Garlic – Your Cancer Prevention Super Star!

With the number of local cancer cases on the rise each year, it’s never been more important to ensure that you look after your health and equip your body with the most effective cancer fighting defences available.

According to the National Cancer Institute, several population studies have revealed a link between increased intake of garlic and reduced risk of certain cancers, including breaststomachcolonesophagus and pancreas cancers. These studies consider the various causes, cases and spread of a disease related to diet, nutrition and environmental factors.

How Garlic Acts to Prevent Cancer 

  • The protective effects from garlic are thanks to garlic’s strong antibacterial properties, according to Ruddock PS, Liao M and Foster BC’s Phytotherapy Research 17
  • Garlic has an ability to reduce cell production or induce cell death – Asian Pacific Journal of Cancer Prevention 2005 10
  • Garlic’s ability to stop the formation of cancer-causing substances, reported by Shenoy NR and Choughuley AS in Cancer Letters 199218 
  • Garlic’s ability to halt the activation of cancer-causing substances, as published in the Advances in Experimental Medicine and Biology 200119
  • Garlic enhances DNA repair, as found in Genetika 2002 20

Cancer Prevention Study Results

1.       Interestingly, an analysis of data from seven population studies published in the Journal of Nutrition 2001 – A Critical Review Of The Epidemiologic Literature 5 revealed that the more raw and cooked garlic eaten, the lower the risk of stomach and colorectal cancer 

2.       Similarly, the European Prospective Investigation into Cancer and Nutrition (EPIC) is an ongoing multinational study of men and women from 10 different countries, considering the effects of nutrition on cancer. In the study, higher consumption of garlic is linked to reduced risk of intestinal cancer 6 

3.       The Iowa Women’s Study – a large  study investigating whether diet, body fat distribution and other risk factors are related to cancer incidence in older women – revealed that women who ate the highest amounts of garlic had a 50% lower risk of cancer of the distal colon (the last part of the left descending colon) compared with women who had the lowest level of garlic consumption 7 

4.       In another study published in the Asian Pacific Journal of Cancer Prevention, the consumption of vegetables containing allium (especially garlic and onions), was linked to a reduced risk of stomach cancer 9 

5.       The Journal of the National Cancer Institute reveals that a greater intake of allium vegetables (more than 10 g per day vs. less than 2.2 g per day), specifically garlic and scallions, was related to an approximated 50% decline in the risk of prostate cancer 10 

6.       Evidence also suggests that multiplying the amount of garlic you eat may reduce pancreatic cancer risk. A study conducted in the San Francisco Bay area found that pancreatic cancer risk was 54% less in people who ate larger amounts of garlic compared with those who ate lower amounts, as published in Cancer Epidemiology Biomarkers & Prevention 11 

7.       In addition, the European Journal of Epidemiology references a study in France which found that increased garlic consumption was associated with a statistically significant reduction in breast cancer risk. After considering total calorie intake and other established risk factors, breast cancer risk was reduced in those consuming greater amounts of fibre, garlic, and onions 12

How Much Garlic for Cancer Prevention?

Although the National Cancer Institute (part of the National Institutes of Health), does not recommend any dietary supplement for the prevention of cancer, it recognises garlic as one of several vegetables with potential anti-cancer properties. 

Because all garlic preparations are not the same, it is tricky to determine the exact amount of garlic that may be needed to reduce cancer risk. Furthermore, the active compounds present in garlic may lose their effectiveness with time, handling, and processing. 

The World Health Organization’s (WHO) guidelines for general health promotion in adults is a daily dose of 2g to 5g of fresh, crushed garlic (roughly one clove), 0.4g to 1.2g of dried garlic powder, 2mg to 5mg of garlic oil, 300mg to 1,000mg of garlic extract or other formulations that are equal to 2mg to 5mg of allicin. 

How to Get the Garlic Goodness

The best way to maximise garlic’s benefits is to simply eat it crushed raw as, like most vegetables, the cooking process will decrease nutrients and antioxidants.

It is important to remember that the health benefits of garlic, cooked or raw, are only experienced when the clove has been crushed – this is when the super fighter Allicin is released.  One of the recommended ways to take garlic if just swallowing a clove is to put it between your teeth, crush gently so that it breaks and then swallow. Easy! Here are few tips other tips:

  • Crush a garlic clove or cut it into chunks, let is stand for 7 – 10 minutes to let the allicin develop then swallow it with water
  • Add chopped raw garlic into your daily salads
  • Spread your freshly crushed garlic on bread with honey
  • Add freshly crushed garlic to a glass of hot water with ginger, lemon and honey for a refreshing tea


