Vitamin D supplementation positively affects activity but impairs stimulus response behavior in an age and sex specific manner in C57BL/6 mice

Several studies have begun to demonstrate the possible cognitive and physiological benefits of a fortified vitamin D diet. However, the behavioral effects of a high vitamin D fortified diet during adolescence has not been fully explored. In the present study, a 4-week vitamin D fortified diet (20,000 IU/Kg) compared to controls (1500 IU/Kg) was administered during the juvenile (4 weeks old) or early adult period (8 weeks old) in C57BL/6 J mice to investigate the effects of fortification on cognition, behavior, and their bone phenotype. After 4 weeks on the diet, vitamin D-treated and control groups underwent a 4-week battery of behavioral tests while remaining on their respective diets. We found that a fortified diet affected behavior in both an age- and sex-specific manner. When vitamin D was administered to juveniles, both sexes displayed impaired habituation to a loud tone. However, females also presented with impaired prepulse inhibition compared to female controls. In the adult treated group, the fortified diet increased only time spent in the open field and had no effect on anxiety-like behavior in the elevated plus maze. Juvenile mice treated with a high vitamin D fortified diet showed a decrease in the total volume compared to the control group in the proximal metaphysis and midshaft region of their femur. There were no differences in bone measurements for mice treated during adulthood. Overall, our results suggest that the juvenile period is a more sensitive time point to the startle response and bone effects of a diet supplemented with high vitamin D, while adults exhibited alterations in locomotive behavior.

The determinants and longitudinal changes in vitamin D status in middle-age: a Northern Finland Birth Cohort 1966 study

PURPOSE

Populations living in the Nordic countries are at high risk for vitamin D (VitD) deficiency or insufficiency. To reduce the risk, nationwide interventions based on food fortification and supplementation are being implemented. However, there is limited evidence about the impact of such public health campaigns on target populations.

METHODS

We studied an unselected sample of 3650 participants (56.2% females) from the longitudinal Northern Finland Birth Cohort 1966 with repeated measures of serum 25-hydroxyvitamin D [25(OH)D] at ages 31 (1997) and 46 (2012-2013). Timepoints corresponded to the period before and during the food fortification. We examined the effect of VitD intake from the diet and supplementation, body mass index and previous 25(OH)D concentration on 25(OH)D concentration at 46 years using a multivariable linear regression analysis. A 25(OH)D z score adjusted for sex, season, latitude and technical effect was used in the analysis.

RESULTS

We observed an increase of 10.6 nmol/L in 25(OH)D, when the baseline 25(OH)D was 54.3 nmol/L. The prevalence of serum 25(OH)D below < 50 nmol/L was halved. The changes were found for both sexes and were more pronounced in winter compared to summer months. Regular VitD supplementation had a significant positive effect on 25(OH)D at the age of 46, as well as had the dietary intake of fortified dairy products and fish, and the previous 25(OH)D concentration. However, the intake of fat-spreads albeit VitD-fortified, did not predict 25(OH)D.

CONCLUSION

Our results demonstrated the positive impact of the fortification programme on VitD status in middle-aged population.

A History of Cow's Milk Allergy Is Associated with Lower Vitamin D Status in Schoolchildren

BACKGROUND/AIMS

Vitamin D insufficiency is common in children. We aimed to evaluate the main determinants of vitamin D status in Finnish school-aged children, including the history of allergic diseases.

METHODS

We conducted a cross-sectional study on 171 ten-year-olds where serum 25-hydroxyvitamin D (25[OH]D) levels were measured, and data on food consumption and use of vitamin D supplements were collected. The history of allergic diseases was evaluated with a validated questionnaire.

RESULTS

Vitamin D insufficiency (<50 nmol/L) was observed in 16% of the children. In children with a history of cow's milk allergy, the mean 25(OH)D levels were lower than in children without allergy (60.5 ± 12.6 nmol/L vs. 75.5 ± 22.3 nmol/L, p = 0.004). Lack of vitamin D supplementation, female gender, non-Caucasian ethnicity, and a history of milk allergy were associated with lower vitamin D status.

