Trying to stay healthy can seem like a full-time job sometimes. Especially during a pandemic. But I’m here to make that goal a little easier. Welcome to the Nutrition Facts podcast, I’m your host Dr. Michael Greger.
Today, the mighty power of oats. Now, I don’t recommend you wear a feedbag around your neck. But I will say that oats are a very versatile grain. Here’s my first story.
Fiber continues to be singled out as a nutrient of public health concern. There is a fiber gap in America. We’re getting only about half the minimum, considered a public health concern for all Americans. Well, not all Americans. Less than 3% meet the recommended minimum, meaning less than 3% of all Americans eat enough plant-based foods–the only place fiber is found–though a nominal 0.1 is thrown in for the meat category, in case someone eats a corndog or nibbles on the garnish.
If even half of the adult population ate three more grams a day, like a quarter-cup of beans, or a bowl of oatmeal, we could save billions in medical costs–and that’s just for constipation. The consumption of plant foods, the consumption of fiber-containing foods, reduces risk for diabetes, heart disease, stroke, cancer, and obesity as well.
The first to make this link between fiber intake and killer disease was probably Dr. Hugh Trowell many decades ago. He spent 30 years practicing medicine in Africa and suspected it was their high consumption of corn, millet, sweet potatoes, greens, and beans that protected them from chronic disease. This kind of got twisted into the so-called fiber hypothesis, but he didn’t think it was the fiber itself, but the high-fiber foods that were so protective. There are hundreds of different things in whole grains besides fiber that may have beneficial effects. For example, yes, the fiber in oatmeal can lower our blood cholesterol levels so less gets stuck in our arteries, but there are anti-inflammatory and antioxidant phytonutrients in oats that can help prevent atherosclerotic build-up and then help maintain arterial function.
Visionaries like Trowell were not entrapped by the reductionist “simple-minded” focus on dietary fiber and insisted that the whole plant foods should receive the emphasis. Fiber intake was just kind of a marker for plant food intake. Those with the highest fiber intake, and the lowest cholesterol, were those who ate exclusively plant-based diets.
Risk factors like cholesterol are one thing, but can these individual foods actually affect the progression of heart disease? We didn’t know, until this study was published. Hundreds of older women were subjected to coronary angiograms, where you can inject dye into the coronary arteries of the heart to see how wide open they are. They got an angiogram at the beginning of the study, and then one a few years later, all while analyzing their diets. This is what they found. The arteries of women eating less than a serving of whole grains a day significantly narrowed, whereas the arteries of women who ate just a single serving or more also significantly narrowed, but they narrowed less. These were all women with heart disease eating the standard American diet, and so their arteries were progressively clogging shut. Heart disease is the #1 killer of American women, but there was significantly less clogging in the women eating more whole grains, significantly less progression of their atherosclerosis, in fact, almost as much slowing of their disease as they might get taking cholesterol-lowering statin drugs. Statins can also slow the rate at which our arteries close. But do we want to just slow the rate at which we die from heart disease, or not die from heart disease at all?
A whole foods plant-based diet has been shown to reverse the progression of heart disease, opening arteries back up. Whole grains, like the drugs, can help counter the artery-clogging effects of the rest of the diet. Having oatmeal with bacon and eggs is better than just eating bacon and eggs, but better perhaps to stop eating an artery-clogging diet altogether?
In our next story, oats are put to the test against certain chemo side effects to see just how soothing and anti-inflammatory they can be.
Oatmeal has been used for centuries as a topical soothing agent on the skin to relieve itch and irritation in dermatology. Of course, this is coming from Johnson & Johnson, that sells a brand of oatmeal lotion, but look, if it helps with dry skin or a bug bite, I can imagine it having some soothing quality–but this study shocked me.
There’s a class of chemo drugs, like cetuximab, that causes an awful rash. It’s bad enough you have some horrible cancer, but then to have a painful itchy rash on top of it. Various treatments have been tried and failed. There was no clear preventive or curative treatment for this eruption. Or is there?
