Cardiometabolic disease – is sugar or fat to blame?

In this, my fourth report on the 5th International Plant-Based Nutrition Healthcare Conference (PBNHC), I’m covering 4 presentations that focused on cardiovascular disease and its risk factors: ‘The Bitter Truth of Sugar Addiction’ by Dr Robert Lustig, ‘Sugar and Heart Disease: What Does the Research Say?’ by Dr Kim Williams, ‘Prevent and Reverse Heart Disease’ by Dr Caldwell Esselstyn and ‘The Scientific Skinny on Saturated Fat’ by Dr Joel Kahn.

(Haven’t read the first 3 reports yet? Check out The 3 secrets of transforming your life, Beating diabetes and Cancer prevention and treatment.)

I must admit that when I saw Dr Robert Lustig’s name on the faculty list for this year’s PBNHC, I did a double-take. Kim Williams, Essy and Joel Kahn are well-known advocates of a wholefood plant-based diet, but Robert Lustig is most definitely not. In fact, he’s an enthusiastic advocate of a high-fat, animal food-based diet. He firmly believes that saturated fat has been unfairly vilified, and points the finger of blame for our current epidemics of obesity, diabetes, non-alcoholic fatty liver disease and cardiovascular disease solely at sugar, or more specifically fructose.

I figured we would be in for some argy-bargy between Lustig and the plant-based docs, and my prediction turned out to be accurate!

Robert Lustig is a paediatric endocrinologist, and he’s deeply concerned about the health state of America’s children. He has good reason to be worried! Childhood obesity rates are at all-time highs, and consequently type 2 diabetes (formerly called ‘mature onset diabetes’ because it was only ever seen in older people) is now being diagnosed in pre-teen children.

Type 2 diabetes is caused by insulin resistance, which also affects the liver, causing non-alcoholic fatty liver disease (NAFLD). In NAFLD, fat in the form of triglycerides accumulates in liver cells, and this fat blocks the action of insulin, the hormone that allows glucose in the bloodstream to enter cells, in order to be burnt as fuel. If you have NAFLD, your risk of developing type 2 diabetes is 3.5 times greater, and NAFLD is also a major risk factor for cardiovascular events such as heart attacks. To top it all off, NAFLD can progress to cirrhosis of the liver – even in someone who never consumes alcohol.

So the findings of a study that Lustig mentioned, in which 17% of obese children who died in car accidents were found on autopsy to have NAFLD, are hugely worrying. The rising tide of obesity-induced type 2 diabetes and NAFLD probably explains the fact that after decades of decline, the rate of death from cardiovascular disease in the US is now rising again.

No one would argue with Robert Lustig that we should take obesity, diabetes and NAFLD in children seriously. Where the arguments begin, is in identifying the culprit(s) and thus the solution.

Lustig insists that sugar, specifically fructose, is the sole villain. He makes much of studies showing that fructose is converted to fat in the liver, which seems credible until you actually read the studies… and find that in order to make the liver turn fructose into fat, you have to feed obese individuals 104 to 250 g of fructose per day on top of their normal diet, which equates to an additional 18%-97% of their usual total daily energy intake. (For comparison, an apple and 1 cup of blueberries each contain 10 g of fructose.)

Dr Garth Davis, who spoke the day after Lustig, has amassed the evidence that contradicts Lustig’s position into a blog post which is well worth taking the time to read in its entirety. As just one example, the EPIC-Norfolk study found that fructose intake was inversely related to diabetes risk – that is, the higher the fructose intake, the lower the risk of diabetes – and that replacing 5% of energy intake from saturated fat with an equivalent number of kilojoules from fructose was associated with a 30% lower risk of developing diabetes.

Dr Kim Williams (whose opening keynote at the 2015 PBNHC I summarised here) concurred with Lustig that there is convincing evidence that sugar consumption is a risk factor for heart disease, especially in the form of sugar-sweetened beverages such as soft drinks, ‘fruit juice drinks’ and cordials. He noted that sugar increases the activity of the sympathetic nervous system, resulting in raised blood pressure, insulin resistance and other known risk factors for cardiovascular disease.

However, he took issue – in his characteristically soft-spoken, gentlemanly fashion – with Lustig’s sole emphasis on sugar. While Lustig argued that triglycerides (which are raised by consumption of refined carbohydrates, including sugar) are a better predictor of cardiovascular risk than LDL levels, Williams countered that the combination of high LDL with a raised C-reactive protein (CRP – a marker of inflammation) is associated with the highest risk of death from cardiovascular causes, and CRP along with other inflammatory markers has been consistently found to be lower in plant-based eaters.

Dr Caldwell Esselstyn (whose previous PBNHC presentations I’ve summarised here and here) also acknowledges the crucial role played by inflammation in coronary heart disease. In fact, he contends that the low-fat plant-based diet that he prescribes to open up the clogged arteries of his ‘cardiac cripple’ patients, eliminate their angina within weeks, and protect them against future cardiovascular events with a close to 100% success rate, works primarily through its anti-inflammatory effects.

The number of anti-inflammatory compounds in whole, minimally-processed plant foods are too numerous to count, but Esselstyn highlighted recent findings that a compound called 3,3-dimethyl-1-butanol (DMB) inhibits the formation of TMA, which is converted by gut bacteria into artery-toxic TMAO – although not in vegans, whose guts don’t harbour the offending bacteria. Where do we get DMB? It’s found in red grapes, and therefore in the balsamic vinegar that Essy instructs his patients to ‘anoint’ their green leafy vegetables with, and to eat 6 portions of this combination per day. That’s a pretty tasty prescription for heart health!

Dr Joel Kahn was clearly exasperated with Lustig’s insistence that sugar, and not saturated fat, is the villain in heart disease. Kahn has systematically countered the claims by sat-fat denialists here as has Dr David Katz here, here, here; and for a mind-bendingly thorough examination of the saturated fat-heart disease link, you simply can’t go past Plant Positive’s video series, which is comprehensively referenced.

Kahn also shot down Lustig’s claim that HDL, not LDL, was the most important cholesterol subfraction, and that high HDL is protective against heart disease, pointing out that drugs which raise HDL actually double the risk of a cardiovascular event.

Esselstyn concurs, citing evidence that the total amount of HDL cholesterol bears no relation to its efflux capacity – that is, the ability of HDL to remove cholesterol from arterial plaque and shuttle it to the liver for excretion. He points out that the Tarahumara Indians of Mexico have an astonishingly low HDL level – an average of 32 mg/dl, or 0.08 mmol/L in Australian measures, yet heart disease is virtually unknown amongst these people.

Let’s cut to the chase: the only diet which has ever been shown to reverse heart disease – even in cases so severe that bypass surgery had been scheduled – is a low fat, plant-based diet. This is the diet that Esselstyn prescribes, along with Dr Dean Ornish, whose heart disease reversal program is funded by US Medicare… because it works, and it saves Medicare a lot of money by slashing the number of angioplasties and bypasses that have to be performed on heart patients, not to mention their pharmaceutical bill.

This diet-style is low in fat, particularly saturated fat, and high in unrefined carbohydrates. Given that Robert Lustig has never treated people with coronary heart disease, while all the plant-based doctors who argued against him do that for a living, I’d be inclined to take any advice he gives on preventing it with a grain of salt… or maybe not, given the role of sodium in promoting heart disease ;-).

It’s not that any of these doctors think that eating sugar is a good idea, and all of them advocate for a diet low in any kind of refined carbohydrates including sugar. But the epidemiological, mechanistic and clinical evidence linking saturated fat intake to cardiovascular disease is just so strong that it cannot be dismissed.

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