–Salim Yusuf says new evidence fails to support many major diet recommendations.
One of the world’s top cardiologists says that many of the major nutrition guidelines have no good basis in science.
“I’m not a nutrition scientist and that may be an advantage because every week in the newspaper we read something is good for you and the same thing the next week is bad for you,” said Salim Yusuf, MD, DPhil,(McMaster University), at Cardiology Update 2017, a symposium presented by the European Society of Cardiology and the Zurich Heart House.
Yusuf presented evidence that many of the most significant and impactful nutrition recommendations regarding dietary fats, salt, carbohydrates, and even vegetables are not supported by evidence.
Yusuf’s talk relied heavily on findings from the PURE study, a large ongoing epidemiological study of 140,000 people in 17 countries. Though PURE is an observational study, “its design and extensive data collection are geared toward addressing major questions on causation and development of the underlying determinants of cardiovascular disease.”
Much of the data presented by Yusuf has not been published yet and should be considered preliminary, he said. In 2014 publication of the sodium results stirred considerable controversy.
The results from PURE will likely add fuel to the ongoing fiery debate over carbohydrates and fats. Yusuf displayed data showing that the incidence of cardiovascular disease in the PURE population increases as carbohydrate intake (as a percentage of total calories) rises.
“Previous guidelines said reduce fats and compensate for it by increasing carbohydrates … and so essentially we’ve increased carbohydrate intake in most Western countries and this is likely damaging. We were in for a big surprise. We actually found that increasing fats was protective.”
The PURE data show a steep increase in CV risk as carbohydrate intake increased beyond 55% of total energy. WHO guidelines state that up to 75% of energy can come from carbohydrates. “But that is wrong,” said Yusuf.
Dietary Fat
“We actually found that increasing fats was protective,” he said. Low consumption of total fat was associated with increased risk. Very high fat is also “probably bad,” Yusuf said, based on earlier studies from Finland with people who had “extremely high fat levels, not the usual fat levels that populations consume.”
No clear patterns emerged for different types of fats, Yusuf reported. Trends suggested that saturated fats were not harmful and perhaps even beneficial, while monounsaturated oils appeared beneficial. Polyunsaturated oils had a neutral effect, he said.
“You’ve got to think about the change in oils that have occurred in the world in the last 30 years,” said Yusuf. “It was entirely industry driven. We went from natural fats, which are animal fats, to vegetable fats, because they [industry] can produce it and therefore charge for it, and this was swallowed hook, line, and sinker by the AHA, and the WHO just repeated it.”
Yusuf also took aim at milk consumption trends in the US. “Even if you consume milk they want you to consume 2% or 1% of fat” but, he asked, “what is the evidence?” “A big, big, zero,” he said. In fact, he said, there “really are no data at all to reduce the fat content of milk.”
Yusuf came down squarely in favor of fats over carbohydrates: “Fundamentally, some fats are good, some fats may be neutral, but it’s carbohydrates that are the worst thing.” He offered a piece of advice: “so when you eat a hamburger throw away the bun and eat the meat.”
Yusuf summarized the PURE findings, which found that saturated fats from dairy sources were protective and saturated fats from meats were neutral. White meat from chicken or fish appeared to have a beneficial effect, while red meat in moderate quantities was not associated with harm.
Yusuf volunteered a strong endorsement for Nina Teicholz, author of The Big Fat Surprise, who has been heavily criticized by the nutrition establishment for her defense of dietary fat. “She shook up the nutrition world but she got it right,” said Yusuf.
“Why did we go wrong? We went wrong because of surrogate endpoints.”
The demonization of fats— saturated fats in particular— stemmed from earlier observations linking saturated fat consumption to LDL levels. Yusuf reported that PURE confirmed this finding, but he also noted that the overall difference in LDL was small and that there was a large amount of variance. More importantly, randomized studies that have looked at fat reduction to reduce cardiovascular events have not shown benefit, except in cases where fat levels were extremely high, he said.
Yusuf said that the ApoB/ApoA ratio is a much more highly sensitive marker of risk. Data from PURE shows that this ratio goes up with carbohydrate consumption but is neutral with saturated fats or polyunsaturated fats and declines with monounsaturated fats.
Regarding salt consumption Yusuf restated findings from the previous published reports from PURE and the more recent report from a working paper from WHO. He said the low sodium position was based on the well-established relationship between sodium and blood pressure. But, he argued, the benefits of extremely low levels of sodium have never been tested in a randomized controlled trial. Further, since sodium is an essential nutrient it is inevitable that taking sodium levels too low will be harmful. He also pointed out that although reducing blood pressure through sodium reduction may turn out to be beneficial in people with hypertension, it is entirely possible that non-hypertensives will derive no benefits from sodium reduction but they may well be susceptible to the harms associated with low sodium levels.
