Onion and garlic may reduce risk of breast cancer

By Angela Betsaida B. Laguipo, BSNSep 24 2019

Onion and garlic are staple spices for many cuisines across the globe. There are numerous recipes requiring these two elements, and they may now be key ingredients in cutting the risk of breast cancer.

A team of researchers at the University of Buffalo and the University of Puerto Rico found that eating garlic and onions daily may drastically reduce one’s risk of developing breast cancer, one of the most aggressive types of cancers across the globe.

Breast cancer is the second most common cancer in general, representing about 12 percent of all new cancer cases in 2012, alone. It’s also the topmost frequently diagnosed cancer in women worldwide.

Published in the journal Nutrition and Cancer, the study highlights the use of plant-based foods in combatting cancer, particularly breast cancer. It is the first population-based study to explore the correlation between onion and garlic intake and breast cancer in Puerto Rico. In the country, a popular condiment is sofrito, wherein onions and garlic are key ingredients.

Puerto Rican Sofrito. Image Credit: MikeHerna / Shutterstock

Onion and garlic tied to lower breast cancer risk

The researchers found that among women in the country, the combined consumption of onion and garlic, as well as sofrito, is tied to a lower risk of breast cancer. Those who consumed more than once per day of the said condiment had a 67 percent reduced risk compared to those who never consumed it.

The country is a perfect location for the study since most women are fond of eating lots of onions and garlic, compared to women in the United States and Europe. Aside from sofrito, women consume onions and garlic through eating guisos or stews, and other bean-based or rice-based dishes.

Interestingly, Puerto Rico has lower breast cancer rates compared to the U.S. and this study highlights a possible reason why. The study will provide a better understanding of the reasons why breast cancer rates are lower in Puerto Rico than in mainland U.S.

“There is very little research on breast cancer in Puerto Rico. This study was a collaboration between my colleagues here at UB and at the University of Puerto Rico to help us understand why rates there are lower than in the rest of the U.S., and why rates there are continuing to increase while they are decreasing in the rest of the United States,” Jo Freudenheim, PhD, chair of epidemiology and environmental health at UB, and study co-author, said in a statement.

To arrive at their findings, the researchers identified primary breast cancer cases among women between the ages of 30 and 79 years old. They collected the data from clinic and hospital records. Also, controls were recruited, and they had no history of cancer.

The team estimated food intake through a food frequency questionnaire, wherein total onion and garlic intake were taken into consideration. The study period lasted between 2008 and 2014, which included a total of 314 women with breast cancer and 346 healthy controls.

The results of the study show that high onion and garlic consumption has protective properties against breast cancer.

Garlic bulbs with garlic cloves. Image Credit: spicyPXL / Shutterstock

What is inside onions and garlic?

Onions and garlic are rich in organosulfar compounds and flavonoids,  which are known to have antioxidant properties. Garlic, for example, contains potent compounds such as diallyl disulfide, diallyl sulfide, and S-allylcysteine. Onions contain sulphoxides and alk(en)yl cysteine. All these compounds show anticancer properties in humans.

Flavonoids have gained immense importance and attention as anti-cancer agents. In fact, they have shown great potential as cytotoxic anti-cancer compounds that can trigger apoptosis or programmed cancer cell death.

Like other phytonutrients, flavonoids are potent antioxidants with immune system benefits and anti-inflammatory properties. Diets that are rich in flavonoids are linked to preventing cancer, cardiovascular diseases and neurodegenerative conditions.

Organosulfar compounds in garlic have been known to possess beneficial effects for many types of cancers, like breast cancer, stomach cancer, and colorectal cancer. They show protective effects and can inhibit carcinogenesis in forestomach, colon, esophagus, mammary glands, and lungs.