The Oatmeal Cure

You know the feeling you get – when you learn something new about a health problem you’ve been trying to reverse – maybe high blood pressure, diabetes, or heart disease. Well – there’s nothing I like better than bringing you the information that will help you do just that. Welcome to the NutritionFacts podcast. I’m your host – Dr. Michael Greger.

Today, we discover the mighty power of oatmeal. Did you know that before there was insulin – there was the “oatmeal cure”?

The life of many diabetics was saved or prolonged by Carl von Noorden’s oatmeal diet, which he apparently stumbled upon accidentally. Some of his diabetic patients had gastrointestinal issues; so, he put them on oatmeal, and instead of the sugars spilling over into their urine getting worse, they started getting better. He published his findings in 1903, which was received with a great deal of skepticism. But the skeptics were overcome, however, in the following years by the weight of the evidence.

A turning point came when a doctor as notable as James B. Herrick gave it a try. Dr. Herrick is acclaimed for his description of sickle cell anemia, which was originally known as Herrick’s syndrome. When Dr. Herrick began to try out the oatmeal diet on his patients, he was very skeptical, but was astonished by the results. Intense skepticism was how Herrick put it. His first experience in prescribing it was far from encouraging. After taking one or two meals, the patient said, “Doctor, I will die before I taste another spoonful of that oatmeal mush.” And indeed, tragically, she did. Other doctors echoed patient reticence to tolerate so monotonous an equine diet. But in general, Herrick said, he went on to experience little difficulty in putting patients on the oatmeal diet and in keeping them there for a few weeks. And nothing, he reported, was more surprising or more gratifying than the salutary effects he witnessed of the oatmeal diet in diabetes of the young, leading to the 1909 proclamation that no case of juvenile or adolescent diabetes should be deprived of the benefits of the oatmeal cure.

The great Elliott Joslin, founder of the oldest and largest diabetes clinic in the world, described the effects of the oatmeal as sometimes magical, describing the oatmeal cure as an unsolved mystery, referred to back then as one of the greatest puzzles in diabetes. They did have some clues though. They found that animal protein had to be strictly excluded, as it annihilates the favorable action of oatmeal-type diets. They used to use eggs with the oatmeal diet, but they got better results without them.

And now we know, over a century later that indeed, animal protein intake intensifies insulin resistance, which is the cause of prediabetes and type 2 diabetes, whereas plant-based foods enhance insulin sensitivity, which is the opposite. Animal-protein intake is not just associated with insulin resistance and a clear association with an increased risk of type 2 diabetes (and this included animal protein from meat, dairy, and fish—higher insulin resistance and risk of prediabetes and type 2 diabetes).

But not just an association; you can put it to the test. Swapping in beans for beef improves cardiometabolic risk factors. And it doesn’t take much. Replace just two servings of red meat with lentils, chickpeas, split peas, or beans a few days a week, and you can significantly significantly improve fasting blood sugars and insulin levels––along with the improvements you’d expect, like lowering cholesterol and triglycerides. Based on over a dozen randomized controlled trials, even just swapping like a third of protein from animal to plant sources can significantly improve blood sugar control.

What is the difference between animal protein and plant protein? We think it’s the branched-chain amino acids concentrated in animal protein. How do we know branched-chain amino acids are playing a role? Because if you give vegans branched-chain amino acid supplements, you can make them as insulin resistant as meat eaters. Their insulin sensitivity dropped to the level resembling omnivores and only improved again after stopping the supplements.

But wait a second. I thought insulin resistance stems from the excess accumulation of fat inside your muscle cells, particularly saturated fat. Insulin resistance directly correlates with increased saturated fat inside your muscles. I’ve got tons of videos on this, but basically you can show a substantial and consistent impairment of insulin action, substantial and consistent insulin resistance, after just a single day consuming a diet high in saturated fat. In fact, even a single meal rich in saturated fat reduces insulin sensitivity. A single dose of butter, for example, impairs insulin sensitivity, even in healthy subjects. And over time, reducing cholesterol and fat intake may even enhance the ability of your pancreas to pump out insulin in the first place. Now, the saturated fat getting lodged in your muscles may come from the foods going into your mouth. Or, if you have excess abdominal fat, from previous meals spilling over into your blood stream. But either way, what does animal protein have to do with it?

