Use of vitamin supplements and risk of total cancer and cardiovascular disease among the Japanese general population: a population-based survey

Suboptimal Health, Dietary Supplementation, and Public Health Approaches to Regulatory Challenges in Dubai

Objectives: Presently, limited data are available on dietary supplements (DSs) and their associated effects on health status although the consumption of DS continues to expand. This study is aimed to explore the possible relationship between DSs consumption and suboptimal health status (SHS) in Dubai, United Arab Emirates (UAE). Methods: This study was a cross-sectional research held among a sample of citizens and residents in the Emirate of Dubai in the UAE using a well-structured, self-administered, anonymous survey. Frequency tables, odds ratios, and confidence intervals were generated during the data analysis using SPSS version 23. Results: A total of 618 participants were enrolled in this study and fully completed the questionnaire. In this study, 317 participants (51.3%) (95% CI: 47.3%-55.3%) reported the use of DS products. A significant association between DS consumption and suboptimal health status was detected (P < .001). DS consumers had a 1.5-fold increased odds of suboptimal health status when compared with non-DS consumers (95% CI 1.4-1.7). Conclusion: The findings of this study suggest a need to develop policies and programs that will help minimize the risk of possible adverse events that are associated with the utilization of DSs.

Effects of vitamin supplements on clinical cardiovascular outcomes: Time to move on! - A comprehensive review

BACKGROUND & AIMS

Vitamin supplementations have increasingly been advertised on media and reported to be widely used by the general public to improve cardiovascular health. Due to the COVID-19 pandemic, people have become more interested in ways to improve and maintain their health. Increased awareness of people on healthy lifestyle is translating into inquisition regarding dietary supplements.

AIM

First, focus on the most commonly used vitamin supplements and comprehensively review the evidence for and against recommending them to patients to improve and/or maintain cardiovascular health. Second, illustrate how the interest in studies shifted over time from Vitamin A, E, C, and B to Vitamin D and observational studies led to randomized controlled trials.

METHODS

A thorough PubMed search with the phrase: "Vitamin supplements and cardiovascular health" was performed. In the present review, focus was maintained on the evidence for the use of vitamin supplements in the prevention of major cardiovascular events and/or the maintenance of cardiovascular health by comprehensively reviewing all previous studies indexed in PubMed. Studies with clinical 'hard' end-points were included only.

RESULTS

A total of 87 studies met the inclusion criteria and were reviewed in the present article. High-quality evidence suggesting benefits for the use of vitamin supplements to maintain or improve cardiovascular health in people is minimal to non-existent.

CONCLUSIONS

Vitamin supplementation does not improve clinical cardiovascular outcomes in general population. Counseling on the importance of maintaining a healthy lifestyle with adequate and nutritious food intake seems more appropriate to improve and maintain cardiovascular health.

Efficacy of Multivitamin/mineral Supplementation to Reduce Chronic Disease Risk: A Critical Review of the Evidence from Observational Studies and Randomized Controlled Trials

We reviewed recent scientific evidence regarding the effects of multivitamin/mineral (MVM) supplements on risk of chronic diseases, including cancer, cardiovascular disease, and age-related eye diseases. Data from randomized controlled trials (RCTs) and observational, prospective cohort studies were examined. The majority of scientific studies investigating the use of MVM supplements in chronic disease risk reduction reported no significant effect. However, the largest and longest RCT of MVM supplements conducted to date, the Physicians' Health Study II (PHS II), found a modest and significant reduction in total and epithelial cancer incidence in male physicians, consistent with the Supplémentation en Vitamines et Minéraux Antioxydants (SU.VI.MAX) trial. In addition, PHS II found a modest and significant reduction in the incidence of nuclear cataract, in agreement with several other RCTs and observational, prospective cohort studies. The effects of MVM use on other subtypes of cataract and age-related macular degeneration remain unclear. Neither RCTs nor prospective cohort studies are without their limitations. The placebo-controlled trial design of RCTs may be inadequate for nutrient interventions, and residual confounding, measurement error, and the possibility of reverse causality are inherent to any observational study. National surveys show that micronutrient inadequacies are widespread in the US and that dietary supplements, of which MVMs are the most common type, help fulfill micronutrient requirements in adults and children.

