Role of Vitamin D in Preventing and Treating Selected Extraskeletal Diseases-An Umbrella Review.

Evidence is accumulating that vitamin D may have beneficial effects on respiratory tract, autoimmune, neuro-degenerative, and mental diseases. The present umbrella review of systematic reviews (SRs) of cohort studies and randomised controlled trials (RCTs), plus single Mendelian randomisation studies aims to update current knowledge on the potential role of vitamin D in preventing and treating these extraskeletal diseases. Altogether, 73 SRs were identified. Observational data on primary prevention suggest an inverse association between vitamin D status and the risk of acute respiratory tract infections (ARI), dementia and cognitive decline, and depression, whereas studies regarding asthma, multiple sclerosis (MS), and type 1 diabetes mellitus (T1DM) are scarce. SRs of RCTs support observational data only for the risk of ARI. No respective RCTs are available for the prevention of chronic obstructive pulmonary disease (COPD), MS, and T1DM. SRs of RCTs indicate beneficial therapeutic effects in vitamin D-deficient patients with asthma and COPD, while effects on major depression and T1DM need to be further elucidated. Mendelian randomisation studies do not consistently support the results of SRs. Since several limitations of the included SRs and existing RCTs do not permit definitive conclusions regarding vitamin D and the selected diseases, further high-quality RCTs are warranted.

Revised Reference Values for Potassium Intake.

BACKGROUND: The nutrition societies of Germany, Austria and Switzerland have revised the reference values for potassium intake in January 2017. METHODS: For adults, the estimated value was based on the 24-h urinary potassium excretion and on preventive considerations regarding hypertension and stroke. The estimated values for children and adolescents were extrapolated from the adult estimated value considering differences in body mass. For infants aged 0 to under 4 months, the estimated value was set based on the potassium intake via breast milk. From this reference value, the estimated value for infants aged 4 to under 12 months was also derived by extrapolation. The estimated value for lactating women takes into account the potassium loss via breast milk. RESULTS: The estimated values for potassium intake are set at 400 mg/day for breastfed infants aged 0 to under 4 months, 600 mg/day for infants aged 4 to under 12 months, 1,100-4,000 mg/day for children and adolescents, 4,000 mg/day for adults and pregnant women and 4,400 mg/day for lactating women. CONCLUSIONS: The consumption of potassium-rich foods should be generally increased. Supplemental intake beyond the estimated values has no health benefit and is therefore not recommended.