White Rice vs. Brown Rice

In 2012, a meta-analysis was published tying white rice consumption to diabetes, especially in Asian countries. Even in the United States, where we eat much less white rice, research shows the regular consumption of white rice was associated with higher risk of type 2 diabetes though brown rice was associated with lower risk, and that was after controlling for other lifestyle and dietary factors such as smoking, exercise, and meat, fruit, and vegetable consumption. The researchers estimated that replacing even just a third of a serving per day of white rice with the same amount of brown rice might lower diabetes risk by 16 percent.

Since the publication of that 2012 meta-analysis, a study out of Spain suggested white rice consumption was associated with decreased diabetes risk. However, it was a tiny study compared to the others, with only hundreds in contrast to hundreds of thousands of people involved. In Spain, rice is usually consumed in paella, which is commonly prepared with the spice saffron that research indicates may have therapeutic potential against diabetes. Additionally in Spain, white rice consumers also ate more beans, which appear to have antidiabetic properties, as well. This gives a sense of how difficult it is to infer cause-and-effect relationships from population studies, since we can’t control for everything. Yes, we can control for weight, smoking, alcohol, exercise, and so on, but maybe people who are smart enough to eat brown rice are also smart enough to wear seatbelts and bike helmets, install smoke detectors, and forgo bungee jumping. What we need is a way to fund randomized interventional studies, where we switch people from white rice to brown rice and see what happens. “Until then, the effect of the consumption of white rice on the development of type 2 diabetes will remain unclear.” But we didn’t have such studies…until now.

As I show in my video Is It Worth Switching from White Rice to Brown?, researchers conducted a study in which overweight women were randomized into two groups: one following a weight-loss diet with a cup or so of cooked white rice every day and another with a cup of cooked brown rice every day. After six weeks, the groups switched, and the white rice group ate brown rice and vice versa. When the subjects were eating brown rice, they got significantly more weight loss, particularly around the waist and hips, lower blood pressure, and less inflammation. 

Researchers found similar effects for prediabetics: Substituting brown rice for white rice led to significantly more weight loss, more waist loss, and better blood pressures.

Brown rice may not just help get rid of tummy fat, but also preserve our artery function. High blood sugars can stiffen our arteries, cutting in half their ability to relax within an hour, whether you’re diabetic, have prediabetes, or are nondiabetic. For diabetics, though, their arterial function goes down and stays down. We also know that brown rice can have blood sugar lowering effects compared to white rice. So, can switching to brown rice help preserve arterial function? In folks with metabolic syndrome, within an hour of eating about a cup of cooked white rice, we can get a drop in arterial function, but not so with brown rice.

Despite all the benefits of whole grain rice, Asian people often prefer white rice, considering it softer and tastier than brown rice. In a focus group of Chinese adults, however, researchers found that only a minority of them had ever even tried brown rice.  “Before tasting brown rice, the majority of participants considered it to be inferior to white rice in terms of taste and quality…” So, the researchers simply served some up, and, after actually tasting it and learning about it, most changed their minds.


For more information on research on white rice consumption in China, check out my video If White Rice Is Linked to Diabetes, What About China?.

If brown is good, then what about all the even more colorful varieties? See Brown, Black, Purple and Red (Unlike White on) Rice

For another interventional trial with whole grains, check out Whole Grains May Work as Well as Drugs.

What about the so-called rice diet? See:

How could the simple difference between whole and refined grains make such a difference? For a clue, see my video Gut Dysbiosis: Starving Our Microbial Self.

Arsenic in rice? I did a deep-dive into this issue and produced an entire video series. Check it out to learn more.

And for more on the paella spice saffron, see:

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

Vinegar Caveats

As I note in my chapter on greens in my book How Not to Die, vinegar may be one condiment that’s actually good for you. Randomized controlled trials involving both diabetic and non-diabetic individuals found that adding just two teaspoons of vinegar to a meal may improve blood sugar control, effectively blunting the blood sugar spike after a meal by about 20 percent. How? I discuss this in my video Vinegar Mechanisms and Side Effects.

Originally, we thought it was because vinegar delayed the gastric emptying rate, slowing the speed at which a meal leaves your stomach, which makes sense because there are acid receptors in the first part of the small intestine where the stomach acid is neutralized. So, if there is excess acid, the body slows down stomach emptying to give the intestine time to buffer it all. The acid in vinegar was thought to slow the rate at which food leaves the stomach, resulting in a blunted sugar spike. But then, studies were published where taking apple cider vinegar before bedtime resulted in lower blood sugars the next day. How does that work? That’s obviously not some acid-induced stomach-slowing effect. Indeed, anyone who actually went to the trouble of sticking an ultrasound probe on someone’s stomach could have told you that—no difference in stomach-emptying times was found comparing vinegar to neutralized vinegar. So, it’s not just an acid effect.

Back to square one.

Additional studies offered the next clue. Vinegar appeared to have no effect on blood sugars, but this was after giving people a straight glucose solution. Glucose is a byproduct of sugar and starch digestion, so if vinegar blunts the blood sugar spike from cotton candy and Wonder Bread but not glucose, maybe it works by suppressing the enzymes that digest sugars and starches. And, indeed, vinegar appears to block the enzyme that breaks down table sugar. It wasn’t just an acid effect, however. There appears to be something unique about acetic acid, the acid in vinegar. These findings were based on intestinal cells in a petri dish, though. What about in people? Feed people some mashed potatoes with or without vinegar, and glucose flows into the bloodstream at the same rate either way—so, there’s another theory shot down.

