Is there a metabolic basis for dietary supplementation?

Aging under Pressure: The Roles of Reactive Oxygen and Nitrogen Species (RONS) Production and Aging Skeletal Muscle in Endothelial Function and Hypertension-From Biological Processes to Potential Interventions

The proportion of adults living with hypertension increases significantly with advancing age. It is therefore important to consider how health and vitality can be maintained by the aging population until end of life. A primary risk factor for the progression of cardiovascular diseases (CVD) is hypertension, so exploring the factors and processes central to this burden of disease is essential for healthy aging. A loss of skeletal muscle quantity and quality is characteristic in normal aging, with a reduction of vasodilatory capacity caused by endothelial dysfunction, and subsequent increase in peripheral resistance and risk for hypertension. Reactive Oxygen and Nitrogen Species (RONS) encompass the reactive derivatives of NO and superoxide, which are continuously generated in contracting skeletal muscle and are essential mediators for cellular metabolism. They act together as intra and intercellular messengers, gene expression regulators, and induce programmed cell death. In excessive amounts RONS can inflict damage to endothelial and skeletal muscle cells, alter signaling pathways or prematurely promote stress responses and potentially speed up the aging process. The age-related increase in RONS by skeletal muscle and endothelial mitochondria leads to impaired production of NO, resulting in vascular changes and endothelial dysfunction. Changes in vascular morphology is an early occurrence in the etiology of CVDs and, while this is also a normal characteristic of aging, whether it is a cause or a consequence of aging in hypertension remains unclear. This review serves to focus on the roles and mechanisms of biological processes central to hypertension and CVD, with a specific focus on the effects of aging muscle and RONS production, as well as the influence of established and more novel interventions to mediate the increasing risk for hypertension and CVD and improve health outcomes as we age.

Nutritional Supplement and Functional Food Use Among Medical Students in India

This study was conducted to assess the pattern of use of nutritional supplements (NSs) and functional foods (FFs), reasons for their use, factors influencing their use, and perception toward their use among medical students. Data were collected from 400 randomly chosen participants using a self-administered semistructured questionnaire. The most common source of information on these substances was from medical professionals (n = 140 [35%]). Multivitamins were consumed by 48 (45.3%) participants. Most common reasons stated for the use of supplements were for good health (n = 39 [36.8%]), doctor's prescription (n = 36 [34%]), and to balance a poor diet (n = 34 [32.1%]). Sixty-six (62.3%) users used NSs on a daily or more than once daily basis. In 17.9% of the users, supplements were not recommended by a doctor or a dietician. The use of NSs was significantly more among females (p < .001), participants who exercised regularly (p < .001), participants who habitually skipped breakfast (p = 0.04), those with a family history of use of these products (p < .001), and those with "poor to fair" self-rated health (p = .017). Use of FFs was associated with family history of use (p < .001) and intensity of exercise (p = .039). Participants who significantly used multiple NSs in this study were those who were vegetarians (p = .044) and those with "poor to fair" self-rated health (p = .047). Participants who used multiple FFs were female (p < .001). Only 18 (16.9%) users felt that regular use of NSs results in side effects. In multivariate analysis, family history of NS use was found to influence its usage among participants (p < 0.001). It is a matter of concern that there is lack of knowledge on NSs and FFs among medical students. Therefore, they need to learn more about the indications and the safety of prescription of these products.

A cross-sectional survey on dietary supplements consumption among Italian teen-agers

Introduction

In the last decades, dietary supplements consumption has increased in the Western world for all age groups. The long-term potentially dangerous effects related to an indiscriminate consumption of dietary supplements are still unknown and are becoming a matter of public health concern. Therefore, the aims of the present study were: to explore the contribution of dietary supplements to micronutrient daily intake, and to evaluate awareness and knowledge about dietary supplements.

Methods

Participants (age ranging from 14 to 18 years) were recruited among students attending 8 high schools in the province of Frosinone (Italy). An anonymous questionnaire, composed of 12 multiple-choice items, was administered to all the participants. T-test and the analysis of variance (ANOVA) were performed to describe differences between means of the groups, while the chi-square test was used to compare observed and expected frequencies. The logistic regression model, aimed at identifying the characteristics of potential consumers of dietary supplements,

Results

A total of 686 teenagers (288 males and 398 females, average age: 17,89±0,91 years) participated in the study. The 83,6% of participants affirmed to be aware of dietary supplements. 239 participants consumed dietary supplements: 118 males and 121 females. 49,1% of females consumed dietary supplements less than twice a week, whereas 43,6% of males consumed dietary supplements from 2 to 5 times per week. Statistically significant differences emerged between the genders with respect to the source of information regarding dietary supplements, the perceived indications for their use, and the choice of the store/place to purchase them.

Discussion

Findings in the present study provide insight into the consumption of dietary supplements among young Italians, highlighting the need to foster further awareness among adolescents about the correct use of dietary supplements, especially in terms of indications and contraindications.