It turns out a branched-chain amino acid breakdown product appears to stimulate fat uptake and accumulation inside the muscle cells. But oatmeal doesn’t have any saturated animal fat or animal protein. Okay, but neither does any plant food. Why might oatmeal work particularly well? That’s the question I explore next.

It is now widely accepted that diets high in animal fat and processed foods are an important risk factor for development of type 2 diabetes. And it’s not just animal fat, but animal protein intake intensifies insulin resistance, which predisposes people to type 2 diabetes. No wonder studies have shown that elevated consumption of animal products and low intake of unprocessed plant foods increases the risk of not only cardiovascular disease but diabetes. But of all the whole plant foods to pick, why choose oatmeal to treat diabetes, which, as I discussed, was used for the treatment of diabetes before insulin was discovered.

We’ve long known that higher consumption of whole grains, including oats, is associated with a lower risk of diabetes. But you don’t know, until you put it to the test. There have been over a dozen randomized controlled trials looking at the metabolic effects of oats intake in patients with type 2 diabetes. Oats were found to significantly improve both short-term blood sugar control and long-term blood sugar control, in addition to lowering cholesterol levels. We think the benefits arise from a fermentable fiber in oats called beta glucan, because you can get cholesterol-lowering even if you just give the oat fiber straight––as well as an improvement in blood sugar control and insulin sensitivity in both type 2 diabetics as well as type 1 diabetics. How exactly does the fiber do that? Well, we know one of the underlying cholesterol-lowering mechanisms of oatmeal consumption might be its microbiome-manipulating ability––in other words, having a beneficial effect on our intestinal bacteria. 

They were talking about the anti-inflammatory effects of the short-chain fatty acids that our good gut flora make from fiber. There are dozens of randomized controlled trials showing the types of fiber found in oats and beans can improve long-term blood sugar control in diabetics—in fact, nearly double the FDA threshold required for new blood sugar-lowering drugs. Why? Because the gut bacteria selectively promoted by dietary fiber intake can help alleviate type 2 diabetes.

In fact, on the basis of 50 distinct bacterial markers of the feces, you can tell who does and does not have diabetes. But change your diet, and you can change your gut flora within one day. We feed them with fiber, and in return, they feed us right back with these short-chain fatty acids, like butyrate, that have all these wonderful effects. Put people on a diet packed with oats, beans, fruits, vegetables, and nuts, and the number of fiber-feeders churning out the beneficial short-chain fatty acids shoots up, and fasting diabetic blood sugars drop about 25 percent within one month. And the more fiber-feeders they fostered, the better their blood sugar control. When the fiber-promoted short-chain fatty acid producers were present in greater diversity and abundance, participants had better improvement in their hemoglobin A1c levels (which is a measure of longer-term blood sugar control). Then, before-and-after fecal transplant studies helped nail down cause and effect.

The oat fiber itself has been shown to act as a prebiotic, boosting the growth of beneficial bacteria like lactobacillus and bifidobacteria. So, between the lack of animal protein, lack of animal fat, and bursting at the seams with prebiotic fiber, it’s no wonder that oatmeal diets grew to become part of the clinical routine in the treatment of diabetics. However, over time, this practice has later become increasingly forgotten, a disappearance that’s been compared to the fate of unpopular theories in successive editions of Soviet encyclopedias.

Despite advances in therapy, we still have many people with poorly controlled diabetes. Thankfully, this forgotten tool is back. I’ll review all the new oatmeal diet studies next.

Thousands of years ago in ancient Egypt, diabetes was described as a “too great emptying of urine” and, more poetically, as being “like the River Nile between the thighs.” The recommended remedy, ironically, was a diet consisting of wheat grains, grapes, honey, and berries. The guy who coined the term “diabetes” about 500 years later also prescribed a high-carbohydrate diet. Then, right up until we had insulin, doctors were saving the lives of diabetics with an oatmeal diet. This wouldn’t make any sense until Sir Harold Himsworth arrived on the scene, the first to separate out type 1 diabetes from type 2 diabetes and define this concept of insulin resistance. After just a few days on a high-fat diet, you can get twice the blood sugar spike in response to drinking sugar water, compared to after eating a high-carb diet.

