Normal Artery Atherosclerotic Artery

Total cholesterol< 200 mg / dL (for >19 y/o)

Triglycerides< 150 mg / dL

HDL-c40 – 60 mg / dL

LDL-c< 100 mg / dL

NORMAL VALUES:

Allium sativum

• antioxidant• antimicrobial,• antihypertensive• antithrombotic• antineoplastic • hypolipidemic effects

– HMG-CoA reductase inhibitor • Decreases hepatic cholesterol

synthesis

– Central nervous system• Affecting satiety

MECHANISM

“Does garlic supplementation have a lipid lowering effect in hyperlipidemic patients?”

METHODOLOGY

CRITERIA FOR CONSIDERING STUDIES

• Randomized Controlled Trial- May or may not involve crossover period

• May be unblinded, single-blinded or double-blinded

• Published or Unpublished

• English Articles

TYPE OF STUDY

• Adults (19 years old above)• With mild, moderate or severe

hypercholesterolemia• No comorbid illnesses• No other pathological serum clinical

chemistries• Not taking any other medications• Not taking any substantial amount of

garlic in the diet

TYPES OF PARTICIPANTS

• Garlic Supplementation– Any form (tablet, capsule, aged garlic

extract or oil for) versus placebo – May have minor ingredients that are not

known to have an effect on the outcome– May or may not be taken with meals– Any dose– At least six weeks of intervention

TYPES OF INTERVENTIONS

• Total Cholesterol

• Low Density Lipoprotein Cholesterol (LDL-C)

• High Density Lipoprotein Cholesterol (HDL-C)

• Triglycerides

TYPES OF OUTCOME MEASURES

• Systematic online article search via PubMed– MESH terms “garlic AND dyslipidemias”– LIMITS: humans, RCTs, English, All adult

19+

SEARCH METHODS FOR IDENTIFICATION OF STUDIES

LIMITS: RCT, Humans, all adults > 19 y/o, English only

LIMITS: RCT, Humans, all adults > 19 y/o, English only

24RCTs 24RCTs

Studies that met the inclusion criteria

(n=14)

Studies that met the inclusion criteria

(n=14)

3 Full-text RCTs cannot be retrieved3 Full-text RCTs cannot be retrieved

11 Full-text RCTs included

11 Full-text RCTs included

Excluded studies (n=10)Excluded studies (n=10)

“Garlic” [MESH] AND “dyslipidemias” [MESH] (n=111) “Garlic” [MESH] AND “dyslipidemias” [MESH] (n=111)

• Cross-referencing of all appraised articles– 2 articles included

• Free text search via Yahoo and Google search engine– Various combinations of the search terms

(cholesterol-lowering effects, garlic, allicin, allium sativum, hyperlipidemia, and hypercholesterolemia)

– 1 article included

SEARCH METHODS FOR IDENTIFICATION OF STUDIES

SEARCH METHODS FOR IDENTIFICATION OF STUDIES

• Local study article search via Herdin online– Search terms “garlic AND dyslipidemia” and

“garlic AND hypercholesterolemia”

• Manufacturers of locally available garlic supplements

• Cardiologists at St. Luke’s Medical Arts Building and Cathedral Heights Building Complex (CHBC) were also contacted through telephone and/or visits to their clinics

SEARCH METHODS FOR IDENTIFICATION OF STUDIES

TOTAL NUMBER OF INCLUDED STUDIES

FOURTEEN

• Assessed using the EBM approachRating Description No. of Studies

A All of the primary and secondary criteria was met 3

B At least one secondary criteria not met 2

C At least one primary criteria was not met but dropouts <20%

9

D At least one primary criteria was not met but dropouts >20%

0

*Study by Sobenin et al., was not placed into any category because number of dropouts was not mentioned

METHODOLOGICAL QUALITY

• All double-blinded RCTs (n=14)– 4 studies with crossover

• Population– Hyperlipidemic male and female adults – No other comorbidities– Not taking any garlic supplementation,

any other medications– Substantial amount of garlic in their diet

DESCRIPTION OF STUDIES

• All of the studies are homogenous at baseline

• Thirteen randomized hyperlipidemic subjects with garlic versus placebo or no intervention

• One article randomized hyperlipidemic subjects with garlic versus anethum graveolens or placebo

