Let’s talk about treating weight loss, cholesterol, and PCOS with diet. What can an eighth of a teaspoon a day of onion powder do to body fat, and what can raw red onions do to lower cholesterol?
In one of my previous videos about onions, I talked about the data that supports—or does not support—the role of onions in increasing testosterone in men, protecting bone health, controlling allergies, and dealing with the side effects of chemotherapy. What about weight loss? Enter “Effect of Onion Consumption (ONIRO) on Body Fat and Metabolic Profiles in Obese Subjects.” The researchers used burnt onions, which have no spice and have a weak smell, so they could better disguise them as a placebo. They dry them into onion powder and give people a small amount—about an eighth of a teaspoon (300 mg) a day. Indeed, a small daily dusting of onion powder will not affect people’s weight. But check out the results reported in the abstract: Measurements using a DEXA scan showed a significant reduction in body fat, and a CT scan revealed a significant decrease in total, visceral, and subcutaneous fat areas.
Hold on tight. If onion powder is so effective in weight loss, why was it not included in my book How not to eat? Because, as often happens in studies, the spin on the abstract does not accurately represent the real data. The DEXA scan results did not measure a significant fat change in the group that received the placebo tablets. They appeared to lose about a teaspoon (7 g) of fat, while the group unaware that they took an eighth of a teaspoon of onion powder stuffed into the pills lost about one and a half pounds of body fat—a significant decrease from baseline, but not a statistically significant decrease compared to the placebo group, meaning the loss could have been due to luck. The same thing with the CT scan results: a 5-fold loss of total fat and a 30-fold loss of dangerous visceral fat, but the results did not reach statistical significance compared to placebo.
A recent study tried four teaspoons (9 g) of onion powder per day and similarly failed to accelerate visceral, total, or subcutaneous fat loss compared to a placebo—but the placebo was four teaspoons (9 g) of onion powder per day. They used yellow onions versus white onions, and it seems that both caused abdominal fat loss, without a significant difference between them. In any case, you can look at these two studies and think, sure, but which ones are bad? It’s only an eighth of a teaspoon of onion powder a day, so why not try it? It won’t hurt, but we don’t have enough evidence to be sure it will really help.
Let’s talk about polycystic ovary syndrome, also known as PCOS. It is one of the most common hormonal problems, affecting 5% to 10% of older women. In addition to causing symptoms such as irregular periods, “PCOS is a pre-diabetes condition, with decreased insulin sensitivity.” PCOS treatment is challenging because of the side effects of medications. So, are there any diets? What about randomized controlled clinical trials of red onion consumption?
Why onions? However, onion extract can apparently improve blood sugar and insulin sensitivity in diabetic rats and, more importantly, it has been found to lower blood sugar levels in diabetics, but apparently not in non-diabetics. People with PCOS are pre-diabetic, so can it work for them? First, let’s look at those two other lessons. To study the “Metabolic Effects of Onions and Green Beans,” people with diabetes spent a week eating a small onion (60 g) each day or the same meal with about six cups (600 g) of green beans instead—and both methods worked. Onions lowered people’s blood sugar levels by about 10% compared to a control diet with onions, while green beans lowered them by about 15% compared to controls.
Here’s a study that says it doesn’t show blood sugar benefits in people without diabetes. It’s true—onions don’t seem to lower blood sugar, which is great, but check out what happens when you feed people sugar. Have people eat about two and a half tablespoons (50 g) of corn syrup, and their blood sugar levels rise for the next two hours before their bodies can lower it. But give people exactly the same amount of sugar and more onion extract, and the spike in blood sugar is greatly reduced, almost as if you gave them an antidiabetic drug, as you can see below and at 4:00 in my video. Onions Tested for Weight Loss, Cholesterol, and PCOS Treatment.
We see the same blunting effect on blood sugar when people get a shot of adrenaline and eat onion extract, compared to getting adrenaline without onion extract, as you can see below and at 4:11 in mine. video.
So, are there blood sugar benefits for both people with and without diabetes? No difference was found in blood sugar levels or other markers of insulin resistance between the high onion and low onion groups of PCOS patients, and there was no difference in inflammatory markers between the two groups. But women with PCOS aren’t just at higher risk for diabetes and inflammation—they’re also at higher risk for high cholesterol.
Women with PCOS are seven times more likely to develop heart disease and have heart disease, the number one killer of women. But eating red and green onions appears to be effective in lowering cholesterol, although the group that ate the onion only reduced LDL cholesterol by about 5 points (5 mg/dL), which was not significantly different from the group that ate fewer onions.
I found this study 50 years ago where researchers fed people almost a whole stick (100 g) of butter, and their cholesterol increased about 30 points within hours of consumption but only 9 points or 3 points when combined with about a third of a cup (50 g) of green or boiled onions. Moral of the story: Don’t eat butter.
Doctor’s Note
Check out the previous video I mentioned: Friday Favorites: Do Onions Benefit Testosterone, Osteoporosis, Allergies, and Cancer?.
