Garlic has been studied in individuals with heart disease and found to be effective. Some clinical trials have demonstrated it can help prevent the build-up of plaques due to high cholesterol. It is thought garlic does this the same way a statin does; by preventing the body from making cholesterol. There have also been trials that have shown garlic can help lower an individual’s blood pressure. The active ingredient in garlic is allicin and a supplement’s allicin content can vary widely from product to product and even between different lots of the same product. This makes recommending an effective dose difficult to determine. Based on research to treat high cholesterol a dose of 600-1200 mg daily in three divided doses is recommended. The dose for lowing blood pressure is 600-900 mg daily. Four grams of fresh garlic to treat both hypertension and high cholesterol has also been used.
Common side effects are often associated with stomach upset. Individuals may be experience breath and body odor, a burning feeling in the mouth or throat, heartburn, gas, nausea and vomiting. Garlic can also increase the risk of bleeding so caution should be used when starting garlic in patients on blood thinners such as Coumadin (warfarin) and antiplatelet drugs such as Plavix (clopidogrel) and aspirin.
In addition to interactions with blood thinners and antiplatelet medications, garlic should be avoided in patients taking isoniazid which is used to treat tuberculosis. It should also be avoided with certain HIV/AIDs medications including Sustiva (efavirenz), Rescriptor (delavirdine), Viramune (nevirapine) and Invirase (saquinavir). Some evidence also suggests that garlic supplements can decrease the effectiveness of cyclosporine and birth control. These drug interactions are not usually a problem with the amount of garlic found in the average individual’s diet but they do become problematic when being taken on a daily basis at the concentrations found in these supplements.
By Sarah Livings