CONCLUSION

The vitamin D status in our study sample of Finnish schoolchildren was sufficient, which suggests that health policy strategies - such as the recommendation of vitamin D supplementation and the fortification of food products with vitamin D - have been successful in improving vitamin D status in children. Special concern should be given to children with a history of milk allergy to ensure their vitamin D sufficiency.

Food sources of vitamin D and their association with 25-hydroxyvitamin D status in Dutch older adults

Various populations are at increased risk of developing a low vitamin D status, in particular older adults. Whereas sun exposure is considered the main source of vitamin D, especially during summer, dietary contributions should not be underestimated. This study aims to identify food sources of vitamin D that associate most strongly with serum vitamin D concentration. Data of 595 Dutch adults, aged ≥65 years, were analysed. Vitamin D intake was assessed with a food frequency questionnaire and 25-hydroxyvitamin D (25(OH)D) was determined in serum. Associations of total vitamin D intake and vitamin D intake from specific food groups with serum 25(OH)D status were examined by P-for trend analyses over tertiles of vitamin D intake, prevalence ratios (PRs), and spline regression. The prevalence of vitamin D deficiency was high, with 36% of the participants having a 25(OH)D status <50nmol/L. Participants with adequate 25(OH)D concentrations were more likely to be men and more likely to be younger than participants with vitamin D deficiency. Total median vitamin D intake was 4.3μg/day, of which 4.0μg/day was provided by foods. Butter and margarine were the leading contributors to total vitamin D intake with 1.8μg/day, followed by the intake of fish and shellfish with 0.56μg/day. Participants with higher intakes of butter and margarine were 21% more likely to have a sufficient 25(OH)D status after adjustment for covariates (T1 vs. T3: PR 1.0 vs. 1.21 (95%CI: 1.03-1.42), P-for trend 0.02). None of the other food groups showed a significant association with the probability of having a sufficient 25(OH)D status. This study shows that vitamin D intake was positively associated with total serum 25(OH)D concentration, with butter and margarine being the most important contributors to total vitamin D intake.

Effects of vitamin D-fortified low fat yogurt on glycemic status, anthropometric indexes, inflammation, and bone turnover in diabetic postmenopausal women: A randomised controlled clinical trial

BACKGROUND & AIMS

Low levels of serum 25-hydroxy vitamin D (25(OH)D) are common in type 2 diabetic patients and cause several complications particularly, in postmenopausal women due to their senile and physiological conditions. This study aimed to assess the effects of vitamin D-fortified low fat yogurt on glycemic status, anthropometric indexes, inflammation, and bone turnover in diabetic postmenopausal women.

METHODS

In a randomized, placebo-controlled, double-blind parallel-group clinical trial, 59 postmenopausal women with type 2 diabetes received fortified yogurt (FY; 2000 IU vitamin D in 100 g/day) or plain yogurt (PY) for 12 weeks. Glycemic markers, anthropometric indexes, inflammatory, and bone turnover markers were assessed at baseline and after 12 weeks.

RESULTS

After intervention, in FY group (vs PY group), were observed: significant increase in serum 25(OH)D and decrease of PTH (stable values in PY); significant improvement in serum fasting insulin, HOMA-IR, HOMA-B, QUICKI, and no changes in serum fasting glucose and HbA1c (significant worsening of all indexes in PY); significant improvement in WC, WHR, FM, and no change in weight and BMI (stable values in PY); significant increase of omentin (stable in PY) and decrease of sNTX (significant increase in PY). Final values of glycemic markers (except HbA1c), omentin, and bone turnover markers significantly improved in FY group compared to PY group. Regarding final values of serum 25(OH)D in FY group, subjects were classified in insufficient and sufficient categories. Glycemic status improved more significantly in the insufficient rather than sufficient category; whereas the other parameters had more amelioration in the sufficient category.

CONCLUSIONS

Daily consumption of 2000 IU vitamin D-fortified yogurt for 12 weeks improved glycemic markers (except HbA1c), anthropometric indexes, inflammation, and bone turnover markers in postmenopausal women with type 2 diabetes.

TRIAL REGISTRATION

www.irct.ir (IRCT2013110515294N1).