Nutrition and health

Objectives:
Omega-3 polyunsaturated fatty acids (n-3 PUFA) have been suggested as a cognitive enhancing agent, though their effect is doubtful. Therefore, this review article has been conducted.

Does supplementation of n-3 PUFA improve cognitive functions of non-demented individuals exclusively of middle age or older? 

Study design:
This review article included 24 RCTs with a total of 9,660 participants.
The length of intervention ranged from 3 to 36 months and the daily dose of n-3 PUFA ranged from 230 to 4000 mg/day. 
6  studies were conducted in countries where the nationwide blood levels of DHA + EPA were notably low, measuring ≤ 4% in erythrocyte equivalents. 

Results and conclusions:
The investigators found that the beneficial effect on executive function demonstrated an upward trend within the initial 12 months of intervention. 
This effect was prominently observed with a daily intake surpassing 500 mg of n-3 PUFA and up to 420 mg of eicosapentaenoic acid (EPA). 

The investigators found a descending curve following 12 months of n-3 PUFA intervention and when the dosage of EPA exceeded 420 mg/d.  

The investigators found, furthermore, these trends exhibit heightened significance in regions where the levels of blood docosahexaenoic acid (DHA) + EPA are not very low.

The investigators concluded supplementation of n-3 PUFA (a daily intake surpassing 500mg n-3 PUFA or up to 420mg of EPA during 12 months) has potential benefits to executive function in non-demented individuals exclusively of middle age or older, particularly in individuals whose dietary DHA + EPA level is not substantially diminished. 

Original title: 
The influence of n-3 polyunsaturated fatty acids on cognitive function in individuals without dementia: a systematic review and dose–response meta-analysis by Suh SW, Lim E, […], Kim KW. 

Link: 
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10929146/

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

Objectives:
Previous cohort studies have indicated that consumption of total and animal proteins are related to fracture risk; however, results were inconclusive. Therefore, this review article has been conducted.

Does a high dietary intake of protein reduce risk of fractures?

Study design:
This review article included 20 cohort studies with serious to moderate risk of bias involving 780,322 individuals. 

Results and conclusions:
The investigators found a non-statistically significant relation between intake of animal proteins and dairy products and all fracture risk. 

The investigators found, however, a significantly 43% decreased incidence of fracture per 100 g/day total protein dietary intake [RR = 0.57, 95% CI = 0.36 to 0.93]. 

The investigators found, however, a significantly 5% decreased incidence of fracture per 15 g/day fish protein dietary intake [RR = 0.95, 95% CI = 0.91 to 0.99]. 

The investigators found every 100 g/day total and animal protein dietary intake and every 15 g/day fish dietary intake were significantly linked to 48%, 50% and 5% lower hip fracture risk. 

The investigators found greater dietary animal protein intake might reduce risk of hip but not fracture at any site. 

The investigators concluded greater total protein (per 100 g/day) and fish (per 15 g/day) dietary intake may reduce risk of any or hip fracture. May reduce because the cohort studies had serious to moderate risk of bias.

Original title: 
Association between total and animal proteins with risk of fracture: A systematic review and dose-response meta-analysis of cohort studies by Zeraattalab-Motlagh S, Mortazavi AS, […], Mohammadi H.

 

Link: 
https://pubmed.ncbi.nlm.nih.gov/37855886/ 

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

100 grams of protein consumption per day corresponds to a diet with 20 En% protein. A diet with 20 En% protein mainly consists of products with 20 En% protein. Find here which products in the supermarket contain 20 En% protein.

20 En% protein means that the number of grams of protein contributes 20% to the total calorie content of the product in question.

Calculate here whether your daily diet contains 20 En% protein. This tab is only visible after gratis inlog. 

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.