DESCRIPTION OF STUDIES

• Intervention– Garlic supplementation

• Form–Capsule or tablet

• Dose–Range: 400mg/day-7,200mg

• Duration–Range 6 weeks-5 months

DESCRIPTION OF STUDIES

• Mean change from baseline– Total Cholesterol, LDL-Cholesterol, HDL-

Cholesterol and Triglycerides

• Mean percent change– Total Cholesterol, LDL-Cholesterol, HDL-

Cholesterol and Triglycerides

MEASUREMENTS OF TREATMENT EFFECT

SUBGROUP ANALYSIS

• Diet– No change in diet (n=7)– Diet Advice (n=2)– Strict Dietary Regimen (n=5)

• Sex– All males (n=3)– Males and Females (n=11)

• Crossover Trials– The group used the lipid parameters

given in the study prior to the crossover period

• One study (Steiner, et al.) did not show the exact values , the group estimated the values through the given graphs

UNIT OF ANALYSIS ISSUES

• Random Effects Model

• Fixed Effects Model

DATA SYNTHESIS

RESULTS AND DISCUSSION

14 INCLUDED STUDIESAge: 19-80 years

1 excluded from statistical analysis

MEAN CHANGE(N = 592-625 )

MEAN PERCENT CHANGE(N = 183 )

SEX DIET

MIXED (M& F)

MALES only

NO dietary change

Dietary advice

Diet regimen

SEX DIET

MIXED (M&F)

MALES only

NO dietary change

Dietary advice

Diet regimen

Total cholesterol, LDL-C, HDL-C, Triglyceride

RESULTS

STANDARD DEVIATION

• Only 3 studies showed the SD for mean change and/or mean percent from baseline:1. Isaacsohn et al.2. Kojuri et al.3. Superko et al.

• 10/13: no SD cited SD values were imputed

NOT INCLUDED IN THE STATISTICAL ANALYSIS

• Berthold et al. No significant effect

• Mader et al. and Vorberg and Schneider Significantly decreased total cholesterol and

triglyceride levels

• Silady et al. no significant differences bet. the 2 groups

TOTAL CHOLESTEROL (TC)

Fig.2 Comparison of Mean Change from Baseline of Total Cholesterol Levels

TOTAL CHOLESTEROL (TC)

Fig.3 Comparison of Mean Percent Change from Baseline of Total Cholesterol Levels

LDL-C

Fig.4 Comparison of Mean Change from Baseline of LDL-C Levels

LDL-C

Fig.5 Comparison of Mean Percent Change from Baseline of LDL-C Levels

HDL-C

Fig.6 Comparison of Mean Change from Baseline of HDL-C Levels

HDL-C

Fig.7 Comparison of Mean Percent Change from Baseline of HDL-C Levels

TRIGLYCERIDE (TG)

Fig.8 Comparison of Mean Change from Baseline of Triglyceride Levels

Fig.9 Comparison of Mean Percent Change from Baseline of Triglyceride Levels

TRIGLYCERIDE (TG)

SUMMARY OF RESULTS• Mean change from baseline of TC and LDL-C Favored the garlic treatment group Significantly decreased levels

• Mean change from baseline of HDL-C and TG Favoured the garlic treatment group, but not significant

• Mean percent of all lipid parameters Not significant small number of participants

Subgroup analysis(Jacy girl’s part)

CONCLUSION • Garlic treatment significantly reduces

the total cholesterol and LDL-C levels among hyperlipidemic patients.

• However, a larger number of participants may be needed to make the conclusion more robust.

• There is no sufficient evidence that garlic affects the HDL-C and triglyceride levels.

IMPLICATION FOR PRACTICE• Recommend the use of garlic as a

supplement to lower the lipid levels among hyperlipidemic patients.

• However, this should not be used as the primary lipid-lowering medication.

• Garlic supplementation markedly improves the serum lipid levels of hyperlipidemic men.

• The hypolipidemic effect is augmented by an approved dietary regimen.

IMPLICATION FOR RESEARCH

• Because the robustness of the results remains debatable, the inclusion of more studies involving a larger number of participants is recommended.

• The population of our study only focused on hyperlipidemic patients. Normolipidemic patients may also be included in the future to determine the applicability of effects of garlic supplementation to these patients.