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- Cinnamon (Cinnamomum spp., Lauraceae)
- Cholesterol
- Triglycerides
- Lipids
- Systematic Review/Meta-analysis
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Date:
05-31-2018 | HC# 101771-593
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Re: Systematic Review/Meta-analysis Finds Cinnamon Significantly Lowers Total Cholesterol and Triglycerides, but Not Low-Density Lipoprotein or High-Density Lipoprotein Cholesterol
Maierean
SM, Serban MC, Sahebkar A, et al.; on behalf of the Lipid and Blood Pressure
Meta-analysis Collaboration (LBPMC) Group. The effects of cinnamon
supplementation on blood lipid concentrations: A systematic review and
meta-analysis. J Clin Lipidol. November-December
2017;11(6):1393-1406.
When
plaques build up in the coronary arteries depriving the heart of oxygen-rich
blood, coronary heart disease results. This lack of oxygen-rich blood can
damage the heart and lead to a heart attack, angina, arrhythmia, and heart
failure. Blood lipids, including low-density lipoprotein (LDL) cholesterol,
high-density lipoprotein (HDL) cholesterol, and triglycerides (TG), have been
associated with coronary disease outcomes. Low levels of LDL cholesterol and TG
and high levels of HDL cholesterol are considered beneficial. A supplement that
can safely and effectively modify lipids could be used as an adjuvant with conventional medicine. This could mitigate the need to
increase conventional medicines and lessen their possible adverse effects.
Cinnamon (Cinnamomum spp., Lauraceae)
inner tree bark extract is widely consumed, safe, inexpensive, and a known
source of polyphenols. This systematic review and meta-analysis was conducted
to determine what effect cinnamon has on lipids.
To
identify appropriate articles, the authors searched the SCOPUS, Embase, and
MEDLINE databases for the following terms: randomized controlled trials OR RCT
OR randomized OR lipid OR total cholesterol OR LDL-cholesterol OR
HDL-cholesterol OR triglycerides, and cinnamon. They also used "*" to
enhance search sensitivity. The literature was searched up to July 31, 2015,
and was not limited to English-language publications. Eligible studies (1) were
randomized placebo-controlled trials with a simple or crossover design, (2)
investigated how blood lipid concentrations were affected by any cinnamon
species or by a cinnamon-enriched standardized extract, and (3) contained
sufficient baseline and endpoint data on blood lipid concentrations in the
interventional and control groups. Studies were excluded if they were animal,
observational, or uncontrolled studies; if the intervention was not
standardized or resulted in a daily cinnamon intake of < 5 mg; or if they provided
insufficient baseline or endpoint lipid concentration data. When data were insufficient,
the authors requested additional data.
Thirteen
trials published between 2003 and 2015 were included in the meta-analysis.
Sample size ranged from 17 to 137 patients, with a total of 750 patients; 388
were randomly assigned to the cinnamon treatment groups and 362 to the control
groups. Studies were conducted in China, Germany, Iran (n = 3), the
Netherlands, Pakistan, Sweden, Taiwan, Thailand, the United Kingdom, and the
United States (n = 2), and ranged from six weeks to four months. Most trials
used cinnamon capsules (one used tablets) providing from 120 mg of cinnamon to
6 g of cinnamon a day. One trial used "spray-dried water extract of
cinnamon containing more than 4% type A procyanidins," and another
employed Cinnulin PF® (IN Ingredients, Inc.; Spring Hill, Tennessee),
equivalent to 20 g of ground cinnamon a day. The duration of supplementation
with cinnamon or cinnamon extracts ranged between 60 days and four months. [Note:
According to Table 1, the shortest duration of supplementation was six weeks.] All
13 trials were designed as parallel-group trials.
The
authors found that cinnamon supplementation resulted in a statistically
significant decrease in total cholesterol (P < 0.01) and TG (P < 0.01),
but did not have a statistically significant effect on HDL or LDL cholesterol.
(Total cholesterol = LDL cholesterol + HDL cholesterol + TG/5.) However, with
the removal of one study, HDL cholesterol was significantly elevated (P < 0.01).
Meta-regression
analysis revealed that cinnamon dosage and lipid parameter changes had no
significant association. However, supplementation time did have a significantly
positive association with total cholesterol (P < 0.01), LDL cholesterol (P =
0.05), and TG (P < 0.01).
The
authors acknowledge that their analysis is limited by the study population,
which was limited to people with diabetes; the heterogeneity of the cinnamon
species used in the interventions; and the fact that most of the patients
included in the meta-analysis were taking lipid-lowering medications (only two
explicitly excluded patients taking lipid-lowering medication).
The
authors conclude that cinnamon was found to significantly lower total
cholesterol and TG, but not LDL or HDL cholesterol, and that "cinnamon
supplementation may be of marginal benefit to diabetic patients and patients
with impaired glucose tolerance, especially with atherogenic dyslipidemias."
To determine whether these findings are clinically significant, more research
is needed.
The
authors declare no relevant interests.
—Heather
Anderson, MD
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