Chocolate (part 2)
Earlier this month, Mars Wrigley was fined $14,500 by the Occupational Safety and Health Adminstration after two workers fell into a vat of chocolate at its Pennsylvania M&M factory. The workers were not badly injured. This raises a question: Did they accidentally fall or deliberately jump?
I'm joking of course. Nobody over the age of 5 would willingly leap into a vat of chocolate. But I can tell you, in all seriousness, that more cautious engagement with chocolate can be good for your cardiovascular health.
Last week, I discussed evidence that dark chocolate may contain unhealthy levels of cadmium and lead, and I concluded that the bad news isn't as bad as it sounds. This week I'll look at whether dark chocolate and cocoa can promote cardiovascular health. Here the good news may be even better than it sounds. (Although I'm a dark chocolate fan, I tried not to let personal biases distort my reading of the evidence.)
New labels for chocolate and cocoa products
In 2018, a leading chocolate and cocoa manufacturer, Barry Callebaut AG Switzerland, petitioned the FDA to allow labels on certain products to mention reduced risk of cardiovascular disease. On February 1 of this year, the FDA agreed to revised versions of Barry Callebaut's language. So, in the next year or so, we'll probably start seeing new labels.
Barry Callebaut proposed statements such as the following:
"Daily consumption of at least 200mg of cocoa flavanols per serving may reduce the risk of cardiovascular disease. FDA has determined that the evidence is supportive, but not conclusive, for this claim."
On February 1, the FDA responded that it will instead approve statements such as this:
“Cocoa flavanols in high flavanol cocoa powder may reduce the risk of cardiovascular disease, although FDA has concluded that there is very limited scientific evidence for this claim.”
From a consumer perspective, the FDA's wording is a real head-scratcher. Assuming we know what flavanols are, we're told that there's "limited" evidence that they "may" reduce risk of disease. What do you do with that? I'm curious to see whether the chocolate/cocoa industry wordsmiths something a little clearer.
In the meantime, why does the FDA acknowledge the possibility of cardiovascular benefits? And, could those benefits be even greater or more probable than the agency is letting on?
Flavanols
Sadly, not all kinds of chocolate promote cardiovascular health. If milk chocolate, white chocolate, and chocolate milk are good for you, it's only because they make you feel good. I wouldn't discount that. If a glazed chocolate donut helps you be a more relaxed, congenial person, then you and the people around you will be better off. But you won't be more healthy. (One such donut from Krispy Kreme or Dunkin Donuts, for instance, contains just over 350 calories and about a third of the saturated fat you need for the day.)
The chocolate and cocoa products linked to better heart health are the kinds that contain high levels of flavanols.
Flavanols are naturally-occurring chemicals found in cacao seeds. Processing the seeds yields cocoa solids (lots of flavanols) and cocoa butter (no flavanols).
Dark chocolate, and certain kinds of cocoa, contain large amounts of flavanols because they have a lot of cocoa solids. (The same is true of semisweet and bittersweet chocolate, which are dark chocolate varieties that differ in sugar content.) Cocoa powder has lots of flavanols because it's mostly cocoa solids, although "dutch cocoa" has less owing to the way it's processed. Milk chocolate has less flavanols simply because it has less cocoa solids, while products sold as white chocolate have few or no flavanols because they have few or no cocoa solids.
What the FDA is now permitting is a nod to the possibility that products made with high-flavanol cocoa solids promote cardiovascular health. Later I'll discuss which products might be beneficial and how much would need to be consumed.
The benefits of flavanols
The main reason Barry Callebaut petitioned for new labeling is evidence that high flavanol products improve something called flow-mediated dilation (FMD).
FMD tells you how much an artery dilates (i.e., expands) when more blood flows through it. This is essential to cardiovascular health. If your arterial walls can't dilate enough, your heart has to work harder to pump the blood, your blood pressure will rise, the risk of strokes and heart attacks increases, and so on. Thus, low FMD is predictive of cardiovascular disease. This is a consensus view that has been repeatedly expressed in studies, reviews, meta-analyses, and expert commentaries.
