Garlic and Onions Lower Breast Cancer Risk
Gradually, medical science is realizing just how medicinal garlic and onions are. Exhibit one is a recent human study showing that eating garlic and onions significantly reduces the risk of breast cancer. Other human research backs up this research.
More women die from breast cancer than any other form of cancer. The World Health Organization has estimated that 627,000 women died from breast cancer in 2018. In 2019, over 40,000 women are expected to die from breast cancer just in the U.S., with over 265,000 new cases expected. About 1 in 8 U.S. women will develop breast cancer during their lifetimes in the U.S.
It is notable that breast cancer rates are highest among more developed countries according to the World Health Organization.
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Why are garlic and onions so medicinal?
Garlic (Allium sativum) and onions (Allium cepa L.) belong to the Allium plant family. This group also includes over 500 plants, including shallots (Allium ascalonium), scallions (Allium fistulosum), leeks (Allium ampeloprasum var. porrum) and chives (Allium schoenoprasum). These medicinal foods have been used in traditional medicines around the world for thousands of years. Their medicinal abilities stem from a number of compounds that are common in onions and garlic. These include organosulfur compounds such as:
• aliin (S-allyl cysteine sulfoxide)
• allicin (diallyl thiosulphate)
• ajoene (trithiadodeca trieneoxide)
• allylpropyl disulfide
• diallyl disulfide
• diallyl trisulfide
• S-allylmercaptocysteindiallyl sulfide
• isothiocyanate sulforaphane
These organosulfur compounds have been found to stimulate the liver’s production of glutathione products such as glutathione transferase, glutathione peroxidase and glutathione dismutase. These collectively aid the body in reducing oxidative stress and toxicity throughout the body. Indeed, garlic and its cousins also contain enzymes, including allinase, myrosinase and perosidases. For this reason and more, allium foods have been found to stimulate immunity and help the body fight onslaughts, including cancer.
Garlic, onions and other allium foods also contain tremendous phenols and flavonoids. These include quercetins and caffeic acid. These stimulate the immune system and discourage the growth of cancers. Quercetin in specific has been shown to depress the body’s expression of p52 proteins among breast cancer cells. This helps knock down those cells to help the body’s immunity conquer them.
What if women ate more garlic and onions?
Researchers from the University at Buffalo and the University of Puerto Rico1 studied 670 women between 30 and 70 years old, including 314 that had been diagnosed with breast cancer. The researchers studied their diets in particular, along with their age, education, BMI, family history, smoking and so on.
After every other association was examined, the researchers found those who regularly consumed more garlic and onions had a 49 percent reduced risk of developing breast cancer compared to those who consumed less garlic and onions.
Those women who regularly ate a moderate amount of garlic and onions also had reduced risk, to the tune of 41 percent less incidence of breast cancer.
Moreover, the scientists also found that those who ate a sofrito dish more than once a day saw their incidence of breast cancer go down by a whopping 67 percent. Sofrito is a Puerto Rico traditional dish that contains both fresh garlic and onions.
Do other studies confirm these findings?
This is not the first study to find that eating garlic and onions or other allium foods reduces the risk of breast cancer.
A 2016 study published in the Journal of Breast Cancer2 tested 285 women between 25 and 65 years old. They found that those who consumed higher quantities of raw onion had a 37 percent reduced risk of breast cancer.
A 2012 study of over 6,900 women in China4 found that those women who ate the most allium vegetables had the lowest risk of breast cancer. They were graded for various other foods and allium vegetables had the most anti-cancer effect.
The reduced risk was smaller due to the fact that they compared eating more than 14.75 grams per day versus a moderate intake of 3 grams per day. As the study above showed, moderate consumption of garlic and onions also significantly decreases cancer risk for women.
A 2000 study from Mexico6 studied the diets of 198 women between 21 and 79. They found that eating a slice of onion or more per day resulted in a 70 percent decrease in breast cancer.
A 1998 study from France5 tested 690 women, of whom half had been diagnosed with breast cancer. They found that those women who ate more garlic and onions also had a 70 percent decreased risk of developing breast cancer.
These studies are also supported by laboratory studies showing garlic and onions’ ability to deter cancer cells.
Will cooked onions or garlic supplements also work?
Because many of the compounds in onions and garlic are particularly heat-sensitive, cooking may not yield the same effects. As expected, research on garlic supplements and cooked allium foods, for example, has been less encouraging when it comes to reducing breast cancer risk.
For example, a 1995 study from the Netherlands3 found that garlic supplements and [cooked] leaks and onions were not associated with reduced breast cancer risk reduction. In one of the studies discussed above,2 for example, found increased breast cancer risk among those who ate more cooked onions. This may be because cooked onions are often served with meat dishes, which have been linked with greater breast cancer risk.
Note that sofritos utilize fresh onions and garlic.
The bottom line is that eating fresh garlic and onions is a proven way to reduce breast cancer risk. But cooking them may not yield the same benefits.
1. Desai G, Schelske-Santos M, Nazario CM, Rosario-Rosado RV, Mansilla-Rivera I, Ramírez-Marrero F, Nie J, Myneni AA, Zhang ZF, Freudenheim JL, Mu L. Onion and Garlic Intake and Breast Cancer, a Case-Control Study in Puerto Rico. Nutr Cancer. 2019 Aug 12:1-10. doi: 10.1080/01635581.2019.1651349.
2. Pourzand A, Tajaddini A, Pirouzpanah S, et al. Associations between Dietary Allium Vegetables and Risk of Breast Cancer: A Hospital-Based Matched Case-Control Study [published correction appears in J Breast Cancer. 2018 Jun;21(2):231]. J Breast Cancer. 2016;19(3):292–300. doi:10.4048/jbc.2016.19.3.292
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10. Martins N, Petropoulos S, Ferreira IC. Chemical composition and bioactive compounds of garlic (Allium sativum L.) as affected by pre- and post-harvest conditions: A review. Food Chem. 2016 Nov 15;211:41-50. doi: 10.1016/j.foodchem.2016.05.029.