Top Cardiologist Blasts Nutrition Guidelines

Salim Yusuf says new evidence fails to support many major diet recommendations.

by Larry Husten, CardioBrief February 27, 2017 

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.

The Scary Mental Health Risks of Going Meatless

                                 Vegetarianism can come with some unexpected side effects.




More and more women are vegging out...of their minds. New research suggests that along with shedding pounds, slashing cancer risk, and boosting life expectancy, vegetarianism could come with lesser-known side effects: Panic attacks. OCD. Depression. WH investigates the puzzling blow of going meatless—and how to stay plant-based without going mental.


Her symptoms were sudden and severe. Drew Ramsey's 35-year-old patient had always been fit and active, but her energy had flatlined. When she did manage to drag herself to the gym, it didn't help. She felt anxious and was often on the verge of tears for no reason, even when she was with friends. Worst of all were her panic attacks, a rare occurrence in the past but now so common that she was afraid of losing her job because she had trouble getting out of bed, and she'd become terrified of taking the New York City subway.

Ramsey, a Columbia University professor and psychiatrist with 14 years of experience, wanted to put her on medication. His patient demurred. She was so conscious of what she put in her body, she'd even given up meat a year ago, having heard about all the health benefits of vegetarianism. So Ramsey prescribed something else: grass-fed steak.

It may sound like an episode of House, but Ramsey had a hunch. He'd seen a dramatic link between mood and food before (he even researched it for his forthcoming book Eat Complete), and guessed that his patient's well-intentioned meat-free diet was the very thing causing her mental deterioration. Sure enough, six weeks after adding animal protein back onto her plate, her energy rebounded and her panic attacks dropped by 75 percent.

Her case is far from unique. "I hear from vegetarians every day; they have this terrible depression and anxiety, and they don't understand why," says Lierre Keith, author of The Vegetarian Myth. "People think they're eating a beautiful, righteous diet, but they don't realize there's a potential dark side."

It's true that many of America's estimated 8 million vegetarians are drawn to the diet's promise of a healthier weight, heart, and planet. They pass on beef, poultry, and pork, unaware that a growing body of research suggests a link between going meatless and an elevated risk for serious mental disorders.

Garden State

Paleo aside, it's been decades since meat eating has been considered truly healthy. Practically every day, it seems, a new study emerges showing that vegetarian diets are the key to everything from shedding pounds to beating cancer. One group of California researchers even found evidence that ditching meat can tack more than three years onto your lifespan.

The plant-based love has gone well beyond medical opinion—it's become part of a cultural shift. Some 29 million U.S. adults now take part in Meatless Monday. Amazon alone has more than 7,000 vegan cookbooks in its inventory (60 of those are best sellers). Open Table has scores of "top restaurants for vegetarians" lists, highlighting star chefs experimenting with zero-meat meals. Even chains like Wendy's and White Castle are grilling up veggie burgers.

"I hear from vegetarians every day; they have this terrible depression and anxiety, and they don't understand why."

It's tough to argue with the science—and with a movement that's been endorsed by everyone from Gandhi to Beyonce. And it's natural to assume that peak mental health and a perpetually blissed-out attitude are just two more side effects of the glowing vegetarian lifestyle.

So it was startling last year when Australian researchers revealed that vegetarians reported being less optimistic about the future than meat eaters. What's more, they were 18 percent more likely to report depression and 28 percent more likely to suffer panic attacks and anxiety. A separate German study backs this up, finding that vegetarians were 15 percent more prone to depressive conditions and twice as likely to suffer anxiety disorders.

Even the pros find the stats confounding in a chicken-or-egg way. "We don't know if a vegetarian diet causes depression and anxiety, or if people who are predisposed to those mental conditions gravitate toward vegetarianism," says Emily Deans, M.D., a Boston psychiatrist who studies the link between food and mood.