Fruits and Vegetables
Yusuf also raised questions about fundamental recommendations that are almost never subject to critical scrutiny. “Where on earth did the concept that we should eat 5 servings of fruits and vegetables come from?” asked Yusuf.
“Why not 4, why not 3, why not 6, why not 7? Is it all fruits, is it all vegetables, is it what kinds of fruits, what kinds of vegetables?”
He reported that the PURE data found a neutral effect for vegetables, and that the literature is “really inconsistent.” More importantly, he dismissed the idea that foods need to be judged based on their effect on health. “But I have to tell you, when it’s regarding diet, neutral is good. You have to eat something. If you like it eat it. Not every food has to be good or bad.”
Yusuf then pointed out that it is almost impossible for a large portion of the world to follow these fruit and vegetable recommendations. “Why are fruits and vegetables not consumed? All the guidelines are written by people sitting in Geneva or Dallas who are white, rich, and male. They are male, and so they don’t know the cost of foods, they don’t go do the grocery shopping. They’re white and they only think of what happens in their countries.” In high income countries like Canada and Sweden people spend only about 10% of their income on food. But in lower income countries like Pakistan, India, Zimbabwe, 65% of income is spent on food. It is then “no wonder that they’re going to buy the cheapest food,” he said. The cost of buying 2 servings of fruit and 3 servings of vegetables, as recommended by WHO, is completely unaffordable for many.
Related Reading:
- International Experts Call Salt Guidelines Far Too Restrictive
- Top HF Expert Decries ‘Unbelievable Folly’ of Clinical Trials and Guidelines
- Why Guidelines Are Bad For Science
- Recipe For Disaster: The New US Dietary Guidelines
- BMJ Paper Criticizes Proposed US Dietary Guidelines
- Why Guidelines Should Be Waged Like War
- An Expert’s Perspective: Why Salt Is Not Like Tobacco And Why Guidelines Are Tricky
Very interesting article. Nutritional guidelines have always created controversy. A non committed, neutral reader may be confused by all the noise. I enjoyed reading the piece as it’s conclusions are more or less identical to the ones I accepted for several years.
Apart from reading nutritional guidelines and their critical analyses, I used to keenly observe members of the medical community and their leaders while they pick and choose food at buffet lunches or dinners during professional conferences.
During such meetings in India, I saw many physicians (and their wives!) filling plateful of goodies without any restriction. It is as if they do not know that in a buffet lunch you pick and choose small quantities of the foodstuffs you like, come to your seat and enjoy them slowly and return to the food tables if they need some more. Many delegates collected all they can and more at once and once they are finished, over half of the food they collected, will be left behind. I must hasten to add that we see this behavior across the board, among all professionals.
During my professional career, I came across many eminent physicians belonging to different disciplines: surgeons, radiation oncologists, nuclear medicine physicians, cardiologists among others. The settings were different. One of the most eminent among them was a busy surgical oncologist. His lunch was just soup. He never took lunch. If my recollection is correct, he told me that even a modest lunch will make him drowsy and that may interfere with his work. I learnt that we may eat and enjoy everything, but in moderation. If we continue with this simple prescription we do not have to worry over nutritional guidelines.
Human body is too complex a machinery! Part of it follows the simple laws of physics and chemistry. In all probability, what we learn from research on diet and nutrition will be very partial. We should not be obsessed with such knowledge and take the conclusions too seriously. Dr. Salim Yusuf’s narration admirably and emphatically confirmed my conviction. Thank you, Larry Husten, for reproducing Dr. Yusuf’s views.
Very good to have someone speak out on this topic! It’s very difficult for some professionals to give up the status quo for new findings. I recently read that a study at the University of MN in favor of carbs vs fats was erroneously reported. Some of these studies (sugar vs fats) we are finding had direct influence from various industries prior to disclosure requirements. Look around at what a high carb diet has done in America. I really hope some doctors continue to be brave enough to report these findings.
I dropped industrial-produced carbs 5 years ago and lost 30 pounds in 60 days; right back to my college weight! I have never looked back: It is a life with “No Sugars”, “No Grains”, “No Vegetables (Seed) Oils” and very little fruit. I occasional do ketogenic. At 55 years I feel better than in my 20’s.
Dr. Atkins was right (actually he allowed too much protein). It’s all about down-regulating insulin and that is achieved naturally by carbohydrate restriction. Proteins & fats are essential nutrients; carbohydrates are non-essential.
Give it up carboholics! It takes 2-3 weeks to break the addiction, then the magic arrives: say good by to fatigue, depression, joint pain, migraines, etc.
Had the same experience Pete, 60 yrs old now but the same weight as when I was 23, dropped from 14st to 11st 7lbs in about 3 months eating as much as I wanted. The key word there is ‘wanted’
Cardiologists who failed nutrition class please stand up. All of you? ok sit down.
But, this article by Dr. Yusuf is spot on. He is one of the few cardiologists who get it right.
