Nutritional advice

Objectives:
Is there an association between dietary factors and the risk of gout and hyperuricemia?
 
Study design:
This review article included 10 prospective cohort studies (the follow-up duration ranged from 6 years to 26 year) and 9 cross-sectional studies.

Based on the Newcastle-Ottawa Scale (NOS), the quality assessment of included studies yielded a mean NOS score of 7.1, suggesting the presence of high methodologic quality.

Results and conclusions:
The investigators found in meta-analysis that the risk of getting gout significantly increased with:
29% [OR = 1.29, 95% CI = 1.16-1.44] for dietary red meat intake;
31% [OR = 1.31, 95% CI = 1.01-1.68] for dietary seafoods intake;
158% [OR = 2.58, 95% CI = 1.81-3.66] for dietary alcohol intake;
114% [OR = 2.14, 95% CI = 1.65-2.78] for dietary fructose intake.

The investigators found in meta-analysis that the risk of getting gout significantly decreased with:
44% [OR = 0.56, 95% CI = 0.44-0.70] for dietary dairy products intake;
15% [OR = 0.85, 95% CI = 0.76-0.96] for dietary soy foods intake;
14% [OR = 0.86, 95% CI = 0.75-0.98] for dietary high-purine vegetables intake;
53% [OR = 0.47, 95% CI = 0.37-0.59] for dietary coffee intake.

The investigators found in meta-analysis that the risk of getting hyperuricemia (an excess of uric acid in the blood) significantly increased with:
24% [OR = 1.24, 95% CI = 1.04-1.48] for dietary red meat intake;
47% [OR = 1.47, 95% CI = 1.16-1.86] for dietary seafoods intake;
106% [OR = 2.06, 95% CI = 1.60-2.67] for dietary alcohol intake;
85% [OR = 1.85, 95% CI = 1.66-2.07] for dietary fructose intake.

The investigators found in meta-analysis that the risk of getting hyperuricemia (an excess of uric acid in the blood) significantly decreased with:
50% [OR = 0.50, 95% CI = 0.37-0.66] for dietary dairy products intake;
30% [OR = 0.70, 95% CI = 0.56-0.88] for dietary soy foods intake.

The investigators found in meta-analysis that the risk of getting hyperuricemia (an excess of uric acid in the blood) non-significantly increase with:
10% [OR = 1.10, 95% CI = 0.88-1.39] for dietary high-purine vegetables intake.

The investigators found in meta-analysis that the risk of getting hyperuricemia (an excess of uric acid in the blood) non-significantly decreased with 24% [OR = 0.76, 95% CI = 0.55-1.06] for dietary coffee intake in men.
Non-significantly because OR of 1 was found in the 95% CI of 0.55 to 1.06. OR of 1 means no risk/association.

The investigators found in meta-analysis that the risk of getting hyperuricemia (an excess of uric acid in the blood) significantly increased with 58% [OR = 1.58, 95% CI = 1.16-2.16] for dietary coffee intake in women.
Significant because OR of 1 was not found in the 95% CI of 1.16 to 2.16. OR of 1 means no risk/association.

The investigators concluded that the risk of hyperuricemia and gout is positively correlated with the dietary intake of red meat, seafoods, alcohol or fructose and negatively with dairy products or soy foods. High-purine vegetables show no association with hyperuricemia, but negative association with gout. Coffee intake is negatively associated with gout risk, whereas it is positively associated with hyperuricemia risk in women.

Original title:
Dietary factors and risk of gout and hyperuricemia: a meta-analysis and systematic review by Li R, Yu K and Li C.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/30485934

Additional information of El Mondo:
Find more information/studies on food groups and chronic diseases right here.

Objectives:
Postherpetic neuralgia (PHN) is the most distressful complication of herpes zoster. Postherpetic neuralgia results in an impaired quality of life and higher healthcare utilization. Vitamin B12 has been proven to be effective in pain relief for various conditions. Therefore, this review article has been conducted.

