vitamins!
Here is the post from the study.
This article was published online first at www.annals.org on 12 November 2013.
Background: Vitamin and mineral supplements are commonly used to prevent chronic diseases.
Purpose: To systematically review evidence for the benefit and harms of vitamin and mineral supplements in community-dwelling, nutrient-sufficient adults for the primary prevention of cardiovascular disease (CVD) and cancer.
Data Sources: MEDLINE, Embase, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and Database of Abstracts of Reviews of Effects were searched from January 2005 to 29 January 2013, with manual searches of reference lists and gray literature.
Study Selection: Two investigators independently selected and reviewed fair- and good-quality trials for benefit and fair- and good-quality trials and observational studies for harms.
Data Extraction: Dual quality assessments and data abstraction.
Data Synthesis: Two large trials (n = 27 658) reported lower cancer incidence in men taking a multivitamin for more than 10 years (pooled unadjusted relative risk, 0.93 [95% CI, 0.87 to 0.99]). The study that included women showed no effect in that group. High-quality studies (k = 24; n = 324 653) of single and paired nutrients (such as vitamins A, C, or D; folic acid; selenium; or calcium) were scant and heterogeneous and showed no clear evidence of benefit or harm. Neither vitamin E nor β-carotene prevented CVD or cancer, and β-carotene increased lung cancer risk in smokers.
Limitations: The analysis included only primary prevention studies in adults without known nutritional deficiencies. Studies were conducted in older individuals and included various supplements and doses under the set upper tolerable limits. Duration of most studies was less than 10 years.
Conclusion: Limited evidence supports any benefit from vitamin and mineral supplementation for the prevention of cancer or CVD. Two trials found a small, borderline-significant benefit from multivitamin supplements on cancer in men only and no effect on CVD.
Primary Funding Source: Agency for Healthcare Research and Quality.
Vitamins and minerals are commonly used as dietary supplements to promote health and prevent chronic diseases (1
). In the National Health and Nutrition Examination Survey III (1988–1994), nearly half of the U.S. population reported using a dietary supplement. A “multivitamin” was the most frequently used supplement (2
). Americans spend an estimated $11.8 billion each year on vitamin and mineral supplements (3
Cardiovascular disease (CVD) and cancer are the leading causes of illness and death in the United States (4). Cancer and CVD have several shared risk factors, including inflammation, oxidative stress, and methionine metabolism. The rationale for using these supplements is supported by many in vitro and animal studies showing that they protect against these damaging cellular mechanisms.
In 2003, the U.S. Preventive Services Task Force (USPSTF) concluded that there was insufficient evidence to recommend for or against the use of vitamins A, C, and E; multivitamins with folic acid; or antioxidant combinations for the prevention of CVD or cancer (5). The USPSTF recommended against the use of β-carotene supplements, either alone or in combination, because they found good-quality evidence that they not only carried no benefit but in fact caused harm among adults at an increased risk for lung cancer. To help the USPSTF update its recommendation, we identified and reviewed additional evidence on the benefits and harms of vitamin and mineral supplementation to prevent CVD and cancer in the general adult population.
Appendix Table 2. Summary of Evidence of Included Studies
We found consistent null results for CVD incidence and cancer incidence across 6 trials of β-carotene (Figures 1 and 3) (24–29). We found a probable increase in lung cancer incidence in high-risk subgroups (smokers and asbestos workers). We found 5 trials for vitamin E supplementation that showed no effec
Six trials evaluated the effects of vitamin D and calcium supplementation on CVD and cancer incidence when used alone or in combination. Four of these trials provided data on calcium supplementation without vitamin D (40, 43, 45–46) and reported no statistically significant effect on CVD or cancer incidence or on all-cause mortality (Figures 1, 2, and 3). Although the overall cancer rate reported for calcium supplementation was lower than the rate in the placebo group in 2 trials (43, 46), the opposite was observed in another trial (40); neither difference was statistically significant (Figure 3). Vitamin D plus calcium supplementation was specifically studied in 2 trials (43–44), 1 of which examined CVD incidence and found no effect (4
4). Both of these trials reported cancer outcomes, and while the smaller trial found a statistically significant decrease in overall cancer incidence over 4 years (43), the larger trial did not (44). The pooled unadjusted relative risk was 0.98 (CI, 0.91 to 1.04). Another trial examined vitamin D and calcium supplementation under a 2 × 2 factorial design and also found no main effect for either supplement (40).
We found little consistent evidence of harm across studies. Although vitamin A use in 1 trial was associated with increased risk for lung cancer, it was combined with β-carotene (29). Two cohort studies also implicated vitamin A use for increased risk for hip fracture (23, 38), although the total fracture rate was not higher in the study that reported this outcome (38). One study assessed folic acid supplementation in patients with prior colorectal adenomas and found that folic acid supplementation was associated with an increase in prostate cancer incidence.
In conclusion, we found no evidence of an effect of nutritional doses of vitamins or minerals on CVD, cancer, or mortality in healthy individuals without known nutritional deficiencies for most supplements we examined. In most cases data are insufficient to draw any conclusion, although for vitamin E and β-carotene a lack of benefit is consistent across several trials. We identified 2 multivitamin trials that both found lower overall cancer incidence in men (19
). Both trials were methodologically sound, but the lack of an effect for women (albeit in 1 trial), the borderline significance in men in both trials, and the lack of any effect on CVD in either study makes it difficult to conclude that multivitamin supplementation is beneficial.