A Guide to hardneck Garlic Varieties
Are you trying to decide which hardneck garlic varieties to plant? With so many options available, how do you know which ones are best suited for your climate, which last the longest in storage, and which ones have the most flavor? Even though it appears from looking at seed catalogs that there are many garlic cultivars, DNA analysis indicates that many of them are clones of each other and have merely been renamed.
Overview of Hardneck Garlic
What is hardneck garlic?
Hardneck garlic is a type of garlic that is characterized by a hard central stalk that grows through the center of the bulb. This stalk is called the scape, and it is edible. Hardneck garlic varieties also have a more intense flavor than softneck garlic varieties. Hardneck Garlic is typically grown in climates that experinece cold winters. Softneck Garlic is typically grown in climates with mild winters. In simple terms, we can break garlic down into these groups:
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Five (5) hardneck varieties called Porcelain, Purple Stripe, Marbled Purple Stripe, Glazed Purple Stripe, and Rocambole.
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Three (3) varieties of "weakly bolting" hardnecks that can produce softnecks - Creole, Asiatic and Turban.
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Two (2) distinct softneck varieties; Artichoke and Silverskin.
Hardneck Garlic
Hardneck garlic differs from softneck garlic, in that they produce a tall, stiff flower stalk that rises from the center of the bulb. Hardnecks are more suited to northern climates than softneck types, the kind usually found in supermarkets and grown in mild climates. The five (5) hardneck varieties we will focus on here include Porcelain, Purple Stripe, Marbled Purple Stripe, Glazed Purple Stripe, and Rocambole.
Porcelain
Porcelain garlics produce beautiful and robust plants. They grow lush and tall above ground, and the bulbs can grow very large - over three (3) inches in diameter. Often, the bulbs contain 4 to 10 huge cloves, which are fairly easy to peel. Porcelain garlic grows best in Northern climates, though grows surprisingly well in cool, southern climates - as compared to the other hardnecks. Some research claims Porcelains have the highest allicin content, the sulfur compound that gives garlic its therapeutic benefits. The paper covering the individual cloves is thick, uniform, and shimmery. If handled properly (not dropped or banged up!) and placed in a cool, dry environment, Porcelain garlic bulbs store up until mid-April when they begin to sprout.
Home cooks and professional chefs reflect that Porcelains have a medium-to-strong taste and retain the garlic flavor in cooking. Their flavor does vary between cultivars, but not as widely as some groups. Porcelains tend to be hot with aggressive overtones. The cloves are typically large and there are few per bulb, making them a good choice for those who like copious amounts of garlic with little peeling.
It is believed Eastern Europeans brought these cultivars with them to North America when immigrating. Porcelains are popular in the northern tier if North America (north of 40 degrees North Latitude) largely due to how cold-tolerant Porcelains are, making them a reliable choice for most northern growers. Here is a short list of a few Porcelain garlic cultivars:
German Extra Hardy produces a large bulb and large cloves with robust, hot flavor.
Leningrad matures later than most porcelain garlic varieties. The large bulbs generally have approximately 5 cloves.
Music produces a large bulb and large cloves with robust, hot flavor. Music garlic was believed to have been brought to Canada from Italy during the 1980s. The porcelain-type garlic was named for Al Music, a tobacco farmer turned garlic grower who introduced the variety to Canada.
Georgia Fire consists of pale, brown cloves streaked with purple, native to the Republic of Georgia.
Armenian is a flavorful, attractive type of porcelain garlic. The white wrappers are marked with a tint of red.
Romanian Red is a beautiful garlic with purple-striped wrappers and four to eight cloves per bulb. The flavor is hot and pungent.
Georgian Crystal is one of the mildest porcelain garlic varieties, with a flavor that is robust but mellow.
Majestic is appreciated for its large bulbs, each with four to seven cloves. The flavor is strong and delicious.
Russian Giant is a moderately hot type of porcelain garlic. They grow large with a bulb diameter of 3 inches or so.
German White is a vigorous variety that produces large bulbs, each with up to seven bulbs. Music displays more color than most porcelain garlic varieties. The flavor is rich and strong but not overly hot; however, it is sweeter when baked.
Rosewood consists of big, beautiful bulbs of soft, pastel colors.
Zemo has a strong but pleasant taste. It generally produces four to five cloves per bulb.