Do postherpetic neuralgia patients benefit from vitamin B12 supplementation?

Study design:
This review article included 4 RCTs (published between 2013 and 2016) including 383 participants.

Results and conclusions:
The investigators found compared with the placebo group, the vitamin B12 group exhibited a significant decrease in the Numeric Rating Scale score, with a mean difference of -4.01 [95% CI = -4.70 to -3.33].

The investigators found compared with the placebo group, vitamin B12 administration improved the quality of life of postherpetic neuralgia patients with moderate quality evidence and significantly decreased the number of patients using analgesics.

The investigators concluded that vitamin B12 appears to be an attractive complementary therapy for postherpetic neuralgia patients. However, further investigation is needed before conclusive recommendations can be made.

Original title:
Vitamin B12 for herpetic neuralgia: A meta-analysis of randomised controlled trials by Wang JY, Wu YH, [...], Lu PH.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/30477853

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Postherpetic neuralgia (PHN) is a nerve pain (neuralgia) that persists after a shingles rash has cleared. Postherpetic neuralgia is caused by the chickenpox (varicella-zoster) virus.
 

Objectives:
Does magnesium supplementation reduce C-reactive protein concentrations in humans?

Study design:
This review article included 8 RCTs (2004-2014) with 349 participants.

The mean age of participants ranged from 18 to 85 years.
The range of duration of the supplementation intervention across studies was from 8 h to 6.5 months.
The consumed range of magnesium dose in these studies was from 320 to 1500 mg/day. The baseline level (at the start of the study) of the CRP varied between the studies from 0.42 mg/dL as minimum to 9.4 mg/dL as maximum.

Results and conclusions:
The investigators found magnesium supplementation significantly reduced serum CRP levels [WMD = -1.33 mg/dL, 95% CI = -2.63 to -0.02, p 0.001, I2 = 29.1%, p 0.123] across all studies.
In leave-one-out sensitivity analyses, the pooled effect estimates remained similar across all studies for CRP levels [WMD = -1.33 mg/dL, 95% CI = -2.63 to -0.02].

The investigators found after adjustment of the effect size for potential publication bias using the “trim and fill” correction, no potentially missing studies were imputed in the funnel plot [WMD = -1.33 mg/dL, 95% CI = -2.63 to -0.02]. The “fail-safe N” test showed that 146 studies would be needed to bring the WMD down to a non-significant [p > 0.05] value.

The investigators found in random-effects meta-regression changes in serum CRP levels were independent of the dosage of magnesium [slope = -0.004, 95% CI = -0.03 to 0.02, p = 0.720, and duration [slope = -0.06, 95% CI = -0.37 to 0.24, p = 0.681] of supplementation.

The investigators found in 4 RCTs that subjects with a baseline CRP of ≥ 2 mg/dL had more significant reduction in the serum CRP level [WMD = -2.95 mg/dL, 95% CI = -3.35 to -2.25, p 0.001, I2 = 1.1%, p = 0.952] compared with subjects with a baseline CRP of 2 mg/dL [WMD = -0.23 mg/dL, 95% CI = -0.195 to -0.326, p 0.001, I2 = 1.3% p = 0.923].

The investigators found magnesium supplementation non-significantly reduced IL-6 levels [WMD = -0.16 pg/dL, 95% CI = -3.52 to 3.26, p = 0.236, I2 = 2.3%, p = 0.802] across all studies.

The investigators found magnesium supplementation significantly increased TNF-α levels [WMD = 1.97 pg/dL, 95% CI = 1.12 to 2.82, p = 0.043, I2 = 2.1%, p = 0.869] across all studies.

The investigators found magnesium supplementation non-significantly decreased fasting blood glucose (FBG) levels [WMD = -0.61 mg/dL, 95% CI = -2.72 to 1.48, p = 0.182, I2 = 6.1%, p = 0.742] across all studies.

