Nutrition and health

Objectives:
Previous studies have suggested that selenium as a trace element is involved in bone health, but findings related to the specific effect of selenium on bone health remain inconclusive. Therefore, this review article has been conducted.

Do both high dietary selenium intake and high serum selenium levels increase bone density?

Study design:
This review article included 8 cross-sectional studies, 7 case-control studies and 3 prospective cohort studies and 1 RCT with a total of 69,672 subjects.

The number of participants ranged from 60 to 21,939, while the mean age varied from 39.4 to 75.8 years, with mean selenium intake ranging from 41.2 to 154.4 μg/d or mean serum selenium level ranging from 66.7 to 131.1 μg/L.
All the observational studies had a NOS score ≥ 4, namely moderate- to high-quality scores.
There was no publication bias.

Results and conclusions:
The investigators found a significantly positive association between dietary selenium intake [β = 0.04, 95% CI = 0.00 to 0.07, p = 0.029, I2 = 95.91%] as well as serum selenium [β = 0.13, 95% CI = 0.00 to 0.26, p = 0.046, I2 = 86.60%] and bone mineral density.

The investigators found high dietary selenium intake significantly reduced risk of hip fracture with 56% [OR = 0.44, 95% CI = 0.37 to 0.52, p 0.001, I2 = 65.2%].

The investigators found osteoporosis patients had lower serum selenium level than healthy controls [WMD = -2.01, 95% CI = -3.91 to -0.12, p = 0.037, I2 = 0%].

The investigators concluded persons with higher dietary selenium intake and higher serum selenium have higher bone mineral density. Furthermore, high selenium dietary intake reduces hip fracture.

Original title:
The association between selenium and bone health: a meta-analysis by Xie H, Wang N, […], Wang Y.

Link:
https://boneandjoint.org.uk/article/10.1302/2046-3758.127.BJR-2022-0420.R1

Additional information of El Mondo:
Find more information/studies on selenium and preventing fractures right here.

Circulating concentration of selenium in blood (serum selenium level) can be increased by eating foods that are high in selenium and/or taking selenium supplements.

Objectives:
Magnesium, an essential cation for numerous cellular processes, is a major component of bone. However, its relationship with the risk of fractures is still uncertain. Therefore, this review article has been conducted.

Do lower serum magnesium concentrations increase risk of incident fractures?

Study design:
This review article included 3 prospective cohort studies and 1 retrospective cohort study with a total of 119,755 participants and a mean follow-up duration of 79 months.
The mean age was 62 years, with a mean percentage of 33% women.
The analyses were adjusted for a mean of 15 potential confounders.
All 4 studies included in the meta-analysis were of high quality (Newcastle-Ottawa Scale of 9 for all).

Results and conclusions:
The investigators found lower serum magnesium concentrations were associated with a significantly higher risk of 58% for incident fractures [RR = 1.579, 95% CI = 1.216 to 2.051, p = 0.001, I2 = 46.9%].
The results were not affected by any heterogeneity [I2 = 31.2%, p = 0.201] nor publication bias [Egger’s test = 0.94 ± 0.43, p = 0.10]. After trimming, the recalculated effect size was only slightly reduced [RR = 1.25, 95% CI = 1.09 to 1.43].
Significant because RR of 1 was not found in the 95% CI of 1.09 to 1.43. RR of 1 means no risk/association.

The investigators concluded lower serum magnesium concentrations increase risk of incident fractures.

Original title:
Association between Serum Magnesium and Fractures: A Systematic Review and Meta-Analysis of Observational Studies by Dominguez LJ, Rodas-Regalado S, […], Barbagallo M.

Link:
https://www.mdpi.com/2072-6643/15/6/1304

Additional information of El Mondo:
Find more information/studies on magnesium and preventing fractures right here.

Circulating concentration of magnesium in blood can be increased by eating foods that are high in magnesium and/or taking magnesium supplements.

Objectives:
Given their potent antioxidation properties, carotenoids play a role in delaying and preventing dementia and mild cognitive impairment (MCI). However, observational studies have found inconsistent results regarding the associations between blood carotenoid levels and the risk of dementia and MCI. Therefore, this review article has been conducted.

Is a lower blood carotenoid level (like lycopene, zeaxanthin, lutein) a risk factor for dementia or mild cognitive impairment?

Study design:
This review article included 23 studies with 1,422 patients with dementia, 435 patients with mild cognitive impairment and 4,753 controls (persons without dementia or mild cognitive impairment).