High folic acid intake reduces natural killer cell cytotoxicity in aged mice

Presence of unmetabolized folic acid in plasma, which is indicative of folic acid intake beyond the metabolic capacity of the body, is associated with reduced natural killer (NK) cell cytotoxicity in postmenopausal women ≥50years. NK cells are cytotoxic lymphocytes that are part of the innate immune system critical for surveillance and defense against virus-infected and cancer cells. We determined if a high folic acid diet can result in reduced NK cell cytotoxicity in an aged mouse model. Female C57BL/6 mice (16-month-old) were fed an AIN-93M diet with the recommended daily allowance (1× RDA, control) or 20× RDA (high) folic acid for 3months. NK cytotoxicity was lower in splenocytes from mice fed a high folic acid diet when compared to mice on control diet (P<.04). The lower NK cell cytotoxicity in high folic acid fed mice could be due to their lower mature cytotoxic/naïve NK cell ratio (P=.03) when compared to the control mice. Splenocytes from mice on high folic acid diet produced less interleukin (IL)-10 when stimulated with lipopolysaccharide (P<.05). The difference in NK cell cytotoxicity between dietary groups was abolished when the splenocytes were supplemented with exogenous IL-10 prior to assessment of the NK cytotoxicity, suggesting that the reduced NK cell cytotoxicity of the high folic acid group was at least partially due to reduced IL-10 production. This study demonstrates a causal relationship between high folic acid intake and reduced NK cell cytotoxicity and provides some insights into the potential mechanisms behind this relationship.

[A survey of self-medication practices and related factors in the general population: the Ohasama study]

Encouraging self-medication is expected to reduce healthcare costs. To assess the current situation of self-medication practices in the general population, we conducted a questionnaire survey regarding the use of over-the-counter (OTC) medications or dietary supplements in 1008 participants (37% men; mean age, 64±13 years) from Ohasama, a rural Japanese community. A total of 519 (52%) participants used OTC medications or dietary supplements, with common cold medication (36%) and supplements (28%) such as shark cartilage products representing the most common choices. Stepwise logistic regression showed female gender, a higher frequency of visits from a household medicine kit distributor, dyslipidemia, and lower home systolic blood pressure levels as predictors for the use of such materials (chi-square values: 25.3, 12.6, 7.0, and 4.6, respectively; all p<0.03). Stratifying the participants according to the use of antihypertensive treatment showed a negative association between systolic blood pressure and the use of OTC medications or supplements only in participants being treated for hypertension. These results suggest that although the adoption rate of self-medication in Japan can be increased in rural areas, it may remain lower in urban areas. The present study clarifies the factors associated with the use of OTC medications or dietary supplements and indicates that appropriate self-medication practices might improve the control of hypertension, particularly in patients undergoing antihypertensive treatment.

Concomitant use of dietary supplements and medicines in patients due to miscommunication with physicians in Japan

We previously reported that some patients used dietary supplements with their medication without consulting with physicians. Dietary supplements and medicines may interact with each other when used concomitantly, resulting in health problems. An Internet survey was conducted on 2109 people who concomitantly took dietary supplements and medicines in order to address dietary supplement usage in people who regularly take medicines in Japan. A total of 1508 patients (two admitted patients and 1506 ambulatory patients) and 601 non-patients, who were not consulting with physicians, participated in this study. Purpose for dietary supplement use was different among ages. Dietary supplements were used to treat diseases in 4.0% of non-patients and 11.9% of patients, while 10.8% of patients used dietary supplements to treat the same diseases as their medication. However, 70.3% of patients did not declare dietary supplement use to their physicians or pharmacists because they considered the concomitant use of dietary supplements and medicines to be safe. A total of 8.4% of all subjects realized the potential for adverse effects associated with dietary supplements. The incidence of adverse events was higher in patients who used dietary supplements to treat their disease. Communication between patients and physicians is important for avoiding the adverse effects associated with the concomitant use of dietary supplements and medicines.

