While randomized controlled trials are highly reliable in assessing interventions like drugs, they’re harder to do with diet. Dietary diseases can take decades to develop. It’s not like you can give people placebo food, and it’s hard to get people to stick to assigned diets, especially for the years it would take to observe effects on ha…
While randomized controlled trials are highly reliable in assessing interventions like drugs, they’re harder to do with diet. Dietary diseases can take decades to develop. It’s not like you can give people placebo food, and it’s hard to get people to stick to assigned diets, especially for the years it would take to observe effects on hard endpoints like heart disease or colon cancer. That’s why observational studies of large numbers of people and their diets over time are used to see which foods appear to be linked to which diseases. If you compare data obtained from observational population studies versus randomized trials, on average, there is little evidence for significant differences between the findings. Not just in the same direction of effect, but of the same general magnitude of the effect, in about 90 percent of the treatments they looked at. We don’t need the same level of certainty telling someone to eat more broccoli or less meat, compared to whether or not you want to prescribe someone some drug. After all, prescription drugs are the third leading cause of death in the United States. It goes heart disease, cancer, then doctors. About 100,000 Americans are wiped out every year from the side effects of prescription drugs taken as directed or some procedures instead of prevention. So, given the massive risks, you better have rock-solid evidence that there are benefits that outweigh the risks. Randomized double-blind, placebo-controlled trials for drugs, absolutely, but when you’re just telling people to cut down on doughnuts or cured meat, you don’t need the same level of proof.
The industry-funded sugar paper concluding that the dietary guidelines telling people to cut down aren’t trustworthy, because they’re based on such “low-quality evidence,” is an example of the inappropriate use of the drug trial paradigm in nutrition research. NutriGrade, a scoring system specifically designed to assess and judge the level of evidence in nutrition research, is the standard, not RCT.
One of the things about NutriGrade is that it specifically takes funding bias into account, so industry-funded trials are downgraded—no wonder the industry-funded authors chose the inappropriate drug method instead. HEALM is another one, Hierarchies of Evidence Applied to Lifestyle Medicine, specifically designed because existing tools such as GRADE are not viable options when it comes to questions that you can’t fully address through randomized controlled trials (RCTs). Each research method has its unique contribution. In a lab, you can explore the exact mechanisms, RCTs can prove cause and effect, and huge population studies can study hundreds of thousands of people at a time for decades.
THERE are randomized controlled trials showing trans fats increased risk factors for heart disease, and we had population studies showing that the more trans fats people ate, the more heart disease they had. So, taken together, these studies forged a strong case for the harmful effects of trans fat consumption on heart disease, and as a consequence, it was largely removed from the U.S. food supply, preventing as many as 200,000 heart attacks every year. Now, it’s true that we never had randomized controlled trials looking at hard endpoints, like heart attacks and death, because that would take years of randomizing people to eat like canisters of Crisco every day. You can’t let the perfect be the enemy of the good when there are tens of thousands of lives at stake.
Even if RCTs are unavailable or impossible to conduct, there is plenty of evidence from observational studies on the nutritional causes of many cancers, such as on red meat increasing the risk of colorectal cancer. So, if dietary guidelines aiming at cancer prevention were to be assessed with the drug-designed GRADE approach, they’d reach the same conclusion that the sugar paper did—low quality evidence. And so, it’s no surprise a meat-industry-funded institution hired the same person who helped conceive and design the sugar-industry funded study. And boom, lead author saying we can ignore the dietary guidelines to reduce red and processed meat consumption, because they used GRADE methods to rate the certainty of evidence, and though current dietary guidelines recommend limiting meat consumption, their results predictably demonstrated that the evidence was of low quality.
I appreciate your well thought out comment. Point taken. But saying something like no RCT is just an opinion which are a dime a dozen. Arguments based on evidence and examples are needed to make opinions useful. At least that is what the emails I got thanking me for my "lot of words," suggests.
Yes, for comparing a drug to placebo, RCT is the gold standard. As my "lot of words" points out, RCT is neither appropriate nor possible for studies on how diet affects health, or specifically in this case, whether cured meats and other animal foods cause colon cancer. In this case, long term observational studies are the gold standards. I can see I did not write enough words to make that clear.