The researchers had heard about this study, in which human skin fragments from plastic surgery were subjected to an inflammatory chemical, and adding an oatmeal extract appeared to help; so, what do you have to lose? Of the ten patients with chemo rashes who were able to get access to try some oatmeal lotion, six had a complete response, and four a partial response, giving an overall oatmeal response rate of 100%.
Doctors wrote in from around the world. Significant improvement in all patients? Seemed rather too good to be true, but out of desperation they tried it, and got the same astonishing results. Oatmeal, a simple topical agent, producing such spectacular benefit where more complex therapies have failed. In an age when ever more expensive treatments are consistently being championed, it would be a great pity if this inexpensive, natural approach to relieving distressing symptoms were to be overlooked.
Ironically, two of the cancer cell lines found resistant in vitro to this kind of chemotherapy were found to be sensitive to avenanthramides, which are unique phytonutrients found in oats, suggesting that people should apply oatmeal to their insides as well.
Finally today, is whole grain consumption just a marker for healthier behaviors, or do whole grains have direct health benefits?
If oatmeal is so powerful that it can clear up some of the ravages of chemotherapy just applied to the skin, what might it do if we actually ate it?
The pharmacology of oatmeal. Oats are reported to possess varied drug-like activities like lowering of blood cholesterol and blood sugar, boosting our immune system, anti-cancer, antioxidant, anti-atherosclerosis, in addition to being a topical anti-inflammatory, and may also be useful in controlling childhood asthma, body weight, etc.
Whole grain intake in general is associated with lower risk of type 2 diabetes, cardiovascular disease, and weight gain. All the cohort studies on type 2 diabetes and heart disease show whole grain intake is associated with lower risk. They observed the same for obesity—consistently less weight gain for those who consumed a few servings of whole grains every day.
Yes, all the forward-looking population studies demonstrate that a higher intake of whole grains is associated with lower body mass index and body weight gain. However, these results do not clarify whether whole grain consumption is simply a marker of a healthier lifestyle, or a factor favoring “per se” lower body weight.
For example, high-whole grain consumers—those who eat whole wheat, brown rice, and have oatmeal for breakfast—tend to be more physically active, smoke less, and consume more fruit, vegetables, and dietary fiber than those who instead reach for Fruit Loops. Statistically, one can control these factors, effectively comparing only non-smokers to non-smokers with similar exercise and diet, as most of the studies did, and they still found whole grains to be protective, via a variety of mechanisms.
So, for example, in helping with weight control, the soluble fiber of oatmeal forms a gel in the stomach, delaying stomach emptying, making one feel full for a longer period, which helps with weight loss, and then there are other effects in the small and large intestine. So, it all seems plausible that whole grain intake does indeed offer direct benefits; however, only results from randomized controlled intervention studies can provide the evidence of cause and effect.
In other words, the evidence is clear that oatmeal consumers have lower rates of disease, but that’s not the same as proving that if we start eating more oatmeal, our risk will drop. To know that we need an interventional trial, ideally a blinded study where you give half the people oatmeal, and the other half fake placebo oatmeal that looks and tastes like oatmeal to see if it actually works. As you can imagine, this has not been done, until now. Double-blinded randomized trial of overweight and obese men and women, and almost 90% of the real oatmeal-treated subjects had reduced body weight compared to no weight loss in the control group–a slimmer waist on average, a 20-point drop in cholesterol, and an improvement in liver function.
Non-alcoholic fatty liver disease, meaning a fatty liver caused by excess food rather than excess drink, is now the most common cause of liver disease in the United States, found on autopsy in up to 90% of obese individuals, and can lead in rare cases to cirrhosis of the liver, cancer of the liver, and death. Theoretically, whole grains could help prevent and treat fatty liver disease, but this is the first time it had actually been put to the test like this. A follow-up study in 2014 confirmed these findings of a protective role of whole grains, but refined grains were associated with increased risk. So, one would not expect to get such wonderful results with Wonder Bread.
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