Most likely, says Deans, there's truth to both theories. People with anxious, obsessive, or neurotic tendencies might be more inclined to micromanage their plates (in one study, vegetarians had triple the risk of developing an eating disorder compared with meat lovers). Yet experts all agree that, regardless of where you rank on a scale of 1 to OCD, what you swallow plays a major role in what happens in your head.

"Food is a factor in mental health," says Ramsey. "We should be talking about it. You can't just make a sweeping change to your diet and expect it won't have any effect on you mentally."

Risky Nutrition

Quick: Name some "brain foods." Well, there's avocado. Olive oil. Nuts. Red meat? Not so much. Yet anthropological evidence shows that, long before we could choose to subsist on cashew cheese and tofu, animal flesh provided the energy-dense calories necessary to fuel evolving cerebellums. Without meat, we'd never have matured beyond the mental capacity of herbivores like gorillas.

Today, stronger brains are still powered by beef—or at least, by many of the nutrients commonly found in animal proteins. At the top of the list are B vitamins, which your noggin needs to pump out neurotransmitters such as glutamate; low levels of it have been linked to depression, anxiety, and OCD (sound familiar?). Similarly, meager levels of zinc and iron, two nutrients far more prevalent in meats than veggies, may manifest as moodiness—or worse. "I've had vegetarians come in thinking they're having panic attacks when it's really an iron deficiency," says Deans. Without iron to help blood shuttle oxygen around, the brain gets less O2, leaving it sluggish and more prone to misfiring. Then there's tryptophan, an essential amino acid found almost exclusively in poultry. Your body can't make it on its own and needs it to produce serotonin, a hormone that acts as the brain's natural antidepressant.

"Today, stronger brains are still powered by beef—or at least, by many of the nutrients commonly found in animal proteins."

Some vegetarians inadvertently dig themselves in deeper by filling up on white bread, rice, and pasta; sugar-laden cereals; and cookies. This so-called carbitarian diet is free of meat but rich in problems, says internist Vincent Pedre, M.D., author of Happy Gut. "The resulting seesaw of blood sugar and hormone levels may lead to even more irritability, depression, and anxiety."

Meat in the Middle

Of course, plenty of vegetarians never experience so much as a single mental-health hiccup, and savvy ones are able to eat around the aforementioned nutritional deficiencies (see "Eat Your Feelings," page 143). Clearly, it's possible to adjust to, even thrive on, a meat-free existence.

But quitting meat shouldn't be done cold turkey, cautions Deans. Consult a nutritionist or doctor beforehand, especially if you're susceptible to mood disorders or have a family history of them. Then cut down gradually. "Start using meat as a garnish in a dish rather than as the main attraction," suggests Diana Rice, R.D., a dietitian in New York City. Other healthy ways to lean in to veggie-based eating: Scale back to just one meaty meal per day; nix meat only on weekends or certain weekdays; or practice flexitarianism—the term for when you eat meat only on occasion, or don't do meat but still eat dairy, eggs, and fish.

As you go, keep tabs on how you feel, physically and mentally. "Everyone responds to going vegetarian differently," says Rice. "Some feel amazing right away, some may feel the same, and some realize they're better off with a little bit of animal protein in their diets after all."

Isabel Smith, 27, was one of the latter. Just like Drew Ramsey's patient, she was active and energetic and thought a vegetarian diet was the perfect complement to her health-conscious lifestyle. But after a few weeks sans meat, she found herself uncharacteristically weepy. "I was tired and frustrated and got upset more easily, especially over things that wouldn't normally bother me," she says. "I would find myself sad for no reason." Shortly after she started eating meat again, she noticed an uptick in her mood.

The twist? Smith is a registered dietitian. One who now understands personally what she studies professionally: Not everyone is cut out for a life without meat. For many people, it's crucial to realize that the emphasis in food writer Michael Pollan's oft-quoted advice to eat "mostly plants" shouldn't always be on the second word.

Learn which meat substitutes are our favorite and get other healthy-eating tips in the December issue of Women's Health, on newsstands now.