Purple Stripe
Purple stripe garlic is beautiful. The gorgeous purple and dark-blue hues in the delicate protective garlic coverings are mesmerizing. Named because of the vivid purple coloration and striping on the bulb wrappers and clove skins, it is a strikingly attractive garlic. Researchers identified this type as one of the most ancient of horticultural groups within the garlic family. Botanists have determined, through genetic testing, that Purple Stripes are closely related to original garlic. Obviously, there's something that must have come before Purple Stripe, but this is the oldest known species that is recognizable as a true garlic... allium sativum (and in this case, because it is a hard-neck) ophioscorodon.
Most cultivars have 5 to 10+ cloves per bulb. They store slightly longer than Rocamboles and peel almost as easily. Based on research, Purple Stripe's genetics are very similar to the original line of garlic that other varieties evolved from. They have a strong, complex and rich garlic flavor, without being overly sulfurous. They are great for roasting, usually winning “best baked garlic” taste tests. They do not have the sweetness of Rocamboles, but some of the best maybe even more characterful. Like all other porcelains, Purple Stripe does best in cooler Northern climates with cold winters. Purple Stripes tend to mature a little later in the season than many other varieties, pushing back the harvest date. Here is a short list of a few Purple Stripe garlic cultivars:
Persian Star: White wrappers with purple streaks and a full, mellow, mildly spicy flavor. Persian Star has a pleasant flavor with a mild spicy zing; it averages 8-12 cloves per bulb. It is a beautiful garlic with thick white bulb wrappers streaked with purple.
Metechi: A very hot, heirloom variety. The outer covering is white, getting progressively deeper purple as the wrapper is removed. This is a large hardneck garlic with a very strong flavor and exceptional clove productivity on blushed wrappers with purple streaks. ‘Metechi’ stores well, and produces a bonus of delicious gourmet garlic scapes in summer.
Purple Glazer: A tall plant with deep green leaves showing a tinge of blue in sunlight. Wrappers are solid white wrappers closer to the cloves are nearly purple inside. Produces large, elongated cloves wrapped in satiny wrapped striped with purple. Strong, rich, long-lasting garlic flavor with sweetness. 6-10 large cloves per bulb.
Chesnok Red: Large, attractive garlic consisting of white cloves with reddish-purple stripes. Retains its full flavor when cooked. Like other hardnecks, Chesnok Red is a cold-hardy variety known for its fine flavor and smooth texture when roasted. Produces large bulbs with 8–12 medium-sized cloves per head. Stores 6 months when cured.
Bogatyr: Large garlic that packs a punch! Hot garlic with a long storage life. The outer skin is white, turning brownish-purple closer to the cloves. Bogatyr is one of the spiciest varieties around.
Marbled Purple Stripe
Marbled Purple Stripes are beautiful in appearance and have a wonderful garlic taste. Bulbs have a marbled purple-splash appearance as the name suggests. Similar to other hardnecks, the plants grow 3-4 feet tall with long green leaves. Depending on soil conditions, marbled purple stripe have stunning purplish bulb wrappers. Marbled Purple Stripes have grown steadily in popularity due to their consistent clove size, consistent taste, dependable growth in the garden and field, and relatively long storage life (six months and more). Marbled Purple Stripe is another subgroup related to Purple Stripe, no more closely associated (genetically) with Purple Stripe than is Porcelain or Rocambole. Marbled Purple Stripe flourish in colder climates due to the extended period of dormancy and exposure to cold wintery conditions. Some growers claim that Marbled Purple Stripes are more forgiving of wetter conditions than other varieties tend to be. Here is a short list of a few Marbled Purple Stripe garlic cultivars:
Belarus: Deep, reddish-purple garlic. Flavor: Belarus garlic starts out mild and has an intense finish when eaten fresh. Sweet and very mild when cooked.
Siberian: A rich, mild variety. Siberian garlic is known for its robust, well-rounded flavor and creamy consistency. Siberian garlic is favored for its long-term storage capabilities as it can keep for 6-7 months, and can complement a wide variety of flavors without overpowering the dish.
Russian Giant : Large cloves with a mild flavor. Consistently large with great taste. Not uncommon to be 3 inches. It's a beauty.