Continuing education module-maternal calcium intake and metabolism during pregnancy and lactation

Calcium is an essential nutrient during pregnancy and lactation. Calcium contributes to bone development in the fetus and neonate and is considered a critical nutrient. Physiological changes in calcium metabolism occur during pregnancy and lactation. Some women may lose some of their bone density during pregnancy and/or lactation, and then regain it after the cessation of lactation. Implications for childbirth educators include content regarding the topic of calcium in their classes.

Micronutrient requirements of physically active women: what can we learn from iron?

The health benefits of physical activity are well established and there is increasing recognition of the importance of fitness as a key modulator of chronic disease. The impact of physical activity on micronutrient requirements is a topic of tremendous interest to the lay public, but the interest is in sharp contrast to data from well-designed studies. Research in this area is poorly controlled for nutritional status of the participants, standardized exercise protocols, markers and cutoff points for measurement of micronutrient status, and variability in subject characteristics. The micronutrient status of women in the general population is of concern, but it is not clear that physical activity increases the requirement of most micronutrients. When dietary intake is adequate, the results of most studies are either equivocal or show no benefit to performance of supplementation. In the few instances where exercise does appear to increase an individual's requirement, the increase can be obtained within the additional calories required for energy balance. In the absence of consistent data, micronutrient supplementation is often indiscriminate without regard to nutrient status. Because iron is such a key nutrient for physical activity, and the status in women is often compromised, it serves as a useful example of how current research limits the ability to make recommendations regarding the impact of exercise on micronutrients requirements in women. With the recent recognition of the importance of physical activity to the prevention and treatment of chronic diseases through the life span, more attention should be focused on the impact of exercise on micronutrient requirements, especially in the context of weight loss regimens.

The validity of questionnaire-based micronutrient intake estimates is increased by including dietary supplement use in Swedish men

Although many validation studies of FFQ have been reported, only a few addressed the effect of inclusion of dietary supplement use on the validity of micronutrient estimates. The purpose of the present study was to assess reproducibility and validity of a self-administered FFQ, intended to measure total nutrient intake from diet and from dietary supplements, in a random population-based sample of 248 middle-aged and elderly men (40-74 y old) in central Sweden. Fourteen 24-h recall interviews were used as the reference method. Participants were telephoned about once a month for 1 y, covering every day of the week, twice in random order. Spearman correlation coefficients increased 13% (from 0.49 to 0.62), between FFQ-based micronutrient estimates and the fourteen 24-h recall interviews (reference method) when supplement use was included. Correct classification into highest quintiles was also improved by 14% (from 37 to 51%). There were no differences in mean intraclass correlation coefficients for 1-y reproducibility between total micronutrient intake and micronutrients from foods only. The increase in the validity of micronutrient estimates due to inclusion of supplements in nutrient intake assessment has important implications for sample size in epidemiologic studies. Because a dramatic increase in dietary supplement use has occurred in recent decades in many countries, the issue of including supplements in dietary assessment should be of highest priority in nutritional epidemiologic studies of chronic diseases.

Micronutrients and Cancer Therapy

The effect of micronutrient supplementation on the effectiveness of cancer chemotherapeutic agents is reviewed, and the efficacy of antioxidants, folic acid, and other vitamins and minerals is discussed. Although some micronutrients show promise in enhancing the cytotoxicity of anticancer agents in vitro, caution should be exercised in recommending micronutrient supplementation for cancer patients receiving chemotherapeutic drugs. To date, few well-controlled clinical trials have been conducted to evaluate the efficacy of micronutrients in promoting the sensitivity of tumors to chemotherapeutic agents.

Suplementação de vitaminas na prevenção de câncer

Este trabalho constitui uma revisão de dados epidemiológicos sobre a relação entre o consumo de vitaminas e prevenção de câncer. Estudos observacionais evidenciam uma associação inversa consistente entre a ingestão de frutas e hortaliças e risco de câncer, e um efeito protetor das vitaminas C, E e dos carotenóides contra certos tipos de câncer. Resultados de estudos de intervenção, na prevenção primária de câncer, são contraditórios, sendo que em dois desses estudos o beta-caroteno, suplementado em doses consideradas farmacológicas, isolado ou associado à vitamina E ou à vitamina A, mostrou-se deletério para tabagistas. Ao contrário, a ingestão de doses mais fisiológicas de antioxidantes parece ser mais eficaz, sendo que a ação sinérgica dessas substâncias na quimioprevenção de câncer já foi demonstrada tanto em modelo in vivo de carcinogênese quanto em estudo epidemiológico de intervenção. Como estratégia de prevenção de câncer preconiza-se o consumo de dietas ricas em frutas e hortaliças, que aportem cerca de 150 mg de vitamina C, 30 mg de vitamina E e 4 mg de carotenóides. A ingestão de quantidades mais elevadas, na forma de suplementos, não está recomendada.