Omega 3 Fatty Acids

Sources of Omega 3 Fatty Acids 

Food preferences and product tolerances will determine what sources are best for your CKD patient. There are two different ways to obtain omega 3 fatty acids from food. One can consume foods high in EPA and DHA, or consume foods high in alpha linolenic acid (ALA), which then needs to be converted to EPA and DHA (done through an elongation process). One can also use omega 3 fatty acids supplements in their final elongated form of EPA and DHA. Other literature suggests that a combination of sources may be the most effective for the overall health benefits of omega 3 fatty acids in CKD.9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19

Food Sources of Omega 3 Fatty Acids 

Foods sources of omega 3 fatty acids can achieve some or all of patient needs for these fatty acids (Table 1). However, it may be difficult to meet this requirement to achieve some of the therapeutic benefits as shown below. ALA is the major omega 3 fatty acid in the human diet. However, the desaturation and elongation enzymes that convert ALA to EPA and DHA can vary from less than 0.1% into DHA and 15% into EPA.4, 9, 10, 11 DHA seems to be the most limiting in this conversion and may be one reason more preformed DHA will be important in therapeutic treatment.9, 10, 11 The desaturation and elongation enzymes that convert ALA acid to EPA also convert linoleic acid (LA) to arachidonic acid. Although ALA is the preferred substrate for this pathway, only small amounts of ALA are converted to EPA, probably because of the high ratio of LA:ALA present in cells. This is suggested as a reflection of the high ratio of LA:ALA observed in our Western diets. The ideal ratio of ALA to LA is 4:1; the typical American diet is estimated at 20:1.15, 17

Table 1. Plant and Animal Sources

		Portion	Omega 3 g	Calories	Protein (g)	NA (mg)	K+ (mg)	P04 (mg)
	Plant sources
	Flaxseed oil (linseed oil)	1tablespoon	7.1	120	0	0	0	0
	Canola oil (rapeseed oil)	1tablespoon	1.6	124	0	0	0	0
	Sunflower or safflower oil	1tablespoon	0.2	120	0	0	0	0
	Coconut oil	1tablespoon	0.8	117	0	0	0	0
	Wheat germ oil	1tablespoon	1.0	120	0	0	0	0
	Egg with enhanced omega 3 fatty acids⁎	50 g	0.56	60–75	6	60–65	60–165	60–80
	Soybeans, roasted⁎	3 oz	1.5	387–499	30–34	2–140	1,264–1,173	312–558
	Walnuts, english	3 oz	6.8	555	13	3	375–580	194
	Walnuts, black	3 oz	3.3	525	20	3	444	435
	Spinach-raw chopped	1 cup	.39	7	<1	24	167	15
	Broccoli-raw	1 cup	.097	25	3	25	287	58
	Animal sources
	Tuna, raw⁎	3 oz	0.24–1.28	118–120	20–25	33–40	214–484	208–216
	Tuna, light canned, drained, in oil	3 oz	0.26	168	25	301	176	264
	Tuna, white, canned in water, drained	3 oz	0.73	109	20	320	201	184
	Salmon, pink, canned	3 oz	1.48	90	15	420	173	141
	Salmon, chinook, raw	3 oz	1.48	153	16	40	335	246
	Salmon, Atlantic wild, raw	3 oz	0.9–1.56	121	17	37	417	170
	Salmon, Atlantic farmed, raw	3 oz	1.09–1.83	156	16	50	308	198
	Halibut, raw⁎	3 oz	0.4–1.0	75–120	18–21	48–58	353–383	189–242

Note. Data from USDA Nutrient Database for Standard Reference, National Sunflower Association, Flax Council of Canada; Mahan L and Escott-Stump S: Krause’s Food, Nutrition and Diet Therapy, 11th ed. New York, Elsevier, 2004, pp. 1244-1245; Pennington J, Douglas J: Bowes and Church’s Food Values of Portions Commonly Used, 18th Ed. Baltimore, MD, Lippincott, Williams, and Wilkins, 2005; Patel G. Essential fats in walnuts are good for the heart and diabetes. J Am Diet Assoc 105:1096-1097, 2005; and Raper N, Cronin F, Exler J: Omega-3 fatty acid content of the US food supply. J Am Coll Nutr 11:304-308, 1992

⁎ More than one product was evaluated to determine this range of values.

Patients should be counseled on avoiding over consumption of LA to optimize elongation from food high in ALA. The LA will compete for the same elongase and desaturase enzymes, interfering with omega 3 fatty acids metabolism to DHA and EPA from ALA.4

The literature is unclear regarding whether this elongation process is as efficient in diabetes mellitus and certain dermatological conditions, potentially because of a lack of the necessary enzyme (catalyst) for making this conversion. Other variables possibly impacting this conversation are trans fats, age, and gender. For people choosing to take ALA versus preformed EPA and DHA, consuming oils high in gamma linolenic acid (GLA) may help in this rate-limiting step delta 6-desaturase (D6D), such as black current oil, evening primrose oil, or borage oil. Vitamin B6 may also help in this conversion process.14, 19, 20, 21

Dosing Recommendations 

The recommended oral dose of omega 3 fatty acids depends on the indication. The following doses are recommended1, 3:

Supplements of Omega 3 

For many patients, taking a supplement of omega 3 will be easier given the higher dose they may require. Table 2 is a list of recommended products based on current literature and resources available. These products were based on contents that seem acceptable to CKD patients and are more concentrated in content (to avoid the necessity of excess pill volume).

Table 2. A Sampling of Omega 3 Supplements

	Product	Manufacturer City and State Contact Number	Contents
	Advocare Omegaplex Advocare International www.advocare.com	Carrollton, TX 972-478-4500	Per soft gel: 300 mg EPA and 200 mg DHA
	Coromega Erbl, Inc. www.coromega.com	Vista, CA 877-275-3725	Per packet: 20 calories, 350 mg EPA, 230 mg DHA, 70 mg other omega 3s, 25 mg vitamin C, 3 IU vitamin E, 50 μg folic acid.
			Other ingredients: egg yolk, 5 mg stevia leaf extract (sweetener), natural orange flavor, and vanillin
	Kirkland Signature Natural Fish Oil Concentrate Costco Wholesale Corporation www.costco.com	Issaquah, WA 800-774-2678	Per soft gel: 150 mg EPA, 100 mg DHA
	Vitamin World Naturally Inspired Super DHA Natural Fish Oil Vitamin World www.vitaminworld.com	Bohemia, NY 888-645-7135	Per soft gel: 10 calories, 300 mg EPA, 200 mg DHA.
			Other ingredients: gelatin and glycerin
	Carlson Super Omega 3 Fish Oils www.carlsonlab.com	Arlington Heights, IL 847-255-1600	Per soft gel: 10 calories, 300 mg EPA, 200 mg DHA, 10 IU vitamin E (d-alpha).
			Other ingredients: beef gelatin, glycerin, water
	Omega-3 700 Solgar Vitamin and Herb www.Solgar.com	Leonia, NJ 877-SOLGAR-4	Per soft gel: 15 calories. 360 mg EPA, 240 mg DHA, 100 mg other omega-3s, 4 IU vitamin E.
			Other ingredients: caramel
	Omacor www.omacorrx.com	Reliant Pharmaceuticals 877-311-7515	Per capsule: 465 mg EPA, 375 mg DHA, 60 mg DPA (docosapentaenoic acid)

Note. Data from www.consumerlab.com and www.supplementinfo.org. Abbreviations: DHA, docosahexaenoic acid; EPA, eicosapentaenoic acid.

For CKD patients, it is best to avoid products with added vitamin A and D, most likely derived from halibut or shark oils. Fish oil supplements that contain some vitamin E have been recommended to prevent rancidity.1, 4 In addition to EPA and DHA, some products contain mixed oil supplements. These additions are often expensive and unnecessary. Products that contain mainly EPA and DHA should be recommended.

Risks 

Until recently, risks associated with omega 3 fatty acid supplements seemed minimal. Some concerns pertain to excessive intake on immune function and potentially increased risk of excessive bleeding and hemorrhagic stroke. An intake of <2 g/day is unlikely to cause this bleeding.4 A recent study suggested that patients with pacemakers might be at a slightly higher risk for arrhythmias with omega 3 supplements.18

If one is taking anticoagulation agents, in addition to omega 3 supplements, it has been suggested to routinely check prothrombin times (PT), in addition to careful monitoring of unusual bruising.1