Glazed Purple Stripe
Glazed Purple Stripe garlic have lovely wrappings and is truly beautiful. When harvested, the outer skins on the bulb may appear white or cream-colored. As you remove the outer layers, the glazed-purple colors emerge. Glazed Purple Striped garlics derive their name from the beautiful purple striping on the bulb wrappers and clove skins. The cloves are not difficult to peel, but their clove skins tightly wrap the cloves. This tightness protects the cloves and causes the Purple Striped garlics to last longer in storage. Like Marbled Purple Stripes, Glazed Purple Stripes were once considered to be a sub-type of the Purple Stripe group rather than their own distinct category. Here is a short list of a few Glazed Purple Stripe garlic cultivars:
Red Rezan These garlics are beautiful and their taste is also desirable. Red Rezan Hardneck Garlic has a well-rounded garlic flavor and strong aromatic warmth both raw and cooked. Red Rezan is known for its rich depth and heat. Easy to grown in cold climates, these beautiful purple cloves with a metallic sheen, has all the colors of purple, blue, gold and violet. Bulbs contain 6-12 cloves and store 5-7 months. Growers can quickly increase yeilds with this type, since it contains more cloves per bulb.
Celeste: These garlics produces garlic with a warm, rich flavor. The outside wrappers may appear white, though the Inner bulb wrappers are nearly solid purple. Celestes are tall plants with dark green very elongated leaves with a dark blue hue. Their leaves are not as wide as the Marbled group while the main group are clearly smaller. Celeste's bulb parchment-like wrappers are sleek and as layers are peeled away the outer wrappers more and more purple striping shows up and they become almost solid purple by the time you get down to the cloves.
Rocambole
Rocambole Garlic is known for its robust, well-rounded, true garlic flavor. Not only are they perfect for many recipes, they are also great for roasting. The raw heat is nicely balanced by a deep and rich flavor, with sweet undertones. Rocamboles have skins and are easy to peel and bulbs can be large and cloves are an attractive brown to red with a hard shell. Rocambole garlic craves cold winters and do well in the northern climates.
By early summer, Rocamboles, like other hardnecks, send up a scape (stalk) that forms a complete loop and often a double loop. The bulb is comprised of eight to ten cloves arranged in a circular fashion about a central scape and have few or no smaller internal cloves (similar to the composition of a mandarin orange). They do not grow well in warmer climates and they appear to do best in climates with cold winters and a cooler spring with adequate moisture.
In some parts of the world the term Rocambole is used interchangeably with the term garlic itself, which leaves those people who use the term in this way at a loss as to what the distinction is. Among botanists and most growers, however, it's understood that Rocambole refers to this incredible family of outstanding garlics and while it isn't synonymous with garlic itself, it is nearly synonymous with great garlic.
Spanish Roja: These garlics produce garlic with a warm, rich flavor. They are considered mid-season garlic. Probably the most popular hardneck type, because most garlic lovers find the flavor to be “true garlic”. A Northwest heirloom that was reported to have been brought into Northwest Oregon before 1900, it is often called Greek garlic by home gardeners throughout the region.
Bavarian Purple: This is considered a mid-season, Rocambole type. Bavarian Purple garlic has a mildly pungent flavor and is exceptionally versatile, utilized in both raw and cooked applications such as roasting and sautéing. Bavarian Purple garlic is considered a rocambole variety that is highly favored by garlic enthusiasts in the United States. Though garlic has been cultivated since ancient times. The bulbs have a relatively short shelf life compared to other hardnecks and will keep 3-6 months when stored in a cool, dry, and dark place. Bavarian Purple garlic is known for its complex, pungent flavor and grows well in cool climates.
Propagation of Hardneck Garlic
Garlic is a hardy perennial that can be grown in a variety of soil types. The plants perform best when planted in a light, well-draining, organic loam with a pH between 6.0 and 7.0. The plant grows well in cool weather but will tolerate a range from 9–28°C (48.2–82.4°F). Garlic should be planted in an area that receives full sun for most of the day. Garlic requires a period of cold followed by a period of light and heat to develop properly. The plants will perform best when they have 6-8 weeks below 4.4ºC (40ºF). It may be beneficial to chill bulbs before use if planting in an area that does not fulfill these temperature requirements.
Planting Most garlic varieties do not produce fertile seeds so the plant is propagated from the cloves. Individual cloves are obtained by breaking apart the bulb. Generally, garlic should be planted in the Fall around the same time spring bulbs such as daffodils are planted. Planting in the Spring does not allow sufficient time for the root system to develop and the garlic may not form heads. The soil should be prepared for planting by digging with a fork to loosen it and break up any large clumps. Cloves should be planted 5–8 cm (2-3 in) deep, leaving 8–10 cm (3.1–3.9 in) between individual plants and 15–20 cm (5.9–7.9 in) between rows. The cloves should be planted pointed side up with the basal plate positioned downwards. The roots will grow from the basal plate. Each clove will produce a whole head of garlic which can be harvested and cured before use.