The investigators found magnesium supplementation non-significantly decreased systolic blood pressure levels [WMD = -0.93 mmHg, 95% CI = -3.03 to 1.20, p = 0.293, I2 = 3.6%, p = 0.526] across all studies.

The investigators found magnesium supplementation non-significantly decreased diastolic blood pressure levels [WMD = -0.30 mmHg, 95% CI = -2.80 to 2.19, p = 0.639, I2 = 3.8%, p = 0.489] across all studies.

The investigators found magnesium supplementation non-significantly increased BMI levels [WMD = 0.27 kg/m², 95% CI = -0.59 to 1.15, p = 0.542, I2 = 2.0%, p = 0.906] across all studies.  

The investigators concluded that 320 to 1500 mg/day magnesium supplementation decreases serum CRP levels, especially with the baseline values ≥ 2 mg/dL. To provide more conclusive results and clarify the mechanistic pathways, RCTs with a larger sample size and a long-term follow-up period are warranted.

Original title:
Effect of magnesium supplements on serum C-reactive protein: a systematic review and meta-analysis by Mazidi M, Rezaie P and Banach M.

Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6040119/

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

Objectives:
Dietary salt reduction in the general population lowers blood pressure and cardiovascular risk. Despite being widely recommended, there is limited evidence as to whether this is applicable to individuals with end-stage renal disease (ESRD) receiving dialysis. Therefore, this review article has been conducted.

Study design:
This review article included 4 RCTs (91 participants), of which 3 were crossover trials and 1 was a parallel study.
Participants were 18 years and over; a reduction in salt intake of at least 1 g/day over 1 week and no concomitant interventions during the study.
The primary outcome was change in systolic and diastolic blood pressure.

Results and conclusions:
The investigators found dietary salt reduction was associated with an 8.4 mmHg [95% CI = 4.8-12.0, Ι2 = 0%] reduction in systolic blood pressure and a 4.4 mmHg [95% CI = 2.2-6.6, Ι2 = 0%] reduction in diastolic blood pressure.

The investigators concluded that a reduction in salt intake of at least 1 g/day over 1 week reduces blood pressure among individuals with end-stage renal disease (ESRD) receiving dialysis.

Original title:
The effect of dietary salt on blood pressure in individuals receiving chronic dialysis: a systematic review and meta-analysis of randomised controlled trials by Cole NI, Swift PA, […], Suckling RJ.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/30413764

Additional information of El Mondo:
Find more information/studies on lowering blood pressure, salt intake and chronic disease right here.
 

Objectives:
The association between coffee consumption and the circulating level of adiponectin and leptin has been evaluated in several epidemiological studies with conflicting results. Therefore, this review article has been conducted.

Is there an association between coffee consumption and the circulating level of adiponectin and leptin in humans?

Study design:
This review article included 12 cross-sectional studies.

Results and conclusions:
The investigators found when compared the highest versus the lowest coffee intake category, coffee consumption was associated with a higher circulating adiponectin level [SMD = 0.11, 95% CI = 0.06 to 0.17, p 0.001].

The investigators found in subgroup analysis when compared the highest versus the lowest coffee intake category, coffee consumption was associated with a higher circulating adiponectin level in women [SMD = 0.11, 95% CI = 0.02 to 0.20, p = 0.01], but not in men [SMD = 0.03, 95% CI = -0.08 to 0.14, p = 0.59].

The investigators found when compared the highest versus the lowest coffee intake category, coffee consumption was associated with a lower circulating leptin level [SMD = -0.19, 95% CI = -0.28 to -0.10, p 0.001].

The investigators concluded that coffee consumption is associated with a higher circulating level of adiponectin in women and a lower circulating level of leptin. However, more well-designed prospective cohort studies and randomised controlled trials are needed to further elaborate the concerned issues.

Original title:
Associations of coffee consumption with circulating level of adiponectin and leptin. A meta-analysis of observational studies by Zhang Y and Zhang DZ.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29513118

Additional information of El Mondo:
Find more information/studies on coffee consumption, diabetes and overweight right here.