Picture of Garlic

  1. Milner JA. Garlic: Its anticarcinogenic and antitumorigenic properties. Nutrition Reviews1996; 54:S82–S86.
  2. Ross SA, Finley JW, Milner JA. Allyl sulfur compounds from garlic modulate aberrant crypt formation. Journal of Nutrition 2006; 136(3 Suppl):852S–854S.
  3. Amagase H, Petesch BL, Matsuura H, Kasuga S, Itakura Y. Intake of garlic and its bioactive components. Journal of Nutrition 2001; 131(3s):955S–962S.
  4. Amagase H. Clarifying the real bioactive constituents of garlic. Journal of Nutrition2006; 136(3 Suppl):716S–725S.
  5. Fleischauer AT, Arab L. Garlic and cancer: A critical review of the epidemiologic literature. Journal of Nutrition 2001; 131(3s):1032S–1040S.
  6. Gonzalez CA, Pera G, Agudo A, et al. Fruit and vegetable intake and the risk of stomach and oesophagus adenocarcinoma in the European Prospective Investigation into Cancer and Nutrition (EPIC-EURGAST). International Journal of Cancer 2006; 118(10): 2559–2566.
  7. Steinmetz KA, Kushi LH, Bostick RM, Folsom AR, Potter JD. Vegetables, fruit, and colon cancer in the Iowa Women’s Health Study. American Journal of Epidemiology 1994; 139(1):1–15.
  8. Gao CM, Takezaki T, Ding JH, Li MS, Tajima K. Protective effect of allium vegetables against both esophageal and stomach cancer: A simultaneous case-referent study of a high-epidemic area in Jiangsu Province, China. Japanese Journal of Cancer Research1999; 90(6):614–621.
  9. Setiawan VW, Yu GP, Lu QY, et al. Allium vegetables and stomach cancer risk in China. Asian Pacific Journal of Cancer Prevention 2005; 6(3):387–395.
  10. Hsing AW, Chokkalingam AP, Gao YT, et al. Allium vegetables and risk of prostate cancer: A population-based study. Journal of the National Cancer Institute 2002; 94(21):1648–1651.
  11. Chan JM, Wang F, Holly EA. Vegetable and fruit intake and pancreatic cancer in a population-based case-control study in the San Francisco bay area. Cancer Epidemiology Biomarkers & Prevention 2005; 14(9):2093–2097.
  12. Challier B, Perarnau JM, Viel JF. Garlic, onion and cereal fibre as protective factors for breast cancer: A French case-control study. European Journal of Epidemiology 1998; 14(8):737–747.
  13. Li H, Li HQ, Wang Y, et al. An intervention study to prevent gastric cancer by micro-selenium and large dose of allitridum. Chinese Medical Journal (English) 2004; 117(8):1155–1160.
  14. You WC, Brown LM, Zhang L, et al. Randomized double-blind factorial trial of three treatments to reduce the prevalence of precancerous gastric lesions. Journal of the National Cancer Institute 2006; 98(14):974–983.
  15. Tanaka S, Haruma K, Kunihiro M, et al. Effects of aged garlic extract (AGE) on colorectal adenomas: A double-blinded study. Hiroshima Journal of Medical Sciences2004; 53(3–4):39–45.
  16. Tilli CM, Stavast-Kooy AJ, Vuerstaek JD, et al. The garlic-derived organosulfur component ajoene decreases basal cell carcinoma tumor size by inducing apoptosis. Archives of Dermatological Research 2003; 295(3):117–123.
  17. Ruddock PS, Liao M, Foster BC, et al. Garlic natural health products exhibit variable constituent levels and antimicrobial activity against Neisseria gonorrhoeae, Staphylococcus aureus and Enterococcus faecalis. Phytotherapy Research 2005; 19(4):327–334.
  18. Shenoy NR, Choughuley AS. Inhibitory effect of diet related sulphydryl compounds on the formation of carcinogenic nitrosamines. Cancer Letters 1992; 65(3):227–232.
  19. Milner JA. Mechanisms by which garlic and allyl sulfur compounds suppress carcinogen bioactivation. Garlic and carcinogenesis. Advances in Experimental Medicine and Biology 2001; 492:69–81.
  20. L’vova GN, Zasukhina GD. Modification of repair DNA synthesis in mutagen-treated human fibroblasts during adaptive response and the antimutagenic effect of garlic extract. Genetika 2002; 38(3):306–309.
  21. Boon H, Wong J. Botanical medicine and cancer: A review of the safety and efficacy. Expert Opinion on Pharmacotherapy 2004; 5(12):2485–2501.
  22. Piscitelli SC, Burstein AH, Welden N, Gallicano KD, Falloon J. The effect of garlic supplements on the pharmacokinetics of saquinavir. Clinical Infectious Diseases 2002; 34(2):234–238.






Share This Post