Fajitas, roast, chili, soup… What do all these cuisines have in common? By eating them, you may be able to raise your HDL “good” cholesterol numbers. Research from Tufts University reveals that eating onions daily can increase HDL cholesterol levels by as much as 30%. That’s huge! For example, if your HDL level is 50 mg/dL (when the doctor wants it above 60), eating onions could raise that level up to 65. Your doctor will be smiling and he may be able to forgo prescribing a statin drug.
Increasing HDL cholesterol levels is very important! Why? In order to have a healthy cholesterol ratio, your total cholesterol numbers should be high in HDL “good” and low in LDL “bad” cholesterol. It’s not enough to simply lower your LDL levels and not increase your HDL levels at the same time. While there are a plethora of natural remedies that help lower LDL “bad” cholesterol, the variety of antidotes that raise HDL “good” cholesterol are limited. Onions, however, add to the repertoire of foods that can naturally help balance your cholesterol ratio.
Eat Your Onions
Aside from improving cholesterol numbers, onions have a wide range of therapeutic benefits. The plants are effective in maintaining good health due to their high content of beneficial compounds including flavonoids, polyphenols and a combination of vitamins and minerals (vitamin C, vitamin B6, folate and potassium).
- Heart Health – Onions contain the powerful antioxidant quercetin, which helps to make blood cells less sticky, dissolves clots and lowers blood pressure.
- Bone Health – Studies have shown that onions can increase bone density and thus may be of special benefit to both perimenopausal and postmenopausal women. In addition, there is evidence that women over the age of 50 may be able to lower their risk of hip fracture by more than 20% through frequent consumption of onions.
- Antimicrobial – Onion have been shown to help prevent and eradicate bacterial infections including E. coli, Salmonella and certain strains of Streptococcus bacteria as well as kill the Aspergillus fungus.
- Anti-inflammatory – Onions contain a unique sulfur molecule in the bulb portion of the plant called Onionin-A, which has been shown to inhibit the activity of macrophages, specialized white blood cells that play a key role in the body’s immune system. While macrophage activity is typically a good thing, inhibition of their activity can be critical in getting unwanted inflammation under control such as in the case of a new injury or for chronic inflammatory conditions.
How to Prepare Onions
Now that you know about the health benefits of onions, you might be wondering which preparation method is most effective. Below are a few tips to help you get your daily dose of the plant:
- First, know that yellow onions have a slightly higher ranking of flavonoids and vitamins C compared to other onion varieties. However, there is not a huge significant difference in the nutritional values between yellow, white or red onions so eating any of these three varieties will deliver the therapeutic benefits you’re looking to achieve.
- Although eating onions in any amount will provide excellent nutrition, most research indicates that one medium-sized onion needs to be consumed each day in order to achieve the therapeutic activity of increasing HDL cholesterol numbers. This equates to approximately 1 cup of diced onions per day.
- Studies also indicate that raw onions are more nutritious than cooked onions. However, when onions are simmered (while making soups, chili or stew), the amount of quercetin does not get degraded; it simply gets shifted into the water part (or sauce) of the dish. By simmering onions on low heat, you can preserve the content of this key flavonoid.
- Since cooking onions in oil does cause some degradation of the nutrients, as a rule of thumb, you need to eat double or triple the amount of cooked or caramelized onions (2 to 3 cups per day) to receive the same amount nutrients found in raw onions. Also, onions have the ability to soak up oils so make sure you prepare them with a heart-friendly oil (grapeseed, virgin olive oil, or coconut oil) instead of corn or vegetable oil.
- If you do not like the strong taste and smell of onions, there are onion supplements, essential oils, and extracts available. Make sure you purchase the Allium cepa variety of onion and the bottle is clearly labeled onion “bulb”. Follow the manufacturer’s dosing instructions as product potency can vary.
So, is your doctor after you about improving your cholesterol numbers by raising your HDL level? The tasty answer you’ve been looking for just might be onions!
 “Quercetin Reduces Blood Pressure in Hypertensive Subjects.” Journal of Nutrition. 2007 Nov. 137:2405-2411.
 “The association between onion consumption and bone density in perimenopausal and postmenopausal non-Hispanic white women 50 years and older.” Menopause. 2009 Jul-Aug;16(4):756-9.
 “Antibacterial and antioxidant activities of quercetin oxidation products from yellow onion (Allium cepa) skin.” J Agric Food Chem. 2006 May 17;54(10):3551-7.
 “Onionin-A from Allium cepa Inhibits Macrophage Activation.” Journal Nat. Prod. 2010 Feb.
Originally published in 2012, this blog has been updated.