Research Roundup 2

Today, we feature a wide variety of research. And, we start with a study that reveals the most effective way to help people reduce their meat consumption. 

According to a survey of more than 30,000 U.S. residents, a third of American adults self-identify as meat reducers, meaning one in three of us is trying to cut down on our meat consumption. Why? For those earning less than $40,000 a year, the #1 reason is cost; for those earning more than $40K, the #1 reason is health. And indeed, if we were to define a healthy diet, compared to how we’re eating now, we should be eating more plant‐based foods, including fresh fruits and vegetables, whole grains, legumes—meaning beans, split peas, chickpeas, and lentils—seeds, nuts, and, at the same time, lower in animal foods––particularly fatty and processed meats.

In an editorial entitled “Plant-Based Diets for Personal, Population, and Planetary Health,” co-authored by the chair of Nutrition at Harvard, healthy plant-based diets are not only more sustainable, but have also been associated with lower risk of chronic diseases, such as obesity, type 2 diabetes, cardiovascular disease, and some cancers. What do we mean by plant-based? Basically, any diet that reduces the amount of animal products and increases the amount of plants—again, vegetables, fruits, whole grains, legumes, nuts, and seeds. Transitioning global diets towards healthy plant-based dietary patterns would require large-scale public health efforts but could be instrumental in ensuring future human and planetary health.

Indeed, the Intergovernmental Panel on Climate Change (IPCC) describes plant-based diets as a major opportunity for mitigating and adapting to climate change, and includes a policy recommendation to reduce meat consumption. Okay, but how do you do it? In a systematic review of experimental studies on strategies to reduce meat consumption, one of the most effective experiments came out of the Midwest. Sadly, research shows that the provision of information on its own can be of limited utility in facilitating behavioral change. However, default interventions have been successfully employed in a variety of prosocial contexts, making the right option (or the healthiest option) the easiest option—the default option. 

Take, for example, organ donation. Every year, thousands of people in the United States have died waiting for a suitable donor organ. But wait – 85 percent of Americans approve of organ donation, yet less than half have made a decision about donating, and fewer still have granted permission by signing a donor card. If you look at Europe, there’s nearly a ten-fold difference in the organ donor rates across different countries. In some countries, consent is only about 10 percent, while in others it’s up to like 99.9 percent. What’s the difference? In opt-out countries, the default is that people are organ donors unless they actively register not to be, and in the opt-in countries, like the United States, the default is that nobody is an organ donor without explicitly registering to be one. So, there are all sorts of calls for campaigns to change public attitudes about organ donation. But remember 85 percent are already on board. If we want to change behavior and not just attitudes, changing the default condition may be more effective. So, does it work for diet?

In the DEFAULT treatment, participants received at their table a menu listing only five meat-free options. But they were informed—verbally and in writing on the menu—that they could also consult a second menu that was posted on the wall about a dozen feet away, which had your standard array of popular nonvegetarian dining hall dishes. In the control condition, both lists of options were mixed together on the same menu they were handed.

When you do that, only a minority of people choose the meat-free options––between 5 and 40 percent, depending on if you describe the meat-free options in an appealing way, like pasta with Provençal vegetables, or in unappealing terms, like vegan calzone. Okay, but what about the default condition, where the menu in front of them is all meat-free? They can still get up and order all the meat they want, but the alternate menu is a few steps away. You’re not taking away any people’s options, but just by making it the default, meat-free choices shot up like to 75 and 90 percent. Even an unappealingly described meat-free option totally won out.          

Even just adding more veg options, from a quarter of the options to half the options, increased the sales of the veg options between about 40 to 80 percent.

In our next story, I share a touching story of the power of plant-based eating for chronic kidney failure.

Is it possible to ameliorate chronic kidney disease using a whole food, plant-based diet? While animal-based protein ingestion—meat, dairy, and egg white protein ingestion—promotes an acidic environment in the kidneys, inflammation, and stresses the kidneys into what’s called hyperfiltration mode, plant-based protein can be alkaline-producing and anti-inflammatory, and contain kidney-protective properties. So, what if you gave kidney patients eat a plant-dominant low-protein diet, abbreviated adorably as PLADO, I guess for plant-dominant.

If you fashion up a plant-based diet index score, where you get points for healthy plant foods and get points deducted for eating animal foods, those with serious kidney disease with higher scores were found to have lower systemic inflammation. But does that actually translate into living a longer life?

Apparently so. Even a 10 percent increase in the proportion of plant-based protein was associated with a significant reduction in all-cause mortality. Even just eating more servings of fruits and vegetables, like two a day compared to two a week, is linked to living longer.

Without fully functioning kidneys, there are concerns about phosphorus and potassium overload, though, on plant-based diets. But the phosphorus in plant-based foods is not as much of a problem as the phosphorus additives in processed and animal foods. And the risk of potassium overload from plant-based diets appears overstated and not supported by the evidence. But you don’t know about ameliorating chronic kidney disease using a whole food plant-based diet, until you put it to the test.