When the ground begins to freeze, it is good practice to cover the garlic plants with a layer of straw mulch. This helps to protect the plants overwinter, prevents frost heaving, and helps to suppress weeds in the Spring. Garlic requires additional irrigation during dry periods but watering should be ceased a few weeks before harvest to allow the papery skin around the bulb to dry and to prevent the development of disease. Garlic benefits from the addition of fertilizer during the growing season. Nitrogen should be applied in early Spring, later applications may delay bulb development. Hardneck garlic should be pruned when the flowering stalks (scapes) begin to straighten. Removal of the flower head directs the plant's energy to bulb production. Softneck garlic does not require pruning. Harvesting Garlic is ready to harvest when the plants begin to turn yellow or brown and begin to fall over. Dig the plants while there are still some green leaves remaining on the plant. Harvest the bulbs by digging the plant carefully and lifting the bulbs using a fork. The garlic can be used straight away or it can be cured for longer storage. Garlic can be cured by hanging the plants in bunches or by spreading them out on a rack or screen. The plants should be kept intact while they cure, do not remove the tops until the garlic is dry. Curing should be carried out in a cool, dry place with good ventilation such as a barn, attic, or garage. Once dry, the bulbs will keep for up to a year. (Source: Penn State University).
How to grow hardneck garlic
Hardneck garlic can be grown in most cool climates, and it is best suited for cold climates, like that of Minnesota, Montana, Colorado, Wisconsin, and Idaho (to name only a few states). It should be planted in the fall and harvested in the summer. To plant hardneck garlic, you will need to divide a bulb into individual cloves. Each clove should be planted with the pointed end up, about 6 inches apart and 3 inches deep. Water the cloves well and mulch the soil around them to help retain moisture. Hardneck garlic needs full sun and well-drained soil. It is important to water the garlic regularly, but do not overwater it. Too much water can cause the garlic to rot. Hardneck garlic is ready to harvest when the leaves start to turn yellow and fall over. The bulbs should be dug up and cured in a cool, dry place for several weeks before storing them.
Tips for growing hardneck garlic
Plant hardneck garlic cloves in the fall, about six weeks before the first frost. Plant cloves in well-drained soil. Water the cloves regularly, but do not overwater them. Mulch the soil around the cloves to help retain moisture. Harvest the garlic bulbs in the summer, when the bottom leaves start to turn yellow.
Store the garlic bulbs in a cool, dry place for several months.
Science has provided garlic growers and garlic connoisseurs, definitive information about the confusing subject of garlic groups and varieties. In 2003, Dr. Joachim Keller of the Institute the Leibniz Institute for Plant Genetics and Crop Plant Research in Gatersleben Germany, and Dr. Gayle Volk of the USDA in Colorado, used science to perform DNA analyses of garlic. They classified garlic into ten distinct groups including:
Overview of Hardneck Garlic
Garlic, Allium sativum, is a herbaceous, annual, bulbous plant grown for its pungent, edible bulb of the same name. The name "garlic" comes from garleac, an old Anglo-Saxon word meaning "spear leek." Garlic is believed to be descended from Allium longicuspis, a wild strain of Asian garlic but its origins are still in question. Garlic, and other members of the Alliaceae (Previously Amaryllidaceae) are native to central Asia and derive their characteristic flavor from the enzyme alliinase that acts on Sulphur compounds. All plants in this family are herbaceous, cool-season, biennial vegetables that are grown as annuals. Root systems are fibrous. Bulbs form from enlarged leaf bases called scales. Cold temperatures, combined with day length and soil temperature trigger bulb formation. Garlic (Allium sativum) is a cool-season hardy perennial made up of multiple cloves. Each clove is made up of one papery leaf and a second, thickened storage leaf which makes up most of the clove. Garlic leaves are solid, folded, and flattened. This bulbous plant grows vertically to an approximate height of 3 feet (1 meter). Garlic scapes can extend the height of this plant. Garlic rarely produces a hermaphrodite flower. The name Chicago is derived from the local Indian word chicagoua for the native garlic plant (not onion) Allium tricoccum.