My thoughts:
a) I largely agree with Dr Yusuf. In fact he’s not the only one suggesting these ideas. He’s also mentioned Nina and other groups who have in the recent past dared to challenge the Diet-heart hypothesis and Ancel Keys theory. Whenever something gets repeated/cited/shown too often, we start believing it and that’s what happened in case of fats I think. There is a lot more we can discuss in person re this issue. I think piece meal vs holistic vision leads to erroneous interpretations.
b) However I will still lobby for a balanced approach guided by the moderation principle. Natural fats (or fat fractions), natural food items or fractions have repeatedly shown larger benefits than isolated single nutrients or fad diets. However this must be viewed in the context of today’s environmental pollution and widespread use of pesticides and forbidden chemicals. The whole foods and natural products also therefore may not exhibit all benefits as per our expectations. Here, isolated (but purified) single nutrients in gels or industry prepared concoctions for research may earn an edge over. But don’t be misled, I will argue. Locally grown natural foods with minimal human intervention will still yield better health impact.
c) I think one more imp factor in all this discussion is the role of exercise, our daily routines, home cooked vs eating out etc. These things play a major role too in disease epidemiology.
d) I do not agree with Dr Yusuf’s comments on FVs fully. I think plenty of large studies have shown benefits of fresh FVs. He may question them, sure. Details re how much, in what format, when, by what age group etc may be discussed further. But I will still have my reservations re rejecting the entire research wisdom behind consuming FVs.
e) One more thing- nutrition epidemiology is one of the most challenging types of research largely because everything in food can be split to indefinite micro levels. This gets further exacerbated by the fact that we research single nutrients but those get out to masses as promotion of supplement sales or food based recommendations. In theory or real world, the interactions and effect modifications between constituents of food, various fractions and sub fractions all exist and determine final impact. Two plus two does not yield 4 in nutrition studies always as a lot of other factors modify outcomes. But for a common man these get ignored and thus differential effects are observed for apparently the same intervention and that’s when people start getting all confused. This confusion comes back in research sphere and affects all of us.
Hope I made some sense. Look forward to hearing everyone else’s thoughts around this controversial issue.
Best Regards
Shweta Khandelwal
However I will still lobby for a balanced approach guided by the moderation principle. << when MDs or nutritionists can tell a patient the SCIENTIFIC definition of "moderation" then good.
Can you tell me? If we are all diverse genetically..then what degree of "moderation" works for an Asian who can eat a lot of rice and be thin, and a Norwegian who consumes high fish oils fats??
NO ONE ever advises a patient exactly what "moderation" means..you would advise differently for a 60 year old woman, overweight, in a wheelchair, than a 25 year old overweight man. right? Please think about this.
Dr Yusuf says “Why not 4, why not 3, why not 6, why not 7? Is it all fruits, is it all vegetables, is it what kinds of fruits, what kinds of vegetables?”
It is like asking how many hours of sleep do we need. Standard is 8 hours. But many manage with 6 or 7 or 9. Or Blood Pressure. Standard guide is 120/80. But 110/30 or 130/85 is not abnormal.
There is clear evidence that we should eat mainly whole plants in their unprocessed form. Claiming that it does not matter what you eat and bashing carbohydrates is ludicrous. We don’t eat fats, proteins or carbohydrates. We eat food. And that food should be whole and what occurs in nature. Not processed foods such as oils of different kinds, white flour, white rice etc.
There is even clearer evidence emerging supporting animal meats/fats. Life-long vegans and vegetarians are also starting to figure this out as well.
While it’s very possible to eat ketogenically and still be vegan, it’s met with many twists, turns, combining, etc. and has proven to be a bit difficult for many. And they still end up with serious vitamin deficiencies and muscle atrophy.
I’ll stick with grass fed/finished beef, pastured pork, chicken, etc. and enjoy my already glowing health
I’ve been eating plant based for about a year. The idea that those eating a plant-based diet end up with vitamin deficiencies and muscle atrophy is a fallacy. I would bet I’m getting a lot more variation in vitamins from food sources than you. It’s not that hard. I’m not experiencing any “twists and turns”, bloodwork is stellar (LDL cholesterol level plummeted), mental energy is noticeably better, training for a marathon. I have no problem with your preference for meat, but unless you’ve tried eating my diet, don’t knock it till you’ve tried it.
Another myth like global warming discredited
https://zhh.ch/en/joint-communication The rest of the story. Errors. Apologies. Removal of the talk from public domain. A travesty of dishonesty
Excellent summary of all the current nutritional issues and the folly of food recommendations that are not scientifically proven. Much of this is based on the false Lipid Hypothesis, which as covered in the lay press (Time Magazine, 2014) was debunked. Now the AHA comes out demonizing all saturated fats again. The public will once again be completely confused by this dictum and further believe none of the “experts”: can be believed when it comes to nutritional recommendations.