There's also a consensus that consumption of flavanols can increase FMD. At least seven experimental studies, some number of observational studies, and a meta-analysis have shown that cocoa flavanols can have this effect.
The methodology used in the literature looks pretty rigorous. Here's a typical example: In a 2015 study, 100 healthy, middle-aged participants with no cardiovascular problems were given a drink powder to mix with water and consume twice per day for a month. Half the participants were given powder with 450 mg of flavanols; the other half received powder with no flavanols. (The powders tasted the same.) All participants were also instructed to avoid eating high flavanol foods. FMD was measured before and after the one-month period. The researchers found that from the beginning to the end of the month, only the high-flavanol group showed a significant increase in FMD. (Blood pressure and cholesterol were also favorably influenced.) Especially good news is that a significant decrease in 10-year risk of cardiovascular disease could be extrapolated from the data.
Most of the studies I saw resembled this one, in the sense of being methodologically rigorous, and reporting good news that was not only statistically significant but clinically meaningful. The studies tended to rely on small samples, but the consistency of the results from study to study offsets this limitation.
FDA cautiousness
In spite of the extensive literature I just alluded to, the FDA refused to consider most of the evidence. They acknowledged that these studies exist but explicitly declined to review them. Instead, on the basis of just two studies (focusing on blood pressure), they decided to only allow highly cautious, potentially confusing labeling (“Cocoa flavanols in high flavanol cocoa powder may reduce the risk of cardiovascular disease, although FDA has concluded that there is very limited scientific evidence for this claim.”)
Why did the FDA ignore so much evidence? Because in their view – which is contrary to scientific consensus – FMD isn't a suitable outcome variable. Here's how the agency put it:
"FMD is not…a validated surrogate endpoint or biomarker for CVD [cardiovascular disease]. For a biomarker to be considered a valid surrogate, it should explicitly serve as a replacement for the true clinical outcome(s)... [The] literature suggests an association, but not surrogacy, between FMD and risk of CVD."
In other words, low FMD isn't the same as cardiovascular disease. It's merely associated with cardiovascular disease (which is to say, studies show that it predicts CVD). The FDA is saying, in effect, that we shouldn't care that flavanols increase FMD, and higher FMD lowers risk of cardiovascular disease, because low FMD isn't the same as cardiovascular disease. This is like saying that when you drive, you shouldn't care about how much alcohol you've had. Even if the more you drink, the more erratically you drive, erratic driving is not the same as an automobile accident.
FDA logic
On the whole, I'm appreciative of the work that the FDA does, but the agency's logic here is baffling – and inconsistent with its own practices.
1. The association between low FMD and cardiovascular disease has been demonstrated in dozens of studies. And, it's more than a statistical association. We know the underlying causal mechanism. When your arteries can't dilate enough, your heart works harder, your blood pressure rises, and the risk of cardiovascular damage increases. Again, the association between FMD and cardiovascular disease is sort of like the association between erratic driving and the risk of an accident.
2. In recent years, the FDA has allowed other surrogates that clearly aren't replacements for clinical outcomes. For instance, as I discussed recently, in 2021 the FDA granted accelerated approval for Aduhelm, a drug used to treat Alzheimer's disease, because the drug was shown to reduce amyloid plaques. However, the FDA itself acknowledges that we have no clear evidence that reducing plaques actually alleviates Alzheimer's symptoms (a point that was reiterated by the expert panel that advised the FDA not to approve the drug). This is shocking. Plaque reduction is not the same as symptom reduction. Plaque reduction isn't even clearly related to symptom reduction, which is the intended purpose of Aduhelm, and yet the drug was approved. Meanwhile, the scientific evidence is clear that FMD is predictive of cardiovascular health, but the FDA refused to consider any flavanol studies showing impacts on FMD.
