Welcome to Straight Talk on Health. I’m your host Dr. Chet Zelasko. Straight Talk on Health is a joint production with WGVU in Grand Rapids MI. I examine the world of health. Nutrition. Exercise. Diet. Supplementation. If there’s something new, I look at the science behind them, and let you know whether it’s real or not. You can check out other things that I do on my website Drchet.com and sign up for my free emails.
Ultra-processed food (UPF) has been in the news again—and not in a good way. Researchers have claimed that they found a relationship between plant-sourced Ultra-Processed Food (UPF) and cardiovascular disease (CVD) and CVD mortality. The health news writers were brimming with opinions on what the study meant. The comment that got my attention was that UPF manufacturing destroyed all the good nutrients found in plant foods to the point that there was no benefit to eating them. Store bought cereals and cookies are worthless no matter how much fruit or nuts are added. That seems like a pretty serious claim.
But is that true? We’ll get to that.
Let’s begin by looking at the study. Researchers used data from a United Kingdom data base that allows analyses of the large amount of health data they’ve collected. The researchers selected only the participants who completed at least two 24-h dietary recalls. I know that you’re used to me ranting about Food Frequency Questionnaires, but this was a lot different. It correlated well with a 24-hr food recall done with a registered dietician. It focused only on foods that were eaten in the past 24 hours. The diet recall used pictures to help identify foods and drilled down as to the way the food was sourced and prepared. My only issue was that two diet histories in the 9 years of follow-up isn’t collecting as much nutritional information to improve specificity. Still, it’s better than the way that most diet information was collected in countless other studies.
The researchers could use diagnostic and mortality data from electronic medical records as all participants were part of the healthcare system in the UK. The total number of subjects was 118,397 after eliminating those with present CVD, pregnant or became pregnant, as well as potential subjects with missing data. That total loss was over 3,000 potential subjects, about 3% subject pool.
Researchers divided the dietary data into four groups and please, listen carefully as these are some tongue typing descriptors: non-UP plant-sourced foods, UP plant-sourced foods, non-UP animal-sourced foods and UP animal-sourced foods. The researchers ran a variety of statistical analyses, itself a problem as I’ve talked about in the past, but in the simplest yet relevant analytics, here are the two main findings: with higher intake of UP plant-sourced foods, the risk of CVD and CVD mortality were significantly increased; second, the increase of non-UP plant-sourced foods reduced the risk of CVD morbidity and mortality. I think those results were to be expected. But that’s not all the researchers found. Let’s take a closer look to see whether the expert diatribes about negating the benefits of UPF-plant-sourced foods were warranted.
I think the results of this UPF study were interesting, but the researchers went further. They estimated how substituting non-UP plant-sourced foods for any of the other three sources of food resulted in a reduction of CVD morbidity and mortality. Further, and what got the headlines, substituting UP plant-sourced foods for any of the other three increased the risk of CVD morbidity and mortality.
That led some experts to speculate about how processing destroyed fiber and phytonutrients and that the processing may even increase the amounts of negative chemicals that have been associated with disease in UP plant-sourced foods. The problem is that there are no randomized-controlled trials to prove that. There aren’t even any simple studies that prove that. That doesn’t mean there weren’t issues so let me lay them out for you.
The most important issue was this: The determination made about increasing or decreasing the risk of CVD disease was theoretical and based on calculations, not on actual data. They used a 10% substitution for the non-UP or UP plant-sourced foods to calculate the raising or lowering of risk. That isn’t clear as some health gurus didn’t seem to understand that concept when condemning UPF.
What the researchers could have done was divide the subjects into actual groups based on percentage of nutrients they actually ate instead of running theoretical statistical formulae. My impression is that so few people were diagnosed or died from CVD during the 9-year observational period that they wouldn’t have enough subjects to be able to get enough subjects into each potential group.
So, few subjects were diagnosed or died? In the entire subject population, there were only 7806 people diagnosed with CVD and only 529 deaths from CVD. Only? There were over 117,000 subjects in the study, and they were followed for 9 years. Most of the subjects were between 40 and 70 years of age, prime time for being diagnosed with some form of CVD.
Moving on, when looking at the percentage of UP-plant-sourced foods, the highest percentages were from industrialized packaged breads (10%), pastries, buns, and cakes (7%) and biscuits (cookies in the US) at 4%. That’s over half the amount of UP-plant based foods on the list provided in the research paper. While wheat and other grains were certainly stripped of nutrients in the ultra-processing, that’s nothing new as that’s happened to flour for over 100 years. What was missing were any fruits or vegetables that were processed in that manner. How do the phytonutrients get destroyed if they were not in the foods that people ate?
Don’t get the impression that I think that UP plant-based foods should be eaten in mass quantities. I don’t. But I don’t think this study provided much direction in a reasonable response to the issue. While the authors, as well as some of the health writers, correctly stated that this type of study can’t prove cause or effect, they all seemed to imply that conclusion. Time will tell, or more correctly stated, research will tell. The best advice for now? Everything in moderation including moderation.
The one real benefit to reviewing this study was that I finally found a dietary history online tool that can provide accurate dietary information about what people actually eat. I examined it in detail. Nothing can guarantee that a person will really spend the time to do a good job of filling in the diet recall. But because it deals with the prior 24 hours, it beats the “How many servings of X did you have per week in the past year” approach FFQ use. Here’s hoping it’s used in more longitudinal studies in the future. I’m out of time. This is Dr. Chet Zelasko saying health is a choice. Choose wisely today and every day.
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