Results and conclusions:
The investigators found meta-analysis showed that patients with dementia had lower blood lycopene [SMD = -0.521, 95% CI = -0.74 to -0.301], α-carotene [SMD = -0.489, 95% CI = -0.697 to -0.281] β-carotene [SMD = -0.476, 95% CI = -0.784 to -0.168], lutein [SMD = -0.516, 95% CI = -0.753 to -0.279], zeaxanthin [SMD = -0.571, 95% CI = -0.910 to -0.232] and β-cryptoxanthin [SMD = -0.617, 95% CI = -0.953 to -0.281] than the controls.

The investigators found owing to insufficient data, no similar and stable relationship between blood carotenoid levels and mild cognitive impairment was observed.

The investigators concluded lower blood carotenoid level is a risk factor for dementia.

Original title:
Low blood carotenoid status in dementia and mild cognitive impairment: A systematic review and meta-analysis by Wang L, Zhao T, […], Jiang Q.

Link:
https://pubmed.ncbi.nlm.nih.gov/36997905/

Additional information of El Mondo:
Find more information/studies on carotenoids and Alzheimer 's disease right here.

Circulating concentration of lycopene in blood can be increased by eating foods that are high in lycopene and/or taking lycopene supplements.

Objectives:
Does a high antioxidant dietary intake reduce risk of Alzheimer's disease and dementia?

Study design:
This review article included 17 cohort studies with 98,264 participants, of which 7,425 had dementia after 3-23 years of follow-up.

Results and conclusions:
The investigators found a high antioxidant dietary intake significantly reduced the incidence of Alzheimer's disease with 15% [RR = 0.85, 95% CI= 0.79 to 0.92, I2 = 45.5%].
However, this reduced risk was not significant for dementia [RR = 0.84, 95% CI = 0.77 to 1.19, I2 = 54.6%].
Significant because RR of 1 was not found in the 95% CI of 0.79 to 0.92. RR of 1 means no risk/association.

The investigators concluded that a high antioxidant dietary intake reduces Alzheimer's disease.

Original title:
Association of Dietary and Supplement Intake of Antioxidants with Risk of Dementia: A Meta-Analysis of Cohort Studies by Zhao R, Han X, […], You H.

Link:
https://pubmed.ncbi.nlm.nih.gov/36846999/

Additional information of El Mondo:
Find more information/studies on antioxidant and Alzheimer 's disease right here.

Objectives:
Lutein and zeaxanthin are thought to have beneficial effects on protecting the lens against cataract formation, but findings from epidemiologic studies have been inconsistent. Therefore, this review article has been conducted.

Does dietary lutein and zeaxanthin intake reduce age-related cataract risk?

Study design:
This review article included 6 prospective cohort studies, involving 4416 cases and 41999 participants.

Results and conclusions:
The investigators found for comparing the highest with the lowest categories of dietary lutein and zeaxanthin intake, a significant reduced risk for nuclear cataract of 25% [RR = 0.75, 95% CI = 0.65-0.85], but the reduced risk was not significant for cortical cataract [RR = 0.85, 95% CI = 0.53-1.17] and for posterior subcapsular cataract [RR = 0.77, 95% CI = 0.40-1.13]. Significant means, there is an association with a 95% confidence.

The investigators found in dose-response analysis that every 300 μg/d increment in dietary lutein and zeaxanthin intake was significantly associated with a 3% [RR = 0.97, 95% CI = 0.94-0.99] reduction in the risk of nuclear cataract.

The investigators found in dose-response analysis that every 300 μg/d increment in dietary lutein and zeaxanthin intake was non-significantly associated with a 1% [RR = 0.99, 95% CI = 0.95-1.02] reduction in the risk of cortical cataract. Non-significantly means, there is no association with a 95% confidence.

The investigators found in dose-response analysis that every 300 μg/d increment in dietary lutein and zeaxanthin intake was non-significantly associated with a 3% [RR = 0.97, 95% CI = 0.93-1.01] reduction in the risk of posterior subcapsular cataract. Non-significantly because RR of 1 was found in 95% CI of 0.93 to 1.01. RR of 1 means no risk.

The investigators concluded dietary lutein and zeaxanthin intake (at least 300 μg/d) is associated with a reduced risk of age-related cataract, especially nuclear cataract in a dose-response manner, indicating a beneficial effect of lutein and zeaxanthin in age-related cataract prevention.

Original title:
A dose–response meta-analysis of dietary lutein and zeaxanthin intake in relation to risk of age-related cataract by Ma L, Hao ZX, [...], Pan JP.

Link:
http://link.springer.com/article/10.1007/s00417-013-2492-3

Additional information of El Mondo:
Find more studies/information on elderly right here.