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BACKGROUND: Coconut oil is high in saturated fat and may, therefore, raise serum cholesterol concentrations, but beneficial effects on other cardiovascular risk factors have also been suggested. Therefore, we conducted a systematic review of the effect of coconut oil consumption on blood lipids and other cardiovascular risk factors compared with other cooking oils using data from clinical trials.
METHODS: We searched PubMed, SCOPUS, Cochrane Registry, and Web of Science through June 2019. We selected trials that compared the effects of coconut oil consumption with other fats that lasted at least 2 weeks. Two reviewers independently screened articles, extracted data, and assessed the study quality according to the PRISMA guidelines (Preferred Reporting Items for Systematic Reviews and Meta-Analyses). The main outcomes included low-density lipoprotein cholesterol (LDL-cholesterol), high-density lipoprotein cholesterol (HDL-cholesterol), total cholesterol, triglycerides, measures of body fatness, markers of inflammation, and glycemia. Data were pooled using random-effects meta-analysis.
RESULTS: 16 articles were included in the meta-analysis. Results were available from all trials on blood lipids, 8 trials on body weight, 5 trials on percentage body fat, 4 trials on waist circumference, 4 trials on fasting plasma glucose, and 5 trials on C-reactive protein. Coconut oil consumption significantly increased LDL-cholesterol by 10.47 mg/dL (95% CI: 3.01, 17.94; I2 = 84%, N=16) and HDL-cholesterol by 4.00 mg/dL (95% CI: 2.26, 5.73; I2 = 72%, N=16) as compared with nontropical vegetable oils. These effects remained significant after excluding nonrandomized trials, or trials of poor quality (Jadad score <3). Coconut oil consumption did not significantly affect markers of glycemia, inflammation, and adiposity as compared with nontropical vegetable oils.
CONCLUSIONS: Coconut oil consumption results in significantly higher LDL-cholesterol than nontropical vegetable oils. This should inform choices about coconut oil consumption.
|Family Medicine (FM)/General Practice (GP)|
|General Internal Medicine-Primary Care(US)|
Especially in my country, Brazil, where there is strong media effort favoring this type of oil for it's supposed health benefits, this article is important.
This well-done and rigorous review and meta-analysis of coconut oil vs non-tropical vegetable oils concludes that coconut oil increases LDL and total cholesterol by amounts that may indeed contribute to excess CV disease. The concomitant small increase in HDL is not cardioprotective and does not offset the LDL increase. The authors bring up theories and observations that are often used to promote coconut oil consumption by industry or lay press, and they systematically refute them. This study is certainly compelling enough that we should be advising patients not to switch to this source of mostly saturated fat in place of nontropical vegetable oils.
I doubt the newsworthiness of the study, since, meta-analysis included poor quality clinical trials with substantial heterogeneity and 8 of the 16 studies had patient population 20 or less with only one study had a sample size of 200. The result may be attributable to chance alone.
I have always told my patients to substitute olive or canola oil for butter for heart health, and warned them against coconut oil, but recently have been getting push-back that coconut oil was good for the heart. This is a useful meta-analysis that concludes I was right - coconut oil raises LDL and has no beneficial effect on body fat, glucose or inflammation. Practical advice.
Coconut oil is also rich in medium-chain fatty acids and increases both LDL-C and HDL-C, 2.5:1 ratio. The balance is maintained. Any changes in lipids are not clinically meaningful until it is accompanied by a change in MACE. Most importantly: all refined oils are slow poisons, all non-refined oils in moderation are good for health. Balance is the key to health.
I would caution putting much weight on this study, given that it examines lab markers and not any patient-important outcomes. It is easy to assume that an increased LDL would result in a lower risk for cardiovascular disease, however that may or may not be the case. Drugs such as fibrates lower LDL without a significant reduction in MACE or mortality.