Adiponectin is a unique adipokine, which is specifically and abundantly expressed in adipose tissues and improves insulin resistance. Having insulin resistance may increase the risk of type 2 diabetes and metabolic syndrome.

Objectives:
Inflammation is associated with an increased risk of a range of chronic diseases. A diet high in fruit and vegetables may help to reduce inflammation, as fruit and vegetables are rich sources of antioxidants and other biologically active substances, which may improve immune function. Therefore, this meta-analysis (systematic review) has been conducted.

Does fruit or vegetables intake reduce inflammation and improve immune function?

Study design:
This review article included 71 clinical trials and 12 were observational studies (n = 10 cross-sectional studies and n = 2 cohort studies).

Results and conclusions:
The investigators found among observational studies (n = 10 studies) an inverse association between intakes of fruit or vegetables and inflammatory biomarkers.

The investigators found the majority of the intervention studies (n = 48 studies) reported beneficial effects of fruit or vegetable intake on ≥1 biomarker of systemic or airway inflammation.

The investigators found a meta-analysis of included studies showed that fruit or vegetable intake significantly decreased circulating levels of C-reactive protein and tumor necrosis factor-α [p 0.05] and significantly increased the γδ-T cell population [p 0.05].

The investigators concluded that higher intakes of fruit and vegetables lead to both a reduction in proinflammatory mediators and an enhanced immune cell profile.

Original title:
Effects of fruit and vegetable consumption on inflammatory biomarkers and immune cell populations: a systematic literature review and meta-analysis by Hosseini B, Berthon BS, […], Wood LG.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29931038

Additional information of El Mondo:
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The level of C-reactive protein (CRP), which can be measured in your blood, increases when there's inflammation in your body.

Tumour necrosis factor-alpha (TNF-alpha) is recognized as an important mediator in many cytokine-dependent inflammatory events.

 

Objectives:
Although glucosamine and chondroitin sulfate have showed beneficial effects on joint tissues in osteoarthritis (OA), their therapeutic use in the clinical setting is still debatable. Therefore, this meta-analysis (systematic review) has been conducted.

Do glucosamine and chondroitin sulfate supplements relieve pain of knee osteoarthritis?

Study design:
This review article included RCTs.

The pain of knee osteoarthritis was measured using the Western Ontario and McMaster Universities Osteoarthritis index (WOMAC) and/or the Visual Analog Scale (VAS).

Results and conclusions:
The investigators found that glucosamine supplements significantly reduced pain of knee osteoarthritis (expressed as Visual Analog Scale (VAS) [WMD = - 7.41 mm, 95% CI = - 14.31 to - 0.51, p = 0.04].
Significant means that there is an association with a 95% confidence.

The investigators found that chondroitin supplements significantly reduced pain of knee osteoarthritis (expressed as Visual Analog Scale (VAS) [WMD = - 8.35 mm, 95% CI = - 11.84 to - 4.85, p  0.00001].
Significant because the found p-value of 0.00001 is less than 0.05.

The investigators found that the combination of glucosamine and chondroitin supplements non-significantly reduced pain of knee osteoarthritis (expressed as Visual Analog Scale (VAS) [WMD = - 0.28 mm, 95% CI = - 8.87 to 8.32, p = 0.95].
Non-significantly because the found p-value of 0.95 is greater than 0.05.

The investigators found that none of the glucosamine, chondroitin supplements or their combination had a significant positive effect on the total WOMAC index and its subscores.

The investigators concluded that oral supplementation with glucosamine or chondroitin sulfate reduces pain in knee osteoarthritis. However, there is no additional effect using both therapeutic agents in combination for the management of symptomatic knee osteoarthritis.

