More Cereal Fiber, Much Less Heart Disease

In Vitamin D and Cholesterol: The Importance of the Sun (2009) by David Grimes, an excellent book, I came across a 1977 study of healthy middle-aged men. The researchers measured their diet and watched them from 1966 to 1976. The question: What diets were associated with better health? There turned out to be associations with cholesterol (lower better) and systolic blood pressure (lower better), but these were less interesting than two strong dietary associations. One was between energy intake and heart disease. Men in the lowest third of energy intake had 23 cases of heart disease; men in the highest third had 7 cases. That’s probably due to exercise: the more you exercise the more you eat. We already know exercise is good.

The other association was with cereal fiber. Men in the lowest third of consumption (2-7 g/day) had 25 cases of heart disease; men in the highest third (8-34 g/day) had 5 cases. (A Wasa cracker has about 2 g cereal fiber.) You might dismiss this as healthy-person bias: healthy people do many healthy things, such as eat fiber. However, there was no association of heart disease and fiber from fruit and nuts. They’re healthy too. “The advantage of a diet high in cereal fibre cannot be explained [by us],” said the authors.

Later studies have found the same thing. For example, a 2006 review reached a similar conclusion: “There is an increasing body of evidence, including that from prospective population studies and epidemiological observational studies, suggesting a strong inverse relationship between increased consumption of wholegrain foods and reduced risk of CVD.” A study of health-conscious people — to reduce healthy-person bias — found a similar association: “Persons who habitually ate wholemeal bread had a lower mortality from cerebrovascular disease.” A 2002 review and a 2013 review provide even more evidence for the association.

Shant Mesrobian has emphasized the importance of fiber for health. Whereas paleo gurus usually say grains are bad. Here, for example, are “10 reasons to avoid grains”.

18 Replies to “More Cereal Fiber, Much Less Heart Disease”

  1. There are still parts of Scotland where people eat lots of oats (porridge, oat cakes), eat lots of fish, and take plenty of exercise. I’ve never seen any suggestion that they are exempt from the high rate of heart deaths in Scotland. But maybe they are.

    (Decades ago my wife attended a seminar on heart attack rates in Glasgow. The figures differed strikingly from one apparently identical neighbourhood to another, where a “neighbourhood” was tiny – just a few streets. The investigator had no explanation to offer.)

    Seth: The study I describe was done in London. Grimes would emphasize the lack of sunlight in Scotland as a cause of heart deaths.

  2. Perhaps it is not the consumption of whole grains giving the positive effect but the fact that the whole grain eaters tend to eschew highly processed flours.

  3. re: heart attack rates in Glasgow. Heart disease has been associated with air pollution. Pollution rates can vary strikingly in a city. Strangely an environmental group has just released an air pollution study naming a street in Glasgow as the most polluted in Scotland.

    Scotland’s most polluted streets identified in Friends of the Earth league table

  4. I agree that lots of paleo people ignore the importance of plant fibre. A couple of things that I think might be important. You might be able to get that fibre from other sources but these just weren’t measured properly. My friend from Lao eats far more whole food than I do and I’ve wondered if my western take of throwing out parts of our food might reduce our fibre intake. He doesn’t throw the apple core away, he eats it. When he eats chicken wings and ribs, he cleans the bones more than anyone I’ve ever seen. I saw a study that found animal fibre being close to scFos in terms of helping pass probiotics.

  5. Interesting. I don’t see how it fits with the observation that the traditional Greenland Inuit diet was associated with low CVD rates. I think this goes back to macro vs. micro nutrients. To convince me of a macronutrient claim it has to be compatible with both the Inuit low-carb diet and the Okinawa low-fat diet.

  6. IMO: Too small of a study to garner much information. Too much information was missing or excluded, etc. And it’s about the only study I’ve ever read that posits there’s no benefit to eating whole grains and unrefined starches over their refined counterparts. (Someone should alert the authorities!) It’s hard to tell how they even controlled for that. I also wonder what they mean by “clinical coronary heart disease”? And using death notices for cause of death is notoriously unreliable. “Heart disease” is usually the go-to, absent an obvious gun-shot wound, blunt force trauma, etc. It also turns on its head, the current conventional wisdom, which is that low trigs, high HDL, and large LDL particles are protective. Grains (and too many carbs) cause trigs to go up, HDL to drop, and LDL particle size to become small and dense (all the better to attack your endothelium). Ditto for sugar.

    And, of course, they didn’t even have a “no grains” arm. That would have been interesting, I think.

    It’s also interesting to note, however, that saturated fat is NOT implicated. Huzzah! And that it’s better to be short than tall. I can’t do much about the latter, but I’m sticking to my game plan: Eat saturated fat, veggies, fruit, and don’t eat grains or sugar.

  7. @kxmoore, I agree that Inuit and Okinawa diet both lack high-processed flours but the study Seth links to shows that neither sugar intake nor refined flour intake was correlated to CVD incidence. The only dietary factor that seemed to count was fibre from brown/whole-grain bread and breakfast cereal. I find that weird, really weird.

    @Joe, I thought the study showed that whole-grains was basically all that counted.

  8. @RAD I should have read more carefully. Yeah, the first study Seth mentioned showed no refined carb cvd correlation. Perhaps the cereal fiber afford a “second meal effect” that mitigates a harmful effect of refined carbs?

  9. RAD: I may be wrong, but I think that’s what this means:

    “Straight tabulations of coronary cases against white bread eaten
    showed no trend. Thus our data do not support the hypothesis that the incidence of CHD is related directly to intake of refined carbo-

    I agree with you, it’s weird.

  10. @Joe, I think the accepted wisdom goes something like “replace refined carbs with whole grains” and the statement you quoted says something like “it doesn’t matter whether or not you eat refined carbs” but the paper addresses the whole grain part elsewhere. Eating whole grains reduces CVD even if you prefer your grains soaked in high fructose corn syrup (poetic license with causation/correlation). That’s the bizarro part for me.

  11. RAD, I couldn’t find it, but I’ll take your word for it. And, yeah, ain’t nothing like a little “high fructose corn syrup” for breakfast!

    New advertisement:

    Eat Kellogg’s Cocoa Krispies, now with HEART-HEALTHY high fructose corn syrup!

  12. kxmoore, did you notice the study was funded by a CEREAL group?

    I guess that helps to explain the lack of an eggs and bangers arm.

  13. In all fairness, I would have liked to see an article named “10 reasons to avoid meat” right along side of the article “10 reasons to avoid grains”. No doubt more people who do not get enough grains and fiber are having medical problems because they are constipated, which impairs the circulation of their blood and energy, which may lead to cerebrovascular disease and other problems.

    Who knows? Not me.

  14. Jack, constipation is a complicated matter. But the amount of fiber you eat may, or may not, be a contributing factor.

    “Stopping or reducing dietary fiber intake reduces constipation and its associated symptoms”

    Things like lack of exercise, taking certain medications, not drinking enough water, not eating enough fat, etc., all can contribute to it. Eskimos eat almost zero fiber and they have little to no constipation. People who are forced to eat liquid diets for weeks and longer can still have regular bowel movements. Etc.

    I always try to “have my cake and eat it,” whenever I can, and I eat a good amount of veggies and fruits (along with animals and fish), mostly for the nutrients, but also for the fiber. And it all goes through me like you-know-what goes through a goose.

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