INTRODUCTION: A brand new study published last week in Nutrients looked at health and nutrition data from 158 countries worldwide and found that total fat and animal fat consumption were least associated with the risk of cardiovascular disease. As well, the study found that high carbohydrate consumption, particularly as cereals and wheat was most associated with the risk of cardiovascular disease. Significantly, both of these relationships held up regardless of a nation’s average national income.
Data from this study adds to the mounting evidence from 8 recent meta-analyses and systemic reviews of randomized control trials (RCT) summarized in this article that did not find an association between saturated fat intake and the risk of heart disease[1-8]. It also supports evidence from the recent global PURE (Prospective Urban and Rural Epidemiological) study published in The Lancet this past December which found that those who ate the largest amounts of saturated fats had significantly reduced death rates, and that those that ate the lowest amounts of saturated fat (6-7% of calories) had increased risk of stroke .
Global Correlates of Cardiovascular Risk: a comparison of 158 Countries
This new study compared the average intake of 60 food items with obesity rates and life expectancy in 158 countries and found that a relationship existed between eating specific foods and raised blood pressure, death from cardiovascular disease and raised blood glucose (high blood sugar) — all of which are associated with cardiovascular disease. The study examined nutritional data from 1993-2011 and found that total fat consumption and animal fat consumption were the dietary factors least associated with the risk of cardiovascular disease and that high carbohydrate consumption, especially as cereals and wheat was the dietary factor most associated with the risk of cardiovascular disease .
These findings add to the mounting evidence which calls into question whether dietary saturated fat is related to heart disease.
Total Cholesterol and Cardiovascular Risk
The present study found that eating animal fat and animal protein raised total cholesterol, however total fat and animal protein consumption were found to have a very impressive negative relationship with cardiovascular death in the European data, and a moderately negative relationship to cardiovascular death, worldwide. That is, the more total fat and animal protein eaten, the lower cardiovascular death rates were.
Often in studies, the assumption is that high LDL is linked to risk of cardiovascular disease – not that there is a direct relationship between animal / saturated fat and cardiovascular disease. That is, high LDL is a surrogate marker of cardiovascular disease. But does that assumption hold weight?
Perhaps a better question is “which LDL“? Small, dense LDL cholesterol which easily penetrates the artery wall is associated with heart disease [11,12,13,14], but the large, fluffy LDL cholesterol is not [15,16], so studies seeking to impute LDL as the cause of cardiovascular diseasee need to differentiate between these LDL particles.
As well, total cholesterol is made up of the different sub-particles of LDL cholesterol, HDL cholesterol, VLDL cholesterol and triglycerides (TG), so lumping them all in together as ‘total cholesterol‘ doesn’t tell us anything about risk of cardiovascular disease. We know that dietary saturated fat consistently raises the “good” HDL-cholesterol — which moves cholesterol away from the arteries and back to the liver where it can either be re-used or eliminated [17,18], so higher saturated fat intake will raise “good” HDL cholesterol, which in turn will raise total cholesterol. Total cholesterol going up is not a ‘bad’ thing.
What is important is not that total cholesterol went up but that along with increased total cholesterol, cardiovascular disease went down.
Higher Blood Sugar Associated with Higher Consumption of Cereals and Wheat
One finding of this study was that higher blood sugar (a known risk factor for cardiovascular disease) was most strongly associated with indicators of obesity such as high body mass index (BMI). What was new however is that higher consumption of cereals, especially cereals and wheat was associated with higher cardiovascular disease.
Researchers remarked that such results were not surprising “because the links between raised blood glucose, obesity, type 2 diabetes and cardiovascular disease are well established ”.
“…regardless of the statistical method used, the results always show very similar trends and identify high carbohydrate consumption (mainly in the form of cereals and wheat, in particular) as the dietary factor most consistently associated with the risk of CVDs.
High carbohydrate consumption, particularly as cereals and wheat was the dietary factor most consistently associated with the risk of cardiovascular disease.
Researchers looked at a maximum number of potentially significant variables and compared them to results across different regions and time periods and while they acknowledged that the accuracy of the data from developing countries may be lower, the global results that they found confirmed their earlier 2016 study data from European data only which found a significant link between cardiovascular disease and high carbohydrate consumption .
Of significance, the above associations held up regardless of a nation’s average national income.
Given these finding support those of the PURE epidemiological study  would lend support the notion that one can compare data between countries of substantially different level of income (as the PURE study did) and that high-carbohydrate and low-fat diets are not necessarily associated with poverty, as claimed .
The PURE study findings and those of this present study challenge the very basis of the long-standing ‘diet-heart hypothesis‘ and it certainly results in some uncertainty as to what constitutes a healthy diet.
In my view, what is needed are some well-designed randomized controlled trials to determine if saturated fat intake is directly associated with cardiovascular disease – and not associated with a surrogate marker, such as LDL cholesterol.
Purported Weakness of the Data
Self-reported food-frequency questionnaires on which this study is based have long been criticized as being unreliable, however it is important to note that in the United States the NHANES Dietary Data and the Continuing Survey of Food Intakes by Individuals (USA) has also collected data using food-frequency questionnaires and such data is used as the “cornerstone to inform nutrition and health policy” .
In Canada, the Canadian Community Health Survey (CCHS) relies on a 24-hour recall data which is known to researchers to result in under-reporting of food intake, especially among those with a high BMI and with adolescents . Given that the 2017 Obesity Update found Canada among its most overweight countries — with 25.8% of the population aged 15 and over considered obese , the CCHS data becomes less and less reliable, as obesity rates continue to climb.
Enduring Belief – despite recent evidence
The results of this most recently published study embody the same findings as the recent global PURE (Prospective Urban and Rural Epidemiological) study  publish this past December in The Lancet which found a link between raised cholesterol and lower cardiovascular risk.
This study also confirms the findings of the eight recent meta-analysis and systemic reviews of randomized control trials (RCT) summarized in the previous article which did not find an association between saturated fat intake and the risk of heart disease [1-8].
Yet, in spite of recent robust evidence there is an enduring belief that ‘saturated fat causes heart disease’ — a belief which has influenced nutrition guidelines in both the US and Canada for 40 years (since 1977).
As elaborated on in a recent article, it is now known that the ‘diet-heart hypothesis‘ originated by Ancel Keys and supposedly confirmed in his ‘Seven Countries Study’ omitted known data from 22 available countries and that when all countries were factored in there was a great deal more scatter showing a much weaker relationship between dietary fat and death by coronary heart disease than was suggested by Keys’s data.
Also as covered previously, it has been known since December 2016 that the three Harvard researchers who vindicated sugar as the cause of heart disease and blamed dietary fat — were funded by the sugar industry and that one one of those 3 researchers, Dr. DM Hegsted contributed to and edited the 1977 US Dietary Guidelines which embodied his findings of 10 years earlier, advising Americans to reduce their intake of saturated fat and cholesterol in order to reduce their risk of heart disease.
Also covered in a previous article, Canadian Dietary Recommendations regarding dietary intake of saturated fat were based on ‘health claim assessments’ conducted by Health Canada in 2000 (18 years ago) titled Dietary Fat, Saturated Fat, Cholesterol, Trans Fats and Coronary Heart Disease which was based on the US literature available from 1993-2000 and which concluded that a health risk exists between saturated fat and heart disease.
Given all of the factors mentioned above, it is my conviction that before the American and Canadian governments revise their respective national Dietary Guidelines what is needed is for them to conduct a long-overdue external, independent scientific review of the current evidence for the enduring belief that saturated fat contributes to heart disease.
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