Original title:
Effect of glucosamine and chondroitin sulfate in symptomatic knee osteoarthritis: a systematic review and meta-analysis of randomized placebo-controlled trials by Simental-Mendía M, Sánchez-García A, […], Simental-Mendía LE.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29947998

Additional information of El Mondo:
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Objectives:
In the past, some observational studies have been carried out on the relationship between milk and dairy intake and risk of acne occurrence. However, their results were conflicting. Therefore, this meta-analysis (systematic review) has been conducted.

Does milk and dairy intake increase risk of acne?

Study design:
This review article included observational studies.

Results and conclusions:
The investigators found for highest compared with lowest category of dairy intake a significantly increased risk of 161% for acne [OR = 2.61, 95% CI = 1.20 to 5.67].

Significant means that there is an association with a 95% confidence.

The investigators found for highest compared with lowest category of total milk intake a significantly increased risk of 48% for acne [OR = 1.48, 95% CI = 1.31 to 1.66].
Significantly means it can be said with a 95% confidence that a high total milk intake really increased the risk of getting acne with 48%. 

The investigators found for highest compared with lowest category of low-fat milk intake a significantly increased risk of 25% for acne [OR = 1.25, 95% CI = 1.10 to 1.43].
Significant because OR of 1 was not found in the 95% CI of 1.10 to 1.43. RR of 1 means no risk/association.

The investigators found for highest compared with lowest category of skim milk intake a significantly increased risk of 82% for acne [OR = 1.82, 95% CI = 1.34 to 2.47].

The investigators found results of dose-response analysis revealed a significant linear relationship between dairy, whole milk and skim milk and risk of acne and a nonlinear association between dairy, milk, low-fat milk and skim milk intake and acne.

The investigators concluded there is a positive relationship between dairy, total milk, whole milk, low-fat and skim milk consumption and acne occurrence. In contrary, there is no significant association between yogurt/cheese and acne development.

Original title:
Dairy intake and acne development: A meta-analysis of observational studies by Aghasi M, Golzarand M, […], Taheri F.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29778512

Additional information of El Mondo:
Find more information/studies on dairy products and chronic disease right here.
 

Objectives:
The evidence is mixed on the use of long chain omega 3 fatty acids in the prevention and management of childhood asthma. Therefore, this meta-analysis (systematic review) has been conducted.

Does fish consumption reduce risk of childhood asthma?

Study design:
This review article included 23 observational studies on fish intake in association with childhood asthma.

Results and conclusions:
The investigators found in 15/23 studies early introduction of fish (6-9 months) and regular consumption (at least once a week) improved asthma symptoms and reduced risk in children 0-14 years as compared to no fish consumption; 6/23 showed no effect and 2/23 studies suggested adverse effects.

The investigators found a significantly reduced risk of 25% [OR = 0.75, 95% CI = 0.60-0.95] for all fish intake on current asthma in children up to 4.5 years old. 

The investigators found a significantly reduced risk of 38% [OR = 0.62, 95% CI = 0.48-0.80] for all fish intake on current wheeze in children up to 4.5 years old.

The investigators found as compared to no fish intake, a significantly reduced risk of 65% [OR = 0.35, 95% CI = 0.18-0.67] for fatty fish intake on asthma in children 8-14 years old. 

The investigators concluded that introduction of fish early in life (6-9 months) and regular consumption of all fish (at least once a week) reduces asthma and wheeze in children up to 4.5 years old, while fatty fish intake has beneficial effects in older children (8-14 years). Future well-designed clinical trials are recommended to confirm the promising findings documented in this literature analysis.

Original title:
The role of fish intake on asthma in children: A meta-analysis of observational studies by Papamichael MM, Shrestha SK, [...], Erbas B.

Link:
https://www.ncbi.nlm.nih.gov/pubmed/29524247

Additional information of El Mondo:
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Objectives:
Zinc is an essential trace element for living organisms and their biological processes. Zinc plays a key role in more than 300 enzymes and it is involved in cell communication, proliferation, differentiation and survival. Zinc also plays a role in regulating the immune system with implications in pathologies where zinc deficiency and inflammation are observed. Therefore, this meta-analysis (systematic review) has been conducted.