The Egyptians believed in garlic. The Codex Ebers, a medical text dating to 1,500 B.C., mentions garlic as a remedy for skin diseases, poisoning, heart problems, and tumors. Intact cloves of the stuff were found preserved in Tutankhamenís tomb. In the Old Testament, the desert-wandering Israelites sadly remember "the fish which we did eat in Egypt so freely, and the pumpkins and melons, and the leeks, onions, and garlic." Hippocrates prescribed garlic for protecting the skin, and Greek athletes ate it before competing in the first Olympic Games. In ancient China and Japan, garlic was thought to provide energy, lift depression, and improve male potency; in India, it was used to treat arthritis and leprosy.
Garlic is believed to be native to Central Asia. Many plants referred to as “wild garlic” worldwide are members of the Allium family (leeks, onions, shallots, chives) but are not true garlic or Allium Sativum. All cultivated garlic comes from two subspecies A. sativum var. ophioscorodon and A. sativum var. sativum. Like many “wild garlics” elephant garlic, though tasty, is not a “true garlic” but is instead a member of the onion genus. Garlic is a versatile crop. It can be grown in the ground, in containers, in raised beds, and square foot gardens with success. As with many vegetables, the trick is timing and choosing the right variety for your location. Hardnecks will do well with proper vernalization. Vernalization is a cold treatment, similar to that of blooming bulbs such as tulips. This can be accomplished in the ground or in a chest freezer (set at a temperature just at freezing) or a refrigerator for 60+ days prior to planting.
Genetic Diversity among U.S. Garlic
REFERENCES
Ledezma E, DeSousa L, Jorquera A, et al. Efficacy of ajoene, an organosulphur derived from garlic, in the short-term therapy of tinea pedis. Mycoses. 1996;39(9-10):393-395. (PubMed)
Moyers 1996 Moyers, S. (1996) History of garlic. Garlic in Health, History and World Cuisine :1–36 Suncoast Press St. Petersburg, FL.
Bergner and P 1996 Bergner, P. (1996) The Healing Power of Garlic :3–26 Prima Publishing Rocklin, CA.
Block 1985 Block, E. (1985) The chemistry of garlic and onions. Sci. Am. 252:114–119.
Green and Polydoris 1993 Green, O. C., III & Polydoris, N. G. (1993) The chemistry of garlic and onions. Garlic, Cancer and Heart Disease: Review and Recommendations :21–41 GN Communications Chicago, IL.
Ide and Lau 1997 Ide, N. & Lau, B. H. (1997) Garlic compounds protect vascular endothelial cells from oxidized low density lipoprotein-induced injury. J. Pharm. Pharmacol. 49:908–911.
Kahn 1996 Kahn, G. (1996) History of garlic. Koch, H. P. Lawson, L. D. eds. Garlic: The Science and Therapeutic Application of Allium sativum L. and Related Species :25–36 Williams and Wilkins New York, NY.
Lawson 1998 Lawson, L. D. (1998) Garlic: a review of its medicinal effects and indicated active compounds. In: Phytomedicines of Europe. Chemistry and Biological Activity. ACS Symposium Series 691 (Lawson, L. D. & Bauer, R. eds.), pp. 176–209. American Chemical Society, Washington, DC.
Pinto and RivIin 1999 Pinto, J. T. & RivIin, R. S. (1999) Garlic and other allium vegetables in cancer prevention. Heber, D. Blackburn, G. Go, U. L. M. eds. Nutritional Oncology Academic Press San Diego, CA. pp. 393–403.
Riddle 1996 Riddle, J. M. (1996) The medicines of Greco-Roman antiquity as a source of medicines for today. Holland, B. K. eds. Prospecting for Drugs in Ancient and Medieval European Texts: A Scientific Approach :7–17 Harwood Academic Publishers Amsterdam, The Netherlands.
Riviin 1998 Riviin, R. S. (1998) Patient with hyperlipidemia who received garlic supplements. Lipid Management. Report from the Lipid Education Council 3:6–7.
Steiner et al 1996 Steiner, M., Khan, A. H., Holbert, D. & Lin, R.I. (1996) A double-blind crossover study in moderately hypercholesterolemic men that compared the effect of aged garlic extract and placebo administration on blood lipids. Am. J. Clin. Nutr. 64:866–870.
