Welcome to the Nutrition Facts podcast. I’m your host Dr. Michael Greger. I am thrilled that you have decided to join me today. Because the more I learn about latest nutrition research – the more convinced I am that this information can make a real difference in all of our lives. And I like nothing better – than sharing it with you.
Today, back by popular demand, we present the nutrition facts grab bag with the latest news on a whole variety of topics. First up – we help you choose the healthiest coffee, and the effects of adding milk vs. soymilk.
Coffee drinkers live longer than non-coffee drinkers. This may be because “coffee may have beneficial effects on inflammation, lung function, insulin sensitivity, and depression.” This may be in part because of a class of polyphenol phytonutrients found in coffee beans called chlorogenic acids, proven to have favorable effects with studies where they just give it alone in pill form and can show beneficial effects—such as “acute blood pressure-lowering” activity, dropping the top and bottom blood pressure numbers within hours of consumption. Okay, so which coffee has the most? We know how to choose the reddest tomato, the deepest orange sweet potato, since many of the plant pigments are the antioxidants themselves. How do you choose the healthiest coffee?
More than a hundred coffees were tested, and different coffees had different caffeine levels, but the chlorogenic acid levels varied by more than 30-fold. “As a consequence, coffee selection may have a large influence on the potential health potential of coffee intake.” So, all those studies that show that “one cup of coffee” does this or that; what does that even mean when coffee can vary so greatly? Interestingly, “the major contributor to the wide range was the coffee purchased from Starbucks which had an extremely low chlorogenic acid content,” averaging 10 times lower than the others. Maybe it’s because they roast their beans too dark. The more you roast, the less there is. They appear to be partially destroyed by roasting. Caffeine is pretty stable, but a dark roast may wipe out nearly 90% of the chlorogenic acid content of the beans.
The difference between a medium-light roast and a medium roast were not enough, though, to make a difference in total antioxidant status in people’s bloodstreams after drinking them—they both gave about the same boost. Other factors, such as how you prepare it, or decaffeination, don’t appear to have a major effect. What about adding milk?
Longtime fans may remember this ancient video, where the “addition of milk” was shown to prevent the “protective effects of tea” on artery function. Drink black tea, and you get a significant improvement in vascular function within hours, “whereas addition of milk completely blunted the effects of tea.” But drink the same amount of tea with milk, and it’s like you never drank the tea at all. They think it’s the casein to blame—one of the milk proteins binding up the tea phytonutrients. Bottom line, this “finding that the tea-induced improvement in vascular function is completely attenuated after addition of milk may have broad implications on the mode of tea preparation and consumption.” In other words, maybe we should not add milk to tea, or put cream on our berries. Appears to have the same effect on berry phytonutrients, or chocolate. Eat milk chocolate, and nothing much happens to the antioxidant power of your bloodstream. But eat dark chocolate, and get a nice spike within an hour of consumption.
Yeah, but is that just because the milk in milk chocolate crowds out some of the antioxidant-rich cocoa? Milk chocolate may only be like 20% cocoa, whereas a good dark chocolate may be like 70% or more cocoa solids.
Okay, that’s cocoa beans; what about coffee beans? “When milk was added to the coffee [in like a test tube], antioxidant activity decreased” by more than half with just a splash of milk, and down like 95% in a latte, or something with lots of milk.
Okay, but what happens in a test tube doesn’t necessarily happen in a person. You don’t know…until you put it to the test. And indeed, over the course of a day, significantly fewer chlorogenic acids made it into people’s bloodstreams drinking coffee with milk compared to black—cutting absorption by more than half.
What about soy milk? In a test tube, coffee phytonutrients do appear to bind not only to dairy proteins, but also egg and soy proteins. But what happens in a test tube or computer simulation doesn’t necessarily happen in a person. Eggs haven’t been put to the test, so we don’t know if having omelets with your black coffee would impair absorption, and neither has soy milk… until now.
Yeah, either way soy milk has some inherent benefits over cow’s milk, but does it have the same nutrient-blocking effects? And the answer is…no. No significant difference in the absorption of coffee phytonutrients drinking coffee black or with soy milk. What seemed to be happening is that the soy proteins do initially bind the coffee compounds up in the small intestine, but then your good bacteria can release them so they can be absorbed down in the lower intestine. So, “considering the reversible nature of binding,” as opposed to the dairy proteins, “it seems not to be as relevant” as to whether or not you add soy milk.
Our next story is about the best foods for late pregnancy. We discuss how dates are put to the test in a randomized, controlled trial for cervical ripening.
In the 19th chapter of the Koran, Mary is giving birth to Jesus. I didn’t even know Jesus was in the Koran. The things they don’t teach you in Hebrew school. It says, “And the pains of childbirth drove her to the trunk of a palm tree.” She cries out, and she is answered by Gabriel, Archangel and, evidently, obstetrician—who knew? Shake the tree, he says, and “it will drop upon you ripe, fresh dates,” and you’ll be all better—no epidural necessary.
