Superfoods Series: Onions
By: John King
Bad for your breath but good for your body, onions are a nutritional powerhouse. A delicious addition to stews, soups, salads and sandwiches; onions are loaded with flavonoids, sulfur-containing compounds, Vitamin C, Folic Acid, Selenium, Potassium and Zinc.
Regularly consuming onions supports cardiovascular health in several ways. When administered to diabetic animals, sulfur-containing amino acids found in onions (specifically S-methyl cysteine sulfoxide) reduced serum lipid levels along with blood sugar. This is good news for diabetes sufferers as they are at an increased risk for heart disease.
Onions are also a rich source of Quercetin, a flavonoid that helps prevent the oxidation of LDL cholesterol. LDL oxidation is probably the biggest contributor to cardiovascular disease. Inhibiting LDL oxidation reduces the formation of arterial plaque slowing the progression of atherosclerosis. A 2004 study conducted in Tokyo, Japan showed that animals prone to hypertension, when fed a diet high in raw onions, gained significant protection against heart attack and stroke.
Quercetin also plays a very important role in cancer prevention because of it’s ability to detoxify the body from hormones, heavy metals and environmental toxins. A 1998 French case-control study revealed that French women who consumed the most onions had a lower incidence of breast cancer. A more profound cancer-inhibiting effect was observed when quercetin was combined with curcumin, the active constituent in turmeric. A 2006 study found the quercetin/curcumin combination drastically reduced the number of polyps associated with Familial Adenomatous Polyposis, a condition that often leads to colon cancer. Other cancers that can be positively affected by onion consumption are: brain, breast, stomach, esophageal, prostate, ovarian, kidney, lung and oral.
Onions are also beneficial for the immune system due to their antiseptic, antibacterial and antifungal properties. These properties are due largely to their Diphenylamine content which is directly cytotoxic to a number of pathogenic bacteria including: Bacillus subtilis, Escherichia coli, Porphyromonas gingivalis, Salmonella, Streptococcus mutans and Streptococcus sobrinus. Onions also benefit immunity indirectly by modulating the release of a number of immune system chemicals such as: Histamine, Serotonin, TNF-alpha and Interleukin 4, 6 and 8 (IL-4, IL-6 & IL-8).
It’s easy to incorporate onions into your diet as they make a delicious addition to almost any dish. The nutrient content in onions are highest when they are fresh, ripe and raw. Onions lose their nutrients during storage, so try to eat them soon after purchase. Don’t use onions that are soft, have brown spots or have begun to sprout. Sweet onions can be refrigerated but all other should be stored in “open air”. Onions should not be rinsed in water before using as this washes away nutrients. To prevent onions from turning bitter and to preserve nutrients use a low heat when cooking. Eating raw is the best way to obtain the health benefits of onions. If you do not tolerate raw onions well, start with small amount and slowly increase your portion size. Often the body will adjust and you will experience less stomach distress. If you tend to get gas from eating raw onions try a digestive enzyme designed for this purpose. To get rid of “onion breath” try chewing on a little fresh parsley or mint.
Best in Health,
John