Allium sativum, more commonly known as garlic, has been used since ancient times, establishing a long history in the culinary and medicinal world. Medicinal usage of garlic has a plethora of purported beneficial effects which include: antioxidative, anti-inflammatory, antifungal, anticancer, antimicrobial, neuroprotective, alleviating diabetic symptoms, and preventative effects on cardiovascular diseases. In the modern world today, many still use garlic in culinary applications and in supplement form (Kodera, Ushijima, Amano, Suzuki, & Matsutomo, 2017). Depending on the style of preparation, garlic contains many different molecules and chemicals that contribute to the myriad of claimed health benefits. The claimed benefits are largely due to organosulfur compounds, which are found in high amounts in garlic. Organosulfur compounds’ such as alliin, allicin, and S-allyl cysteine have been studied for their antioxidative, antimicrobial, anti-inflammatory properties (Balamash, Albar, Wang, & Ahmed, 2012). When aged over a prolonged period, aged garlic extract can be made, which produces more organosulfur compounds, such as S-allyl cysteine, in more stable forms (Nillert, Pannangrong, Welbat, Chaijaroonkhanarak, Sripanidkulchai, & Sripanidkulchai, 2017).
Garlic’s role in prevention of heart diseases are due to the anti-inflammatory effects, reducing issues such as hypertension and providing protection against atherosclerosis (buildup of cholesterol in the arteries). In a study conducted by Ried, Frank, & Stocks (2012), 79 patients were divided into separate groups, where either a placebo or varying doses of aged garlic extract (240/480/960 mg) were given. The study found promising results with hypertensive participants. While a daily dose of one capsule (240 mg) of aged garlic extract did not report any significant reductions in blood pressure when compared to the placebo group. A daily dose of two capsules (480 mg) found statistically significant reductions in blood pressure compared with the placebo group; reporting this reduction to be comparable with antihypertensive medication. The participants who consumed a daily dose of four capsules (960 mg) also found statistically significant reductions in blood pressure compared with the placebo group. However, what is interesting is the reduction in the four dosage group did not provide a large difference, compared to those who took only two. The study suggests that the participants in the four dosage group had less compliance due to reported gastrointestinal side effects – which may have led to smaller difference in reduction.
In another study, the application of aged garlic extract was conducted on 65 participants who were at intermediate risk for atherosclerosis. Participants were either given a placebo or a 1200 mg dose of aged garlic extract. The study found beneficial effects in reducing the progression of atherosclerosis and inflammation, these results are congruent with similar studies. It is important to note that the participants were also given a dose of Coenzyme Q10 (CoQ10; 120 mg), which also boast antioxidative properties and have been shown to lower LDL (the bad cholesterol) levels. A study conducted by Balamash, Albar, Wang, & Ahmed (2012), attempted to prove the claimed health benefits for diabetic individuals. The study, however, failed and found no significant changes in fasting blood glucose. Although, the authors state that previous studies have found beneficial effects in the blood glucose of rat models, but were unable to replicate the results on human trials. The study did find some decline in blood lipid profiles, but they were deemed not statistically significant. Issues with this study is that it was completed over a three-month intervention, a small sample size of 48 participants, and the study did not utilize varying doses.
References
Balamash, K., Albar, O., Wang, Q., & Ahmed, N. (2012). Effect of Kyolic® aged garlic extract on glycaemia, lipidaemia and oxidative stress in patients with type 2 diabetes mellitus. Journal of Diabetes Research and Clinical Metabolism, 1(1), 18. doi:10.7243/2050-0866-1-18
Kodera, Y., Ushijima, M., Amano, H., Suzuki, J., & Matsutomo, T. (2017). Chemical and Biological Properties of S-1-Propenyl-ʟ-Cysteine in Aged Garlic Extract. Molecules, 22(4), 570. doi:10.3390/molecules22040570
Ried, K., Frank, O. R., & Stocks, N. P. (2012). Aged garlic extract reduces blood pressure in hypertensives: A dose–response trial. European Journal of Clinical Nutrition, 67(1), 64-70. doi:10.1038/ejcn.2012.178
Zeb, I., Ahmadi, N., Kadakia, J., Larijani, V. N., Flores, F., Li, D., . . . Nasir, K. (2012). Aged garlic extract and coenzyme Q10 have favorable effect on inflammatory markers and coronary atherosclerosis progression: A randomized clinical trial. Journal of Cardiovascular Disease Research, 3(3), 185-190. doi:10.4103/0975-3583.98883