Distribution of vitamin E intake among Japanese dietary supplement and fortified food users: a secondary analysis from the National Health and Nutrition Survey, 2003-2009

This study was performed to: (1) assess the prevalence of dietary supplement and fortified food use, (2) examine the differences in vitamin E intake with and without dietary supplementation and/or fortified food use, and (3) determine whether some individuals consume vitamin E above the tolerable upper intake level (UL). Data were obtained from 64,624 individuals (age, ≥1 y; 47.4% males) who completed a 1-d household dietary assessment that was part of the National Health and Nutrition Survey conducted in Japan, 2003-2009. The survey also obtained information on the brand or generic name of each dietary supplement or fortified food reported, including their ingredients, through dietary assessment. The prevalence of a potential risk of excess was estimated by the proportion of persons above the age-/sex-specific ULs provided by the Dietary Reference Intakes for Japanese 2010. Supplement use was reported by 5.8% of men and 7.7% of women, whereas fortified food consumption was reported by only 2.9% of men and 3.6% of women. Use of dietary supplements was most common among older women, whereas use of fortified foods was most common among younger women. Both dietary supplement and fortified food use accounted for maximum vitamin E intake; however, the use of dietary supplements and fortified foods had little effect on the median and 95th percentile intake values. None of the subjects consumed nutrients above the UL. The collected data confirm that the use of both dietary supplements and fortified foods contributes a small amount to nutrient intake in Japanese subjects.

General supplement use, subsequent use and cancer risk in the UK Women's Cohort Study

BACKGROUND/OBJECTIVES

To determine whether general dietary supplement use is associated with cancer risk in UK women and to estimate risks related to use at one and two recording points.

SUBJECTS/METHODS

Cox's proportional hazard regression models were used to estimate cancer risks for 32 665 middle-aged women in the UK Women's Cohort Study relating to any current supplement use recorded in a baseline questionnaire. During a median follow-up of 15 years, there were 3936 registered cancer incidences, including 1344 breast, 429 smoking-related and 362 colorectal cancers. Cancer risks for 12 948 of these women, who also completed questionnaires on average 4.4 years later, were estimated in relation to any supplement use at both time points (1527 cancers, including 561 breast, 131 smoking-related and 141 colorectal cancers). Adjustments were made for baseline confounders.

RESULTS

Total smoking-related cancers were associated with baseline supplement use (hazard ratio (HR)=1.41, 95% confidence interval (CI): 1.10, 1.81) compared with non-use, but not associated with use at both recording points (HR=1.29; 95% CI: 0.78, 2.13) compared with use at neither. There was no evidence of the associations between total, colorectal or breast cancers and baseline supplement use, or use at both recording points. In sub-analyses, no significant associations with breast cancer were found for premenopausal or postmenopausal baseline users, or similarly for use at both points (HR=1.35, 95% CI: 0.91, 2.01; and HR=0.93, 95% CI: 0.68, 1.26, respectively).

CONCLUSIONS

There was evidence that general supplement use was associated with increased smoking-related cancer risk, but there was no evidence of associations with total, colorectal and breast cancers.

High plasma folate is negatively associated with leukocyte telomere length in Framingham Offspring cohort

PURPOSE

Shortening of telomeres, the protective structures at the ends of eukaryotic chromosomes, is associated with age-related pathologies. Telomere length is influenced by DNA integrity and DNA and histone methylation. Folate plays a role in providing precursors for nucleotides and methyl groups for methylation reactions and has the potential to influence telomere length.

METHOD

We determined the association between leukocyte telomere length and long-term plasma folate status (mean of 4 years) in Framingham Offspring Study (n = 1,044, females = 52.1 %, mean age 59 years) using data from samples collected before and after folic acid fortification. Leukocyte telomere length was determined by Southern analysis and fasting plasma folate concentration using microbiological assay.

RESULTS

There was no significant positive association between long-term plasma folate and leukocyte telomere length among the Framingham Offspring Study participants perhaps due to their adequate folate status. While the leukocyte telomere length in the second quintile of plasma folate was longer than that in the first quintile, the difference was not statistically significant. The leukocyte telomere length of the individuals in the fifth quintile of plasma folate was shorter than that of those in the second quintile by 180 bp (P < 0.01). There was a linear decrease in leukocyte telomere length with higher plasma folate concentrations in the upper four quintiles of plasma folate (P for trend = 0.001). Multivitamin use was associated with shorter telomeres in this cohort (P = 0.015).

CONCLUSIONS

High plasma folate status possibly resulting from high folic acid intake may interfere with the role of folate in maintaining telomere integrity.