Let’s figure this out. If sugar enters the bloodstream at the same rate with or without vinegar, but vinegar leads to significantly less sugar in the blood, then logically it must be leaving the bloodstream faster. Indeed, vinegar ingestion appears to enhance sugar disposal by lowering insulin resistance (the cause of type 2 diabetes), and also appears to improve the action of insulin in diabetics. The mystery of how vinegar works appears to have been solved, at least in part.

So, diabetics can add vinegar to their mashed potatoes—or just not eat mashed potatoes. If you add vinegar to a high-fiber meal, nothing happens, which explains results such as no effects of vinegar in diabetics in response to a meal. That’s no surprise, because the meal in question in the study was mostly beans. If you are going to eat high glycemic index foods like refined grains, vinegar can help—though there are some caveats.

Don’t drink vinegar straight, as it may cause intractable hiccups and can burn your esophagus, as can apple cider vinegar tablets if they get lodged in your throat (not that apple cider vinegar tablets necessarily actually have any apple cider vinegar in them in the first place). Don’t pour it on your kid’s head to treat head lice either. It’s “not harmful except when it leaks on to the face or penetrates the eyes,” and it turns out it doesn’t even work. Vinegar can also cause third-degree burns if you soak a bandage with it and leave it on.

Though as many as a total of six tablespoons a day of vinegar was not associated with any side effects in the short-term, until we know more, we may want to stick with more common culinary type doses, like two tablespoons max a day. For example, drinking 2,000 cups of vinegar was found to be a bad idea.


Other good-for-you condiments include (salt-free) mustard and horseradish. You may be interested in my Second Strategy to Cooking Broccoli video. For more on my book, check out the trailer.

This is the final installment of my five-part series on vinegar. If you missed any, here they are:

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live, year-in-review presentations:

How Much Vinegar Every Day?

Consuming vinegar with a meal reduces the spike in blood sugar, insulin, and triglycerides, and it appears to work particularly well in those who are insulin resistant and on their way to type 2 diabetes. No wonder the consumption of vinegar with meals was used as a folk medicine for the treatment of diabetes before diabetes drugs were invented.

Many cultures have taken advantage of this fact by mixing vinegar with high glycemic foods. For example, in Japan, they use vinegar in rice to make sushi, and, in the Mediterranean, they dip bread into balsamic vinegar. Throughout Europe, a variety of sourdough breads can lower both blood sugar and insulin spikes. You can get the same effect by adding vinegar to boiled white potatoes then cooling them to make potato salad.

Adding vinegar to white bread doesn’t just lower blood sugar and insulin responses—it increases satiety, or the feeling of being full after a meal. As you can see in my video Optimal Vinegar Dose, a study found that if you eat three slices of white bread, it may fill you up a little, but in less than two hours, you’re hungrier than when you began eating. If you eat that same amount of bread with some vinegar, though, you feel twice as full and, even two hours later, still feel nearly just as full as if you had just eaten the three pieces of bread plain. But this remarkable increase and prolongation of satiety took nearly two tablespoons of vinegar. That’s a lot of vinegar. What’s the minimum amount?

It turns out that even just two teaspoons of vinegar with a meal can significantly decrease the blood sugar spike of a refined carb meal, a bagel and juice, for instance. You could easily add two teaspoons of vinaigrette to a little side salad or two teaspoons of vinegar to some tea with lemon. Or even better you could scrap the bagel with juice and just have some oatmeal with berries instead.

What if you consume vinegar every day for months? Researchers at Arizona State University randomized pre-diabetics to take daily either a bottle of an apple cider vinegar drink—a half bottle at lunch, and the remaining half at dinner—or an apple cider vinegar tablet, which was pretty much considered to be a placebo control: While the bottled drink contained two tablespoons of vinegar, the two tablets only contained about one third of a teaspoon. So in effect, the study was comparing about 40 spoonfuls of vinegar a week to 2 spoonfuls for 12 weeks.

What happened? On the vinegar drink, fasting blood sugars dropped by 16 points within one week. How significant is a drop of 16 points? Well this simple dietary tweak of a tablespoon of vinegar twice a day worked better than the leading drugs like Glucophage and Avandia. “This effect of vinegar is particularly noteworthy when comparing the cost, access, and toxicities” associated with pharmaceutical medications. So the vinegar is safer, cheaper, and more effective. This could explain why it’s been used medicinally since antiquity. Interestingly, even the tiny amount of vinegar in pill form seemed to help a bit. That’s astonishing. And, no: The study was not funded by a vinegar company.

What about long-term vinegar use in those with full-blown diabetes? To investigate this, researchers randomized subjects into one of three groups. One group took two tablespoons of vinegar twice a day, with lunch and supper. Another group ate two dill pickles a day, which each contained about a half tablespoon’s worth of vinegar. A third group took one vinegar pill twice a day, each containing only one sixteenth of a teaspoon’s worth of vinegar. I wasn’t surprised that the small dose in the pill didn’t work, but neither did the pickles. Maybe one tablespoon a day isn’t enough for diabetics? Regardless, the  vinegar did work. This was all the more impressive because the diabetics were mostly well controlled on medication and still saw an additional benefit from the vinegar.


Make sure to check out my other videos on vinegar’s benefits:

This vinegar effect seems a little too good to be true. There have to be some downsides, right? I cover the caveats in Vinegar Mechanisms and Side Effects.

There are a few other foods found to improve blood sugar levels:

The best approach, of course, is a diet full of healthy foods:

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live, year-in-review presentations: