Objectives:
The role of chromium as a weight loss agent remains questionable and although previous meta-analyses findings have reported small reductions in body weight in individuals with overweight/obesity following chromium supplementation, there have been significant limitations with these findings. Therefore, this review article has been conducted.

Scientific studies on the relationship between diet/nutrients and sport performance:
A review article of randomized, placebo-controlled double blind clinical trials (RCTs) will answer the following question:
"Do taking dietary supplements make sense?" Yes for a positive conclusion and no for a negative conclusion.

A review article of cohort studies or case-control studies will answer the following question:
"Should I change my diet?".

Objectives:
Intermittent preventive treatment (IPT) with sulphadoxine-pyrimethamine (SP) is recommended for preventing maternal and fetal effects of malaria in pregnancy. Increasing parasite resistance to sulphadoxine-pyrimethamine has necessitated the search for an alternative medication. Therefore, this review article has been conducted.

Objectives:
Is there an association between poultry and egg consumption and brain cancer risk?

Study design:
This review article included a total of 10 articles (6 articles for poultry consumption and 5 articles for egg consumption).

A review article of randomized, placebo-controlled double blind clinical trials (RCTs) will answer the following question:
"Do taking dietary supplements make sense?" Yes for a positive conclusion and no for a negative conclusion.

A review article of cohort studies or case-control studies will answer the following question:
"Should I change my diet?".

Objectives:
Anemia is one of the most common hematologic problems occurs among patients with tuberculosis (TB). Many studies have been carried out estimating the prevalence of anemia among tuberculosis patients in different countries reported various results. Therefore, this review article has been conducted.

Objectives:
Dietary proteins, including those obtained from animal and plant sources, have inconsistently been correlated with type 2 diabetes mellitus (T2DM) risk. Therefore, this review article (meta-analysis) has been conducted.

Does dietary protein intake increase risk of type 2 diabetes mellitus?

Objectives:
Iron has been shown to promote breast carcinogenesis in animal models through generation of oxidative stress and interaction with estrogen. Heme iron, which is found exclusively in animal-sourced foods, is suggested to have a more detrimental effect. Epidemiological evidence of the association between iron and breast cancer risk remains inconclusive and has not been comprehensively summarized. Therefore, this review article has been conducted.

Does dietary iron consumption increase breast cancer risk?

Objectives:
Although many studies have shown that low zinc status is associated with diabetes, the putative effects of zinc supplementation on glycemic control are inconclusive. Therefore, this review article (meta-analysis) has been conducted.

Does zinc supplementation reduce risk of diabetes mellitus?

Objectives:
Does maternal vitamin D deficiency during pregnancy increase risk of low birth weight?

Study design:
This review article included a total of 16 studies.

Results and conclusions: