“Researchers cautioned on making an anti-inflammatory claim for krill oil. Rather, they concluded, “Our findings demonstrate that fish oil and krill oil are comparable dietary sources of [omega-3 fats]. However, when similar doses of [omega-3 fats] are administered, krill oil seems to have a greater potential to promote [fat breakdown].””
By Greg Arnold, DC, CSCS, September 24, 2012, abstracted from “Krill oil versus fish oil in modulation of inflammation and lipid metabolism in mice transgenic for TNF-alpha” published online August 25, 2012 in the European Journal of Nutrition
The Center for Disease Control defines “overweight” as having a body mass index of greater than 25 kg/m2, with obesity is defined as a BMI of 30 kg/m2 or higher. Being overweight or obese increases the risk for a number of diseases that include heart disease, type 2 diabetes, cancer (endometrial, breast, and colon), high blood pressure, stroke, liver/gallbladder disease, and osteoarthritis (1).
A significant contributor to this increased risk of disease is due to the release of a number of inflammatory proteins called adipokines by adipose (fat) tissue that produces a state of chronic low-grade inflammation (2) that can set of a cascade of inflammatory proteins (3). .
As a result, helping maintain healthy levels of inflammation by helping lower levels of fat in the blood may be a way to help manage the harmful inflammatory effects of obesity. Now a new study (4) suggests that krill oil may help with fat breakdown.
In the study, 18 mice genetically manipulated to have high TNF-alpha levels (called “hTNF-alpha transgenic mice”) were divided into 3 groups and given 3 different diets, all of which contained the same amount of calories and consisting approximately 21 %protein, 46 %fat, 33 % carbohydrate for 6 weeks:
– CONTROL GROUP: High-fat diet with (23.6% by weight – 21.3% lard and 2.3% soybean oil)
– FISH OIL GROUP: High-fat diet with (23.7% by weight: 18.5% lard, 2.3% and soybean oil,
and 2.9% fish oil)
– KRILL OIL GROUP: High-fat diet (23.7% by weight – 15.6% lard, 2.3% soybean oil and 5.8%
The researchers had to use twice the amount of krill oil than fish oil (5.8% versus 2.9%) to equalize the omega-3 fat content of the diets. They compared fish oil and krill oil because, while both are rich in omega-3 fatty acids, they differ in structure. In fish oil, the omega-3 fats are attached to a fat molecule called a triacylglyceride (TAG, normally referred to as triglycride), while in krill oil they are attached to a fat molecule called a phospholipid and, as a result, are thought to have slightly different effects in the body (5, 6). Krill oil’s higher antioxidant content is thought to make it more stable against cell damage and have a better benefit in the body (7).
By the end of 6 weeks, researchers observed levels of TAG to decrease by 19% (1.07 to 0.9 millimoles/Liter) in the krill oil group compared to no changes in either the fish oil group or the control group (p < 0.05). When they looked at fat breakdown, the krill oil group had a 32% higher rate than the control group (0.29 vs. 0.22 millimoles/minute/milligram) and a 7% higher rate than the fish oil group (0.29 vs. 0.27 mmol/min/mg). There was also 71% greater activation of an enzyme called ACOX1 in the krill group versus the control group (3.6 vs. 2.1 nanoamoles/minute/milligram, p < 0.0001 ) and 16% greater ACOX1 activation compared to the fish oil group (3.6 vs. 3.1 nmol/min/mg, p < 0.0001).
This increased fat breakdown will help decrease overall adipose tissue levels in the body and may lead to decreased release of pro-inflammatory proteins, thereby maintaining a healthier level of inflammation. But the researchers cautioned on making an anti-inflammatory claim for krill oil. Rather, they concluded, “Our findings demonstrate that fish oil and krill oil are comparable dietary sources of [omega-3 fats]. However, when similar doses of [omega-3 fats] are administered, krill oil seems to have a greater potential to promote [fat breakdown].”
1. “Causes of Consequences of Obesity” from the CDC website
2. Berg AH. Adipose tissue, inflammation, and cardiovascular disease. Circ Res 2005; 96(9):939–949
3. Fernandez-Real JM. Insulin resistance and chronic cardiovascular inflammatory syndrome. Endocrin Rev 2003 Jun;24(3):278-301
4. Vigerust NF. Krill oil versus fish oil in modulation of inflammation and lipid metabolism in mice transgenic for TNF-alpha .Eur J Nutr 2012 Aug 25 [Epub ahead of print]. DOI 10.1007/s00394-012-0441-2
5. Deckelbaum RJ, Worgall TS, Seo T (2006) n-3 fatty acids and gene expression. Am J Clin Nutr 83(6 Suppl):1520S–1525S
6. Mori TA, Woodman RJ (2006) The independent effects of eicosapentaenoic acid and docosahexaenoic acid on cardiovascular risk factors in humans. Curr Opin Clin Nutr Metab Care 9(2):95–104\
7. Tou JC. Krill for human consumption: nutritional value and potential health benefits. Nutr Rev 2007; 65(2):63–77
Greg Arnold is a Chiropractic Physician practicing in Hauppauge, NY.
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