While randomized controlled trials are highly reliable in assessing interventions like drugs, they’re harder to do with diet. Dietary diseases can take decades to develop. It’s not like you can give people placebo food, and it’s hard to get people to stick to assigned diets, especially for the years it would take to observe effects on hard endpoints like heart disease or colon cancer. That’s why observational studies of large numbers of people and their diets over time are used to see which foods appear to be linked to which diseases. If you compare data obtained from observational population studies versus randomized trials, on average, there is little evidence for significant differences between the findings. Not just in the same direction of effect, but of the same general magnitude of the effect, in about 90 percent of the treatments they looked at. We don’t need the same level of certainty telling someone to eat more broccoli or less meat, compared to whether or not you want to prescribe someone some drug. After all, prescription drugs are the third leading cause of death in the United States. It goes heart disease, cancer, then doctors. About 100,000 Americans are wiped out every year from the side effects of prescription drugs taken as directed or some procedures instead of prevention. So, given the massive risks, you better have rock-solid evidence that there are benefits that outweigh the risks. Randomized double-blind, placebo-controlled trials for drugs, absolutely, but when you’re just telling people to cut down on doughnuts or cured meat, you don’t need the same level of proof.
The industry-funded sugar paper concluding that the dietary guidelines telling people to cut down aren’t trustworthy, because they’re based on such “low-quality evidence,” is an example of the inappropriate use of the drug trial paradigm in nutrition research. NutriGrade, a scoring system specifically designed to assess and judge the level of evidence in nutrition research, is the standard, not RCT.
One of the things about NutriGrade is that it specifically takes funding bias into account, so industry-funded trials are downgraded—no wonder the industry-funded authors chose the inappropriate drug method instead. HEALM is another one, Hierarchies of Evidence Applied to Lifestyle Medicine, specifically designed because existing tools such as GRADE are not viable options when it comes to questions that you can’t fully address through randomized controlled trials (RCTs). Each research method has its unique contribution. In a lab, you can explore the exact mechanisms, RCTs can prove cause and effect, and huge population studies can study hundreds of thousands of people at a time for decades.
THERE are randomized controlled trials showing trans fats increased risk factors for heart disease, and we had population studies showing that the more trans fats people ate, the more heart disease they had. So, taken together, these studies forged a strong case for the harmful effects of trans fat consumption on heart disease, and as a consequence, it was largely removed from the U.S. food supply, preventing as many as 200,000 heart attacks every year. Now, it’s true that we never had randomized controlled trials looking at hard endpoints, like heart attacks and death, because that would take years of randomizing people to eat like canisters of Crisco every day. You can’t let the perfect be the enemy of the good when there are tens of thousands of lives at stake.
Even if RCTs are unavailable or impossible to conduct, there is plenty of evidence from observational studies on the nutritional causes of many cancers, such as on red meat increasing the risk of colorectal cancer. So, if dietary guidelines aiming at cancer prevention were to be assessed with the drug-designed GRADE approach, they’d reach the same conclusion that the sugar paper did—low quality evidence. And so, it’s no surprise a meat-industry-funded institution hired the same person who helped conceive and design the sugar-industry funded study. And boom, lead author saying we can ignore the dietary guidelines to reduce red and processed meat consumption, because they used GRADE methods to rate the certainty of evidence, and though current dietary guidelines recommend limiting meat consumption, their results predictably demonstrated that the evidence was of low quality.
That's a lot of words to say no RCT.
I appreciate your well thought out comment. Point taken. But saying something like no RCT is just an opinion which are a dime a dozen. Arguments based on evidence and examples are needed to make opinions useful. At least that is what the emails I got thanking me for my "lot of words," suggests.
There is no better evidence than a well designed and executed RCT. It is the gold standard.
Yes, for comparing a drug to placebo, RCT is the gold standard. As my "lot of words" points out, RCT is neither appropriate nor possible for studies on how diet affects health, or specifically in this case, whether cured meats and other animal foods cause colon cancer. In this case, long term observational studies are the gold standards. I can see I did not write enough words to make that clear.