Intake of Vitamin and Mineral Supplements and Longitudinal Association with HbA1c Levels in the General Non-Diabetic Population--Results from the MONICA/KORA S3/F3 Study

Scientific opinion on the tolerable upper intake level for selenium

Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver a scientific opinion on the tolerable upper intake level (UL) for selenium. Systematic reviews of the literature were conducted to identify evidence regarding excess selenium intake and clinical effects and potential biomarkers of effect, risk of chronic diseases and impaired neuropsychological development in humans. Alopecia, as an early observable feature and a well-established adverse effect of excess selenium exposure, is selected as the critical endpoint on which to base a UL for selenium. A lowest-observed-adverse-effect-level (LOAEL) of 330 μg/day is identified from a large randomised controlled trial in humans (the Selenium and Vitamin E Cancer Prevention Trial (SELECT)), to which an uncertainty factor of 1.3 is applied. A UL of 255 μg/day is established for adult men and women (including pregnant and lactating women). ULs for children are derived from the UL for adults using allometric scaling (body weight0.75). Based on available intake data, adult consumers are unlikely to exceed the UL, except for regular users of food supplements containing high daily doses of selenium or regular consumers of Brazil nuts. No risk has been reported with the current levels of selenium intake in European countries from food (excluding food supplements) in toddlers and children, and selenium intake arising from the natural content of foods does not raise reasons for concern. Selenium-containing supplements in toddlers and children should be used with caution, based on individual needs.

Effect of thiamine supplementation on glycaemic outcomes in adults with type 2 diabetes: a systematic review and meta-analysis

BACKGROUND

Patients with type 2 diabetes mellitus (T2DM) have been shown to have thiamine deficiency. Dietary supplementation is an economic strategy to control blood glucose. Objective: To evaluate effectiveness of thiamine supplementation on glycaemic outcomes in patients with T2DM.

METHODS

Eligibility criteria: Studies that assessed effect of thiamine supplementation in adults with T2DM which measured glycaemic outcomes-HbA1c, fasting blood glucose (FBG) and/or postprandial blood glucose (PPG) were included. Information sources: PUBMED, Tripdatabase, the Cochrane Central Register, National Institute of Health Clinical Database and Google Scholar were searched until December 2021 for RCTs. Risk of bias: It was assessed using standardised critical appraisal instruments from the Joanna Briggs Institute for RCTs. Synthesis of results: Where possible, studies were pooled in a meta-analysis. Results were presented in a narrative format if statistical pooling was not possible.

RESULTS

Included studies: Six trials involving 364 participants. Synthesis of results: No significant beneficial effects were observed on glycaemic outcomes with 100-900 mg/day of thiamine or benfotiamine for up to 3 months (HbA1c: MD, -0.02%, 95% CI: -0.35 to 0.31; FBG: MD,-0.20 mmol/L; 95% CI: -0.69 to 0.29; PPG: MD, - 0.20 mmol/L, 95% CI: -2.05 to 1.65 (mean difference, MD)). There was a significant increase in high-density lipoprotein (HDL) (MD, 0.10; 95% CI: 0.10 to 0.20) at 3-month follow-up. Benfotiamine reduced triglyceride level (MD, -1.10; 95% CI: -1.90 to -0.30) in 120 mg/day dose as compared with placebo 150 mg/day, however this was not demonstrated in higher doses.

DISCUSSION

Limitations of evidence: Inclusion of single-centre trials published only in English, small sample sizes of included studies, lack of trials investigating outcomes for same comparisons and varying follow-up periods. Interpretation: Thiamine supplementation does not affect glycaemic outcomes, however reduces triglycerides while increasing HDL. Multicentre well-designed RCT with higher doses of thiamine and a follow-up period of 1-2 years will provide better evidence.

PROSPERO REGISTRATION NUMBER

CRD42020170520.

Perspectives on the systematic review for the 2020 Dietary Reference Intakes for Koreans for calcium

An accurate assessment of the recommended calcium (Ca) intake may contribute to reducing the risk of fractures and chronic diseases, ultimately improving quality of life. This review was performed to summarize key findings of Ca studies, investigate the effect of Ca intake on health outcomes, and determine the adequacy of evidence to revise the 2015 Dietary Reference Intakes for Koreans (KDRIs) for Ca in 2020. Databases were searched for intervention studies that assessed health outcomes by providing Ca in diets or as supplements. The framework of the systematic review comprised conducting literature searches, data extraction, quality assessment of the literature, and summarizing key findings relevant to set the Estimated Average Requirement (EAR) and Tolerable Upper Intake Level (UL) for Ca for the 2020 KDRI. The final search was performed in June 2019. A total of 13,309 studies were identified through databases and manual search. Sixtyfive studies were included in the final quality assessment and were summarized according to health indicators. As bone health was used as an indicator of the EAR for Ca, literature reports on bone health were further categorized by the life-cycle stage of the participants. This systematic review did not find new evidence that could be applied to the general Korean adult population, including postmenopausal women, for defining a new EAR for Ca in the 2020 KDRIs. Evidence in most of the reviewed literature was considered weak; however, some evidence was found that could improve the criteria on how the EAR for Ca was determined in children and adolescents. A review of the literature for the 2020 KDRIs for Ca did not find strong evidence in order to change the recommended values of the 2015 KDRIs. More clinical interventions are required among Koreans to strengthen the body of evidence to warrant the revision of the KDRIs.

Dietary intervention with a specific micronutrient combination for the treatment of patients with cardiac arrhythmias: the impact on insulin resistance and left ventricular function

Background

Cardiac arrhythmias (CA) are very common and may occur with or without heart disease. Causes of these disturbances can be components of the metabolic syndrome (MetS) or deficits of micronutrients especially magnesium, potassium, B vitamins and coenzyme Q10. Both causes may also influence each other. Insulin resistance (IR) is a risk factor for diastolic dysfunction. One exploratory outcome of the present pilot study was to assess the impact of a dietary intervention with specific micronutrients on the lowering of IR levels in patients with CA with the goal to improve the left ventricular (LV) function.

Methods

This was a post hoc analysis of the randomized double blind, placebo-controlled pilot study in patients with CA (VPBs, SVPBs, SV tachycardia), which were recruited using data from patients who were 18–75 years of age in an Outpatient Practice of Cardiology. These arrhythmias were assessed by Holter ECG and LV function by standard echocardiography. Glucose metabolism was measured by fasting glucose, fasting insulin level and the Homeostasis Model Assessment of IR (HOMA-IR) at baseline and after 6 weeks of dietary supplementation.

Results

A total of 54 randomized patients with CA received either a specific micronutrient combination or placebo. Dietary intervention led to a significant decrease in fasting insulin ≥58 pmol/l (p = 0.020), and HOMA-IR (p = 0.053) in the verum group after 6 weeks. At the same time, parameters of LV diastolic function were improved after intervention in the verum group: significant reduction of LV mass index (p = 0.003), and in tendency both a decrease of interventricular septal thickness (p = 0.053) as well as an increase of E/A ratio (p = 0.051). On the other hand, the premature beats (PBs) were unchanged under verum.

Conclusions

In this pilot study, dietary intervention with specific micronutrient combination as add-on to concomitant cardiovascular drug treatment seems to improve cardio metabolic health in patients with CA. Further studies are required.

Study registration

The study was approved by the Freiburg Ethics Commission International and was retrospectively registered with the U.S. National Institutes of Health Clinical Trials gov ID NCT 02652338 on 16 December 2015.