News
International Coconut Community says coconut oil not linked to heart disease
The International Coconut Community has sent us the following statement in response to an article published on October 25. The statement says:
On behalf of coconut stakeholders in Sri Lanka and beyond, the International Coconut Community (ICC) strongly refutes claims aired in the Sunday Times article headlined ‘Now coconut oil is bad for your heart’, by Kumudini Hettiarachchi (the Sunday Times, Sri Lanka, October 25, 2020).
Ms. Hettiarachchi cites a research review paper: Jayawardena et al — “Effect of coconut oil on cardio-metabolic risk: A systematic review and meta-analysis of interventional studies”. Diabetes & Metabolic Syndrome: Clinical Research & Reviews, 2020: Volume 14:6; 2007-2020.
The ICC does not believe that the article has effectively ‘sift[ed] fact from assumption’. The cited review is based on a meta-analysis, but Jayawardena et al’s analysis mixes short-term and small studies with long-term and large studies and treats them as if they are of equal significance. He has committed the error of ‘comparing apples and oranges’. Second, he makes conclusions based on questionable criteria, like LDL-C, while ignoring others which are well established, like HbA1c and triglyceride levels. Thirdly, the review raises questions about the selective bias and quality of the data used. Their analysis leads to a flawed conclusion. This paper is misleading for several reasons.
First, the conclusion focused exclusively on changes in LDL-C levels but ignored the more important point regarding whether the resulting LDL-C levels were unhealthy; they were not. In fact, the consumption of coconut oil did not result in unhealthy levels of LDL-C. In January 2020, Astrup and co-authors questioned the use of LDL-C as a link to heart disease. The concern with LDL-C is a theory that is not universally accepted and remains unproven.
Second, the Jayawardena study downplayed the beneficial changes in lipid parameters that were due to coconut oil. In particular, coconut oil raised HDL-C and gave a favourable ratio of total cholesterol to HDL-C. HDL-C, the so-called “good cholesterol” is associated with heart health. The article also acknowledged that coconut oil lowered the levels of HbA1c, the average level of blood sugar, and did not raise triglyceride levels. High triglycerides appear to be more strongly linked to heart disease than LDL-C. Why is the article discounting these beneficial effects of coconut oil?
In one statement, Prof. Jayawardena, stresses that “we have to understand the level of evidence. Systematic review and meta-analysis of randomised clinical trials (RCTs) are the ultimate evidence, although isolated small studies have different conclusions”. Systematic reviews and meta-analyses present results by combining and analysing data from different studies conducted on similar research topics. The high level of evidence produced by RCTs overrides the isolated evidence, he says. In their review, the team had examined over 1,000 research articles, selecting only 23 of the human clinical trials for inclusion in the analysis.
Of the few publications on coconut oil and cholesterol, there had been two local interventional dietary studies by Prof. Shanthi Mendis and co-workers from three decades ago. However, stressing that their results came from a systematic review and meta-analysis from findings of studies considered to be of the “highest quality evidence”, he says there is no value in comparing the results of isolated evidence. We do not agree: putting aside such evidence is just a way of ignoring an inconvenient truth. In the same way, Prof. Jayawardena ignored a recent meta-analysis by Eyres (2016) on 8 clinical trials and 13 observational studies concluding that coconut-based diets are not linked to an increase in the risk of cardio-vascular disease (CVD).
The best way to counter such an argument is by using the same “highest-quality evidence”, by providing other meta-analysis studies. In 2017 Lancet published a meta-analysis study involving a team of 37 researchers from 18 countries. They gathered data on 135,000 subjects to evaluate heart disease risk in relation to fat intake and found no correlation between saturated fat consumption and cardiovascular disease; they recommended that current dietary restriction on saturated fat should be revised.
In 2010, a groundbreaking study was published in the American Journal of Clinical Nutrition. This meta-analysis study combined the data from 21 previously published studies, involving over 347,000 subjects.
The study showed that there was no connection between saturated fat consumption and heart disease. Those people who ate the greatest amount of saturated fat were no more likely to suffer a heart attack or stroke than those who ate the least. No matter how much-saturated fat one ate, the incidence of heart disease was not affected. This was the most complete review of the medical research on saturated fat ever done up to this time.
Four years later, a different group of researchers from the University of Cambridge published another meta-analysis study. This time the researchers combined the data from 72 previously published studies involving more than 600,000 participants from 18 countries.
The results confirmed the previous meta-analysis there is no connection between saturated fat intake and heart disease. The studies are clear, neither saturated fat nor coconut oil causes or even promotes heart disease. Because they raise good HDL-C and lower the cholesterol ratio, if anything, they help to protect against heart disease.
The Jayawardena study committed the serious error of comparing populations from countries such as South Asian, Southeast Asian and Pacific island states (which consume coconut oil in their normal diet) with short-term studies conducted in Western countries that do not normally consume coconut oil. How could they use data from these small one to four-week studies done in the West to infer health outcomes in Asian countries and draw conclusions about the prevalence of CVD in South Asia? Jayawardena cited a long-term study but did not give it the significance that it deserved. Vijayakumar and co-workers (2016) reported their results of a study that involved 200 participants who used coconut oil or sunflower oil as cooking oil for two years. The study showed that coconut oil gave comparable LDL-C values compared to sunflower oil.
Clearly, a critical assessment of the Jayawardena paper and other supporting evidence show that coconut oil is not linked to heart disease.