Garlic and Onions: Their Cancer Prevention Properties

Changing dietary habits can be a practical and cost-effective way to reduce cancer risk and change tumor behavior.About 30-40% of cancers are preventable with proper diet and nutrition, physical activity and maintaining a healthy weight.This means that making food choices helps maintain a healthy weight, reducing your consumption of foods like red or processed meat can increase cancer risk, and increasing food consumption can reduce your risk cancer, including foods of plant origin. There is a growing public health need to identify dietary patterns, bioactive foods, and compounds that may reduce cancer risk. The genus Allium is a particular food group that has attracted considerable interest due to its supposed cancer-preventing properties.Illium is the Latin word for garlic.It is part of the genus of monocotyledonous flowering plants commonly known as the onion genus. The genus includes about 500 species, including edible onions (A.cepa), garlic (A.sativum), shallots (A.ascalonicum), shallots (A.schoenoprasum) and leeks (A.porrum). Garlic and onions are native to Central Asia and are among the oldest crops in the world.Onion vegetables contain similar amounts of nutrients, especially macronutrients, although garlic is a richer source of minerals, including selenium.Onions, because they are eaten in larger quantities than other Allium vegetables, are a good source of carbohydrates, fiber, potassium, iron and vitamin C. Onion vegetables contain many bioactive compounds, including flavonoids, oligosaccharides, arginine and selenium; However, the majority of Allium's health benefits and the majority of research on it focus on its sulfur-containing ingredients. Although epidemiological studies support a definite link between increased onion and/or garlic consumption and a reduced risk of certain cancers, data are limited and sometimes contradictory.In addition, Onion vegetables are often grouped together for epidemiological analysis, which prevents separation of effects.

The strongest epidemiological evidence points to a protective effect of garlic and/or onions against gastrointestinal cancers.A recent meta-analysis of 19 case-control studies and 2 cohort studies found that consuming large amounts of Allium vegetables reduces the risk of stomach cancer.Compare the highest and lowest drinking groups (odds ratio (OR):0.54; 95% CI 0.43-0.65).Results were similar for each of the Allium vegetables, including garlic, onion, leeks, Chinese chives, scallions, and garlic stalks, but without the onion leaves.The summary OR of the reduction in stomach cancer risk when increasing total Allium vegetable intake to 20 g/day (mean weight of one garlic bulb) was 0.91 (95% CI 0.88 to 0.94).A meta-analysis of 8 different prospective cohort studies on total Allium vegetable consumption and colorectal cancer risk found that the risk did not decrease with increased Allium consumption.The WCRF/AICR panel found no statistically significant reduction in colorectal cancer risk with the highest garlic consumption in two prospective cohorts, while three case-control studies showed an increased risk of colorectal cancer.Colorectal cancer decreased significantly for those who ate the most garlic and three other case-control studies.Chen et al found that raw garlic/onion consumption at least once a week was associated with an adjusted OR of esophageal cancer of 0.2 (95% CI 0.1-0)., 5) in Taiwanese men.

Cooked garlic or onions were not included in this study.Case-control studies in Italy and Switzerland also reported that eating at least 7 servings of onions per week was protective against esophageal cancer (OR = 0.12; 95% CI 0.02–0.58) and increased garlic consumption had a protective effect (p< trend; 0.0001) with the highest intake associated with an OR of 0.74 (0.64-0.86).The WCRF/AICR report looked at a cohort and eight case-control studies to collectively evaluate the effects of garlic, onions, or Allium onions on the risk of esophageal cancer.Only one of the case-control studies showed a statistically significant reduction in risk.