Everyone else in the world seems to recognize that high flavanols promote high FMD, and that higher FMD predicts better cardiovascular health. For example, the European Food Safety Authority, the independent agency that provides advice on food chain-related risks to European Union countries, responded to an earlier petition from Barry Callebaut by appointing a panel to review the literature. Here's what they found:
"The Panel concludes that a cause and effect relationship has been established between the consumption of cocoa flavanols in the [high flavanol] cocoa extract (i.e. in capsules or tablets) and maintenance of normal endothelium-dependent vasodilation. In order to obtain the claimed effect, 200 mg of cocoa flavanols should be consumed daily. This amount could be provided by less than one gram of HF cocoa extract in capsules or tablets, and can be consumed in the context of a balanced diet."
That's admirably clear.
How to get your flavanols
Although other foods (teas, apples, berries, wines, etc.) contain flavanols, they don't contain as much by weight as cocoa solids. So, let's assume a goal of 200 mg of cocoa flavanols per day. That's a somewhat artificial goal, because (a) the data don't quite justify that much precision, and (b) the actual amount that's beneficial would depend on your size, your metabolism, the rest of your diet, and probably your activity level. But, assuming you wanted to consume 200 mg of flavanols per day, how could you do it?
(a) 1.4 ounces of most brands of sweetened dark chocolate contain between 272 and 880 mg of flavanols. So, if you like dark chocolate, just a fraction over one ounce should get you 200 mg.
(b) Two tablespoons of most brands of unsweetened cocoa powder contain between 74 and 260 mg of flavanols. So, if you like cocoa, you need to either find the right brand or use more than two tablespoons. You could also purchase cocoa pill supplements.
How can you figure out the exact flavanol content of each brand of chocolate or cocoa? Some brands tell you explicitly. Some product review sites provide data. You can pay ConsumerLabs for an online report. Or, if you're at the store looking at chocolate products, you can go by the cocoa content – the more cocoa, the more the flavanols – although studies have shown that the correlation isn't perfect, owing to the impact of manufacturing on flavanol content.
Conclusions
1. (From last week): You probably shouldn't be concerned about the lead and cadmium content of dark chocolate unless you consume a substantial amount of it most days, in which case you can either choose your brands carefully or eat it less frequently.
2. You may soon see labels indicating that certain chocolate and cocoa products can benefit cardiovascular health. The wording of these labels will almost surely be too cautious. The flavanols in dark chocolate and cocoa increase FMD, which in turn promotes cardiovascular functioning.
3. It's hard to pinpoint an ideal amount of flavanol consumption for cardiovascular health, but the European Food Safety Authority and some experts recommend 200 mg per day. (Not surprisingly, many chocolate manufacturers, including Hershey and Barry Callebaut, concur with this figure.)
4. If you eat dark chocolate for the flavanols, don't forget the rest of the ingredients. For instance, consider the brand with the most flavanols by weight: Montezuma's 100% Cocoa Absolute Black Dark Chocolate. One ounce has about 1,000 mg of flavanols. But it's also missing a popular ingredient (sweetener), and one ounce has about 45% of the saturated fat you should consume in a day…
5. Flavanols probably do very little to offset an unhealthy lifestyle. Studies only show that when everything else is held more or less constant, flavanols promote cardiovascular health. In other words, in most studies, the participants tend to be similar in key characteristics like cardiovascular functioning, and the main difference between them is the amount of flavanols they consume. But the effects on FMD are small to moderate. It's clear from other studies that obesity, unhealthy eating habits, heavy smoking and/or drinking, a sedentary lifestyle, and/or excessive stress can have a much larger impact on FMD over time. So, if you eat a dozen glazed chocolate donuts for breakfast every morning and wash them down with a tumbler of scotch, switching out the donuts for dark chocolate won't help much. In theory it will help a little, but a healthier breakfast would help more.
Thanks for reading!