Do zinc deficiency increase risk of autoimmune disorders?

Study design:
This review article included 62 case-control studies.

The manner of collecting and investigating zinc samples was very heterogeneous.

Results and conclusions:
The investigators found in fixed model that serum zinc concentration of autoimmune disease patients was significantly lower than in controls [mean effect = -1.19, 95% CI = -1.26 to -1.11].

The investigators found in fixed model that plasma zinc concentration of autoimmune disease patients was significantly lower than in controls [mean effect = -3.97, 95% CI = -4.08 to -3.87].

The investigators concluded that a deficiency of zinc in serum and plasma increases risk of autoimmune disorders in humans.

Original title:
Zinc Status and Autoimmunity: A Systematic Review and Meta-Analysis by Sanna A, Firinu D, […], Valera P.

Link:
http://www.mdpi.com/2072-6643/10/1/68/htm

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An autoimmune disease is a condition in which your immune system mistakenly attacks your body. These are the most common autoimmune diseases:  

1. Addison’s disease: Caused by an adrenal hormone insufficiency. Addison’s disease can lead to muscle weakness and fatigue, nausea, weight loss, irritability, low blood pressure, low blood sugar and depression.
2. Celiac disease (gluten allergy): Celiac disease is a reaction to gluten (found in barley, rye and wheat) that causes damage to the lining of the small intestine.
3. Graves’ disease: Caused by extremely overactive thyroid gland. People who have Graves’ disease may have difficulty sleeping, bulging of the eyes, irritability, brittle hair, unexplained weight loss, sensitivity to heat, muscle weakness, light menstrual periods and shakiness of the hands. On the other hand, some people with Graves’ disease may experience no symptoms at all.
4. Hashimoto’s disease: Caused by inflammation of the thyroid gland. Although sometimes no symptoms occur, Hashimoto’s thyroiditis often results in a goiter (enlargement of the thyroid gland, which may be visible as a bulge in the neck), weight gain, fatigue, muscle weakness, depression, cold sensitivity, dry hair and skin, and constipation.
5. Inflammatory bowel disease: This disease refers to a group of inflammatory diseases of the colon and small intestine.
6. Multiple Sclerosis or MS: This disease affects the brain and spinal cord. People who have MS may experience weakness, trouble with balance and coordination, problems speaking and walking, tremors, paralysis and numbness in the extremities.
7. Psoriasis: This is a skin condition that causes redness and irritation as well as thick, flaky, silver-white patches.
8. Pernicious anemia: Caused by the inability to absorb vitamin B12 leading to a decrease in red blood cells.
9. Reactive arthritis: Caused by inflammation of joints, the urethra and eyes.
10. Raynaud’s phenomenon: People with Raynaud’s have a problem with blood flow, resulting in numbness, tingling of the fingers, discoloration, toes and tip of the nose with exposure to cold temperatures.
11. Rheumatoid arthritis: In rheumatoid arthritis, autoimmunity causes the immune system to attack tissues in the joints. It typically affects the small joints in your hands and feet causing painful swelling, stiffness and loss of movement in the joints that can eventually result in bone erosion and joint deformity.
12. Scleroderma: Scleroderma is a connective tissue disease that causes changes in skin, muscles, blood vessels and internal organs.
13. Sjögren’s syndrome: Caused by destruction of the glands that produce tears and saliva causing dry eyes and mouth.
14. Systemic lupus erythematosus: In lupus, antibodies made by the immune system attack the body. Systemic lupus erythematosus can affect skin, kidneys, joints and brain.
15. Type 1 diabetes: In type 1 diabetes, the immune system attacks cells in the pancreas that produce insulin. When your insulin levels are insufficient, your body cannot control your blood glucose level, which can lead to a number of problems, including kidney failure, stroke, vision loss, circulation problems and heart disease.