Steiner and Lin 1998 Steiner, M. & Lin, R. S. (1998) Changes in platelet function and susceptibility of lipoproteins to oxidation associated with administration of aged garlic extract. J. Cardiovasc. Pharmacol. 31:904–908.
Woodward 1996 Woodward, P. W. (1996) Changes in platelet function and susceptibility of lipoproteins to oxidation associated with administration of aged garlic extract. Garlic and Friends: The History, Growth and Use of Edible Alliums :2–22 Hyland House Melbourne, Australia.
Nantz MP, Rowe CA, Muller CE, Creasy RA, Stanilka JM, Percival SS. Supplementation with aged garlic extract improves both NK and γδ-T cell function and reduces the severity of cold and flu symptoms: a randomized, double-blind, placebo-controlled nutrition intervention. Clin Nutr. 2012;31(3):337-344. (PubMed)
Keys A. Wine, garlic, and CHD in seven countries. Lancet. 1980;1(8160):145-146. (PubMed)
Wirth J, di Giuseppe R, Boeing H, Weikert C. A Mediterranean-style diet, its components and the risk of heart failure: a prospective population-based study in a non-Mediterranean country. Eur J Clin Nutr. 2016;70(9):1015-1021. (PubMed)
Ackermann RT, Mulrow CD, Ramirez G, Gardner CD, Morbidoni L, Lawrence VA. Garlic shows promise for improving some cardiovascular risk factors. Arch Intern Med. 2001;161(6):813-824. (PubMed)
Wojcikowski K, Myers S, Brooks L. Effects of garlic oil on platelet aggregation: a double-blind placebo-controlled crossover study. Platelets. 2007;18(1):29-34. (PubMed)
Zeng T, Zhang CL, Zhao XL, Xie KQ. The roles of garlic on the lipid parameters: a systematic review of the literature. Crit Rev Food Sci Nutr. 2013;53(3):215-230. (PubMed)
Ried K, Toben C, Fakler P. Effect of garlic on serum lipids: an updated meta-analysis. Nutr Rev. 2013;71(5):282-299. (PubMed)
Koscielny J, Klussendorf D, Latza R, et al. The antiatherosclerotic effect of Allium sativum. Atherosclerosis. 1999;144(1):237-249. (PubMed)
Siegel G, Klussendorf D. The anti-atheroslerotic effect of Allium sativum: statistics re-evaluated. Atherosclerosis. 2000;150(2):437-438. (PubMed)
Almoudi M, Sun Z. Coronary artery calcium score: Re-evaluation of its predictive value for coronary artery disease. World J Cardiol. 2012;4(10):284-287. (PubMed)
Kwon SW, Kim YJ, Shim J, et al. Coronary artery calcium scoring does not add prognostic value to standard 64-section CT angiography protocol in low-risk patients suspected of having coronary artery disease. Radiology. 2011;259(1):92-99. (PubMed)
Matsumoto S, Nakanishi R, Li D, et al. Aged Garlic Extract Reduces Low Attenuation Plaque in Coronary Arteries of Patients with Metabolic Syndrome in a Prospective Randomized Double-Blind Study. J Nutr. 2016;146(2):427S-432S. (PubMed)
Hadamitzky M, Distler R, Meyer T, et al. Prognostic value of coronary computed tomographic angiography in comparison with calcium scoring and clinical risk scores. Circ Cardiovasc Imaging. 2011;4(1):16-23. (PubMed)
Ried K, Travica N, Sali A. The effect of aged garlic extract on blood pressure and other cardiovascular risk factors in uncontrolled hypertensives: the AGE at Heart trial. Integr Blood Press Control. 2016;9:9-21. (PubMed)
Kodali RT, Eslick GD. Meta-analysis: Does garlic intake reduce risk of gastric cancer? Nutr Cancer. 2015;67(1):1-11. (PubMed)
Kim JY, Kwon O. Garlic intake and cancer risk: an analysis using the Food and Drug Administration's evidence-based review system for the scientific evaluation of health claims. Am J Clin Nutr. 2009;89(1):257-264. (PubMed)
US Food and Drug Administration. Guidance for industry: evidence-based review system for the scientific evaluation of health claims - final. In: US Department of Health and Human Services, ed; 2009. ik FM. Does regular garlic intake affect the prevalence of Helicobacter pylori in asymptomatic subjects? Saudi Med J. 2003;24(8):842-845. (PubMed)