Here’s a case report of a 69-year-old man with type 2 diabetes, high blood pressure, and stage 3 chronic kidney disease, resulting in elevated phosphorus and potassium in the blood. He was interested in changing his diet to improve his medical condition. That’s my kind of patient! He was on 12 different medications, eating a diet that may actually be slightly better than the average American’s. Some whole grains and beans, but then his doctor advised him to try eating whole food, plant-based. So, oatmeal with fruit and flax, beans and greens, whole-wheat spaghetti and veggies, fruit as snacks. He was counseled to eat as much as he wanted from whole healthy foods—no carb counting, no calorie counting, no portion size restriction—improving the quality of food rather than restricting the quantity of food.

He adopted the whole food, plant-based diet, packed with carbs, yet rapidly reduced his insulin requirements by more than 50 percent, and subsequently saw improvements in weight, blood pressure, and cholesterol. Because eating healthy can have such a rapid effect on improving your body’s insulin sensitivity, immediate adjustments in insulin dosing were made. Within four days, his insulin dose was able to be reduced from roughly 210 units of insulin a day down to 70 units daily, and an oral blood-sugar lowering medication had to be stopped due to rapidly improving blood sugar.

He also was able to stop his carvedilol, hydrochlorothiazide, amlodipine, and sitagliptin within the first two months, due to improving blood pressure and blood sugars. His insulin dose was steadily titrated downward. His pravastatin dose was cut in half, and he lost about 50 pounds. Okay, so what happened to his stage 3 kidney failure? He was no longer in stage 3 kidney failure!

He experienced an increase in estimated GFR of 73 percent, suggesting that the improvement in estimated kidney function was greater than what would be expected from weight loss alone. For example, lose about 60 pounds with bariatric surgery, and you only get about a 12 to 15 percent boost. Bottom line: for individuals with chronic kidney disease, especially those with obesity, hypertension, or diabetes, a strict, all-you-care-to-eat whole food, plant-based diet may confer significant benefit. I mean, apart from the kidney-specific outcomes, overall mortality is significantly lower among kidney patients who eat more plants. And that’s critical, because most kidney patients don’t even make it to dialysis because they die first, most often from cardiovascular disease.

Let’s hear from the patient: “At the outset, it seemed like this was going to be a difficult and restrictive way to eat,” but “I began feeling different almost immediately, and we had to decrease my insulin after ONE day. It seemed like almost overnight I had more energy than I’d had in years. Weight that I had been trying to lose for a decade began dropping off. As the weight came off, I felt lighter, and more able to move my body again.”

“This lifestyle change has been the greatest gift I’ve ever received. I am off most of my medications, I’ve lost over 70 pounds, and I’ve regained control over my health. I feel empowered by this lifestyle change, and I finally feel like I’m in charge of my health, not just an unlucky victim shuffling from one specialist to the next. My only regret was that I didn’t know about this sooner.”

Finally today, we look at how stress and menstrual cycles can affect the smell of our breath.

According to the American Dental Association, about 50 percent of American adults suffer from oral malodor, with prevalence rates around the world ranging from 2 percent to nearly 80 percent. On average, it seems to be about one in three of us on the planet Earth have bad breath. What effect might stress have on the smell of our breath? Stressed students were found to have significantly higher levels of the rotten egg gas hydrogen sulfide, which is one of the main volatile sulfur compounds related to bad breath, originating from the degradation of the sulfur-containing amino acid cysteine, found concentrated in animal proteins like meat and dairy. Were they eating different diets or just too busy to brush?

The simplest explanation is just the dry mouth you get when you are super-stressed, part of our fight or flight response. It’s the same reason we get morning breath, because we have decreased saliva production when we sleep that would otherwise self-clean the mouth, keeping it from becoming like a stagnant pond. Though maybe stress hormones are having an effect as well.

We suspect sex hormones may play a role, since though men and women have the same before-and-after rise in bad breath compounds after a stressful situation, women seem to start out with higher baseline levels. Gender appears to play an important role. Women have significantly worse morning breath, for example, and bad breath is affected by the menstrual cycle. In fact, that’s listed as one of the causes: so-called menstrual breath.

As you can see, there are higher levels of bad breath compounds in the mouths of women in the premenstrual and menstrual phases compared not just to men, but the follicular phase of their own cycle, meaning like the first half before ovulation. Hmm, so, maybe bad breath is a hormonal thing more than just a dry mouth thing. But salivary flow is also lower in menstrual and premenstrual phases. So, is this all just about having a drier mouth during stress and certain times of the month? How could you tease out the effects? Well, what about studying stressful periods?

Premenstrual syndrome (PMS) is a stressful state characterized by irritability, tension, and mood swings. Is the menstrual dry mouth and bad breath just due to period stress? Apparently so. If you split women up into those who experience PMS and those who don’t, it’s only those with PMS who suffer the rise in bad breath compounds as their period arrives. But the salivary flow was not statistically different. So, the results suggest that a stressful situation can be a predisposing factor for bad breath that may have nothing to do with dry mouth or salivary flow. So, what’s going on? It’s the effects of the stress hormones themselves on the production of bad breath compounds. They dripped some stress hormones on bad breath bacteria—hormones like adrenaline and cortisol—and they started churning out more hydrogen sulphide.

What can we do about it if we can’t treat the cause and reduce the stress? I have videos on dietary changes that may help, as well as a video on tongue-cleaning methods. And, I have videos in the works on the effects of gum chewing and the best mouthwash to use that doesn’t kill the good bacteria in your mouth.