Now that type 2 diabetes is like the Black Death of the 21st century in terms of devastating health impacts, what about revisiting the almost forgotten, short-term dietary oatmeal intervention as an economical, yet—spoiler alert—highly effective tool to achieve better blood sugar control in patients with type 2 diabetes? Basically, patients are offered up to about two and a half cups of oatmeal three times a day as their meals with nothing but some herbs and maybe small amounts of raw vegetables just to mix things up. For how long? Just a couple of days. Note that’s only about a thousand calories; so, the result is a hypocaloric, plant-based dietary intervention that is low in fat—in fact, no added fat—no salt, and excludes animal protein.

Is a few days of oatmeal really going to make much of a difference? Check out this case report of an oatmeal intervention for severe insulin resistance in the ICU. Within 48 hours of admission, the patient developed such severe insulin resistance she required more than 200 units of insulin per day. Up until then, the patient received standard diabetic tube feeds, which obviously were not working. So instead, they dropped oatmeal and vegetables down the tube, presumably using a really good blender. And lo and behold, it worked. But you have got to see the numbers. Yeah, her first blood sugars of the day dropped from up around 250 down to about 100 five days later. But that near-normal blood sugar was on 160 fewer units of insulin, down from over 200 units a day. Lower blood sugars on 160 fewer units of insulin!

Okay, I can see how if you’re trying to save a life in the ICU, an oatmeal diet can be near-miraculous. But just in regular diabetics, what good is eating oatmeal for a few days if you just go back to your regular diet? Several studies have suggested that the beneficial effects could last like a month after the few days of oatmeal. For example, in this randomized controlled crossover trial, not only did insulin needs drop about 40 percent in just two days, compared to just restricting calories alone with a hypocaloric diabetic diet, but also a measure of long-term blood sugar control taken four weeks later reflected the benefit. So, we’re talking about a highly significant reduction of required daily insulin doses, with beneficial effects shown weeks later. Who cares if you have to take huge doses of insulin, though? Because insulin causes weight gain, which just makes the underlying insulin resistance worse. So, it’s like this vicious cycle. But instead, with the oatmeal, you’re actually treating the cause, not to mention the incidence of cancer and overall mortality associated with having such high levels of insulin in your body all the time.

Other new studies have shown the same thing. Two days of oatmeal significantly reducing the required amount of insulin and improved blood sugar levels with beneficial effects noted for up to four weeks. For example, here. Patients with uncontrolled type 2 diabetes, with the two-day oatmeal diet leading to a 40 percent reduction of insulin dose, accompanied with almost normalization of average blood sugars. Although the intervention only lasted for two days, they observed a lasting significant reduction of insulin dosage and ameliorated mean blood sugars for weeks after they were dismissed from the study. And this was after they resumed their regular diets. A massive drop in insulin needs after the oatmeal for two days, but look, a month later they were still needing like 40 percent less insulin. Wait a second. How could this short intervention lead to such dramatic results that somehow continued on for weeks? Although short-term dietary oatmeal interventions cannot be compared to whole food, plant-based diets in terms of maximizing the intake of protective foods—I mean that’s ideally what people should try to eat to reverse their type 2 diabetes completely—but they both strictly exclude the animal-based foods that seem to increase the risk of developing diabetes. So, even cutting out saturated fat for like two days may so reduce insulin resistance you can free ride on that for at least a few weeks, even if you go back to eating crap.

WARNING, though. If you try this oatmeal diet, your physician has to be ready to rapidly deprescribe your blood sugar drugs, else you become dangerously overmedicated. Imagine if this woman was still getting 200 units of insulin. Her sugars would crash so low she’d be dead. So, oatmeal interventions should not be performed in patients that might have difficulties in reporting symptoms of low blood sugars, who you can’t closely monitor. So, the downside of trying oatmeal days is that it may work a little too well; so, it must be done under close medical supervision.

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My last two books are “How to Survive a Pandemic” and the “How Not to Diet Cookbook.” Stay tuned for Dec 5, 2023 for the launch of my one “How Not to Age.” And – of course – all the proceeds I receive from the sales of all my books go to charity. 

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