Do dates really help with labor and delivery? It would take a little over 2,000 years, but researchers finally decided to put it to the test. They had some “anecdotal evidence” that dates might be helping, but they wanted to know for sure “whether the addition of date fruit for the last few weeks of pregnancy would reduce the need for labor induction or augmentation”—that’s where you give drugs to induce uterine contractions, to initiate or accelerate labor. It’s “one of the most commonly-performed obstetrical procedures” in the U.S., dramatically increasing over the last few decades—from less than 10% of deliveries to now nearly a quarter. There are certainly legitimate medical indications, but are often done just for “convenience,” and not necessarily the convenience of the patient, but the provider may also have perverse “financial incentives” and other reasons to want to speed things along. Dates might not help with those factors, but might they help foster a normal spontaneous delivery? Let’s find out.
A prospective study: women eating six dates a day—that’s totally doable—during their last month of pregnancy versus no dates at all, and…”the women who consumed date fruit had significantly better cervical dilation,…significantly higher proportion of intact membranes.” That’s a good thing. And: “Spontaneous labor occurred in 96% of those who consumed dates, compared with 79% women in the non-date” group, with significantly less drugs used, and the “labour was shorter,” as in about seven hours shorter overall. “It is therefore concluded that the consumption of date fruit in the last 4 weeks of pregnancy significantly reduced the need for induction and augmentation of labour…The results warrant a randomised controlled trial.”
Wait, what? The women weren’t randomized? They even talk about how it was hard to find women who would agree to not eat dates because it’s part of their cultural beliefs. So, you can totally imagine how there could be all sorts of differences between the women who ate dates, and those who agreed to go without, that could account for the findings. Maybe the date-eaters were more religious, or higher socioeconomic status, or who knows. Yeah, you can argue, what’s the downside? Might as well give dates a try. But that’s not good enough. I want to know if they actually work. But there had never been a randomized, controlled trial…until three years later.
“The effect of late-pregnancy consumption of date fruit on so-called cervical ripening” in first-time mothers. In the last few weeks of pregnancy hormonal changes cause the cervix, the opening to the uterus, to start to ripen, to soften, so that when the contractions start, it can more easily dilate open.
“At this stage, the cervix loses its integrated structure, and therefore, it becomes soft and dilated as soon as strong contractions begin.” Through a ripe cervix you can push a baby out with like 20 pounds of pressure per square inch, but if the cervix isn’t there yet, it can require more like 200 pounds of pressure. So, it goes without saying that “cervical ripening before the onset of labor is …important” if you want a normal vaginal delivery. “The search for a safe, inexpensive, and easy method of [facilitating] cervical ripening is therefore of great interest.” So, let’s randomize a few hundred women starting at like the 37th week to eat about six dates a day—or not—until their first contraction.
Cervical ripening is rated with a Bishop score. Normally, a score of five or less “indicates an unfavorable cervix,” whereas eight or more and you’re good to go, and…the average Bishop score in the women randomized to the date group was significantly higher, closer to eight, whereas the date-free group was down at around five, and the cervix was more dilated in the date group. And hey, dates are healthy anyway, so maybe dates should be “recommended for pregnant women to help with cervical ripening, particularly in the last weeks” of their pregnancy.
And finally – (I know you’ve waited patiently for this)… Randomized, double-blind, placebo-controlled trials of… blueberries!
The consumption of berries can enhance “beneficial signaling in the brain.” “Plant foods…are our primary source of…antioxidant and anti-inflammatory compounds,” but some plant foods may be better than others. As I’ve explained before, one cup of blueberries a day can improve cognition among older adults, as shown in this randomized, double-blind, placebo-controlled trial. And the same thing in kids after just a single meal of blueberries; though two cups may work better than one.
That single hit of berries may also improve mood. A “double-blind, placebo-controlled, crossover study” in which kids are asked a series of questions. Are you very slightly, or not at all, a little, moderately, quite a bit, or extremely interested, excited, strong, etc. Before and after drinking the placebo, no significant change, but two hours after consuming about two cups of blueberries, their positive mood scores significantly improved. They felt more enthusiastic, alert, inspired, attentive—that kind of thing. That was in the young adults, ages 18 through 21; same thing in seven- to 10-year-old children. Some new dangerous mood-enhancing drug or Ritalin? No, blueberries—and just after a single meal.
Now blueberries can’t do everything. Although a cup of berries certainly appears to improve brain function… “no improvement in walking or balance was observed.” Maybe if you tried two cups of blueberries a day? Let’s do it!
Would “6 weeks of…two cups of frozen blueberries a day affect…the functional mobility in…adults” over age 60? Let’s find out. How awesome is it that this study was ever done in the first place? Anyway, randomized to blueberries or carrot juice as a control, measuring things like walking a plank, seeing if you can maintain your balance along a narrow path.
“Two bright yellow ropes on the floor outlined the narrow path, and participants were instructed to walk down within the roped path.” And the blueberries beat out the carrot juice; “significant improvements,” suggesting “blueberry supplementation may provide an effective countermeasure to age-related declines in functional mobility.” And looking back, they were thinking maybe they should have used something like cucumber as a control, since the carrots may have offered some benefit as well, making the blueberry results even more impressive. “Overall, this study demonstrates the need for greater exploration of blueberry supplementation as a nonpharmacologic countermeasure to the public health issue of age-related declines in…independence.” Or to use the pun version: “Dietary interventions with [phytonutrient]-rich foods, such as blueberries, present a potentially fruitful strategy for combating some of the deleterious effects of age-related neurodegeneration.”
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Thanks for listening to Nutrition Facts. I’m your host, Dr. Michael Greger.